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Antibacterial and Antioxidant Activity of Essential Oils from Citrus spp
Abstract
The antibacterial and antioxidant activities of essential oils from Bitter orange, Sweet orange, Lemon and Mandarin were investigated. The antimicrobial capability of these oils was determined against ten strains of Gram-negative and Gram-positive bacteria, including some phytopathogenic strains. The antibacterial activity of the oils was expressed as minimum inhibitory concentrations (MICs). All oils showed good antibacterial activity against both Gram-negative and Gram-positive bacteria. The MICs for selected oils ranged 15–250 µg/mL. The lowest MICs were 15 µg/mL and 20 µg/mL against Xanthomonas citri strains, respectively. The antioxidant and antiradical scavenging properties of the selected oils were tested by means of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. All examined oils exhibited a free radical scavenging activity, ranging 20–70% of DPPH inhibition. Lemon oil showed the most antioxidant capacity, with DPPH inhibition rate of 70%.
... The lemon (Citrus limon or Citrus limonum) is a fruit tree belonging to the Rutaceae family [4,5]. Global lemon production is projected to exceed 1.2 million tons in the next five years [6,7]. ...
... Recent studies have indicated that limonene from the peel exhibits higher antioxidant activity compared to the control [26]. Conversely, other studies on LEO, particularly limonene, report lower antioxidant activity compared to the control [4]. These variations in IC 50 values are also influenced by external factors affecting the treatment. ...
... Current research explores antioxidant properties, which vary in EO due to differences in plant parts, extraction methods, dominant compounds in EO, antioxidant assays, comparisons with different controls, measured free radicals, and various factors that significantly influence the antioxidant capacity and IC 50 [4,21,[27][28][29][30]. For example, IC 50 values using ABTS indicated inhibition at 28 mg/mL of LEO [12], whereas similar tests reported inhibition at 2.97 mg/mL for the same [25]. ...
Recent studies have explored the antioxidant properties of lemon essential oil (LEO), taking considering factors like plant part, extraction methods, and antioxidant assay. However, due to varied results and limited precision in individual studies, our meta-analysis aims to offer a comprehensive understanding across different experiments, irrespective of location or time. Out of 109 scientific articles published between 1947 and 2024, only 28 successfully validated their data on differences in antioxidant capacity and IC50, using weighted averages of Hedges’ d in meta-analysis. A meta-analysis revealed several key findings: (i) lemon leaf and peel extracts have higher IC50 compared to controls, whereas whole plant extracts show lower values (p < 0.001); (ii) the maceration preserves antioxidant properties better than hydro-distillation and Soxhlet extraction (p < 0.001); (iii) LEO require higher concentrations to achieve comparable free radical inhibition as the standard controls such as AsA, BHT, and quercetin, suggesting lower antioxidant efficiency. This was supported by IC50 result, which showed no significant difference between LEO and other compounds like thymol, Thymus vulgaris EO, and Citrus aurantium EO. However, compared to AsA, BHT, limonene, and trolox, the inhibition efficacy was significantly lower (p < 0.01). These findings consistently demonstrated significant antioxidant activity across multiple assays, including ABTS, β-carotene bleaching, DPPH, and FRAP (p < 0.01). Notably, the predominant components of LEO including α-linoleic acid, D-limonene, limonene, L-limonene, neryl acetate, sabinene, and Z-citral, which demonstrate significant potency as antioxidant agent (p < 0.01). Specifically, limonene and Z-citral make substantial contributions to its antioxidant capacity (p < 0.01). Despite variations in purity among LEO extractions, there is potential for future enhancement through nanoemulsion. In conclusion, LEO show promise as an alternative antioxidant, with emphasis to selecting samples based on leaves or peels and employing maceration extractions for various antioxidant assays. Active components rich in terpenoids, such as limonene and Z-citral, are particularly noteworthy.
Graphical Abstract
... To date, there has been a rising trend in finding natural alternatives to tackle the problem of antibiotic resistance in microorganisms (Balouiri et al., 2016). Essential oils have revealed a potential in antibacterial, anti-fungus, and antioxidant activities that can be promising alternatives to the chemical preservatives to prevent the food spoilages as well as lengthening the shelf-life of foodstuffs (Frassinetti et al., 2011). ...
... Origanum vulgare and Thymus vulgaris EOs showed the bactericidal effects against E. coli O157:H7 in foods (S. A. Burt and Reinders, 2003). Lemon oil was reported to have the most antioxidant activity, with DPPH reduction rate of 70% as compared to orange and mandarin oil (Frassinetti et al., 2011). EOs from 14 plant species showed variations in inhibitory effects against common food pathogens (Evrendilek, 2015). ...
... The chemical compositions are summarized and highlighted with predominant constituents in Figure 2. The orange peel EOs were obviously observed with the dominant compound of limonene (90.42%) followed by β-myrcene (4.7%) and α-pinene (1.22%). This result was consistent with those reported in previous studies (Evrendilek, 2015;Farhat et al., 2011;Frassinetti et al., 2011;Torres-Alvarez et al., 2017) with the limonene content greater than 90%. However, Gursoy, Tepe, and Sokmen (2010) showed the variations in the chemical components in the orange peel EOs in which limonene contributed to only 76.77% followed by 8.24% and 3.01% of γ-terpinene and linalool, respectively. ...
The continuous fresh consumption or juice production of orange fruits (citrus nobilis) has discarded a vast number of orange peels, which has caused significant impacts on environmental issues. This study attempted to utilize discarded orange peels to extract essential oils (EOs) and evaluated their physiochemical properties, antibacterial, antifungal, and antioxidant activities. EOs were extracted via a distillation system using a Clevenger apparatus and gas chromatography - mass spectrometry analysis was employed to characterize their chemical components. The antibacterial and antifungal test were evaluated using a well diffusion method, and antioxidant activity was determined based on DPPH radicals scavenging effect and ferric reducing antioxidant power (FRAP). The obtained EOs with the yield of 3.29 ± 0.24% in which limonene was found to be the most abundant compound in the EOs (90.42%) followed by β-myrcene (4.7%) and α-pinene (1.22%). The result showed that Gram-positive bacterium (Bacillus cereus) was susceptible to the 50% EOs than Gram-negative bacterium (Escherichia coli) with respect to inhibitory zone diameter of 15.00 ± 0.58 mm and 11.33 ± 0.58 mm. The 50% EOs also inhibited nearly 70% of the mycelial growth of Aspergillus flavus as well as exhibiting antioxidant activity with IC50 values of 0.15 ± 0.01 mg/mL and 18.29 ± 0.13 mg/mL for DPPH and FRAP assay, respectively. The orange peel EOs could be a promising alternative to synthetic preservatives in food industry due to their antimicrobial and antifungal activity as well as their antioxidant activity.
... Besides usage in cosmetology [43], these properties have been essentially investigated with reference to multiple favorable effects on health and ensuing pharmaceutical relevance. This refers to possible applications in the treatment of neurological [44] and vascular disorders [45], and as antioxidant [12,[46][47][48][49][50], anticholesterolemic [51], antidiabetic [12] and antitumor agents [43,52]. The latter effects have been also studied with reference to purified products, such as citral [53,54], bergamottin and 5-geranyloxy-7-methoxycoumarin [13]. ...
... These concern use of EOs not only as alternative antibiotics in the medical field [12,[55][56][57][58][59][60], but particularly as food additives. The latter usage, that may also involve EOs extracted from other plants which are not considered in this article, aims at improving the quality of a wide array of food products with reference to both possible contamination with human pathogens and preservation of organoleptic properties after inhibition of deteriorating microbial agents [47,50,56,[61][62][63][64][65][66]. Of course, the latter is a priority aspect in the case of citrus fruits, which generally need to overcome prolonged postharvest periods before undergoing either fresh consumption or industrial transformation. ...
... Inhibitory properties against the agent of bacterial canker Xanthomonas citri subsp. citri were displayed by EOs extracted from C. aurantium [76], from C. aurantifolia and C. aurantium [68] and from C. reticulata, C. limon, C. sinensis and C. aurantium [47]. ...
Citrus essential oils (EOs) are widely used as flavoring agents in food, pharmaceutical, cosmetical and chemical industries. For this reason, their demand is constantly increasing all over the world. Besides industrial applications, the abundance of EOs in the epicarp is particularly relevant for the quality of citrus fruit. In fact, these compounds represent a natural protection against postharvest deteriorations due to their remarkable antimicrobial, insecticidal and antioxidant activities. Several factors, including genotype, climatic conditions and cultural practices, can influence the assortment and accumulation of EOs in citrus peels. This review is focused on factors influencing variation of the EOs’ composition during ripening and on the implications on postharvest quality of the fruit.
... e productivities of C. reticulata and C. aurantifolia were annually reported at 153,375 and 213,716 tons in ailand [6]. Several biological properties of crude extracts and essential oils from Citrus spp., C. reticulata and C. aurantifolia, have been reported, including antioxidant [7][8][9][10][11], antibiofilm [12], antibacterial, and antifungal activities [10,13]. e dried peel and pulp extracts of C. aurantifolia from Indonesia possessed antioxidant, antidiabetic, and antibacterial activities against S. aureus and K. pneumoniae [9]. ...
... Additionally, antibacterial activities of crude extracts and essential oils (EOs) from different parts (leaves, stems, roots, flowers, and peels) of C. reticulata and C. aurantifolia have demonstrated broad-spectrum antibacterial activities toward clinically important pathogens with a major activity against Gram-positive bacteria, especially S. aureus [7,[9][10][11][14][15][16][17][18][19][20]. Previously, some studies have investigated the antistaphylococcal effect of these citrus-derived products, mostly against the reference strains of MRSA and methicillin-susceptible S. aureus (MSSA). ...
... is is similar to the previous study review that mentioned the contents of limonene in CREO and CAEO of 67.0 to 86.0% [7,11,14,20,32]. However, the contents of limonene found in CREO and CAEO in this study were higher than previous studies that reported 29.3 to 58.9% of limonene [16,17,33]. ...
Citrus reticulata Blanco and Citrus aurantifolia are the edible plants which contain several biological properties including antibacterial activity. The aims of the present study were to determine the chemical compositions and evaluate antibacterial activities of citrus essential oils extracted from the fruit peels of C. reticulata (CREO) and C. aurantifolia (CAEO), alone and in combination with gentamicin, against a panel of clinically isolated methicillin-resistant S. aureus (MRSA) (n = 40) and methicillin-susceptible S. aureus (MSSA) (n = 45). Gas chromatography-mass spectrometry analysis revealed that 12 and 25 compounds were identified in CREO and CAEO with the most predominant compound of limonene (62.9–72.5%). The antibacterial activities were determined by agar disk diffusion and resazurin-based microdilution methods. The results found that almost all MRSA isolates were resistant to ciprofloxacin, erythromycin, and clindamycin, and some isolates were resistant to gentamicin. CREO and CAEO exhibited inhibitory effects toward clinical isolates (MIC: 1.0–32.0 and 8.0–32.0 mg/mL, respectively), with a similar trend to limonene (MIC: 1.0–32.0 mg/mL). However, the higher antibacterial effects were found in CREO and limonene when compared to CAEO (p < 0.01). In combination effect, the results showed the synergistic interaction of gentamicin with CREO and limonene on the MRSA and MSSA isolates (FIC indexes: 0.012–0.258 and 0.012–0.375), but that interaction of gentamicin with CAEO was observed only on MRSA (FIC index: 0.012–0.016). These findings demonstrated the potential of these citrus essential oils as natural antibacterial agents that may contribute to reduce the emerging of antimicrobial-resistant bacteria.
... Results revealed that all the NL and PO EO analyzed showed antioxidant activity (Figure 4). This result is in accordance with other antioxidant studies of several Citrus EO, such as C. aurantium [40,41], C. aurantifolia [41], C. reticulata [8,40], C. sinensis [40], C. limon [40], C. lumia [42], and other Citrus species [43][44][45]. In our study, the values of antioxidant activity ranged from 5.03% ± 3.76 to 39.43% ± 5.39 for NL, and from 12.10% ± 4.99 to 31.54% ± 3.04 for PO, including all dates of the two seasons. ...
... Results revealed that all the NL and PO EO analyzed showed antioxidant activity (Figure 4). This result is in accordance with other antioxidant studies of several Citrus EO, such as C. aurantium [40,41], C. aurantifolia [41], C. reticulata [8,40], C. sinensis [40], C. limon [40], C. lumia [42], and other Citrus species [43][44][45]. In our study, the values of antioxidant activity ranged from 5.03% ± 3.76 to 39.43% ± 5.39 for NL, and from 12.10% ± 4.99 to 31.54% ± 3.04 for PO, including all dates of the two seasons. ...
... Results revealed that all the NL and PO EO analyzed showed antioxidant activity (Figure 4). This result is in accordance with other antioxidant studies of several Citrus EO, such as C. aurantium [40,41], C. aurantifolia [41], C. reticulata [8,40], C. sinensis [40], C. limon [40], C. lumia [42], and other Citrus species [43][44][45]. In our study, the values of antioxidant activity ranged from 5.03% ± 3.76 to 39.43% ± 5.39 for NL, and from 12.10% ± 4.99 to 31.54% ± 3.04 for PO, including all dates of the two seasons. ...
Chemical characterization of clementine varieties (Citrus clementina Hort. ex Tan.) essential oils (EO) can lead to variety identification and valorization of their potential use in food and aroma industries. The goal of this study was the chemometric discrimination between two very closely related and morphologically identical clementine varieties, Clemenules (NL) and Clemenpons (PO), based on their rind EO, to identify the differential volatile organic compounds (VOCs) and to determine their antioxidant capacity. EO rind volatile profile was determined by gas chromatography coupled to mass spectrometry in Citrus fruit at different ripening stages grown two independent years in two different locations. Untargeted metabolomics and multivariate data analysis showed an evolution of EO volatile profiles markedly parallel in both varieties. Although EO qualitative composition was identical in both varieties, PLS-DA allowed the identification of characteristic VOCs, quantitatively discriminating them along all the ripening process. PO showed higher accumulation of several mono- and sesquiterpene compounds such as trans-carveol, while NL showed higher levels of aldehyde and alcohol non-terpenoids like dodecanal. Both varieties evinced identical EO antioxidant activities, indicating a similar value for food preservation. Hence, untargeted metabolomics approach based on rind EO volatiles was revealed as a powerful technique able to differentiate between morphologically undistinguishable Citrus varieties.
... Several research groups have performed studies regarding characterizations and antioxidant activities of different Citrus EOs [10][11][12]. Moosayv and coworkers [12] analyzed the EO of C. limon grown in Iran and found four main compounds: limonene (46.93%), terpinene (16.89%), tricyclene (6.67%), and -pinene (4.69%). Gursoy and colleagues [11] reported that the EO from C. nobilis peels contains limonene (76.77%), -terpinene (8.24%), linalool (3.01%), and myrcene (2.38%). ...
... They suggested limonene as the compound mainly responsible for the antioxidant activity of C. nobilis EO. Meanwhile, Frassinetti and coworkers [10] found that among commercial Citrus EOs in Italy, C. limon EO is the most active antioxidant. ...
... Each EO exhibits a different inhibition profile in scavenging DPPH free radicals ( Figure S2). The EO of C. limon shows the highest antioxidant activity with IC50 of 4.25 ± 0.08 μL/mL (Table 2), consistent with the work published by Frassinetti and colleagues [10]. The antioxidant activity of C. limon EO even higher than that of ascorbic acid. ...
Citrus essential oils (EOs) have various bioactivities like antioxidants, with many applications. Antioxidant activities depend on the chemical compositions of the EOs, which are affected by climate, soil, and geographical region. Thus, investigations on chemical compositions and antioxidant activities of Citrus EOs in different countries are valuable. In this study, we distilled EOs from peels of Indonesian-grown Citrus, including C. nobilis, C. limon, C. aurantifolia, C. amblycarpa, and Citrus spp.Chemical compositions of EOs were analyzed using Gas Chromatography-Mass Spectrometer (GC-MS), whereas the antioxidant activities were determined by employing 2,2-diphenyl-2-picrylhydrazyl (DPPH) method. Furthermore, principal component analysis (PCA) was applied to elucidate the main contributing compounds for antioxidant activity. The results show that all EOs possess unique chemical characteristics, with limonene as the majority constituent. For antioxidant activities, C. limon and C. amblycarpa EOs are the two strongest, IC50 values below 7.00 μL/mL. PCA approach suggests that -terpinene mainly contributes to the high antioxidant activities of C. limon and C. amblycarpa. Moreover, o-cymene, thymol, p-cymene, and α-pharnesene may also be responsible for the antioxidant activity of C. limon EO. These results are valuable information for the applications of Citrus EOs as antioxidant sources.
... Studies also showed that d-limonene and Citrus karna EOs have a similar antioxidant potential (39.6% and 38.3%, respectively) [52]. According to Frassineti et al. [53], oils from mandarin, lemon, sweet orange, and bitter orange showed 20-70% DPPH inhibition in free radical scavenging activity. Lemon oil demonstrated the highest antioxidant capacity, with a 70% DPPH inhibition rate [53]. ...
... According to Frassineti et al. [53], oils from mandarin, lemon, sweet orange, and bitter orange showed 20-70% DPPH inhibition in free radical scavenging activity. Lemon oil demonstrated the highest antioxidant capacity, with a 70% DPPH inhibition rate [53]. ...
Kumquat is one of the smallest citrus fruits (from the Rutaceae family), and its essential oil’s biological effects have not yet been sufficiently researched, in contrast to the essential oils of its relatives. Therefore, the aim of this large-scale study was to investigate the chemical profile of kumquat essential oils (KEOs) isolated by microwave-assisted distillation (MAD) and Clevenger hydrodistillation using GC-MS analysis. To test the bioaccessibility of their bioactive components, in vitro digestion with commercially available enzymes was performed. The final step of this research was to test their cytotoxic activity against a cervical cancer cell line (HeLa), a human colon cancer cell line (HCT116), a human osteosarcoma cell line (U2OS), and a healthy cell line (RPE1). Two methods were used to test the antioxidant activity: DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity). The antibacterial activity was tested in relation to the growth and adhesion of Escherichia coli and Staphylococcus aureus on a polystyrene surface. The GC-MS analysis showed that the major compound in both kumquat essential oils was limonene, which was stable before and after in vitro digestion (>90%). The results showed that the cytotoxic activity of the KEOs in all three cancer cell lines tested was IC50 1–2 mg/mL, and in the healthy cell line (RPE1), the IC50 value was above 4 mg/mL. The antibacterial activity of the KEOs obtained after MAD and Clevenger hydrodistillation was 4 mg/mL against E. coli and 1 mg/mL against S. aureus. The KEOs after MAD and Clevenger hydrodistillation reduced the adhesion of E. coli by more than 1 log, while there was no statistically significant effect on the adhesion of S. aureus to the polystyrene surface. Both KEOs exhibited comparable levels of antioxidant activity using both methods tested, with IC50 values of 855.25 ± 26.02 μg/mL (after MAD) and 929.41 ± 101.57 μg/mL (after Clevenger hydrodistillation) for DPPH activity and 4839.09 ± 91.99 μmol TE/g of EO (after MAD) and 4928.78 ± 275.67 μmol TE/g of EO (after Clevenger hydrodistillation) for ORAC. The results obtained show possible future applications in various fields (e.g., in the food, pharmaceutical, cosmetic, and agricultural industries).
... The accumulation of EO in the cytoplasm leads to cell lysis and leakage of intracellular components. This alters the mechanisms of energy production, nutrition, structural molecules, and growth regulators (Frassinetti et al., 2011;Ngan et al., 2020;Song et al., 2020). It was reported in another study (Hamdan et al., 2013), that limonene, the major compound in our EO, exhibited moderate antibacterial activity against B subtilis, Staphylococcus capitis, Micrococcus luteus, and P fluorescens (Hamdan et al., 2013). ...
... It was reported in another study (Hamdan et al., 2013), that limonene, the major compound in our EO, exhibited moderate antibacterial activity against B subtilis, Staphylococcus capitis, Micrococcus luteus, and P fluorescens (Hamdan et al., 2013). This effect could be explained by the accumulation of limonene in the membrane of bacterial cells which alters its integrity, inhibits the respiration and ion transport process, and causes the cell wall rupture, which blocks energy production and finally cells death (Chueca et al., 2014;Frassinetti et al., 2011;Ngan et al., 2020). EC and SA were subject to several, varied effects of limonene. ...
Introduction: Multidrug-resistant bacteria pose major challenges for clinicians. Essential oils hold great promise for the development of new and effective anti-infective treatments. This study investigated the chemical composition and antibacterial activity of essential oils extracted from the barks of Citrus sinensis, Citrus limon, and Citrus aurantium.
Methods: The essential oils from citrus peels were obtained by hydrodistillation using a Clevenger apparatus and analyzed by gas chromatography–mass spectrometry (GC-MS). Antibacterial activity was assessed by both agar diffusion and broth microdilution methods. We tested these essential oils against six bacterial strains, including four clinical multidrug-resistant bacteria: extended-spectrum β-lactamase-producing Escherichia coli, carbapenem-resistant Acinetobacter baumannii, ceftazidime-resistant Pseudomonas aeruginosa, and methicillin-resistant Staphylococcus aureus, in addition to two reference bacterial strains, Escherichia coli (EC) ATCC 25922 and Staphylococcus aureus (SA) ATCC 29213.
Results: The chemical analysis revealed the presence of 26 compounds, with D-Limonene being the dominant one. The essential oils demonstrated significant antibacterial properties against all examined bacterial strains. They exhibited low MICs, ranging from 110 µg/mL to 140 µg/mL, against EC ATCC 25922, carbapenem-resistant Acinetobacter baumannii, extended spectrum β-lactamase-producing Escherichia coli, and ceftazidime-resistant Pseudomonas aeruginosa. Moreover, they also effectively inhibited SA ATCC 29213 and methicillin-resistant
Staphylococcus aureus at slightly higher MICs, ranging from 200 µg/mL to 220 µg/mL.
Conclusions: In this report, we demonstrate the significant antibacterial activity of citrus peel essential oils against multidrug-resistant bacteria. This could be the result of synergistic interactions between the various natural chemical compounds, encouraging their use in the discovery of new antibacterial drugs.
... All examined oils exhibited a free radical scavenging activity, ranging 20-70% of DPPH inhibition. Lemon oil showed the most antioxidant capacity, with DPPH inhibition rate of 70% [71]. Antioxidant assays based on the consumption of stable free radicals (ABTS and DPPH) and assays based in the capacity of antioxidants to reduce ions (FRAP and CUPRAC), were carried out to evaluate the antioxidant capacity of essential oils from Citrus species including Citrus limon from Argentina and the United States [72]. ...
... The possible action mechanisms of essential oil. Source: [76] Frassinetti et al. [71] investigated the antimicrobial activity of four Citrus species essential oils including Citrus limon against ten strains of gram-negative and gram-positive bacteria and reported all oils showed good antibacterial activity against both gram-negative and gram-positive bacteria. The minimum inhibitory concentration (MIC) for Citrus limon oils ranged 20-200 µg/Ml depending on the microorganisms. ...
Abstract— The growing demand for non synthetic preservatives has increased research interest in natural substances with bioactivity. Among recent natural substances investigated for their bio properties are cranberry juice and lemon essential oil. This review discussed the antioxidant and antimicrobial properties of cranberry juice and lemon essential oil.
Keywords— Cranberry juice; Lemon essential oil; Antioxidant property; Antimicrobial property; Preservatives.
... Citrus spp. essential oils (EO) have reportedly exhibited various therapeutic properties and/or beneficial pharmacological effects, such as antibacterial [5,6], anticancer [7,8], anti-inflammatory [9,10], and antioxidant [11][12][13] activities. It is worth noting that these associated bioactivities and their organoleptic properties are attributed to the complex pool of phytoconstituents in Citrus EO, which vary according to genetic variability and diversity, origin, climate, seasonal factors, and others [14]. ...
... The current results demonstrated that the antioxidant potential of Citrus oils might be attributed to the variations in their phytoconstituents [32]. A few studies have reported that antioxidant activity might be correlated to the level or proportion of limonene within Citrus EOs [11,33,34]. Overall, the current findings indicated that the antioxidant activity was higher in oils containing a higher proportion of limonene. ...
The essential oil derived from Citrus plants has long been used for medicinal purposes, due to its broad spectrum of therapeutic characteristics. To date, approximately 162 Citrus species have been identified, and many investigational studies have been conducted to explore the pharmacological potential of Citrus spp. oils. This study investigated the volatile constituents of essential oil distilled from the leaves of C. hystrix, C. limon, C. pyriformis, and C. microcarpa, using gas chromatography–quadrupole mass spectrometry. A total of 80 secondary compounds were tentatively identified, representing 84.88–97.99% of the total ion count and mainly comprising monoterpene (5.20–76.15%) and sesquiterpene (1.36–27.14%) hydrocarbons, oxygenated monoterpenes (3.91–89.52%) and sesquiterpenes (0.21–38.87%), and other minor chemical classes (0.10–0.52%). In particular, 27 compounds (1.19–39.06%) were detected across all Citrus species. Principal component analysis of the identified phytoconstituents and their relative quantities enabled differentiation of the Citrus leaf oils according to their species, with the loading variables contributing to these metabolic differences being identified. The Citrus leaf oils were tested for their antioxidant and antiproliferative activities using 2,2-diphenyl-1-picryl-hydrazylhydrate (DPPH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The results indicated that C. limon displayed the highest DPPH radical scavenging ability (IC50 value of 29.14 ± 1.97 mg/mL), while C. hystrix exhibited the lowest activity (IC50 value of 279.03 ± 10.37 mg/mL). On the other hand, all the Citrus oils exhibit potent antiproliferative activities against the HeLa cervical cancer cell line, with IC50 values of 11.66 μg/mL (C. limon), 20.41 μg/mL (C. microcarpa), 25.91 μg/mL (C. hystrix), and 87.17 μg/mL (C. pyriformis).
... Citrus EOs can exhibit good antimicrobial properties on strains such as Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus spp., Saccharomices spp., Aspergillus niger, Pseudomonas aeruginosa, and Xanthomonas spp. [7,15,16], for this reason, they are intensely approached in the food preservation industry and research. ...
... Yagzan et al. focused on comparing the antibacterial effect of lemon EO and lemon EO-loaded NEs on common fish spoilage bacteria (i.e., P. damselae, E. fecalis, V. vulnificus, P. mirabilis, S. liquefaciens and P. luteola) and food-borne pathogens (i.e., S. aureus, K. pneumoniae, and S. paratyphi A) and concluded that nano-emulsification increased the antibacterial effect of lemon EO for most of the studied bacteria. The study assessed the inhibition zone of Lemon EO NEs in comparison with the same concentration of pure EO as in the loaded NEs and obtained higher inhibition zones for most food-borne pathogens (for pure EO/loaded NEs the inhibition zone were 16 [30] due to possible confusion in the process of obtaining that could easily lead to microemulsions if the order of reagents is not respected strictly [26]. Low-energy methods for NEs production are spontaneous methods that require a minimum amount of energy and rely on physico-rheological properties of the mixture (e.g., interfacial tension). ...
Citrus essential oils possess many health-promoting benefits and properties of high interest in the food and agri-food sector. However, their large-scale application is limited by their sensitivity to environmental factors. Nanostructures containing citrus essential oils have been developed to overcome the high volatility and instability of essential oils with respect to temperature, pH, UV light, etc. Nanostructures could provide protection for essential oils and enhancement of their bioavailability and biocompatibility, as well as their biological properties. Nano-encapsulation is a promising method. The present review is mainly focused on methods developed so far for the nano-encapsulation of citrus essential oils, with emphasis on lipid-based (including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and micro-emulsions) and polymer-based nanostructures. The physico-chemical characteristics of the obtained structures, as well as promising properties reported, with relevance for the food sector are also discussed.
... This good feature of antioxidant activity of films is due to the presence of EOL encapsulated in nanogels. As Di Vaio et al. [60] and Frassinetti et al. [61] have stated, EOL has very good antioxidant activity due to the presence of monoterpenes, particularly γ-terpinene, and limonene, which are the most abundant ingredient in EOL. ...
... Therefore, the nanogel containing essential oil of lemon peel can cause the antimicrobial properties of the films are simultaneously improved [64]. As stated by Frassinetti et al. [61] and Zhang et al. [65], Escherichia coli as gram-negative bacteria showed more resistance to lemon peel essential oil compared to Staphylococcus aureus as gram-positive bacteria. This may be related to the cell wall of the membrane. ...
In this study, the impact of adding lemon peel extract loaded nangel made of gelatin and guar gum in casein/basil seed gum film was examined. The films' mechanical, thermal stability, morphology, barrier, transmittance, antibacterial, antioxidant, and biocompatibility properties were investigated. The findings of this study demonstrated that incorporating the nanogels loaded with lemon peel extract in casein-basil seed gum (CB) film led to improve the properties of CB film including the mechanical properties, thermal stability, hydrophobicity, water vapor permeability, and water solubility, and also changed the color of the films, and slightly decreased the light transmission. The SEM images showed that in low percentages of nanogel, there is no significant difference in the roughness of the surface, but in higher percentages, an accumulation of nanoparticles has occurred on the surface. All films containing nanogel had good antioxidant properties and it was also observed that they had an inhibitory effect against Escherichia coli and Staphylococcus aureus bacteria. None of the films had toxicity for endothelial cells line for 72 h. Therefore, CB films containing nanogel loaded with lemon peel extract have good potential for food packaging.
... The juice of another member of this genus, C. sinensis or sweet orange, is the most consumed fruit juice worldwide for being an excellent source of vitamin C and for its properties as a natural antioxidant that strengthens the immune system [5]. It has been traditionally used to treat constipation, cramps, colic, diarrhea, cough, hypertension, anxiety, depression and stress [15]. Singh et al. [16] revealed the main components of two kinds of orange essential oil as D-limonene, follow by E-citral, Z-citral and carveol, which are recognized as natural antioxidants and food preservatives. ...
... In regard to the treatment with essential oils, Frassinetti et al. [15] found an antibacterial activity from C. sinensis on E. coli by measuring cultures optical density, according to their results there was over 90% reduction in absorbance at 25 μg/mL, and raised the conclusion that time of exposure to EOs could be a determining factor to observe its antibacterial activity. Similarly, Dhiman et al. [29] used microdilution and disc diffusion method (DDM) to show that methanolic extract of C. sinensis peel had antibacterial activity on E. coli with a minimum inhibitory concentration of 0.78 μg/mL and a minimum bactericidal concentration of 6.25 μg/mL. ...
Essential oils of Citrus sinensis and Citrus latifolia have shown biological functions as antiseptics, anti-inflammatories, antioxidants, antifungal and antimutagenic, so the evaluation of their antibacterial capacity, by themselves or in combination with standard antibiotics, presents an alternative for infection treatment. Flow cytometry opens the door for the design of faster and more accurate measurement of antibacterial activity. We use a SYTO9/PI staining system on E. coli ATCC 25922 to determine antibacterial activity by counting live and dead cells through flow cytometry. We found that dual staining showed highly variable results due to wavelength overlapping and instead we used fluorochrome individual staining that highly correlated with viable counts. Chloramphenicol and cefotaxime treatments did not present a dose-response behavior, rendered diffuse readings and/or gave filament formation on fluorescence microscopy. Amikacin was a better comparison standard because it presented a dose-response behavior. Essential oils had low antibacterial activity as compared to amikacin, with a maximum of 10% and 20% for C. latifolia and C. sinensis, respectively. Combinations of essential oils with antibiotic resulted in an unforeseen strong inhibition of amikacin activity. Although a low antibacterial activity was found, a series of standardization steps are proposed for antibacterial activity measurement by flow cytometry.
... The antibacterial and antioxidant activities of citrus EOs have been extensively studied. Frassinett et al. have shown that EOs of the bitter orange, the sweet orange, lemons and broad-skin citrus fruit have good antibacterial and antioxidant activities [17]. Djenane et al. studied the antibacterial activity and antioxidant activity of oranges, lemons and bergamot peel EOs [18]. ...
... Plant EOs have been reported to scavenge the free radicals that lead to cell death and tissue damage and the development of chronic diseases [16][17][18]. Citrus EOs have antioxidant activity which can delay or prevent cell damage caused by physiological oxidants by inhibiting or eliminating the initiation or propagation of excess reactive species and reduce the risk of potential health effects in humans related to oxidative stress or free radicals [19,20]. In order to explore the potential application of our four citrus EOs in food, cosmetic or pharmaceutical industries, measurement of their antioxidant activities is important. ...
Nanfeng mandarins (Citrus reticulata Blanco cv. Kinokuni), Xunwu mandarins (Citrus reticulata Blanco), Yangshuo kumquats (Citrus japonica Thunb) and physiologically dropped navel oranges (Citrus sinensis Osbeck cv. Newhall) were used as materials to extract peel essential oils (EOs) via hydrodistillation. The chemical composition, and antibacterial and antioxidant activities of the EOs were investigated. GC-MS analysis showed that monoterpene hydrocarbons were the major components and limonene was the predominate compound for all citrus EOs. The antibacterial testing of EOs against five different bacteria (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhimurium) was carried out using the filter paper method and the broth microdilution method. Kumquat EO had the best inhibitory effect on B. subtilis, E. coli and S. typhimurium with MIC (minimum inhibitory concentration) values of 1.56, 1.56 and 6.25 µL/mL, respectively. All citrus EOs showed the antioxidant activity of scavenging DPPH and ABTS free radicals in a dose-dependent manner. Nanfeng mandarin EO presented the best antioxidant activity, with IC50 values of 15.20 mg/mL for the DPPH assay and 0.80 mg/mL for the ABTS assay. The results also showed that the antibacterial activities of EOs might not be related to their antioxidant activities.
... Reviewing the literature, MIC of CSEO against S. aureus, K. pneumoniae and E. coli was reported as 0.062, 0.25, and 0.12 mg.mL -1 (23). The related value for P. aeruginosa was 0.75 mg.mL -1 (24). ...
... MIC of CSEO against S. aureus, K. pneumoniae and E. coli was reported as 0.062, 0.25 and 0.12 mg.mL -1 (23). The related value for P. aeruginosa was 0.75 mg.mL -1 (24). MIC of ZOEO on targeted bacteria, including P. aeruginosa 31.25, S. aureus 7.81 E. coli 62.5 (25), and K. pneumoniae 20 (26) were reported. ...
Background and objectives:
Essential oils (EOs) with different biological activities, such as antibacterial properties, are a valuable resource for developing new drugs.
Materials and methods:
Ingredients of six medicinally important EOs, including Artemisia dracunculus, Anethum graveolens, Citrus limon, Citrus sinensis, Cinnamomum zeylanicum and Zingiber officinale, were identified using GC-MS analysis. Moreover, their five major compounds were also listed. Furthermore, the half-maximal inhibitory concentration (IC50) against four important human bacteria was also investigated using the 96-well plate microdilution.
Results:
C. sinensis EO with IC50 of 1.0 and 4.7 mg.mL-1 have the most effect on the growth of S. aureus and P. aeruginosa. Moreover, EOs of Cinnamomum zeylanicum (IC50: 1.0 mg. Ml-1) and Artemisia dracunculus (IC50: 1.3 mg.mL-1) significantly showed better inhibitory effect on E. coli and K. pneumoniae.
Conclusion:
These EOs could be used for developing inexpensive, potent, and green antibacterial agents.
... LEO was able to reduce the stable, purple-colored radical DPPH into yellow-colored DPPH-H with IC 50 of 156.4 µg/mL. Frassinetti et al. (2011), demonstrated the scavenging abilities of Citrus spp. essential oil was ranging from 20 to 70 . ...
The by-product of lemon (Citrus limon) is more than 0.8 million metric tons in 2020/2021 which consist mostly of the peel. This is a problem for management, pollution, and the environment due to microbial spoilage. Lemon peel is a good source of essential oil. Utilization of lemon essential oil (LEO) can provide an efficient and environmentally friendly material for many uses. LEO has GRAS (generally recognized as safe) status, which has generated considerable appeal from the food sector. However, in its implementation, it has to face many problems related to the volatility and variability of the composition.
This study was carried out to extract LEO from lemon peel by steam distillation, to determine its composition, to evaluate its antioxidant and anticancer activities, and to analyze the encapsulation effect of LEO in whey protein-pectin complex on these parameters. The LEO yield was 1.2 % (d.m). The main component in LEO was D-limonene (59.8 %) followed by ß-pinene (15.3 %), γ-terpinene (8.4 %), and α-pinene (3.0 %). Encapsulation of LEO in whey protein pectin-complex changed the composition of volatile compounds with an increase in D-limonene and γ-terpinene, and a decrease in ß-pinene and α-pinene. The LEO and LEO nanocapsules (LEONCs) showed a positive effect on the inhibition of colon-26 cells proliferation with IC50 of 105.9 μg/mL and 2.3 mg /mL, respectively.
... Against DPPH* free radical, HDEO was found inactive, however, it showed mild (3.98 ± 0.36 mgTE/g extract) scavenging activity against ABTS* + . Literature reports revealed that other citrus fruit essential oils exhibited free radical scavenging activities [54][55][56][57], however, grapefruit essential oil is reported almost inactive against DPPH* free radical [58]. Therefore, literature reports substantiated our results, while the activity difference could be attributed to the absence of phenolic components in HDEO. ...
The major commercial crops in Pakistan are citrus fruit trees, which are farmed extensively and serve as the country's principal source of foreign exchange. A local citrus plant, Citrus paradisi, variety Foster is famous for its valuable fruit and fruit juice, however, tons of peels of this fruit are thrown as waste, which otherwise can be utilized in formulating nutraceutical and cosmetics. In the present study, essential oil of fruit peels was obtained through hydro-distillation, which was then analyzed through GC-MS analysis and studied for its antioxidant and enzyme inhibition potential. GCMS analysis revealed the presence of several components; major were found to be limonene, α-terpineol, caryophyllene, δ-amorphene, elemol, γ-eudesoml, nootkatone and di-isooctyl phthalate. Although, the oil showed weak free radical inhibition, it was potentially active in CUPRAC, FRAP, phosphomolybdenum and metal chelating antioxidant assays. The oil also exhibited anti-glucosidase, anti-amylase activities and also exhibited potent inhibition of the enzyme tyrosinase, which makes it strong candidate for nutraceuticals and skin care products. The docking studies also substantiate our results and caryophyllene, γ-eudesoml and nootkatone showed good binding affinity α-glucosidase and α-amylase and all tested compounds showed the higher binding affinity towards the enzyme tyrosinase.
... Orange essential oils have compounds with bioactive potentials, and the antioxidant activities of various citrus species that can be used in the pharmaceutical and food industries have been reported previously [25,26]. Studies have indicated that sweet orange essential oils can exert antioxidant and antimicrobial effects not only through their major constituents (d-limonene) but also due to some other compounds' combined action which makes differences among various citrus species [27,28]. Therefore, orange essential oils were shown to exhibit a free radical scavenging activity, about 50% inhibition for 1000 µg/mL, while when applied to food packaging, the DPPH scavenging rate of enriched chitosan films showed an inhibition from 48% to 58% [27] or it was successfully used to prolong the shelf life of fresh shrimps [29]. ...
In this research, bio-based films were developed using polyelectrolyte complexes derived from chitosan and gelatin for packaging fish oil. To further enhance the antioxidant functionality, the films were enriched with gallic acid and orange essential oils, either individually or in combination. Initially, the films were characterized for their physico-chemical, optical, surface, and barrier properties. Subsequently, the phenolic compounds and antioxidant capacity of the films were assessed. Finally, the films were tested as antioxidant cover lids for packaging fish oil, which was then stored at ambient temperature for 30 days, with periodical monitoring of oil oxidation parameters. This study revealed that the inclusion of gallic acid-induced possible crosslinking effects, as evidenced by changes in moisture content, solubility, and liquid absorption. Additionally, shifts in the FTIR spectral bands suggested the binding of gallic acid and/or phenols in orange essential oils to CSGEL polymer chains, with noticeable alterations in film coloration. Notably, films containing gallic acid exhibited enhanced UV barrier properties crucial for preserving UV-degradable food compounds. Moreover, formulations with gallic acid demonstrated decreased water vapor permeability, while samples containing orange essential oils had lower CO2 permeability levels. Importantly, formulations containing both gallic acid and essential oils showed a synergistic effect and a significant antioxidant capacity, with remarkable DPPH inhibition rates of up to 88%. During the 30-day storage period, fish oil experienced progressive oxidation, as indicated by an increase in the K232 value in control samples. However, films incorporating gallic acid or orange essential oils as active antioxidants, even used as indirect food contact, effectively delayed the oxidation, highlighting their protective benefits. This study underscores the potential of sustainable bio-based films as natural antioxidant packaging for edible fish oil or fresh fish, offering a promising tool for enhancing food preservation while reducing its waste.
... Citrus peels contain a variety of volatile organic compounds (VOCs) with antimicrobial properties; these compounds include olefins, terpenes, aldehydes, and alcohols. Previous studies have demonstrated that these constituents can act as natural antimicrobial and antioxidant agents and prevent pathogenic bacterial infections in citrus plants (Frassinetti, Caltavuturo, Cini, Della Croce, & Maserti, 2011;Magalhães et al., 2020). For instance, bergamot essential oil exhibits antifungal activity against fungi such as Aspergillus niger and Penicillium expansum and has antioxidant properties (Cebi & Erarslan, 2023). ...
Previous studies have shown that polymethoxylated flavonoids-loaded citral emulsion (PCT) can inhibit the growth and reproduction of Penicillium in citrus; however, PCT is difficult to apply to fruit preservation due to its high fluidity and volatility. Therefore, in this study, we combined PCT with chitosan (CS) to investigate the effect of a composite coating on citrus preservation. The results showed that compared to the control group, the CS-PCT group could effectively reduce the decay rate and maintain moisture availability, color difference, and hardness. Moreover, the contents of nonenzymatic antioxidants and volatile substances with antimicrobial activity were better preserved. In addition, the activities of related antioxidant enzymes were greater in the treatment group, and the expression of the corresponding enzyme-encoding genes was upregulated. Consequently, CS-PCT treatment could effectively maintain fruit quality and improve the resistance of citrus fruits during storage; moreover, it can be considered a nontoxic and efficient citrus preservative.
... Research findings indicate that gram-negative E. coli exhibits higher resistance compared to gram-positive S. aureus due to differences in their cell wall structures. Gram-positive bacteria possess a thick cell wall consisting of multilayer peptidoglycan, whereas gram-negative bacteria have a more complex cell wall structure composed of a thin peptidoglycan layer and an outer membrane with barrier properties [67,68]. Consequently, the outer membrane of gram-negative bacteria hinders the penetration of NGs produced by NFs into the bacterial cell. ...
This study aimed to evaluate the effects of nano-gels containing ginger essential oil (GEO) (NGs) made from gelatin and carrageenan gum on ethyl cellulose/casein nano-fibers (NFs). For this purpose, the mechanical, thermal, morphological, antibacterial, antioxidant, hemocompatibility, and biocompatibility properties of the NFs were assessed. It was observed that incorporating NGs into ethyl cellulose/casein NFs improved their morphology, porosity, mechanical properties, and thermal stability. Analysis of the SEM images revealed that adding NGs resulted in NFs with appropriate morphology, devoid of beads, and smaller diameters. The NFs containing NGs exhibited favorable antioxidant properties and inhibited the growth of Escherichia coli and Staphylococcus aureus. Cell viability studies demonstrated that none of the NFs were toxic to normal cells (Human umbilical vein endothelial cells (HUVEC)) and exhibited hemocompatibility. Considering these properties, ethyl cellulose/casein NFs containing NGs and GEO can be utilized as food packaging materials.
... According to the results, all the samples showed a strong radical scavenging activity and similar increasing trend in antioxidant activity with an increase in their concentrations. our result is in accordance with the findings of Frassinetti et al., (2011), evaluating the radical scavenging abilities ranging from 20 to 70% of Citrus spp. EOs. ...
Lemon essential oil (LEOs) is used as a bioactive compound with unique health properties as a medicine or dietary supplement. Nevertheless, essential oils are chemical compounds sensitive to light, oxidation, and thermal processes. Therefore, encapsulation technique can be a good way to protect them from degradation and evaporation. In current study, biopolymeric nanocapsules containing lemon essential oils (LEOs) were prepared by the emulsion method. The nanocapsules were characterized by their particle size and Encapsulation efficiency (%) ranged from 339.3 to 553.3 nm and 68.09% to 85.43%, respectively. Long-term storage (30 days) under different temperatures (4°C, 25°C, and 40°C) conditions showed that nanocapsules stored at 4°C were more stable than samples stored at higher temperatures. DPPH and ABTS free radical scavenging activity were measured to evaluate the values of antioxidant activity of LEOs and nanocapsules. The free LEO and nanocapsules were investigated for its antibacterial activity against common Gram-positive and Gram-negative pathogenic microorganisms (Staphylococcus aureus and Escherichia coli) using disk diffusion followed by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Our results indicated that the encapsulated LEOs had a significant antioxidant and antibacterial activities, as compared to the free LEO. The LEOs nanocapsules in CS and Hicap can be suggested as an important natural alternative with suitable stability, antioxidant, and antibacterial properties to overcome the challenges associated with the direct application of these bioactive compounds in food.
... Regarding medicinal properties, antioxidant, antifungal and anticancer ones are reported [2]. Moreover, citrus oil would be interesting to inflammatory skin diseases [3] and to disorders generating oxygen-generating species [4,5]. Then, citrus oils could be used as adjuvants in the treatment of several skin disorders. ...
Essentials oils from citrus have anti-inflammatory and antioxidant activity.
Furthermore, terpenes are their main phytochemicals, namely limonene is the
most important one. As terpenes are permeation promoters, they have been used to
improve transdermal delivery of drugs. In addition, a proper oil source is a key factor
to obtain desired phytochemicals. Recently, polymeric nanoparticles, solid lipid
nanoparticles, nanostructured lipid carriers, nanoemulsions, liposomes and elastic
liposomes as carriers of citrus essential oils or citrus terpenes have been developed to
achieve more effective formulations. In this chapter, the most recent publications on
nanocarriers containing citrus oils or citrus terpenes were addressed. In that regard,
citrus oil or terpenes loaded in nanotechnological systems improve drugs skin permeation.
Besides, terpenes loaded in nanoparticles also increase transdermal delivery of
drugs. As essential oils and their respective terpenes are volatile compound and prone
to oxidation, its encapsulations reduce oxidation and volatility. Hence, an improved
antioxidant activity can be obtained. Therefore, nanoformulations of citrus oils or
citrus terpenes are potential approaches to skin topical and transdermal delivery.
... Meanwhile, their reducing capacity is attributed to the terpenes present in similar proportions in both oils. Frasinetti et al. [40] attributed the antioxidant capacity of the bitter orange, sweet orange, lemon, and mandarin EOs to the presence of monoterpenes, the main compounds found in these oils. Moreover, some reports have shown that monoterpenes, such as limonene, α-and γ-terpinene, terpinolene, geraniol, β-pinene, myrcene, α-terpineol, and linalool, were mainly responsible for the antioxidant potential of many plant oils, including Citrus oils [41][42][43][44]. ...
The present study evaluates the chemical compositions and antioxidant and antipathogenic properties of commercial orange (Citrus sinensis (L.) Osbeck) essential oils obtained using the cold-press method (EOP) and the cold-press method followed by steam distillation (EOPD). The chemical compositions of the volatilizable fractions, determined by gas chromatography-mass spectrometry, were similar in both samples. A relatively large amount of γ-terpinene was found in the EOPD (1.75%) as compared to the EOP (0.84%). Monoterpene hydrocarbons with limonene (90.4–89.8%) followed by myrcene (3.2–3.1%) as the main compounds comprised the principal phytochemical group. The non-volatile phenolics were eight times higher in the EOP than in the EOPD. Several assays with different specificity levels were used to study the antioxidant activity. Although both essential oils presented similar reducing capacities, the radical elimination ability was higher for the EOP. Regarding the antipathogenic properties, the EOs inhibited the biomass and cell viability of Staphylococcus aureus and Pseudomonas aeruginosa biofilms. Furthermore, both EOs similarly attenuated the production of elastase, pyocyanin, and quorum-sensing autoinducers as assessed using Gram-negative bacteria. The EOP and EOPD showed important antioxidant and antipathogenic properties, so they could represent natural alternatives to extend the shelf life of food products by preventing oxidation and contamination caused by microbial spoilage.
... This variation can be explained by the interaction between the type of EOs and the concentration of EOs. Frassinetti et al. [44] discovered that LEO showed the best antioxidant activity compared to bitter orange, sweet orange and mandarin EO. In our experiment, LEO also had a stronger DPPH free radical scavenging ability compared to the other four citrus EOs, and the ABTS free radicals scavenging rate of LEO and DLEO was comparable to that of the strong antioxidant VC. ...
Increasing concerns over the use of antimicrobial growth promoters in animal production has prompted the need to explore the use of natural alternatives such as phytogenic compounds and probiotics. Citrus EOs have the potential to be used as an alternative to antibiotics in animals. The purpose of this research was to study the antibacterial and antioxidant activities of five citrus EOs, grapefruit essential oil (GEO), sweet orange EO (SEO), bergamot EO (BEO), lemon EO (LEO) and their active component d-limonene EO (DLEO). The chemical composition of EOs was analyzed by gas chromatography–mass spectrometry (GC-MS). The antibacterial activities of the EOs on three bacteria (Escherichia coli, Salmonella and Lactobacillus acidophilus) were tested by measuring the minimum inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and inhibition zone diameter (IZD). The antioxidant activities of EOs were evaluated by measuring the free radical scavenging activities of DPPH and ABTS. We found that the active components of the five citrus EOs were mainly terpenes, and the content of d-limonene was the highest. The antibacterial test showed that citrus EOs had selective antibacterial activity, and the LEO had the best selective antibacterial activity. Similarly, the LEO had the best scavenging ability for DPPH radicals, and DLEO had the best scavenging ability for ABTS. Although the main compound of the five citrus EOs was d-limonene, the selective antibacterial and antioxidant activity of them might not be primarily attributed to the d-limonene, but some other compounds’ combined action.
... . Al-Juhaimi & Ghafoor, 2013;Frassinetti et al., 2011;Jorge et al., 2016;Kammal et al., 2013;Singh et al., 2010;Trabelsi et al., 2014 . ...
b * ، امیری رفتنی زینب b a د آموخته انش و علوم ارشد کارشناسی ساری طبیعی ومنابع کشاورزی علوم دانشگاه غذایی، صنایع ایران ساری، ، b دانشیار غذایی، صنایع و علوم گروه و کشاورزی علوم دانشگاه ساری طبیعی منابع ایران ساری، ، مقاله: دریافت تاریخ 16 / 8 / 1396 مقاله: پذیرش تاریخ 22 / 12 / 1396 چکید ه مقدمه: آنتی ترکیبات منبع عنوان به پرتقال پوست اسانس در موجود فنولیک ترکیبات میزان و نوع بررسی پژوهش این از هدف اکسیدانی می سویا روغن اکسایشی پایداری بر آن تاثیر و طبیعی باشد. روش و مواد ها: از استفاده با پرتقال پوست اسانس در موجود ترکیبات GC/MS خ بررسی شد. تعیین آنتی اصیت آزمون روش به اکسیدانی و آهن احیاکنندگی قدرت DPPH (غلظت چهار در اسانس ادامه در و گرفت صورت 2 ، 5 ، 10 و 20 آنتی و درصد) سنتزی اکسیدان TBHQ (مجاز محدوده در 01 / 0 مزد ان دی و اسید تیوباربیتوریک پراکسید، عدد و اضافه اکسیدان آنتی بدون سویای روغن به درصد) اندازه وج گیری شد. يافته ها: عمده لیمونن، دی حاوی اسانس گرم یک بود. پرتقال پوست اسانس در موجود ترکیب ترین 16 / 0 میلی بر فنولیک ترکیبات گرم سنجش طبق بود. خشک ماده حسب بر اسیدگالیک مبنای DPPH فعالیت خود از پرتقال پوست اسانس احیاءکنندگی، قدرت و آنتی به نسبت کمتری اکسیدانی آنتی فعالیت چند هر داد، نشان اکسیدانی TBHQ کمترین که علت این به داشت EC 50 آزمون در DPPH (09 / 0 میلی میلی بر گرم (آهن احیاءکنندگی قدرت بیشترین و لیتر) 9 / 0 (آهن مول میلی II میلی در) به مربوط نمونه) گرم TBHQ طبق بود. با آون، آزمون نتایج از اسانس غلظت افزایش 2 به درصد 5 و 10 آزمون اساس بر چند هر شد. حاصل بیشتری اکسیدانی آنتی فعالیت درصد نمونه بین آماری، های 5 و 10 معنی اختالف درصد تا غلظت بیشتر افزایش با ولی نشد. مشاهده داری 20 فعالیت خود از اسانس ،% داد نشان پرواکسیدانی (P<0.05). گیری: نتیجه اکسدیدان)، آنتدی (فاقدد کنترل نمونه به نسبت و بوده رادیکالی ضد فعالیت دارای پرتقال پوست اسانس که داد نشان نتایج می نتیجه در شد. حرارتی شرایط طی در سویا روغن اکسایشی پایداری باعث در طبیعدی اکساینده ضد عنوان به پرتقال پوست اسانس از توان ب غذایی، مواد روغن حاوی ویژه ه نمود. استفاده خوراکی، های واژه های کلیدی : اکسیدانی، آنتی فعالیت سویا، روغن پرتقال، پوست اسانس TBHQ * نویسنده مسئول مکاتبات
... Peel waste are being highly perishable and seasonal, is a serious problem to the processing industries and pollution monitoring agencies. A large number of researchers have focused on the study of peel of Citrus fruits and their antimicrobial activities [65], [19], [30], [36], [38], [51], [37]. The citrus fruit peel are rich in nutrients and phyto-chemicals. ...
Concern in environment-friendly textile processing techniques has been augmenting in recent years. Natural products are environment friendly, low toxic and less allergenic owing to the presence of large number of structurally diverse active compounds which makes natural agents as promising options for the development of antimicrobial protective textiles. The purpose of the present study was to investigate the effect of lemon peel treatment on microbial resistant property of cotton fabric. It was found that the cotton fabric treated with lemon peel extract showed 97.89, 98 and 97.16 percent reduction in the growth of P. aeruginosa, E. coli and X. campestris bacteria, 93.49 and 95.83 percent reduction in the growth of B. subtilis and S. aureus bacteria whereas treated fabric showed 94.99, 90.41 and 93.44 percent reduction against A. clavatus, A. flavus and A. awamori fungal strains, respectively. Lemon peel extract treated cotton fabric was further characterized by FESEM and FTIR spectra to study the changes occurred in the fibre structure after treatment. This work is licensed under a Creative Commons Attribution Non-Commercial 4.0 International License.
... The CEOs affect the cell membranes of the bacteria and fungi [36]. Additionally, the plant based essential oils, including CEOs, may cause interruptions in the ion transport processes; interact with compounds within the hosts' cells or the proteins within the cellular membranes [37], disturbing active sites of the enzymes [38]; and disrupt the mitochondrial functions in different ways [39]. Early research on C. x sinensis has also shown that essential oils from different varieties and cultivars offer antifungal or antibacterial activities. ...
Oranges and mandarins in Chongqing, China, are mostly processed for juice and their peels are wasted or landfilled. To add value, it is essential to utilize the peels and extract useful materials, such as citrus essential oils (CEOs). Here, we report the metabolome analysis of the peels of Citrus x sinensis (CS) and Citrus reticulata (CR). In total, 793 metabolites were detected in the CS and CR peels, of which 242 were differentially accumulated. The metabolites were grouped into 12 compound classes. Terpenoids were the highest accumulated class of compounds followed by phenols and alcohols in both fruit peels. CR peels were rich in all types of compounds, whereas CS showed a relatively lower content of the detected compounds. The highest accumulated compounds were β-phellandrene, beta-ocimene, 1,3,6-octatriene,3,7-dimethyl, and d-limonene. Overall, CR showed higher compound diversity than CS. The CS and CR peel extracts showed antibacterial effects against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The peel extracts from CR and CS showed similar antibacterial effects against E. coli and B. subtilis, while CS peel extracts were more effective against S. aureus. Overall, our study concludes that both CS and CR peels should not be wasted owing to the CEOs and respective antibacterial activities.
... Lemon essential oils extracted from plant lemon were introduced into the hydrogel system due to its antiseptic and anti-inflammatory properties. [55][56][57] Besides, high performance liquid chromatography (HPLC) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 analysis has indicated that Lemon essential oil contained D-limonene, which could serve as an antibacterial and anti-inflammatory agent (Figure S13, Supporting information). As depicted in Figure 10a, the hybrid hydrogel was applied on human skin, and EO molecules in the MS were slowly released to inhibit or kill harmful bacteria as well as to bring a fresh smell for suppression of other odors. ...
Flexible electronics has aroused great interests over the past few years due to its unique advantages of being wearable and lightweight. Introducing self-healing function into wearable electronics will contribute to the practical applications of wearable electronics by prolonging devices' lifetime. In this study, a flexible essential oils-loaded mesoporous silica (EO@AMS)/polyacrylate hybrid hydrogel with superb self-healing and antibacterial properties was prepared. The prepared hybrid hydrogel was found with excellent piezoresistive sensing performance, which could be particularly suitable for human vital activity monitoring. Benefiting from the strong ionic bonding and multiple hydrogen bonding between polyacrylate and EO@AMS, the hybrid hydrogel could repair its damaged areas with restored sensing and mechanical properties, which suggested the excellent self-healing ability. In addition, this hybrid hydrogel when applied in wearable devices was found with high anti-bacterial ability owing to the slow-release of lemon essential oils from AMS to kill bacteria. This promising self-healing and antibacterial hybrid hydrogel shows a promising application in wearable electronics for posture monitoring, human-computer interaction and artificial intelligence.
... Gallic acid was taken as standard and values were expressed in mg GAE/g. Antioxidant activity of the citrus peel extracts and oil was examined by DPPH assay as illustrated byFrassinetti, Caltavuturo, Cini, Della Croce, and Maserti (2011). Of note, 0.9 ml of 80% methanolic solution of DPPH was added into 0.1 ml oil solution. ...
Citrus jambhiri processing generates 40% peel waste with considerable waste man-
agement constraints. Interestingly, these peels are a rich source of essential oil.
Hence, in this study, the essential oil was extracted from fresh peels and peel
powder (PP) of C. jambhiri using hydrodistillation (HD) and ultrasound-assisted
hydrodistillation (USHD). Kinetic study, physicochemical, antimicrobial, and chemical
composition of the essential oil obtained from PP and fresh peel with albedo (FPA)
and without albedo (FPWA) using HD and USHD was studied. The kinetic study was
further experimentally validated using the first and second-order kinetic model. The
integrated equations were used to test the fitting of the model with obtained experi-
mental data. Kinetics of oil extraction from PP using USHD showed that extraction
process best fitted in second-order kinetic model with a high coefficient of determi-
nation (R2 = .999), yield (3.63%) and extraction rate constant (K2 = 0.0306), showing
that it validated the process thoroughly. The physicochemical properties of essential
oils obtained from both extraction methods fall within an acceptable range. Specific
gravity, acid value, and total phenolic content showed no significant difference
between both extraction methods while others differed significantly. The antioxidant
and antimicrobial activity increased with ultrasound treatment. GC–MS analysis of
different oil samples revealed that 10 compounds extracted from each extraction
with the highest amount of D-limonene (61.29%) were obtained from PP using
USHD. USHD stands as a fast, efficient, and economical method for extracting essen-
tial oil and can be a potential source for nutraceutical and pharmaceutical industries.
... Lemon (Citrus limon; Rutaceae family) is rich in some valuable bioactive substances including limonene, β-pinene, α-terpineol, nerolidol, acétate geranyl, linalyl acetate, linalool, neryl acetate, and farnesol (Hsouna et al. 2017). Hence, lemon essential oil (LEO) is extensively used in the food industry, medicinal purposes, and animal nutrition due to its various properties including antibacterial, antifungal, antiviral, and antiparasitic properties (Viuda-Martos et al. 2008;Frassinetti et al. 2011;Öntaş et al. 2016). Moreover, the positive effect of dietary LEO was reported on growth performance and health status in several commercial species such as Mozambique tilapia (Oreochromis mossambicus; Baba et al. 2016), African carp (Labeo victorianus; Ngugi et al. 2017), Nile tilapia (O. ...
The dietary effect of lemon essential oil loaded in chitosan nanoparticles (LEO/CNPs) on growth performance, serum biochemical parameters, humoral immune responses, and body composition in rainbow trout was evaluated. Two hundred and forty juvenile fish (4.74 ± 0.14 g) were randomly distributed to four experimental groups with three replicates in 12 fiberglass tanks (140 L; 20 fish per tank). The fish were fed a basal diet (commercial pellet; 50.5% protein and 13.1% fat) supplemented with 0 (control), 0.5, 0.75, and 1% LEO/CNPs for 56 days. At the end of the trial, the highest final weight (32.04 ± 1.22 g), weight gain (27.40 ± 1.36 g), and specific growth rate (3.45 ±0.12% day−1) were observed in 1% LEO/CPN treatment (P < 0.05). Besides, feed conversion rate significantly improved in 1% LEO/CNPs treatment (0.65 ± 0.01) compared to 0.5% LEO/CNPs (0.82 ± 0.07) and the control group (0.79 ± 0.03). Serum aspartate transaminase and alkaline phosphatase values were not affected by dietary LEO/CNPs (P > 0.05), while alanine aminotransferase level (13.21 ± 0.42 U L−1) showed a significant decrease in 1 % LEO/CNPs treatment compared to 0.5% LEO/CNPs and the control group (P < 0.05). The serum cholesterol, triglycerides, and glucose were significantly reduced following the oral administration of 0.75 and 1% LEO/CNPs (P < 0.05). Lysozyme activity (32.26 ± 1.14 U mL−1) and complement C3 (39.64 ± 4.76 mg dL−1) significantly increased in the fish treated with 1% LEO/CNPs. The higher and lower contents of crude protein and lipid were obtained in 1% LEO/CNPs, respectively, than the control group. Overall, the synergistic interaction between LEO and CNPs in 1% LEO/CNPs treatment may be responsible for improving the growth performance and immuno-physiological responses of rainbow trout.
... Both E. coli and S. aureus showed high sensitivity to CrEO with MICs of 10.1 and 9.1 mg.mL −1 , respectively, in this study. In literature, Frassinetti et al. (2011) determined that E. coli and S. aureus were susceptible to C. reticulata oils with MIC of 30 and 200 μg/mL, respectively. Also, it is widely reported that gram-negative species are more resistant than gram positives to active antimicrobials (De Souza et al. 2006). ...
... Both E. coli and S. aureus showed high sensitivity to CrEO with MICs of 10.1 and 9.1 mg.mL −1 , respectively, in this study. In literature, Frassinetti et al. (2011) determined that E. coli and S. aureus were susceptible to C. reticulata oils with MIC of 30 and 200 μg/mL, respectively. Also, it is widely reported that gram-negative species are more resistant than gram positives to active antimicrobials (De Souza et al. 2006). ...
In the present study, we evaluated the antibacterial activity of Citrus reticulata (C. reticulata) essential oil-incorporated gelatin film solution against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The minimum inhibitory concentration (MIC) of C. reticulata essential oil (CrEO) on E. coli and S. aureus were found to be 10.1 and 9.1 mg mL −1 , respectively, using spectro-photometric microdilution technique. The antimicrobial effect of CrEO alone and incorporated gelatin-based film solutions (CrEO-F) against these pathogens were determined by the disc diffusion method. While the inhibition zones of CrEO were 2.4 mm and 10.05 mm, CrEO-F was reported as 1.5 and 7.8 mm against E. coli and S. aureus, respectively. These findings demonstrated that the CrEO can compete with coating agents with antimicrobial additives and it can find a place in the application areas. Besides, the chemical composition of the CrEO was determined by GC-MS. ARTICLE HISTORY
... This might be attributed also to the synergy of some compounds with each other. However, the studied EO showed relatively low antioxidant activity than those reported by Frassinetti et al. (2011), who found that EOs of orange Bitter, sweet orange, lemon and mandarin showed higher antioxidant activity (20-70%) at concentrations ranging from 50 to 1000 lg/ml. This difference in the results is probably due to the methods used in extraction, the plant variety, and the methodology for the evaluation of the antioxidant activity. ...
Hydro-distillation assisted by electromagnetic induction heating (H-EMIH) was employed to extract essential oil (EO) from Algerian fresh orange peels (Citrus sinensis). H-EMIH was compared with conventional hydro-distillation (C–H) in terms of hydro-distillation time, yield, chemical composition and, antibacterial and antioxidant activities. It was found that extraction of EO with H-EMIH gave a maximal yield of 3.77% in 35 min whereas C–H gave 2.72% in 41 min. The extracts obtained by both techniques were analyzed by Gas Chromatography-Mass Spectrometry. Their chemical compositions are relatively similar; limonene and β-myrcene were found as the principal compounds. The antioxidant activity results demonstrated that EO extracted by H-EMIH showed the highest capacity of radical scavenging than EO isolated by C–H process. Otherwise, it was found that EO extracted by H-EMIH exhibited an antimicrobial potential slightly higher than that extracted by C–H.
... In the food matrices, the essential oils can act as antioxidants and antibacterial, besides reproducing the flavor and odor of the plant used (Frassinetti et al. 2011;Chouhan et al. 2017). D-limonene presents biological activities, as antioxidant (Murali and Saravanan 2012) and antimicrobial (Lennartsson et al. 2012). ...
The aim of this study was the application of the electronic nose for detection of volatile release from dark chocolate flavored with orange essential oil during the storage. The detection of volatile in chocolate without and with different concentrations of orange oil (0–10 ppm) was performed using polyaniline (Pani) gas sensor array with different dopants. Orange oil and chocolate were analyzed in relation to water activity, moisture, and acidity. The chocolate maintained unchanged the water activity; however, the moisture and acidity presented alterations during the storage. It was verified a decrease in resistance response of the sensor array with the chocolate during the storage time. The sensor doped with TSA (toluenesulfonic acid) presented the higher sensitivity of the array. Principal component analysis (PCA) revealed five distinct groups corresponding to the volatiles released during the storage time (0, 20, 40, 60, and 100 days). This work demonstrates that the electronic nose technology with Pani gas-sensing array can be effective and successfully applied to discriminate different concentrations of orange essential oil during the dark chocolate storage.
... coli activity of citrus EOs was first observed by Dabbah et al. (1970), where the EOs obtained from orange, lemon and lime were the most effective to inhibit the growth and reduce E. coli population. Similarly, other citrus oils, such as bitter orange (Citrus aurantium), sweet orange (Citrus sinensis), lemon (Citrus limon) and mandarin (Citrus reticulata) were highly effective to inhibit E. coli growth (Bourgou et al. 2012) at MICs ranging from 25 to 40 µg ml À1 (Frassinetti et al. 2011). Nevertheless, the antibacterial activity of citrus oils on E. coli has been shown to be citrus plant species-specific (Thielmann et al. 2019). ...
Aim: This study investigated the in vitro mechanism of action of a commercial citrus EO, Brazilian orange terpenes (BOT), on an enterotoxigenic Escherichia coli (ETEC) isolated from pig gut and on Lactobacillus rhamnosus.
Methods and Results: Firstly, bacteria were exposed sequentially to BOT every 3 h (three times) at sub‐MICs and results showed that sequential exposure to BOT provoked a higher reduction of bacteria viability than a single exposure and the reduction of ETEC viability was higher compared to that of L. rhamnosus. Then, evaluation of the BOT effects on the cell membrane permeability and integrity, indicated that BOT increased the membrane permeability and caused disruptive effects on the integrity of bacterial cells as reflected by an increase of the relative electric conductivity and the release of essential cell constituents. Interestingly, BOT effects were more pronounced on the ETEC than on L. rhamnosus. This was ratified by scanning electron microscopy (SEM), which showed more noticeable morphological damages and disturbances on ETEC cells than L. rhamnosus cells. Limonene was detected as the major compound in BOT by polar/non‐polar GC‐MS (78.65% / 79.38%).
Conclusions: Results revealed that the probable mechanism underlying the selective antibacterial action of the citrus EO, BOT, can be described as altering more remarkable the permeability and integrity of the cytoplasmic membrane as well as the external structure of an ETEC than L rhamnosus.
Significance and Impact of the Study: This study provides information about the mechanism of antibacterial action displayed by a citrus EO, a by‐product of the citrus processing industry, as a natural alternative to antibiotics used in pig production sector to combat pathogens as ETECs.
Citrus limon is a flowering plant belonging to the Rutaceae family. Citrus fruits constitute one of the main valuable sources of essential oil used in foods and medicinal purposes. This study was designed to investigate the effect of adding the essential oil of lemon leaves in yogurt on its rheological and physicochemical parameters in comparison with potassium sorbate. Five batches of yogurt were prepared with different concentrations of the essential oil (0, 1250, 2500, 3750 µg/ml), one batch was dedicated to potassium sorbate (0.1%). Essential oil of lemon leaves was analyzed by gas chromatography/mass spectrometry (GC/MS), yogurts formulated were analysed by the rheometer. The GC/MS analysis allowed the identification of 27 compounds accounted for total percentage of 99.76%. The two dominant compounds were Limonene (57.96%) and β-pinene (16.29%). The essential oil exhibited an excellent DPPH scavenging activity with a half maximal inhibitory concentration an (IC50) of 2,41± 0,04 μg/ml comparable to that of ascorbic acid with an IC50 of 5,87± 0,75 μg/ml. pH values of yogurts with essential oil were significantly the highest after those of yogurts with potassium sorbate (p<0.05), which improves the acidity stability of yogurts during storage.The thixotropic index recorded for yogurts with essential oil was the greatest (3789 Pa/s for the highest concentration), while that with potassium sorbate was the lowest (2280 Pa/s) compared with the control (3329 Pa/s). The viscoelastic behaviour of the control yogurt and the essential oil yogurts were almost the same, the addition of essential oil did affect significantly the thixotropic behaviour of yogurts (p<0.05).
Aim
Black extrinsic tooth stain (BETS) is a health challenge that commonly affects children. Aggregatibacter actinomycetemcomitans ( Aa ) presents in higher prevalence within the polymicrobial community of BETS. In this study, the anti-planktonic and anti-sessile activities of cinnamon essential oil (CEO) and its individual compounds against Aa were evaluated. The preventive effect of CEO and its active substances on BETS formation was also studied in vitro.
Methods
Aa was isolated from a preschool child with BETS and was identified based on the morphological characteristics, MALDI-TOF mass spectroscopy and 16S rRNA sequencing. The effect of CEO and its individual compounds on the growth kinetics of planktonic and sessile Aa cells as well as their antibacterial efficacy and their rate of bacterial killing were examined. The preventive effect of CEO and its active substances on the formation of BETS was evaluated using an ex vivo model. The data were analysed using one-way analysis of variance (ANOVA) and the significance level was set at p < 0.05.
Results
Out of eight individual compounds of CEO, only eugenol, cinnamaldehyde and α-methyl cinnamaldehyde showed anti- Aa activities. The values of the minimum inhibitory concentrations (MICs) were in the following order: CEO (421.5 mg/ml) > α-methyl cinnamaldehyde (26.37 mg/ml) > cinnamaldehyde (0.209 mg/ml) > eugenol (0.052 mg/ml). CEO, eugenol, cinnamaldehyde and α-methyl cinnamaldehyde, respectively, exhibited two-, four-, four- and eightfold increase of sessile MIC compared to their planktonic MIC. The growth kinetics of both planktonic and sessile Aa in the presence of CEO, eugenol, cinnamaldehyde and α-methyl cinnamaldehyde revealed a complete inhibition at the MICs and 5.3%–37.4% biofilm inhibition at sub-MICs. The time-killing study demonstrated that CEO, eugenol and cinnamaldehyde were capable of reducing the survival rate of both planktonic and sessile Aa cells after 15–20 and 25–30 min, respectively. However, α-methyl cinnamaldehyde showed a superior anti-planktonic to anti-biofilm activity. The daily incorporation of CEO, eugenol and cinnamaldehyde at their MICs for 14 days totally prevented the formation of BETS in the ex vivo model; however, in the case of α-methyl cinnamaldehyde, BETS was visually detectable after 10 days.
Conclusion
CEO and its individual compounds have marked antibacterial activity against Aa . The effective results against planktonic and sessile Aa within reasonable time indicate that they can be used to prevent BETS.
Wounds are injuries that break the skin. They include cuts, scrapes, scratches, punctured skin or burns. Minor wounds are not usually serious but it is important to clean them. Some wounds heal by themselves without much treatment. However, some require special care or otherwise might catch an infection. Antiseptic creams are meant to prevent wound infection, promote natural wound healing and soothe the skin. However, most of the strong antiseptics available in the market comprise of chemicals that can have harmful effects on the user's skin. Herbal medicines are plant-based drugs that comprise of natural ingredients like leaves, stem, roots, flowers or fruit for medicinal purposes. Such drugs are nontoxic and free from side effects as compared to the synthetic ones. Hence, the project focused on isolation of Staphylococcus aureus, Escherichia coli & Pseudomonas aeruginosa from wound infections. Extraction of natural extracts from plant parts of Tagetes erecta (marigold), Citrus indica (orange) & Cocos nucifera (coconut) using Soxhlet extraction procedure. The extracts obtained were diluted using Dimethyl sulfoxide and screened for antibacterial activity using Agar cup method. On screening, the antibacterial activity of petals of Tagetes erecta was determined to be the better than of Citrus indica & Cocos nucifera. Hence, an all-natural antiseptic ointment was formulated using Tagetes erecta as the active ingredient. The formulated ointment was evaluated for its physicochemical properties and its antibacterial activity was determined using gradient plate technique.
This research studied the chemical compositions, antioxidant activities, and antimicrobial activities of kaffir lime (Citrus hystrix DC.) and key lime (Citrus aurantifolia (Christm.) Swingle.) peel essential oils extracted by hydrodistillation. GC-MS analysis of kaffir lime essential oil showed four major components as β-pinene (27.37%), β-phellandrene (22.69%), D-limonene (16.21%), and citronellal (12.43%), while in key lime essential oil the predominant component was D-limonene (45.91%), with two minor components as β-pinene (20.27%) and γ-terpinene (8.33%). Both essential oils scavenged free radicals, with amounts of sample required to decrease DPPH concentration by 50% (IC50) 93.20 and 57.90 mg/ml for kaffir lime and key lime essential oils, respectively. Both essential oils showed antibacterial activity against Staphylococcus aureus in the agar diffusion technique.
Dental caries is the most common biofilm-dependent oral disease. Streptococcus
mutans is among the main microorganisms responsible for the development of dental caries. Nano-suspension of Citrus reticulata (tangerine) peel essential oil in
0.5% (v/v) concentration was prepared and its antibacterial effect on S. mutans in
planktonic and biofilm forms as well as its cytotoxic and antioxidant effects were
assessed and compared with chlorhexidine (CHX). The minimum inhibitory concentration (MIC) of free essential oil, nano-encapsulated essential oil, and CHX
was 5.6% (v/v), 0.0005% (v/v), and 0.0002% (w/v), respectively. The percentage
of biofilm inhibition by the free essential oil, nano-encapsulated essential oil, and
CHX at half-MIC was 67.3%, 24%, and 90.6%, respectively. The nano-encapsulated
essential oil had no cytotoxicity and showed significant antioxidant effects in different concentrations. Nano-encapsulation of tangerine peel essential oil significantly
enhanced its biological activities in much lower concentrations than the free essential
oil (11,000 times diluted). It also showed lower cytotoxicity and higher antibiofilm
effects in sub-MICs compared with CHX, indicating the optimal potential of tangerine nano-encapsulated essential oil for incorporation in the composition of organic
antibacterial and antioxidant mouth rinses.
Acne is a chronic, common disease that poses a significant therapeutic, psychological and social problem. The etiopathogenesis of this disease is not fully understood. Drugs used in general and external therapy should have anti-seborrhoeic, anticomadogenic, bactericidal, bacteriostatic, and anti-inflammatory properties. Acne treatment is often associated with the long-term use of antibiotics, contributing to the global antibiotic resistance crisis. In order to solve this problem, attention has been paid to essential oils and their terpene components with potent antimicrobial, anti-inflammatory, and antioxidant properties. Research shows that certain essential oils effectively reduce inflammatory acne lesions through mechanisms related to the sebaceous glands, colonization of Cutibacterium acnes, and reactive oxygen species (ROS). An example is tea tree oil (TTO), a more commonly used topical agent for treating acne. TTO has antimicrobial and anti-inflammatory activity. The paper presents the latest scientific information on the activity and potential use of specific essential oils in treating acne. Evidence of antibacterial, anti-inflammatory, and antioxidant activity of several essential oils and their main components was presented, indicating the possibility of using them in the treatment of acne.
Citrus peel is a major fruit waste generated during the processing of citrus fruits. We extracted and chemically characterised essential oil from four different species of citrus peel waste and evaluated its insecticidal, antioxidant and phytotoxic activities. GC-MS/MS characterisation revealed D-limonene as the major constituent of citrus peel waste essential oil. The essential oils from the four citrus peel wastes showed significant contact, fumigant and repellent activities against two key stored grain pests Tribolium castaneum (Herbst) and Callosobruchus chinensis (L.). DPPH, ABTS, and FRAP assays revealed the antioxidant potential of the citrus peel waste essential oil. The essential oil did not affect the germination of wheat seeds and revealed the safety of essential oil to germinating seeds. Hence, the essential oil extracted from citrus peel waste can be valorised and utilised as a botanical insecticide against T. castaneum and C. chinensis.
Lime essential oil (EO) is rich in different biological properties as an antiseptic and antimicrobial. Agrarian locations (ALs) in Egypt are characterized by different environmental characteristics that affect the content and composition of lime EO and thus its biological properties. Leaves, flowers, and peels of lime were collected from trees cultivated in three ALs, namely, north, central, and Upper Egypt. EO was separated by a hydro-distillation (HD) method; then analyzed using a Gas chromatography (GC) and Gas chromatography/mass spectrometry (GC/MS) analysis. The maximum contents of leaf (0.5 % and 1.3 ml/ 250g), flower (0.2 % and 0.5 ml/ 250g) and peel (0.3 % and 1.3 ml/ 250g) EOs were obtained from the samples collected from Upper Egypt. The major component of leaf and peel EOs were limonene. Dimethyl anthranilate was the main compound of flower EO. Oxygenated monoterpenes (OM) was the main group in leaf and flower EOs, while a monoterpene hydrocarbon (MH) was the main group of peel EO. The maximum values of limonene from leaf EO (40.3 %) and limonene from peel EO (36.5 %), dimethyl anthranilate (22.3 %), OM from flower EO (66.1 %), and MH (59.8 %) were obtained from the samples collected from Upper Egypt AL. The greatest amount of OM from leaf EO (55.9 %) has resulted from the samples collected from the central AL. It may be concluded that this study avail as a reference for choosing the adequate AL to extract the EO according to the compositions of interest.
Is there an effective pharmacotherapy for COVID-19?
Molecules discussed in this article are caffeic acid, glycyrrhizin, rifampicin, doxycycline, cefuroxime, ciprofloxacin, moxifloxacin, formoterol, probiotics, quercetin, resveratrol, bismuth complexes, Gelomyrtol, dabigatran etexilate, rosuvastatin and pentoxifylline. CytoSorb therapy is also discussed in the article.
The research aim was to use orange essential oil and trehalose in a carrageenan matrix to form edible packaging. The edible packaging experimentally produced by casting from an aqueous solution were evaluated by the following analysis: UV-Vis spectrum, transparency value, transmittance, attenuated total reflectance Fourier-Transform spectroscopy (FTIR), scanning electron microscopy (SEM) and antimicrobial activity. The obtained results showed that the combination of orange essential oil with trehalose decreases the transmittance value in the UV and Vis regions (up to 0.14% ± 0.02% at 356 nm), meaning that produced films can act as a UV protector. Most produced films in the research were resistant to Gram-positive bacteria (Staphylococcus aureus subsp. aureus), though most films did not show antibacterial properties against Gram-negative bacteria and yeasts. FTIR and SEM confirmed that both the amount of carrageenan used and the combination with orange essential oil influenced the compatibility of trehalose with the film matrix. The research showed how different combinations of trehalose, orange essential oils and carrageenan can affect edible film properties. These changes represent important information for further research and the possible practical application of these edible matrices.
Since ancient times complementary therapies have been based on the use of medicinal plants, natural preparations and essential oils in the treatment of various diseases. Their use in medical practice is recommended in view of their low toxicity, pharmacological properties and economic impact. This paper aims to test the antimicrobial effect of natural preparation based on clove, orange and bergamot essential oils on a wide range of microorganisms that cause infections in humans including: Streptococcus pyogenes, Staphylococcus aureus, Shigella flexneri, Candida parapsilosis, Candida albicans, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhimurium and Haemophilus influenza. Three natural preparations such as one-component emulsions: clove (ECEO), bergamote (EBEO), and orange (EOEO), three binary: E(BEO/CEO), E(BEO/OEO), E(CEO/OEO) and a tertiary emulsion E(OEO/BEO/CEO) were obtained, characterized and tested for antimicrobial effects. Also, the synergistic/antagonistic effects, generated by the presence of the main chemical compounds, were studied in order to recommend a preparation with optimal antimicrobial activity. The obtained results underline the fact that the monocomponent emulsion ECEO shows antimicrobial activity, while EOEO and EBEO do not inhibit the development of the analyzed strains. In binary or tertiary emulsions E(BEO/CEO), E(CEO/OEO) and E(OEO/ BEO/CEO) the antimicrobial effect of clove oil is potentiated due to the synergism exerted by the chemical compounds of essential oils.
The yield and the composition of the peel essential oils (EO) of six new citrus hybrids obtained from the crosses between Murcott tangor—TM [Citrus reticulata Blanco x Citrus sinensis (L.) Osbeck] and Pera sweet orange—LP [C. Sinensis (L.) Osbeck] was evaluated for the first time. The EO yield of the citrus varied from 0.34% to 0.59%. The hybrids that presented higher EO yield per hectare were TMXLP44 (36 L ha⁻¹) and TMXLP294 (21 L ha⁻¹). The majority compound in all samples was the limonene (>80%). Linalool presented the second highest concentration in the samples, being the sample TMXLP294 the one that presented the highest content of this compound (>13%). The principal components analysis revealed that TMXLP44 is the sample that more differs from the parents, whereas TMXLP372 and TMXLP294 are more similar to their parents Murcott tangor and Pera sweet orange, respectively.
This study aimed to determine the effect of addition of different concentrations (0.1 and 0.3% v/ w) of dry and fresh Iraqi and Egyptian orange (Citrus sinensis) peels extracts on either of microbial activity of microorganisms that cause food spoilage and sensory properties of cake. Oily extracts for both the local and Egyptian had a clear action against gram positive bacteria (Staphylococcus aureus and Bacillus subtilis) while that action was less on negative bacteria (Salmonella typhimurum and Escherichia coli). Diameters of clear zones of B.subtilis and Staph.aureus growth were 7.4 and 7.5mm consequently at concentration of 4000 ppm of local dry peels extract while diameters of clear zones of S. typhimurum and E.coli growth were 6.5 and 3.2 consequently under the same condition. The mold Rhizopus spp was more inhibited at concentrations of 2000 or 4000 ppm where the maximum inhibition (42%) reached when the dry local orange extract was used. The results showed that the addition of Iraqi oil extracted from dry orange peels at percentage of 0.1% to Cake mix, addition of Egyptian oil at percentage of 0.1% to Cake mix and addition of Iraqi oil extracted from fresh orange peels at percentage of 0.1% to Cake mix were most efficient in term of decreasing the total number of bacteria and mold compared with control treatment. It was concluded that oil extracted from the Iraqi dry and fresh peel orange were considered as inhibitors of some food spoiled bacteria and fungi and as an improver of cake sensory properties which reflected in prolonging its shelf life.
Citrus maxima Merr. or Pomelo is a plant with potential antibacterial activity against a broad spectrum of bacterial pathogens that has the key active compound as limonene, which is a major constituent in the fruit peel. This study investigated the antibacterial activity of C. maxima essential oil (CMEO) against methicillin-resistant Staphylococcus aureus (MRSA). The antibacterial activity was determined by the agar disk diffusion and broth macro dilution methods against S. aureus ATCC 25923 (methicillin-susceptible S. aureus; MSSA), S. aureus ATCC 43300 (MRSA) and ten clinical isolates of MRSA. The bacteria-killing rate of 1MIC CMEO at different exposure times was also evaluated by the time-kill assay. The inhibition zones of CMEO against S. aureus ATCC 25923, S. aureus ATCC 43300 and MRSA isolates were 10.0, 9.0 and 9.9 mm, respectively, but no zone was observed for DMSO control, thus indicating a weak activity of CMEO. The inhibition zone of CMEO against MRSA isolates was significantly different from that of limonene (p 0.05), indicating a synergistic effect of limonene with other minor compounds in CMEO. The MIC value of CMEO to S. aureus ATCC 43300 was lower than that of S. aureus ATCC 25923 (4.0 vs 10.7 mg/mL; p 0.05). The MIC value of CMEO against MRSA isolates was 8.14.8 mg/mL with MIC indexes less than 4. Besides, CMEO completely killed both MSSA and MRSA within 4 and 8 hours, respectively. These findings demonstrated the bactericidal effect of CMEO against MRSA; thus, it has the potential to be developed as a novel antibacterial agent.
Origanum vulgare L. (oregano), Lamiaceae, has been known as plant specie with prominent biological properties for a long time. This study aimed to evaluate the antibacterial activity of Origanum vulgare essential oil on various Gram- positive and Gram- negative spoiling and/or pathogen food- related bacteria, as well as to observe its antimicrobial effectiveness in a food conservation micromodel. The results showed a strong antibacterial activity of the assayed essential oil noted by large growth inhibition zones (30- 37 mm). MIC values were between 20-40 mu L/mL for the most bacteria strains. Essential oil was able to cause significant (P< 0.05) inhibitory effect on the bacteria viability providing a bacteriostatic effect after 24hours of exposure. In addition, the MIC provided a significant (P< 0.05) decrease of the autochthonous bacterial flora in ground meat samples stored under refrigeration. These results support the possibility of using Origanum vulgare essential oil as alternative antimicrobial compound in food conservation systems.
The antimicrobial activity of 28 essential oil samples isolated from local plants or plants cultivated in Corsica was evaluated against a large panel of human pathogenic bacteria, including Campylobacter jejuni which appeared as a good model for this purpose. The chemical composition of the 18 oils selected for their efficiency was determined by GC and GC/MS. Among them, the oils of Cistus ladaniferus, Crithmum maritimum, Daucus carota, Juniperus com-munis, Mentha aquatica and Santolina corsica showed compositions without components known as active, suggesting the presence of compounds not previously described as antibacterial agents.
Eleven essential oils, namely, Cananga odorata(Annonaceae), Cupressus sempervirens (Cupressaceae), Curcuma longa(Zingiber-
aceae), Cymbopogon citratus (Poaceae), Eucalyptus globulus(Myrtaceae), Pinus radiata (Pinaceae), Piper crassinervium(Piperaceae),
Psidium guayava(Myrtaceae), Rosmarinus officinalis(Lamiaceae), Thymus x citriodorus (Lamiaceae) and Zingiber officinale (Zingib-
eraceae), were characterized by means of GC and GC–MS and evaluated for their food functional ingredient related properties.
These properties were compared to those of Thymus vulgaris essential oil, used as a reference ingredient. Antioxidant and radi-
cal-scavenging properties were tested by means of 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay, b-carotene bleaching test and lumi-
nol-photochemiluminescence (PCL) assay. In the DPPH assay, C. odorata, C. citratus, R. officinalisand C. longa showed major
effectiveness, with a radical inhibition ranging from 59.6 ± 0.42–64.3 ± 0.45%. In the b-carotene bleaching test, C. odorata
(75.5 ± 0.53%), R. officinalis (81.1 ± 0.57%) and C. longa (72.4 ± 0.51%) gave the best inhibition results. Similar results were
obtained for the same essential oils in the PCL assay. Antimicrobial properties were obtained on five food-spoilage yeasts:Candida
albicans ATCC 48274,Rhodotorula glutinis ATCC 16740,Schizosaccharomyces pomb e ATCC 60232, Saccharomyces cerevisiae
ATCC 2365, Yarrowia lypoliticaATCC 16617 . C. citratus and T. x citriodorus were the most effective against the tested strains. Suggestions on relationships between chemical composition and biological activities are outlined.
Catnip (Nepeta cataria) is an important medicinal herb belonging to the mint family, Lamiaceae. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from Nepeta cataria, and its essential oil composition were investigated. The essential oil, which has 4aalpha,7alpha,7abeta-nepetalactone (70.4%), 4aalpha,7alpha,7abeta-nepetalactone (6.0%), thymol (2.3%), and 4aalpha,7alpha, 7abeta3-nepetalactone (2.5%), as main components, exhibited activity against eleven bacteria, and twelve fungi and a yeast, C. albicans; with Minimum Inhibitory Concentrations (MIC) values ranging from 12.50 to 250 microl/ml; the methanol extract showed weaker activity. The samples were also subjected to a screening for their possible antioxidant activities by using 2.2-diphenyl-1-picrylhydrazyl (DPPH) and beta-carotene/linoleic acid assays. In DPPH assay, the extract showed slight antioxidant activity whereas the essential oil remained inactive. In the latter case, both the extract and the essential oil exerted weak activity having inhibiton ratios of linoleic acid oxidation at 16.4% and 27.0%, respectively. The weak antioxidative nature of the extract could be attributed to the low phenolic content, estimated as gallic acid equivalent at 22.6 +/- 2.07 microg/ml or 2.26%. In both systems, antioxidant capacity of BHT was determined in parallel experiments.
This review describes the use of some natural products in cosmetic preparations, due to their low mammalian toxicity, with a brief description of the major use, plant parts used, the actives responsible for effect and the benefits of such products. Their use in skin care; such as dryness, eczema, acne, free-radical scavenging, antiinflammatory, antiaging and skin protection effects are explained, and also the use in hair care as hair growth stimulants, hair colorants, and for hair and scalp complaints such as dandruff. Essential oils when incorporated into finished products impart many benefits such as a pleasant aroma in perfumery, shine or conditioning effects in hair care products, emolliency and improving the elasticity of the skin.
To evaluate the antibacterial activity of 21 plant essential oils against six bacterial species.
The selected essential oils were screened against four gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus vulgaris) and two gram-positive bacteria Bacillus subtilis and Staphylococcus aureus at four different concentrations (1:1, 1:5, 1:10 and 1:20) using disc diffusion method. The MIC of the active essential oils were tested using two fold agar dilution method at concentrations ranging from 0.2 to 25.6 mg/ml.
Out of 21 essential oils tested, 19 oils showed antibacterial activity against one or more strains. Cinnamon, clove, geranium, lemon, lime, orange and rosemary oils exhibited significant inhibitory effect. Cinnamon oil showed promising inhibitory activity even at low concentration, whereas aniseed, eucalyptus and camphor oils were least active against the tested bacteria. In general, B. subtilis was the most susceptible. On the other hand, K. pneumoniae exhibited low degree of sensitivity.
Majority of the oils showed antibacterial activity against the tested strains. However Cinnamon, clove and lime oils were found to be inhibiting both gram-positive and gram-negative bacteria. Cinnamon oil can be a good source of antibacterial agents.
Essential oils and their volatile constituents are used widely to prevent and treat human disease. The possible role and mode of action of these natural products is discussed with regard to the prevention and treatment of cancer, cardiovascular diseases including atherosclerosis and thrombosis, as well as their bioactivity as antibacterial, antiviral, antioxidants and antidiabetic agents. Their application as natural skin penetration enhancers for transdermal drug delivery and the therapeutic properties of essential oils in aroma and massage therapy will also be outlined.
The essential oils obtained from Satureja montana L. harvested in central part of Dalmatia (Croatia) at three ontogenical stages were evaluated for their chemical composition and antimicrobial activity. GC/MS analyses revealed the presence of 33 compounds in the oils. Carvacrol (52.4>26.2>16.1%) was found to be the main constituent especially before flowering while p-cymene (3.8<15.2<25.6%) increased through flowering. The antimicrobial activity of S. montana oils against five Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella typhi), four Gram-positive bacteria (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Streptococcus faecalis) and five pathogenic fungi (Aspergillus fumigatus, Aspergillus niger, Candida albicans, Candida rugosa and Saccharomyces cerevisiae) was evaluated using the agar-plate dilution assay. The oil showed the strongest activity against all tests strains, with the exception of Pseudomonas aeruginosa. The maximum activity was observed against E. coli, S. aureus and fungal organisms. Escherichia coli had the lowest MIC of 0.06% with oils produced before and during the flowering period. These results support the notion that S. montana oil has a role as both a pharmaceutical and a preservative.
The goal of the present work was to evaluate the antioxidant properties of buntan (Citrus grandis Osbeck) using various solvents, such as n-hexane, ethyl acetate (EtOAc), butanol and methanol. The antioxidant activities of crude extracts were evaluated by using the free radical scavenging β-carotene assay and total polyphenol. Ethyl acetate extracts of falvedo exhibited high antioxidative activities, followed by albedo and segment membrane extracts. Chromatography separation of EtOAc extract of flavedo using a silica gel column, yielded six fractions (A, B, C, D, E and F) using gradient elution with benzene and acetone (19:1, 14:1, 9:1, 5:1, 1:1 and 0:l). Among them, two fractions (C and D) showed strong antioxidant activities using the free radical scavenging activity (DPPH) antioxidant assay. These two fractions were further purified using silica gel column chromatography and preparative TLC. Their extracts could well be useful to prevent oxidation in fruit juices and essential oil food products as well as for health supplements. Identification of the responsible components is underway.
Free radical generation is directly related with oxidation in foods and biological systems. Therefore, the search for methods to determine free radical scavenging is important. In this work are described the methods used for this purpose in both substrates as well as in specific cases of their application. The main methods comprise superoxide radicals scavenging (O2·-); hydrogen peroxide scavenging (H2O2); hypochlorous acid scavenging (HOCl); hydroxyl radical scavenging (HO.); peroxyl radical scavenging (ROO.), among them are the methods that use azo-compounds to generate peroxyl radicals, such as the ``TRAP'' method (Total Radical-Trapping Antioxidant Parameter) and the ``ORAC'' method (Oxygen-Radical Absorbance Capacity); the scavenging of radical cation 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonate) or the ABTS or the ``TEAC'' method (Trolox Equivalent Antioxidant Capacity); the scavenging of stable radical 2,2-diphenyl-1-picrylhydrazyl or DPPH . method and the scavenging of radical cation N,N-dimethyl-p-phenylenediamine or DMPD method. At present, in spite of the diversity of methods, there is a great need to standardize measurements of antioxidant activity. The search for more specific assays, giving us chemical information that could be related directly to oxidative deterioration of foods and biological systems could be the objective of future research.
Most pathogenic species of Penicillium have a limited host range, suggesting unique adaptations to particular hosts. P. digitatum and P. italicum are primarily pathogens of mature citrus fruit, while P. expansum has a broad host range, but does not infect citrus. One possible basis of host specificity is that the pathogens are physiologically adapted to grow in the presence of the many bioactive compounds present in the citrus peel. To test this, peels from the fruit of seven Citrus sp. were extracted with 80% ethanol, concentrated and standardized. Growth of P. digitatum, P. italicum and P. expansum on potato dextrose broth, alone, or plus extract, was quantified by measuring conversion of the vital stain, thiazol blue. All citrus peel extracts stimulated growth of P. digitatum andP. italicum at greater dilution and to a greater degree than P. expansum. ‘Marsh’ grapefruit extract was separated into hexanes, ethyl acetate and aqueous partitioning fractions. The aqueous fraction was active at the greatest dilution tested, the hexanes fraction was active only at the highest concentration tested, while the ethyl acetate fraction had no stimulatory activity. When the aqueous and hexanes fractions were combined, growth increased tremendously, indicating a synergistic effect. The primary growth stimulating component in the hexanes fraction of grapefruit was identified as nootkatone. Growth ofP. digitatum and P. italicum is stimulated by components present in citrus peel. Published by Elsevier Science Ltd.
The antiradical activities of various antioxidants were determined using the free radical, 2,2-Diphenyl-1-picrylhydrazyl (DPPH*). In its radical form. DPPH* has an absorption band at 515 nm which dissappears upon reduction by an antiradical compound. Twenty compounds were reacted with the DPPH* and shown to follow one of three possible reaction kinetic types. Ascorbic acid, isoascorbic acid and isoeugenol reacted quickly with the DPPH* reaching a steady state immediately. Rosmarinic acid and δ-tocopherol reacted a little slower and reached a steady state within 30 min. The remaining compounds reacted more progressively with the DPPH* reaching a steady state from 1 to 6 h. Caffeic acid, gentisic acid and gallic acid showed the highest antiradical activities with a stoichiometry of 4 to 6 reduced DPPH* molecules per molecule of antioxidant. Vanillin, phenol, γ-resorcylic acid and vanillic acid were found to be poor antiradical compounds. The stoichiometry for the other 13 phenolic compounds varied from one to three reduced DPPH* molecules per molecule of antioxidant. Possible mechanisms are proposed to explain the experimental results.
This study was designed to examine the in vitro antimicrobial and antioxidant activity of the essential oil and various extracts prepared by using solvents of varying polarity from Cyclotrichium origanifolium (Labill.) Manden. & Scheng. The essential oil was particularly found to possess stronger antimicrobial activity while other non-polar extracts and subfractions showed moderate activity and polar extracts remained almost inactive. GC and GC/MS analysis of the oil resulted in the identification of 26 compounds, representing 99.6% of the oil; pulegone (49.8%), menthone (32.5%) and limonene (6.0%) were the main components. The samples were also subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, the free radical scavenging activity of polar subfraction of deodorized methanol extract (DeMW) was superior to all other extracts. Especially polar extracts exhibited strongest activity than the non-polar extracts. In the case of linoleic acid system, oxidation of linoleic acid was effectively inhibited by non-polar (chloroformic) subfraction methanol extract (MC), where the oil was less effective. MC extract exhibits 79.2% inhibition that is close to synthetic antioxidant reagent BHT when compared to the other extracts tested.
The antioxidant properties of the essential oil from oregano in relation to its chemical composition were examined. The antioxidant activity was investigated with three different methods: the β-carotene bleaching (BCB) test, the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging method and the thiobarbituric acid reactive species (TBARS) assay. It was found that the total essential oil, its fraction as well as its pure constituents have a significant antioxidant effect when tested by each method, respectively. Generally the antioxidant activity of the oregano essential oil is less effective than the ascorbic acid, but comparable with the α-tocopherol and the synthetic antioxidant butylated hydroxytoluene (BHT). The synergy among minor oxygen containing compounds was suggested as possible factor, which influenced the antioxidant power of the oregano essential oil. The antioxidant concentrations influenced its antioxidant power, too.
This study examined the effect of volatile components of citrus fruit essential oils on P. digitatum and P. italicum growth. The hydrodistilled essential oils of orange (Citrus sinensis cvv. “Washington navel”, “Sanguinello”, “Tarocco”, “Moro”, “Valencia late”, and “Ovale”), bitter (sour) orange (C. aurantium), mandarin (C. deliciosa cv. “Avana”), grapefruit (C. paradisi cvv. “Marsh seedless” and “Red Blush”), citrange (C. sinensis x Poncirus trifoliata cvv. “Carrizo” and “Troyer”), and lemon (C. limon cv. “Femminello”, collected in three periods), were characterized by a combination of GC and GC/MS analyses. The antifungal efficacy of the oils was then examined at progressively reduced rates. Findings showed a positive correlation between monoterpenes other than limonene and sesquiterpene content of the oils and the pathogen fungi inhibition. The best results were shown by the citrange oils, whose chemical composition is reported for the first time, and lemon. Furthermore P. digitatum was found to be more sensitive to the inhibitory action of the oils.
The effects of the antioxidants butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on isolated rat hepatocytes were investigated. Both antioxidants were observed to be cytotoxic in a concentration-dependent manner at concentrations ranging from 100 to 750 microM. At equimolar concentrations BHT was more cytotoxic than BHA. Their toxicity appeared to be independent of their metabolism to reactive intermediates since inhibitors of cytochrome P-450 (metyrapone, SKF 525-A and piperonyl butoxide) had no effect on the cytotoxicity and N-acetylcysteine was also without protective effect. In addition, deuterated BHT was equitoxic with BHT. Only low temperature incubation (4 degrees), which has previously been shown to inhibit the insertion of these compounds into biomembranes, was effective in inhibiting the cytotoxic effects. Using isolated rat liver mitochondria we observed that both BHA and BHT inhibited respiratory control primarily by stimulating state 4 respiration and thus acting as membrane uncouplers. BHA and BHT also effectively dissipated membrane potential across the mitochondrial membrane and caused the release of calcium and mitochondrial swelling. These mitochondrial effects were reflected by a rapid decrease in ATP levels in intact hepatocytes which preceded cell death. These results suggest that the observed cytotoxicity of BHA and BHT to hepatocytes is related to their effects on biomembranes and mitochondrial bioenergetics.
During screening of essential oils for their antifungal activities against Aspergillus flavus, the essential oil of Cymbopogon citratus was found to exhibit fungitoxicity. The MIC of the oil was found to be 1,000 ppm, at which it showed its fungistatic nature, wide fungitoxic spectrum, nonphytotoxic nature, and superiority over synthetic fungicides, i.e., Agrosan G. N., Thiride, Ceresan, Dithane M-45, Agrozim, Bavistin, Emison, Thiovit, wettable sulfur, and copper oxychloride. The fungitoxic potency of the oil remained unaltered for 7 months of storage and upon introduction of high doses of inoculum of the test fungus. It was thermostable in nature with treatment at 5 to 100 degrees C. These findings thus indicate the possibility of exploitation of the essential oil of C. citratus as an effective inhibitor of storage fungi.
Fifty-one essential oils extracted from plants of known origin were tested for their antimicrobial activity against three bacteria, Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli and four yeasts, Torulopsis utilis, Schizosaccharomyces pombe, Candida albicans and Saccharomyces cerevisiae using the drop diffusion method. All showed antimicrobial activity against at least one of the micro-organisms. Following this preliminary screening, 13 essential oils showing antimicrobial activity against at least five of the micro-organisms were tested in the range 50 micrograms ml-1 to 500 micrograms ml-1 using broth micro dilution techniques with dimethylsulphoxide (DMSO) as a dispersing solvent. The concentration of most of the oils required for total inhibition of growth was > 500 micrograms ml-1. Further studies on the antimicrobial action of cinnamon oil in the range 10-150 micrograms ml-1 showed that 50-fold higher activity was found when no dispersing solvent was used.
Measuring the minimum inhibitory concentration (MIC) of a substance by current methods is straightforward, whereas obtaining useful comparative information from the tests can be more difficult. A simple technique and a method of data analysis are reported which give the experimentalist more useful information from susceptibility testing. This method makes use of a 100-well microtitre plate and the analysis uses all the growth information, obtained by turbidometry, from each and every well of the microtitre plate. A modified Gompertz function is used to fit the data, from which a more exact value can be obtained for the MIC. The technique also showed that at certain concentrations of inhibitor, there was no effect on growth relative to a control well (zero inhibitor). Above a threshold value, which has been termed the non-inhibitory concentration or NIC, growth becomes limiting until it reaches the MIC, where no growth relative to the control is observed.
Thirty-four kinds of citrus essential oils and their components were investigated for radical-scavenging activities by the HPLC method using 1,1-diphenyl-2-picrylhydrazyl (DPPH). To examine the oils' relative radical-scavenging activities compared with that of a standard antioxidant, Trolox was employed. All of the essential oils were found to have scavenging effects on DPPH in the range of 17. 7-64.0%. The radical-scavenging activities of 31 kinds of citrus essential oils were comparable with or stronger than that of Trolox (p < 0.05). The oils of Ichang lemon (64.0%, 172.2 mg of Trolox equiv/mL), Tahiti lime (63.2%, 170.2 mg of Trolox equiv/mL), and Eureka lemon (61.8%, 166.2 mg of Trolox equiv/mL) were stronger radical scavengers than other citrus oils. Citrus volatile components such as geraniol (87.7%, 235.9 mg of Trolox equiv/mL), terpinolene (87.4%, 235.2 mg of Trolox equiv/mL), and gamma-terpinene (84.7%, 227.9 mg of Trolox equiv/mL) showed marked scavenging activities on DPPH (p < 0.05).
The composition and the antimicrobial activity of the bark oil of Croton stellulifer, an endemic and rare species of these islands (S. Tomé and Príncipe) are reported. Analysis was carried out by GC, GC/MS and 13C-NMR. The major constituents were alpha-phellandrene (15.4-18.6%), p-cymene (14.4-17.7%), linalool (12.0-12.6%) and alpha-pinene (8.1-9.1%). Kessane, a sesquiterpenoid oxide, not yet reported in the genus Croton, was identified by NMR. The essential oil of C. stellulifer was active against both bacterial and fungal strains, except Aspergillus niger.
The use of and search for drugs and dietary supplements derived from plants have accelerated in recent years. Ethnopharmacologists, botanists, microbiologists, and natural-products chemists are combing the Earth for phytochemicals and "leads" which could be developed for treatment of infectious diseases. While 25 to 50% of current pharmaceuticals are derived from plants, none are used as antimicrobials. Traditional healers have long used plants to prevent or cure infectious conditions; Western medicine is trying to duplicate their successes. Plants are rich in a wide variety of secondary metabolites, such as tannins, terpenoids, alkaloids, and flavonoids, which have been found in vitro to have antimicrobial properties. This review attempts to summarize the current status of botanical screening efforts, as well as in vivo studies of their effectiveness and toxicity. The structure and antimicrobial properties of phytochemicals are also addressed. Since many of these compounds are currently available as unregulated botanical preparations and their use by the public is increasing rapidly, clinicians need to consider the consequences of patients self-medicating with these preparations.
In vitro studies have demonstrated antibacterial activity of essential oils (EOs) against Listeria monocytogenes, Salmonella typhimurium, Escherichia coli O157:H7, Shigella dysenteria, Bacillus cereus and Staphylococcus aureus at levels between 0.2 and 10 microl ml(-1). Gram-negative organisms are slightly less susceptible than gram-positive bacteria. A number of EO components has been identified as effective antibacterials, e.g. carvacrol, thymol, eugenol, perillaldehyde, cinnamaldehyde and cinnamic acid, having minimum inhibitory concentrations (MICs) of 0.05-5 microl ml(-1) in vitro. A higher concentration is needed to achieve the same effect in foods. Studies with fresh meat, meat products, fish, milk, dairy products, vegetables, fruit and cooked rice have shown that the concentration needed to achieve a significant antibacterial effect is around 0.5-20 microl g(-1) in foods and about 0.1-10 microl ml(-1) in solutions for washing fruit and vegetables. EOs comprise a large number of components and it is likely that their mode of action involves several targets in the bacterial cell. The hydrophobicity of EOs enables them to partition in the lipids of the cell membrane and mitochondria, rendering them permeable and leading to leakage of cell contents. Physical conditions that improve the action of EOs are low pH, low temperature and low oxygen levels. Synergism has been observed between carvacrol and its precursor p-cymene and between cinnamaldehyde and eugenol. Synergy between EO components and mild preservation methods has also been observed. Some EO components are legally registered flavourings in the EU and the USA. Undesirable organoleptic effects can be limited by careful selection of EOs according to the type of food.
The suitability of citrus peels, generated as a by-product of the juice industry, as a source of antioxidants was investigated. Citrus peel powder was prepared by lyophilizing 70% ethanol extract from citrus peels. Extraction was carried out at room temperature (20 degrees C) for 72 h. The extract was subjected to gamma-irradiation treatment (20 kGy). The aqueous solutions of citrus peel powder were examined for color characteristics and antioxidant potential in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, beta-carotene bleaching and nitrite scavenging activities. There were significant changes in Hunter color values due to irradiation. The a*- and b*-values decreased due to radiation treatment. DPPH radical scavenging, beta-carotene bleaching and nitrite scavenging activities were not affected by irradiation treatment. Nitrite scavenging activity was the highest in the extract at pH 1.2 followed by pH 4.2 and 6.0. These functional properties of the aqueous solution were found to be stable in heat treatment. It could significantly improve oxidative stability of lipids in fish meat system. Based on these results there may be opportunities to use citrus peel powder as a functional component in the food processing industry with gamma irradiation treatment improving its color characteristics without adversely influencing the functional properties.
The antimicrobial and antiplasmid activities of essential oils (orange oil, eucalyptus oil, fennel oil, geranium oil, juniper oil, peppermint oil, rosemary oil, purified turpentine oil, thyme oil, Australian tea tree oil) and of menthol, the main component of peppermint oil, were investigated. The antimicrobial activities were determined on the Gram (+) Staphylococcus epidermidis and the Gram (-) Escherichia coli F'lac K12 LE140, and on two yeast Saccharomyces cerevisiae 0425 delta/1 and 0425 52C strains. The antiplasmid activities were investigated on E. coli F'lac bacterial strain. Each of the oils exhibited antimicrobial activity and three of them antiplasmid action. The interaction of peppermint oil and menthol with the antibiotics was studied on the same bacterial strain with the checkerboard method. Peppermint oil and menthol displayed additive synergy with oxytetracycline. A new mechanism of plasmid curing was established for one of the oil components.
Essential oils from different plant parts are known for their antimicrobial activity but the antifungal effects of essential oil from Citrus sinensis (L.) Osbeck epicarp on growth and morphogenesis of Aspergillus niger has not been observed so far. The mycelial growth was inhibited at 2.5 and 3.0 microg/ml of oil in Potato Dextrose Broth and Agar medium, respectively. These concentrations were fungicidal under the test conditions. The fungitoxicity of oil did not change even at exposure to 100 degrees C and autoclaving. The main changes observed under light and scanning electron microscopy after oil treatment were loss of cytoplasm in fungal hyphae, and budding of hyphal tip. The hyphal wall and its diameter became markedly thinner, distorted and resulted in cell wall disruption. The flattened and empty hyphal tips bifurcated into bud like structures. GC-MS studies of the oil revealed the presence of 10 chemical constituents. Limonene has been found to be major component (84.2%).
The present study showed for the first time the in vitro properties (antioxidant, hypoglycaemic and anticholinesterase) of Citrus medica L. cv. Diamante which belongs to the Rutaceae family. The n-hexane extract of Diamante citron peel is characterized by the presence of monoterpenes and sesquiterpenes. The most abundant constituents were two monoterpenes: limonene and gamma-terpinene. The extract showed significant antioxidant activity that was carried out using different assays (DPPH test, beta-carotene bleaching test and bovine brain peroxidation assay). Oxidative damage, caused by the action of free radicals, may initiate and promote the progression of a number of chronic diseases, including diabetes and Alzheimer's disease. Diamante citron peel extract showed hypoglycaemic activity and an anticholinesterase effect.
Thirteen essential oils were examined for their antioxidant activity using three different assay systems. Jasmine, parsley seed, rose, and ylang-ylang oils inhibited hexanal oxidation by over 95% after 40 days at a level of 500 microg/mL in the aldehyde/carboxylic acid assay. Scavenging abilities of the oils for the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical ranged from 39% for angelica seed oil to 90% for jasmine oil at a level of 200 microg/mL. The greatest inhibitory activity toward malonaldehyde (MA) formation from squalene upon UV-irradiation was obtained from parsley seed oil (inhibitory effect, 67%), followed by rose oil (46%), and celery seed oil (23%) at the level of 500 microg/mL. The main compounds of oils showing high antioxidant activity were limonene (composition, 74.6%) in celery seed, benzyl acetate (22.9%) in jasmine, alpha-pinene (33.7%) in juniper berry, myristicin (44%) in parsley seed, patchouli alcohol (28.8%) in patchouli, citronellol (34.2%) in rose, and germacrene (19.1%) in ylang-ylang.
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