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Antiviral Activity of the Essential Oil of Melaleuca alternifolia (Maiden amp; Betche) Cheel (Tea Tree) Against Tobacco Mosaic Virus
Abstract
Essential oil of Melaleuca alternifolia was tested for antiviral activity against Tobacco Mosaic Virus. When applied to plants of Nicotiana glutinosa as a pre-inoculation spray at 100, 250 and 500 ppm, the oil was effective in significantly decreasing lesion numbers for at least 10 days post inoculation.
... Various plant products such as essential oils, flavonoids, polyphenols and organic, alcoholic and aqueous extracts from plants and natural compounds from other organisms such as fungal metabolites, have been used against a number of plant diseases caused by viruses, phytopathogenic bacteria, fungi, plant parasitic nematodes and parasitic and non-parasitic weeds [15][16][17][18][19] with the aim of finding natural-based products useful for plant protection against pathogens. Some of our previous studies and studies by other authors describe the activity of plant volatiles as natural antiphytoviral compounds [19][20][21][22][23][24][25][26][27]. Since this activity of Plantaginaceae family volatiles has not been tested so far, we investigated the antiphytoviral activity of both essential oil and hydrosol of V. officinalis and V. saturejoides, with the aim of increasing the knowledge about the antiphytoviral activity of essential oils and especially hydrosols, which have been very little studied in this regard. ...
... Until the seventh day after inoculation, the inhibition of local lesions was still pronounced in all treated groups, with 79.09% and 68.38% on the leaves of plants treated with V. officinalis H and V. saturejoides H, respectively, and 62.70% on the leaves of plants treated with V. officinalis EO. We compared these results with the antiphytoviral activity of plant volatiles reported in some of our previous studies and studies by other authors [19][20][21][22][23][24][25][26][27]. Thus, essential oils isolated from the aromatic species Satureja montana ssp. ...
... veronense, Eryngium alpinum and E. amethystinum showed promising antiviral activity rates of 88%, 77.8% and 80.5%, respectively [22,25]. In addition, among the essential oils extracted from 29 indigenous Chinese aromatic plants, the oils of ginger, lemon, tea tree, tangerine peel, artemisia, and lemongrass caused more than 50% inhibition of TMV at the concentrations tested [26,27]. In addition to plant extracts, inhibitors of plant viruses derived from metabolites of microbes are also considered as potential alternatives to chemical pesticides [45]. ...
Extracts from plants of the genus Veronica have been and continue to be used in traditional medicine to treat various diseases throughout the world. Although often considered a weed, many scientific reports demonstrate that these plants are a source of valuable biologically active compounds and their potential for horticulture should be investigated and considered. In this study, free volatile compounds of essential oils (EO) and hydrosols were extracted from two species: Veronica officinalis, which is most commonly used in traditional medicine, and Veronica saturejoides, an endemic plant that could be obtained by cultivation in horticulture. Volatiles were analyzed by gas chromatography coupled with mass spectrometry (GC, GC-MS). The most abundant compounds identified in the EOs were hexadecanoic acid in V. officinalis EO and caryophyllene oxide in V. saturejoides EO. The hydrosols were characterized by a high abundance of caryophyllene oxide in V. saturejoides hydrosol and of p-vinyl guaiacol for V. officinalis hydrosol. The sites where the volatile compounds are synthesized and stored were analyzed using SEM (Scanning Electron Microscopy); glandular and non-glandular trichomes were detected on stems, leaves and the calyx. Further, to investigate the activity of the free volatile compounds against pathogens, isolated volatile compounds were tested on the antiphytoviral activity against tobacco mosaic virus (TMV) infection. The hydrosols of both investigated species and EO of V. officinalis showed significant antiphytoviral activity. To further investigate the biological potential of these extracts they were also tested for their antiproliferative and antioxidant activities. The results indicate that these compounds are a valuable source of potential anticancerogenic agents that should be investigated in future studies. The presented results are the first report of hydrosol and EO activity against TMV infection, suggesting that these extracts from Veronica species may be useful as natural-based antiphytoviral agents.
... angustifolium, which grows Natural antiphytoviral preparations are a new area of research in the field of plant protection against viruses. We hypothesized that the essential oil of Hypericum species may have antiphytoviral activity, which is related to findings that essential oils of aromatic plant species, especially sesquiterpene-rich oils, inhibit viral infection on host plants [23][24][25][26][27][28][29]. Moreover, high solar radiation in the eumediterranean climate and the drought are the stressful conditions that H. perforatum ssp. ...
... In addition, there is a wealth of information on the role of essential oils in plant-plant, plant-animal, or plant-insect interactions [70]. We have previously reported that essential oils from different plant species can trigger a response to viral infections in plants [23][24][25][26][27][28][29], but the same has never been shown for hydrosols. We hypothesise that hydrosols, as water solutions of bioactive components during the distillation process of essential oil, are a readily available and safe natural source of bioactive components that can serve as a mixture of active ingredients that can protect plants against viral infections. ...
... By the fifth day after inoculation, local lesions also developed on the inoculated leaves of the essential oil treated plants, but the percentage of inhibition compared to the control was still high (61.10%); on the seventh day post inoculation, the percentage of inhibition of local lesions on the leaves of the plants treated with essential oil was 50.33% ( Figure 2). Comparing previous results dealing with the antiphytoviral activity of essential oils of different plant species [23][24][25][26][27][28][29] with the current results (Figure 2), we can conclude that pretreatment of local host plants with the essential oil of H. perforatum ssp. veronense shows a promising activity level, especially in the early stage of infection. ...
The chemical profile, antiproliferative, antioxidant and antiphytoviral activities of the species Hypericum perforatum ssp. veronense (Schrank) H. Lindb. (Clusiaceae) were investigated. Free volatiles were isolated and the chemical composition was determined in the lipophilic fraction (essential oil) and for the first time in the water fraction (hydrosol). The aim is to provide phytochemical data for H. perforatum ssp. veronense useful for distinguishing ssp. veronense from ssp. angustifolium, as there are taxonomic disagreements between them and the composition of the secretory products may be helpful in this respect. In the essential oil, the most abundant compounds identified were α-pinene and n-nonane, while in the hydrosol, myrtenol, carvacrol and α-pinene were the most abundant. Overall, the class of monoterpenes and oxygenated monoterpenes dominated in the EO and hydrosol samples. The essential oil showed high antioxidant activity, in contrast to the antiproliferative activity, where the hydrosol showed exceptional activity against three cancer cell lines: Hela (cervical cancer cell line), HCT116 (human colon cancer cell line) and U2OS (human osteosarcoma cell line). Both the essential oil and hydrosol showed antiphytoviral activity against tobacco mosaic virus infection on the local host plants. This is the first report dealing with biological activities of hydrosol of H. perforatum ssp. veronense, and the obtained results suggest that this traditional medicinal plant is a valuable source of volatiles with promising antiproliferative, antioxidant and antiphytoviral activities.
... The multiple roles of the essential oils and their main components make them natural substances of great importance in several fields such as physiological function of growth, ecological function, development (Wink 2003), resistance against diseases and insects . They also possess antimicrobial, antiviral, antimycotic, antioxigenic, antiparasitic and insecticidal properties (Bishop 1995;Lamiri et al. 2001;Juglal et al. 2002;Moon et al. 2006;Michaelakis et al. 2007). ...
... Although various substances of natural and synthetic origin have been assessed for their antiphytoviral activity, only limited number of scientific publications have revealed the antiphytoviral activity of essential oils. In this sense, essential oil of Melaleuca alternifolia (Maiden & Betche) Cheel reduced lesion number in TMV-infected plants (Bishop 1995), while Plectranthus tenuiflorus essential oil inhibited infection with Tobacco Necrosis Virus (TNV) (Othman and Shoman 2004). Essential oil of Satureja montana L. ssp. ...
... Inhibition of TMV infection could be explained with antiviral activity of other oil components or their synergistic effect. This is supported by the fact that different extracts of many plants were tested for antiviral activity and it was explained due to their content of diterpenoids and essential oils (Romero et al. 1989;Bishop 1995). ...
Unefficiency of chemical treatments and recent plant protection that is focused on natural products, have pointed the importance of finding natural substances that can help in a control of plant virus diseases. Current knowledge about the antiviral effects of essential oils, although limited, indicates the potential of these secondary metabolites to control or at least reduce the spread of viral infection. Essential oils isolated form Teucrium species showed antiviral activity in tobacco mosaic virus (TMV) and cucumber mosaic virus (CMV) infected plants. The aim of this chapter is to present findings dealing with antiphytoviral potential of selected species of genus Teucrium and to improve the knowledge about possible application of essential oils for the prevention of diseases caused by plant viruses. Essential oil of Teucrium arduini applied on the leaves of local host plants, significantly reduced the number of lesions on both TMV and CMV infected plants. Aside from Teucrium arduini, four additional Teucrium species (T. montanum, T. polium, T. chamaedrys and T. flavum) are also source of bioactive molecules with antiphytoviral activity against CMV infection. This promising biological activity of Teucrium species opens new area of research that could help in a control of virus diseases of plants.
... We found that most published data refer to the effects of EOs on animal viruses rather than plant viruses [23,24]. Valuable effects of EOs have been documented, such as antiproliferative, antimicrobial, antioxidant, insecticidal, and other effects [25][26][27], and new findings, such as antiphytoviral activity, have been recently documented [21,28,29]. ...
... Authors described that the EOs of all species showed weaker protective effect than inactivating effect. EOs extracted from Melaleuca alternifolia and Plectranthus tenuiflorus species and applied as spray solution to Nicotiana glutinosa plants before inoculation also showed antiviral activity against TMV [29,43]. Several studies have found that plants are able to initiate a defense response to viral infection using a wide range of regulatory mechanisms and the phenylpropanoid pathway plays a role in such defense strategies [44,45]. ...
Agricultural production without pollution is possible using bioactive plant compounds, which include essential oils as important substances of plant origin. The aim of this study was to evaluate the antiphytoviral and antibacterial potentials of lipid (essential oil, EO) and water (hydrosol, HY) extracts from five Veronica species (Plantaginaceae) obtained by Clevenger hydrodistillation (HD) and microwave-assisted extraction (MAE), with analysis by gas chromatography coupled with mass spectrometry. The antiphytoviral activities of both extracts were tested on local host plants infected with tobacco mosaic virus (TMV). The antibacterial potential was tested against ten strains of opportunistic pathogens using the broth microdilution test. Species V. chamaedrys EO-MAE extract, V. arvensis EO from both extractions and V. montana, V. serpyllifolia, and V. persica EO-HD extracts were more effective in inhibiting TMV infection. Furthermore, HY- HD extracts of V. arvensis, V. chamaedrys and V. persica showed significant antiphytoviral activity. HY fractions had no effect on bacterial growth, regardless of the Veronica species tested, likely due to the fact that the maximum concentrations of the HY fractions tested in this study were low (1.83 and 2.91 mg/mL). EOs showed significant antibacterial activity independent of the extraction method. Notably, V. chamaedrys EO-MAE fraction, showed significantly better activity against Listeria monocytogenes and Enterococcus faecalis. Also, the EO-HD fraction of V. arvensis showed slightly better antibacterial activity. By combining extracts and using different extraction methods, valuable bioproducts can be obtained from the investigated Veronica species for safe use in agricultural production and food conservation.
... Trials involving tobacco mosaic virus (TMV) were based on the count of local lesions. Bishop (1995) and Lu (2013) both worked on a Nicotiana glutinosa experimental host, reporting an inhibition of local symptoms development upon treatments with EOs from Melaleuca alternifolia, ginger, lemon, tea tree, tangerine peel, artemisia, and lemongrass. Dunkić et al. (2010) used Satureja montana EO as a treatment for Chenopodium quinoa and Chenopodium amaranticolor hosts infected with TMV and cucumber mosaic virus (CMV). ...
... The use of natural products from plant sources for the treatment of plant viruses is a topic of growing interest and application. Previous studies demonstrated that EOs and HSs are effective in reducing the number of local lesions due to virus infection in experimental hosts for a number of plant/virus pathosystems (Bishop, 1995;Dunkić et al., 2010;Bezić et al., 2011;Lu, 2013;Vuko et al., 2019Vuko et al., , 2021aNazlić et al., 2021). Furthermore, gene expression studies were performed in order to identify genes and metabolic pathways involved in this action (Vuko et al., 2019). ...
In the last decades, the interest in biological activity of natural compounds has been growing. In plant protection, essential oils have been reported to exhibit antiviral, antimycotic, and antiparasitic activities, and are regarded as promising for the formulation of safe antimicrobial agents. Attention has also been focused on hydrosols, the by-products of hydro-distillation of essential oils. Their production is easy, fast, and cheap, and they seem to arise less concern for human health than essential oils. Plant viruses represent a major concern for agricultural crops since no treatment compound is available for virus control. This work was aimed at evaluating the antiphytoviral effectiveness of treatments with three essential oils and corresponding hydrosols extracted from Origanum vulgare, Thymus vulgaris, and Rosmarinus officinalis on Cucurbita pepo plants infected by zucchini yellow mosaic virus or tomato leaf curl New Delhi virus. Treatments were applied either concurrently or after virus inoculation to ascertain an inhibition or curative activity, respectively. Symptoms were observed and samplings were performed weekly. Virus titer and expression levels of phenylalanine ammonia lyase gene (PAL) were measured on treated and untreated infected plants by real-time PCR. PAL gene plays an important role in plant defense response as it is involved in tolerance/resistance to phytopathogens. Results indicated that treatments were effective against tomato leaf curl New Delhi virus whether applied simultaneously with the inoculation or after. A major inhibition was observed with O. vulgare essential oil and hydrosol, resulting in 10–4-fold decrease of virus titer 3 weeks after treatment. Curative activity gave maximum results with all three essential oils and T. vulgaris and R. officinalis hydrosols, recording from 10–2-fold decrease to virus not detected 4 weeks after treatment. An induction of PAL gene expression was recorded at 12 d.p.i. and then was restored to the levels of untreated control. This allows to hypothesize an early plant defense response to virus infection, possibly boosted by treatments. Plant extracts’ composition was characterized by gas chromatography-mass spectrometry. Phenols were largely main components of O. vulgare and T. vulgaris extracts (carvacrol and thymol, respectively), while extracts from R. officinalis were based on monoterpene hydrocarbons (essential oil) and oxygenated monoterpenes (hydrosol).
... The antiviral properties of TTO were first tested on tobacco mosaic virus [100]. Later in a field trial, Nicotiana glutinosa plants were treated with different concentrations of tea tree oil, corresponding to 100, 250, and 500 ppm. ...
... Tobacco mosaic virus was controlled by a spray of TTO at 10, 50, 100 and 500 ppm before viral attack. Later, fewer lesions were observed on Nicotiana glutinosa plants [100]. Melaleuca alternifolia showed effective antifungal control against seed-borne fungi viz. ...
Melaleuca is one of the genera of the Myrtaceae family enriched in tea tree oil (TTO). Tea tree oils of Melaleuca bracteata and Melaleuca alternifolia are of prime importance and have antioxidant and antimicrobial properties. Terpinen-4-ol and 1-8 cineole are major constituents of M. alternifolia oil. The percentages of the compounds in the oils can slightly vary according to the region of plant harvest, the distillation technique, or the part of the plant used for oil extraction. TTO has a bacteri-cidal effect against various bacterial species such as Bacillus cereus, B. subtilis, E. coli, Pseudomonas putida, and S. aureus. Several reports proved that this essential oil is also effective against fungal strains of Fusarium, Aspergillus, and Candida species. It also has antioxidant properties such as radical scavenging activity and reducing power. The antioxidant properties of TTO at a concentration of 30 mM were observed to be greater than those of butylated hydroxytoluene (BHT), commonly used as a synthetic antioxidant. TTO is also an effective organic fungicide, herbicide, and insecticide for use in the agriculture sector. Postharvest application of the oil has been found efficient on sweet basil, citrus, and strawberry. It is concluded that tea tree oil has the potential to be used in the food, agriculture, and pharmaceutical industries as a natural antimicrobial and preservative agent. This review provides comprehensive information regarding the antioxidant and antimicrobial activities of tea tree oil and its potential applications in agriculture.
... Essential oils and other plant extracts have been used against a range of plant diseases caused by phytopathogenic bacteria, fungi, plant-parasitic nematodes, and parasitic and non-parasitic weeds [6]. Previous studies describe the activity of plant volatiles as natural antiphytoviral compounds [21][22][23][24][25][26][27][28][29]. The antiphytoviral activity of D. viscosa extracts has not been tested so far. ...
... TMV is a model virus in plant virology and a very important pathogen of agricultural crops causing significant yield losses. In addition to the antiphytoviral activity of essential oils of aromatic plants [21][22][23][24][25][26][27][28][29], the activity of hydrosol of Hypericum perforatum ssp. veronense was recently demonstrated [26], showing that hydrosols are a readily available natural source of bioactive compounds that can be used for plant protection against viral pathogens. ...
With the increasing interest in obtaining biologically active compounds from natural sources, Dittrichia viscosa (L.) Greuter (Asteraceae) came into our focus as a readily available and aromatic wild shrub widely distributed in the Mediterranean region. This work provides a phytochemical profile of D. viscosa in terms of parallel chemical composition in the lipophilic fraction (essential oil) and the water fraction (hydrosol). GC-MS analysis identified 1,8-cineole, caryophyllene oxide, α-terpenyl acetate, and α-muurolol as the major components of the essential oil, while in the hydrosol p-menth-1-en-9-ol, 1,8-cineole, linalool, cis-sabinene hydrate, and α-muurolol were the major volatile components. 3,4-Dihydroxybenzoic acid was found to be the predominant compound in the hydrosol composition by HPLC analysis. The antimicrobial potential of both extracts was evaluated against thirteen opportunistic pathogens associated with common skin and wound infections and emerging food spoilage microorganisms. The antimicrobial activity of the essential oil suggests that the volatiles of D. viscosa could be used as novel antimicrobial agents. The antiproliferative results of D. viscosa volatiles are also new findings, which showed promising activity against three cancer cell lines: HeLa (cervical cancer cell line), HCT116 (human colon cancer cell line), and U2OS (human osteosarcoma cell line). The decrease in GSH level observed in hydrosol-treated HeLa cells suggests oxidative stress as a possible mechanism of the antiproliferative effect of hydrosol on tumor cells. The presented results are also the first report of significant antiphytoviral activity of hydrosol against tobacco mosaic virus (TMV) infection. Based on the results, D. viscosa might have the potential to be used in crop protection, as a natural disinfectant and natural anticancer agent.
... The secondary metabolites, which are incredibly diverse chemically and taxonomically with unknown functions, are abundant in therapeutic plants. Many phytochemicals have diverse applications in human medicine, veterinary medicine, agriculture, and scientific research, in addition to having inhibitory effects on many kinds of bacteria in vitro [4]. The herbaceous perennial Ocimum sanctum, also referred to as holy basil (Tulsi), is a member of the Lamiaceae family and is regarded as one of the most significant sources of medicine and pharmaceuticals. ...
The current work describes the environmentally friendly green method for fabricating CaO nanoparticles (NPs) using 'tulasi’ (Ocimum sanctum) plant leaf extract as a unique fuel. The obtained CaO NPs have been characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), TEM/HRTEM (Transmission Electron Microscopy), UV–Vis spectroscope, Selected Area Electron Diffraction (SAED), and Energy Dispersive Spectroscopy (EDAX) techniques. The PXRD studies revealed the average crystallite size of 38 nm for CaO NPs and this value is in compliance with the TEM results. DRS studies revealed the energy gap of CaO as 3.20 eV. The plant-mediated CaO NPs showed good photocatalytic activities for the photodegradation of Fast Orange (FO) and Fast Blue (FB) dyes under the UV light irradiation, demonstrating high efficiency within 120 min of light irradiation. Under UV light, the CaO exhibited impressive photodegradation performance of 95.5% and 83.5% in 120 min against the FO and FB dyes. The electrochemical characteristics of CaO were studied using a carbon paste electrode in a 0.1 M NaOH solution. The green CaO NPs exhibited superior sensitivity in cyclic voltammetry tests at different scan rates when lead and lithium were utilized as analytes. The phase angle of CaO was determined to be − 47°, which is close to the behavior of an ideal capacitor (− 90°). Consequently, CaO holds potential for applications in electrochemical sensor technology.
... The tobacco mosaic virus was successfully mitigated by sprays of TTO at concentrations of 100, 250, and 500 ppm. Subsequently, a reduction in lesion development was observed at least 10 days post-application [42]. ...
The use of chemical pesticides in agriculture contributes to soil, water and air pollution, biodiversity loss, and injury to non-target species. The European Commission has already established a Harmonized Risk Indicator to quantify the progress in reducing the risks linked to pesticides. Therefore, there is an increasing need to promote biopesticides, or so-called low-risk pesticides (LRP). Tea tree oil (TTO) is known for its antiseptic, antimicrobial, antiviral, antifungal, and anti-inflammatory properties. TTO has been extensively studied in pest management as well as in the pharmaceutical and cosmetic industry; there are already products based on its active substances on the market. This review focuses on the overall evaluation of TTO in terms of effectiveness and safety as a biopesticide for the first time. The collected data can be an added value for further evaluation of TTO in terms of the authorization extension as a fungicide in 2026.
... The tobacco mosaic virus was successfully mitigated by a spray of TTO at concentration of 100, 250 and 500 ppm. Subsequently, a reduction in lesion development was observed at least 10 day post application [42]. ...
The use of chemical pesticides in agriculture contributes to soil, water and air pollution,
biodiversity loss and can harm non-target species. The European Commission has already
established a Harmonized Risk Indicator to quantify the progress in reducing the risks linked to
pesticides. Therefore, there is an increasing need to promote biopesticides or so-called low-risk
pesticides (LRP). Extract from Melaleuca alternifolia—tea tree oil (TTO) is known for its antiseptic,
antimicrobial, antiviral, antifungal, and anti-inflammatory properties. Tea tree oil has been
extensively studied in pest management as well as in the pharmaceutical and cosmetic industry and
there are already products based on its active substances on the market. This review focuses on the
overall evaluation of tea tree oil in terms of effectiveness and safety as a biopesticide for the first
time. The collected data can be an added value for further evaluation of tea tree oil in terms of the
authorization extension as a fungicide in 2026.
... Potwierdzono znaczący wpływ olejków eterycznych na organizmy żywe. Wykazano działania: przeciwwirusowe, przeciwbakteryjne, przeciwgrzybicze, owadobójcze, przeciwpasożytnicze, przeciwzapalne, przeciwmutagenne, przeciwnowotworowe i przeciwutleniające (2,12,43,55). ...
Essential oils are natural plant products with rich chemical composition and various properties. They are obtained by extraction from plant parts such as flowers, buds, stems, twigs, seeds, fruits, roots, bark and leaves. They contain over sixty organic compounds with low molecular weight, including: phenolic and terpene compounds, aliphatic alcohols, aldehydes, ketones, acids and isoflavonoids. The composition, concentration and proportions of chemical components in essential oils determine their properties. Essential oils have a significant impact on living organisms, including antiviral, antibacterial, antifungal, antiparasitic, anti-inflammatory and antioxidant properties. Depending on the concentration used, essential oils positively or negatively affect the sensory properties of meat products. It is important to obtain a sensorially acceptable concentration of essential oil in the product, which will also ensure effective antimicrobial activity. By applying several essential oils at the same time or using other preservatives or preservation and packaging methods with them, a synergistic effect can be achieved, thanks to which the concentration of the essential oil in the product can be reduced. Factors that can influence the antimicrobial effect of essential oils in food products include: food structure, composition, pH, storage conditions and the type of saprophytic microbiota in the product. Essential oils can have a positive impact on the microbiological quality of food and can be used in the food industry as a factor inhibiting the growth of saprophytic microorganisms that affect the durability of food and pathogenic bacteria that cause food poisoning.
... Apart from terpinen-4-ol, a characteristic compound of this species, geranial and neral were present at significant levels. In addition,terpinene, one of the constituents of the most common chemotype (terpinene-4-ol/γ-terpinene/α-terpinene) of this species [19][20][21][22], was among the dominant components. However, we note the absence of terpinene. ...
... A research group reported the investigation results of essential oils as plant protectants against potato virus X, tobacco mosaic virus, and tobacco ring spot virus in 1989 [64]. In later dates, reports on protective abilities of various essential oils against plant viruses were published [65]. Antiviral potential of essential oil against herpes simplex virus 1 (HSV-1) has been reported since 1997 by a study using Salvia fructicosa essential oil [66]. ...
Background
Essential oils are thought as potential therapies in managing coronavirus disease 2019 (COVID-19). Many researchers have put their efforts to tackle the pandemic by exploring antiviral candidates which consequently changes the research landscape. Herein, we aimed to assess the effect of COVID-19 pandemic toward the landscape of essential oil research.
Methods
This study employed bibliometric analysis based on the metadata of published literature indexed in the Scopus database. The search was performed on December 15, 2022 with using keyword ‘essential oil’ and its synonyms. We grouped the data based on publication year; pre-COVID-19 (2014–2019) and during COVID-19 (2020–2024, some studies have been published earlier). Further, we separated the COVID-19-focused research from COVID-19 (2020–2024) by introducing a new keyword ‘COVID-19’ during the search. All metadata were processed using VoSviewer and Biblioshiny for network visualization analysis. Selections of frequently occurring keywords, clusters of keyword co-occurrence, and the list of most impactful papers were performed by two independent reviewers.
Results
Metadata from a total of 35,262 publications were included for bibliometric analysis, comprised of three groups of datasets namely pre-COVID-19 (n = 18,670), COVID-19 (n = 16,592), and COVID-19-focused (n = 281). Five research topics clusters were found from pre-COVID-19 dataset, eight – from COVID-19 dataset, and nine – from COVID-19-focused dataset. COVID-19 cluster containing the keyword ‘antiviral’ emerged in the COVID-19 dataset, whereas none of the previous research topic clusters contained the keyword ‘antiviral’. Antiviral, angiotensin-converting enzyme 2 (ACE2) inhibitory, and anti-inflammation activities were among the top occurring keywords among studies covering both essential oil and COVID-19. Studies on essential oil use for COVID-19 were most reported by authors from the United States (documents = 37, citations = 405), Australia (documents = 16, citations = 115) and Italy (documents = 23, citations = 366).
Conclusion
A significant increase was found in publications covering essential oil themes, but only a small portion was occupied by COVID-19 research. The COVID-19 pandemic does not alter the ongoing progress of essential oil research but rather offers a new spotlight on the antiviral potential of essential oils. Hence, the COVID-19 pandemic has provided an opportunity to investigate deeper the antiviral potential of essential oils.
... Although they are defined as oils because they do not mix with water, they are different from fixed oils (Ceylan, 1983). Essential oils have important properties such as antibacterial (Boyle, 1955), antiviral (Bishop, 1995), antioxidant (Sarıkurkcu et al., 2018), insecticidal (Karpouhtsis et al., 1998). Phenolic compounds are secondary metabolites produced by plants. ...
The aim of the study is to determine the essential oil profile and antioxidant activity of endemic Marrubium parviflorum subsp. oligodon. The essential oil contents were analyzed by Gas Chromatography-Mass Spectrometry (GC-MS) using Solid Phase Microextraction (SPME). In addition, total phenolic content and the capacity of antioxidant activity measured by DPPH• and FRAP assays were determined. A total of 23 (64.12%) was determined. Pentadecanolide was found to be the major essential oil and palmitic acid was determined as main fatty acid in Marrubium parviflorum subsp. oligodon. Total phenolic content was found to be 39.9±0.31 mg GAE/g sample. FRAP value was found to be 48.91±0.33 µmol Fe/g sample and DPPH scavenging activity was found to be 0.76±0.03 mg/ml. This is the first report in which the essential oil content of Marrubium parviflorum subsp. oligodon was determined by SPME.
... The composition and percentages of different compounds are summarized in Figure 1 and Tables The components of essential oils showed several important roles of natural substances for health, such as resistance to diseases and against insects (Gershenzon & Dudareva, 2007), physiological function of growth, development and ecological function (Wink, 2003). They also possess antimicrobial, antioxigenic, anti-mycotic, antiviral, anti-parasitic and insecticidal properties (Bishop, 1995 The results indicate that the aerial part of B. crassifolium is a potential source of producing volatile profiles of sesquiterpene hydrocarbons where the main compounds are: β -cubebene with 44.64%, β -Caryophyllene with 8.82%, β -Elemene with 7.04%, δ-Cadinene with 4.70%, γ-Cadinene with 4.11%, and β -Elemene with 3.33% and oxygenated sesquiterpenes where the majority compounds are: cis-sesquisabinene hydrate with 1.44% and aromadendrene oxide with 1.22%. We notice the conspicuous absence of monoterpene hydrocarbons, products that make up the major part of the essential oils of higher plants. ...
Bunium crassifolium Batt. (B. crassifolium) (Apiaceae) is an extremely rare endemic species from the North East of Algeria. In this study, we extracted the volatile organic compounds (VOC) of B. crassifolium Batt. aerial parts using an Agilent G1888 network headspace sampler coupled with an Agilent 7890 GC system. The results revealed the presence of twenty-two (22) compounds, twenty (20) of which were identified as representing 97.48% of the total composition, the major components are: 44.67% of β-Cubebene, 8.82% of β-Caryophyllene, 7.04% of γ-Elemene, 4.70% of δ-Cadinene, 4.11% of γ-Cadinene, 3.77% of Ascaridole and 3.33% of β-Elemene, along with other constituents at a relatively low amount.
... Hence essential oils have attracted strong interest among researchers due to their antimicrobial activities for the need of substituting synthetic antibiotics. Some of the traditional uses of essential oils are supported by scientific investigation including antimicrobial [4,7,8], antibacterial [9], antiviral [10], antimycotic [11], ant-toxigenic [12], antiparasitic [13], and insecticidal [14] properties. Therefore, the trend of using essential oils as natural antimicrobial agents is gradually becoming an attractive approach in the field of drug discovery [15] The genus Cucumis (Cucurbitaceae) comprises of about 52 species [16], indigenous to tropical Africa, also Asia, Australia and some islands in the Pacific. ...
Chemical composition of the essential oils obtained by hydrodistillation from various parts of Cucumis ficifolius, Cucumis dipsaceus and Cucumis prophetarum were determined by gas chromatography-mass spectrometry (GC/MS) analysis. Compounds 3,7,11,15-tetramethyl-1-hexadecanol, neophytadiene, and isophytol from leaves, phytol and octacosane from the stems, hentriacontane from the fruits, and octacosane, abietadiene from roots were identified the major constituents of Cucumis ficifolius. Hydrocarbons including Octacosane, tricosane, tetracosane, hentriacontane and hexacosane were the principal components of various parts of Cucumis. dispaceus. While leaves, stems and roots of Cucumis prophetarum contain mainly hentriacontane, neophytadiene and octacosane, respectively. The oils were evaluated for their antibacterial activity using disc diffusion method against four bacterial pathogens including E. coli, P. aeruginosa, S. aureus and S. pyogenes. All tested essential oils were sensitive against the bacterial strains. The essential oil from the leaves of Cucumis dispaceus exhibited the highest inhibition zone against E. coli (11.87±2.42 mm) while the other displayed modest activity compared with the positive control, ceftriaxone. Therefore, the antibacterial activities displayed by the essential oils along with the literature reported for their constituents suggest the use of these plants as an antibacterial agent. Furthermore, the results presented herein also support the traditional use of these plants against bacteria. KEY WORDS: Cucumis ficifolius, Cucumis dipsaceus, Cucumis prophetarum, Antibacteria Bull. Chem. Soc. Ethiop. 2023, 37(3), 703-715. DOI: https://dx.doi.org/10.4314/bcse.v37i3.13
... Galangin [7] isolated from Helichrysum aureonitens showed antiviral activity against HSV-1 and Cox B1 (Meyer et al., 1997), while quercetin [8] which is widely distributed in the plant kingdom exhibited activity against HIV (Kim et al., 1998;www.herbalextractsplus (Sivropou et al., 1997;Deans and Waterman, 1993 The essential oil of Melaleuca alternifolia was effective in decreasing local lesions of tobacco mosaic virus (TMV) in Nicotiana glutinosa (Bishop, 1995). Extracts of Thuja occidentallis and Psidium guajava inhibited the growth of bean common masaic virus (BCMV) (Prasad et al., 2007) while the growth tomato mosaic virus in tomato (ToMV) was checked by extracts from decomposed tomato plants (Avgelis and Morios, 1989 (Khanna. ...
Sweet potato is an important food crop worldwide since it is drought tolerant and acts as a famine relief crop. However, its production is limited by viral, fungal and bacterial infections.
Lack of rapid and sensitive techniques for detection of infections inhibits their control. Use of synthetic chemicals to manage microbial infections causes is discouraged since they are nonbiodegradable. The aim of this study was to identify viruses infecting sweet potato in western Kenya, develop a multiplex PCR protocol for detection of major viruses of the crop, and evaluate
efficacy of medicinal plants for antimicrobial activity against the crop pathogens. Symptomatic sweet potato vines obtained from farmers’ fields were testes for ten viruses using NCM-ELISA.
The mPCR protocol for detection of SPFMV and SPCSV was optimized through variation of test parameters under standard PCR conditions. Extracts from Warburgia ugandensis,
Elaeodendron schweinfurthianum and Terminalia brownii, which are traditionally used to manage microbial infections, were fractionated using chromatographic methods to obtain pure
compounds. Structures of isolates were determined using spectroscopic and physical methods. Extracts and isolates were tested for antimicrobial activity against Alternaria spp, Aspergillus
niger, Fusarium oxysporum, F. solanum, Rhizopus stolonifer (fungi), Ralstonia solanacearum and Streptomyces ipomoeae (bacteria). Five viruses namely SPFMV, SPCSV, SPMMV, SPCFV
and CMV were detected. Eighty nine percent of samples had viral infection with over 80% showing multiple infections. Occurrence of CMV in Kenya was recorded for the first time. An mPCR protocol was successfully developed that detects SPFMV and SPCSV. Phytochemical studies afforded 26 compounds including 7α-acetylugandensolide that was isolated from W. Ugandensis for the first time. All the methanol, ethyl acetate and n-hexane extracts of the three plants were active against one or more of the test organisms. Methanol extract of W. ugandensis exhibited significantly higher activity (24.50 mm) than positive controls against R. stolonifer. Eighteen out of the twenty six compounds isolated exhibited antimicrobial activity against one or
more of the test pathogens at concentrations ≤200 µg/ml. Polygodial, warbuganal, mukaadial, ugandensidial, ugandensolide, deacetoxyugandensolide and muzigadial, exhibited low MIC
(MIC ≤ 50 µg/ml) against one or more pathogens that was comparable to those exhibited by standard drugs. This study provided a quantitative assessment of viruses infecting sweet potato in western Kenya and a simplified mPCR protocol for routine rapid detection of SPFMV and SPCSV. Scientific proof for the efficacy of extracts of W. ugandensis, E. schweifurthianum and
T. brownii as antimicrobial agents against sweet potato pathogens and perhaps other crop pathogens was also provided.
... Often, two or three ICs are major components (20-70%), whereas others are present in trace amounts [7]. EOs have shown to act against food spoilage, due to their antiviral [8], antitoxigenic [9,10], antiparasitic [11,12], insecticidal [13,14], antibacterial [15][16][17] and also antifungal [5,18,19] characteristics. The antimicrobial activities of EOs are predominantly linked to their main components, whereas minor components are attributed to synergistically supporting the activities [17,[19][20][21][22]. ...
Citation: Nißl, L.; Westhaeuser, F.; Noll, M. Antimycotic Effects of 11 Essential Oil Components and Their Combinations on 13 Food Spoilage Yeasts and Molds. J. Fungi 2021, 7, 872.
Abstract: Food safety is important to reduce food spoilage microorganisms and foodborne pathogens. However, food safety is challenging, as customers' demand for natural preservatives is increasing. Essential oils (EOs) and their components (EOCs) are alternative antibacterial and antimycotic food additives. In this study, the minimal inhibitory concentrations (MIC) of 11 different EOCs against 13 food spoilage molds and yeasts were investigated via the microdilution method. Cinnamaldehyde (CA) revealed the lowest MIC for all tested strains and all EOCs (32.81-328.1 µg ml −1). However, CA is organoleptic and was therefore combined with other EOCs via the checkerboard method. Overall, 27 out of 91 combinations showed a synergistic effect, and both respective EOC concentrations could be reduced by maintaining MIC. Thereby, the combination with citral or citronellal showed promising results. The concentration-dependent effect of CA was studied in further detail on Saccharomyces cerevisiae, with CA causing delayed growth-kinetics and reduced total cell numbers. In addition, flow cytometric measurements combined with live-dead staining indicate the fungicidal effect of CA, due to decreasing total cell numbers and increasing relative amount of propidium iodide-positive cells. In this study, we demonstrated that CA is a potent candidate for the use as a natural preservative against food-relevant mold and yeasts showing fungistatic and fungicidal effects. Therefore, CA and EOC combinations with respective lower EOC concentrations reduce organoleptic reservations, which ease their application in the food industry.
... Sejumlah minyak atsiri juga dilaporkan dapat menghambat infeksi dari virus (Koul et al., 2008;Reichling, 2009). Hasil penelitian menunjukkan bahwa minyak atsiri juga efektif terhadap virus pathogen pada tanaman seperti TMV, CPMV, BCMV, MBMV, SBMV, CaVMV (Bishop, 1995;Reitz et al., 2008) Palmer et al. (1998) Tabel 3. Aktivitas minyak atsiri terhadap bakteri patogen tanaman ...
Pest management in the agricultural process has faced worldwide economic and ecological issues related to chemicals usage. Botanical insecticides have long been considered promising alternatives to control pests because botanicals reputedly pose a minor threat to the environment and human health. Some studies have evaluated several botanical insecticides to control aphids in chrysanthemum. The research was conducted under plastic house conditions at the Indonesian Ornamental Crops Research Institute from January to December 2018. Leaf extract of T. sinensis, T. diversifolia and A. indica at the concentration of 3 and 3.5 g/l, processed oil of C. nardus at the concentration of 2.5 and 5 g/l and synthetic insecticide Imidacloprid 1 g/l were sprayed in the morning or late afternoon. The results showed that aphid attacks severity and percentage of attacked plants were lower when the insecticides were applied in the late afternoon. Slightly softer than synthetic chemicals, the leaf extract of T. sinensis at 3 g/l suppressed the aphid development more effective for about 55.93% than other botanicals treatments. On reproductive properties, the leaf extract of T. sinensis at 3 and 3 g/l and T. diversifolia at 3 g/l induced a higher percentage of open flower for more than 65% than synthetic insecticides, Imidacloprid.
... There are more than 3000 EOs that are available, and their antimicrobial properties across species have been studied and reviewed, with the earliest studies dating back to 1948 [12,13]. They are observed to have antibacterial, antiviral, antimycotic, antitoxigenic, antiparasital, and insecticidal properties [14][15][16][17][18][19]. ...
The Mentha arvensis essential oil, due to its poor aqueous solubility and the lack of a proper formulation, has found very limited clinical use. In this study, Mentha oil nanoemulsion was formulated using ultrasonication of Mentha oil with tween 80 and water, and its role as a potential anticancer and antibacterial agent was evaluated. Surfactant concentration and emulsification time play an important role in optimization of nanoemulsions. A clear and stable nanoemulsion (M3C) with a droplet diameter in the nanometric range was obtained in a sonication time of 20 min. The anticancer activity of the nanoscale-based Mentha oil emulsion was evaluated by various cell culture techniques including MTT, colony formation assay, and Annexin V apoptotic assay. The result of Annexin V-FITC assay, marker of apoptosis, clearly displays the induction of early apoptosis in anaplastic/aggressive thyroid cancer cell line (HTh-7). Also, M3C demonstrated antibacterial activity against Staphylococcus aureus (ATCC 29213). In addition, interaction of M3C with the pathogen caused structural changes in the lipid cell membrane of pathogen, with increased leakage of cytoplasmic contents as assessed through the absorbance value of 260 nm. Agar well diffusion, along with membrane integrity analysis, also validated the antimicrobial activity. The results of this translational research are expected to substantiate the potential for use of Mentha oil in therapeutic studies, as well as in anticancer and antibacterial therapy.
... 1,2 Many essential oils are regarded as safe for human applications, and some have shown broad-spectrum antibiotic, anti-fungal, and anti-viral properties through several mechanisms. [3][4][5] Most notably, thymol, a monoterpene, forms a highly reactive phenolic radical that can attack and disrupt the membrane of bacteria. 6 The biggest problems facing the use of essential oils are their high volatility with no control of their release rate, and their poor water solubility limiting the dosage that can be delivered in biological applications. ...
This work demonstrates the use of canola oil as a biologically compatible solvent for a thiol–ene driven suspension polymerization that effectively creates micron-sized particles. A 1 : 1 thiol to alkene functional group stoichiometry was maintained for all formulations. Thymol was incorporated into these particles during synthesis as a naturally derived, lipophilic drug with known anti-microbial properties and use in agriculture as a pesticide. UV-Vis spectroscopy demonstrated the removal of surfactant and any excess reagents to be 99% effective. Particle size was dependent on stirring speed with faster stirring resulting in smaller particles. The release of thymol from the selected ten formulations was measured with UV-Vis spectroscopy at a wavelength of 275 nm for ten days and was shown to be tailorable by altering the amount of crosslinker and surfactant used during the creation of the particles. A smaller molar ratio of 2-functional thiol monomer compared to 4-functional thiol monomer (0.1 : 0.9) crosslinker and a higher molar ratio of 2-functional alkene monomer compared to mono-functional alkene surfactant (0.9 : 0.1) resulted in the slower release of thymol. A higher molar ratio of 2-thiol to 4-thiol monomer (0.8 : 0.2) and a lower molar ratio of 2-alkene to surfactant (0.5 : 0.5) resulted in faster-releasing particles. The Peppas–Sahlin equation used to model the thymol release found that a super case II drug release mechanism that relies on physical interactions between the polymer chains determined the amount of thymol released. The utility of canola oil as a solvent for a polymer particle delivery system holds promise for their use in environmentally sensitive applications such as a pesticide carrier and anti-microbial products.
... For many years, the antibacterial, antifungal, antioxidant, and anticancer effects of biologically active substances, which are obtained from natural sources and used as therapeutic agents, have been investigated [1][2][3][4][5][6][7]. Aromatic plants and their essential oils, herbal teas, and spices have been used for many years in natural medicine [8] and have been screened for phytochemicals for their beneficial properties on human health. ...
In this study, the chemical composition, antimicrobial, antioxidant, and anticancer effects of Thymus convolutus Klokov oil and its main compound camphor were investigated. The oil was isolated from T. convolutus using hydrodistillation method, analyzed by gas chromatography/mass spectrometry (GC–MS), and 66 compounds were identified. The main component was determined as camphor at 16.6%. The antioxidant properties were identified with the DPPH (2,2′-diphenyl-1-picrylhydrazyl) radical-scavenging method and, 33.39 ± 0.25% DPPH was scavenging in 1000 μg/mL of essential oil. The strong antimicrobial activity was observed against Escherichia coli, Enterobacter aerogenes, Proteus vulgaris, and Pseudomonas aeruginosa with MIC values of 125 μg/mL. Aspergillus flavus was more sensitive (28%) against T. convolutus essential oil than other fungi. The cytotoxic effect of oil was analyzed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Camphor was effective on human hepatoma cells (Hep3B) at concentrations of 1 mg/mL, 500, 250, and 125 μg/mL, while essential oil of T. convolutus was found to be effective at concentrations of 250 and 125 μg/mL. A reduction in cell proliferation was observed in colon carcinoma cells (HT-29) treated with 500 μg/mL camphor for 48 h. No statistically significant effect was found in Umbilical Vein Endothelial Cells (HUVEC) treated with essential oil and camphor.
... The multiple roles of the essential oils and their main components make them natural substances of great importance in several fields such as physiological function of growth, ecological function, development (Wink 2003), resistance against diseases and insects (Gershenzon and Dudareva 2007). They also possess antimicrobial, antiviral, antimycotic, antioxigenic, antiparasitic and insecticidal properties (Bishop 1995;Lamiri et al. 2001;Juglal et al. 2002;Moon et al. 2006;Michaelakis et al. 2007). ...
The Mediterranean flora is characterized by an abundance of aromatic plants. These plants make a significant contribution to the Mediterranean ecological communities both in terms of species numbers and biomass. In this area, Teucrium is a polymorphic and cosmopolitan genus of perennial plants, the largest of the Lamiaceae family, which comprises more than 300 species, of which almost 50 are native to Europe. The members of this genus are commonly known as germanders: they are bitter, astringent and antirheumatic herbs, utilized as antispasmodic agents for gastric ulcer and intestinal inflammation, as diuretic, antiseptic, antipyretic and antihelmintic agents. Moreover, they were also used in food preparation. Teucrium species are rich in essential oils and the presence of various biologically active monoterpenoid and sesquiterpenoid with several biological activities has been reported. This review summarizes the chemical features of the essential oils of Teucrium species reported in literature: it provides an overview on their compositions with particular reference to the more abundant components and to the reported biological activities. Teucrium polium, T. chamaedrys, T. flavum and T. capitatum are the most studied taxa concerning the volatile oil composition. Moreover, it is possible to distinguish different types of essential oils, characterized by the prevalence of a specific class of compounds: in particular, we recognized volatile oils rich in caryophyllene and caryophyllene derivatives, α- and β-pinene, germacrene B and D, α-, γ-, δ-cadinene and/or cadinol, limonene, and bisabolol/bisabolene. This richness in chemodiversity confers to the essential oils from Teucrium species distinctive biological properties and applications, often confirming the traditional and folk uses of this genus. This review testifies the high great variability of Teucrium essential oils and shows that the possible factors responsible for the chemical polymorphism of essential oils and consequently for their bioactivity need further investigation.
... The essential oils from oregano and clove has been reported of remarkable antiviral property against a number of non-enveloped DNA and RNA viruses including adeno virus type-3, coxsackie virus B-1 and polio virus [102,103]. The essential oil from Melaleuca alternifolia has been found to produce remarkable antivirus activity against Tobacco Mosaic Virus (TMV) and also resulted in suppressing the lesion formation of Nicotiana glutinosa within 10 days of administration [104]. An in vitro study has shown that essential oil of tea, eucalyptus and thyme and their monoterpenes content has been found substantially active against HSV-1. ...
Essential oils and their chemical constituents have been reported with well documented antimicrobial effects against a range of bacterial, fungal and viral pathogens. By definition, essential oils are a complex mixture of volatile organic compounds which are synthesized naturally in different parts of the plant as part of plants secondary metabolism. The chemical composition of the essential oils is dominated by the presence of a range of compounds including phenolics, terpenoids, aldehydes, ketones, ethers, epoxides and many others inferring that essential oils must be effective against a wide range of pathogens. This review article mainly focuses on the antiviral potential of essential oils and their chemical constituents especially against influenza and coronaviruses. Essential oils have been screened against several pathogenic viruses, including influenza and other respiratory viral infections. The essential oils of cinnamon, bergamot, lemongrass, thyme, lavender have been reported to exert potent antiviral effects against influenza type A virus. The essential oil of Citrus reshni leaves has been shown to be effective against H5N1 virus. The essential oil of Lippia species at a concentration of 11.1 μg/mL has been shown to induce 100% inhibition of yellow fever virus in Vero cells. Essential oils and oleoresins have been shown through in vitro and in vivo experiments to induce antiviral effects against Coronavirus infectious bronchitis virus. A study reported 221 phytochemical compounds and essential oils to be effective against severe acute respiratory syndrome associated coronavirus (SARS-CoV) using a cell-based assay measuring SARS-CoV-induced cytopathogenic effect on Vero E6 cells. The main mechanism of antiviral effects of essential oils has been found to cause capsid disintegration and viral expansion which prevents the virus to infect host cells by adsorption via the capsid. Essential oils also inhibit hemagglutinin (an important membrane protein of various viruses) of certain viruses; this membrane protein allows the virus to enter the host cell. Many essential oils and their components could inhibit the late stages of viral life cycle by targeting the redox signalling pathway. Essential oils of Thymus vulgaris, cymbopogon citratus and Rosmarinus officinalis have been found to destabilize the Tat/TAR-RNA complex of HIV-1 virus, this complex being essential for HIV-1 replication. Being lipophilic in nature, essential oils can penetrate viral membranes easily leading to membrane disintegration. The current comprehensive review will facilitate researchers to find chemical entities from plant sources as possible inhibitory agents against various viruses.
Tobacco mosaic virus (TMV) is a significant viral pathogen that infects various economically important crops, including tobacco, tomatoes, and cucumbers. The current study aimed to develop and optimize essential oil-loaded nanoemulsions using Response Surface Methodology (RSM) to enhance antiviral activity against TMV in Nicotiana tabacum plants. Essential oils from tea tree (Melaleuca alternifolia) and lime peel (Citrus latifolia) were chemically analyzed using gas chromatography-mass spectrometry (GC-MS). Terpinene-4-ol (70.92 %) and trans-isolimonene (33.82 %) were identified as the major components in tea tree and lime peel oils, respectively. RSM was used to optimize the nanoemulsion formulations based on oil concentration, hydrophilic-lipophilic balance (HLB), and stirring speed. Optimal tea tree oil (TTEO) and lime peel oil (LPEO) nanoemulsions were developed and characterized using Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and particle size analysis. The antiviral efficacy of the optimized formulations was tested against TMV using RT-qPCR analysis and physiological measurements. TTEO nanoemulsions significantly inhibited TMV expression by 89.78 %, while LPEO nanoemulsions achieved a 42.22 % reduction after six days. Additionally, these essential oils (EOs) enhanced plant defense mechanisms by modulating the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD), along with maintaining chlorophyll levels. This study demonstrates that TTEO and LPEO nanoemulsions offer promising eco-friendly antiviral agents for TMV management in tobacco plants. The research underscores the potential of essential oil-based formulations in mitigating viral infections in crops, providing a sustainable alternative to synthetic chemicals.
This researh was carried out to determine the effects of adding different levels of fennel volatile oil (VO) to the laying quail diets on performance, internal-external egg quality parameters, and egg's oxidative stability. In the research, totally 105 (6-week-old) laying quails (Coturnix coturnix Pharaoh) were used. Quails were distributed into 3 main groups, and the main groups were also divided into 5 replicate groups. A basal diet that did not contain fennel VO was prepared for the control group, and fennel VO was added to the basal diet at 200 and 400 mg/kg levels for Group 1 and Group 2, respectively. Diets and water were given to quails ad libitum. The research continued for 56 days. At the end of current researh, the addition of fennel VO the quail diets did not effect feed efficiency, haugh unit, egg yolk color, egg weight, shape index, egg shell breaking strength. However, both levels of fennel VO increased feed intake (P
Cumin (Cuminum cyminum L.) is an economically significant spice crop cultivated for its aromatic seeds, widely used in culinary and medicinal applications. However, the cultivation of cumin is frequently challenged by various diseases and pests that can adversely impact both yield and quality. Diseases affecting cumin include fungal, bacterial, and viral infections. Fusarium wilt, caused by Fusarium oxysporum, is a prominent fungal disease that leads to wilting, yellowing, and eventual death of the plant. Bacterial blight, attributed to Alternaria burnsii, A. cucumerina causes leaf spots and blighting, while viral diseases such as Cumin yellow vein virus result in yellowing and stunted growth. To mitigate these diseases, integrated disease management practices involving the use of resistant cultivars, proper crop rotation, and application of biopesticides have proven effective. Cumin cultivation is also susceptible to various pests, with aphids, thrips, and mites being among the most prevalent. Aphids, such as Aphis gossypii, feed on plant sap, causing stunted growth and transmitting viral diseases. Thrips and mites, including Thrips tabaci and Tetranychus urticae, respectively, lead to leaf discoloration and reduced photosynthetic activity. Integrated pest management (IPM) approaches, encompassing the use of predatory insects, insecticidal soaps, and cultural practices like maintaining proper plant spacing, are crucial in minimizing pest infestations.
Background: The world community continues to tackle the life-threatening Coronavirus infection which has spread across the world. In times of pandemic, it is to be expected that people turn to those medicinal plants (MPs) commonly used to protect themselves against disease. Methods: To meet our objectives, we examined all documented findings about the antiviral activity of MPs as well as some other essential compounds, which may act as future research targets for treating Coronavirus (COVID-19). For this purpose, a range of electronic databases have been reviewed up until 15 November 2021: Medline via PubMed, Google Scholar, ScienceDirect and Scopus. Data on MPs that demonstrated one or more of these three actions were recorded, including the extraction method and plant part used, the chemical compounds present, the mechanism of action and the type of study. The compounds in some of these MPs responsible for these activities have also been discussed in the literature. Results: The following findings were obtained: 41 MPs with antiviral activities and 19 phytocompounds under clinical trials. The secondary metabolites with direct or indirect antiviral activity are mainly flavonoids, tannins, phenols, polysaccharides, terpenes, lectins, alkaloids and steroids. Conclusions: These informative data could constitute a starting point for further studies to validate antiviral activities in vivo, as well as meaningful efficacy in humans, for potential therapeutic agents for COVID-19 Keywords: Medicinal plants; Antiviral activity, Phytocompounds; Secondary metabolites, COVID-19 Therapy
Cinnamon (Cinnamomum verum Presi.) is important spice in the world which is cultivate in tropical and subtropical region of the world. It is widely used as beneficial spices and pharmacological agents from the inner bark of plants. The study is fully based on the use of secondary sources of data; related journals, government institutes, and related reports. Medically, this plant is very important but its production is humper due to insect pests and diseases are main barriers for the production of cinnamon fruit. The objective of this study was to document the insect pests and diseases of cinnamon and their management in agroforestry system compared to different cinnamon growing countries. Since many research works were done on these issues but all are not available to the policy makers, extension workers and public in a systematic manner to date. The major insects are jumping plant louse (Trioza cinnamomic), mite (Eriophyesboisi), common mime (Chilasaclytia Lankeswara, Moore), blue bottle (Graphium sarpedon Teredon), leaf and shoot Webber (Orthagavitialis), hairy caterpillar (Euproctis fraternal Moore), wood boring moth or hairy tussock moth (Dasychiramendosa), fruit borer (Alcides morio Heller), leaf miner (Acrocercops spp.), and sorolophasemiculta (Olethreutessemiculta) and major diseases are leaf spot and die back (Colletotrichum gloeosporioides), seedling blight (Diplodia sp.), grey leaf spots/blight (Pestalotia cinnamomic), black sooty mould (Stenella spp.), algal leaf spots (Cephaleuros virescens), stripe canker (Phytophthora cinnamomi), pink disease (Corticium salmonicolor B. and Br.), brown root rot (Phellinus lamaensis Murr.), and leaf spot/blight (Colletotrichum gloesporioides). The paper eventually would help to increase the productivity of C. verum through the management of its insect pests and diseases.
Viral diseases are still one of the major threats to human health all over the world. Novel coronavirus (SARS-CoV-2) is spreading rapidly in most parts of the world, not only threatening serious illness or death to anyone infected, especially the elderly or those in poor health, but also striking a major blow to the global economy. There is no specific treatment currently available. However, a large number of studies have confirmed that essential oils (EOs) and their active components have good inhibitory or killing effects on a series of bacteria, fungi, and viruses. Therefore, in this chapter, we first introduce the antiviral activity of essential oils and their active components. Then the potential pharmacological effects of cinnamon on the treatment of SARS-CoV-2 were summarized. Finally, the potential antiviral mechanism of essential oil was analyzed. This work represents a new approach and hope against SARS-CoV2 and has great potential to complement and/or combine existing treatment strategies. At the same time, it also has important guiding significance for the effective research and development of drugs related to the treatment of SARS-CoV-2 infection.KeywordsCinnamon essential oilActive compoundsAntiviral mechanismSARS-CoV-2Treatment strategies
Coronavirus disease-19 (COVID-19), a serious pandemic due to the SARS-CoV-2 virus infection, caused significant lockdowns, healthcare shortages, and deaths worldwide. The infection leads to an uncontrolled systemic inflammatory response causing severe respiratory distress and multiple-organ failure. Quick development of several vaccines efficiently controlled the spread of COVID-19. However, the rise of various new subvariants of COVID-19 demonstrated some concerns over the efficacy of existing vaccines. Currently, better vaccines to control these variants are still under development as several new subvariants of COVID-19, such as omicron BA-4, BA-5, and BF-7 are still impacting the world. Few antiviral treatments have been shown to control COVID-19 symptoms. Further, control of COVID-19 symptoms has been explored with many natural and synthetic adjuvant compounds in hopes of treating the deadly and contagious disease. Vitamins have been shown to modulate the immune system, function as antioxidants, and reduce the inflammatory response. Recent studies have investigated the potential role of vitamins, specifically vitamins A, B, C, D, and E, in reducing the immune and inflammatory responses and severity of the complication. In this brief article, we discussed our current understanding of the role of vitamins in controlling COVID-19 symptoms and their potential use as adjuvant therapy.
During evolution, plants developed a complex set of morphological, biochemical and molecular, preformed and inducible defense mechanisms that allowed them to live in stressful conditions. In addition, the ability of plants to synthesize organic compounds (primary and secondary metabolites and plant hormones) has ensure success in colonizing challenging environments. With the practice of intensive monoculture, aiming to feed an increasingly numerous population, the incidence of plant viruses has increased almost in the same proportion. Thus, aggressive control practices to the environment and human health such as the use of pesticides began to be recommended in an uncontrolled way, which has encouraged the search for a more sustainable agriculture. Therefore, understanding the mechanisms used by viroses to interfere with metabolism in compatible and incompatible interactions, as well as those used by plants to overcome or not the infection, is fundamental and can help to clarify important points in plant-virus interactions, enabling the recommendation and use of ecologically friendly crop management. In this review, the molecular aspects of plant-virus interactions, the metabolic changes induced by the viruses, the use of natural products to control plant viruses and the application of these compounds in sustainable agriculture will be addressed.
In recent years, natural compounds have gained attention in many fields due to theirwide-range biological activity. In particular, essential oils and their associated hydrosols are beingscreened to control plant pests, exerting antiviral, antimycotic and antiparasitic actions. They are morequickly and cheaply produced and are generally considered safer for the environment and non-targetorganisms than conventional pesticides. In this study, we report the evaluation of the biologicalactivity of two essential oils and their corresponding hydrosols obtained from Mentha suaveolensand Foeniculum vulgare in the control of zucchini yellow mosaic virus and its vector, Aphis gossypii,in Cucurbita pepo plants. The control of the virus was ascertained with treatments applied eitherconcurrently with or after virus infection; choice tests were performed to verify repellency activityagainst the aphid vector. The results indicated that treatments could decrease virus titer as measuredusing real-time RT-PCR, while the experiments on the vector showed that the compounds effectivelyrepelled aphids. The extracts were also chemically characterized using gas chromatography–massspectrometry. Mentha suaveolens and Foeniculum vulgare hydrosol extracts mainly comprised fenchoneand decanenitrile, respectively, while essential oils analysis returned a more complex composition,as expected
(PDF) In Vivo Antiphytoviral and Aphid Repellency Activity of Essential Oils and Hydrosols from Mentha suaveolens and Foeniculum vulgare to control Zucchini Yellow Mosaic Virus and its Vector Aphis gossypii.
Melaleuca alternifolia (Maiden & Betche) Cheel oil (Tea Tree Oil, TTO) is an essential oil appropriate for medicinal and cosmetic usage. Tea tree oil is composed of complex formulation with more than 100 components; however, the most pharmaceutically active one is terpinen-4-ol. TTO can be implemented for decolonization of multi-resistant Staphylococcus aureus, anti-tumor therapy and antifungal activity based on different doses and exposure-duration proportionate with the targeted species. Antioxidant activity is related to α-terpinene, α-terpinolene and γ-terpinene. Hypersensitivity may occur as mild dermatitis or being aggravated to hepatitis and central nervous system reactions due to chronic or acute poisoning. Acne treatment prognosis shows significant improvement after TTO application proceeding by Propionibacterium acnes colony destruction. Plus, TTO usage psoriasis is also possible. Further investigations have premised TTO’s insecticidal effects performed by anticholinesterase activity. Destructive ability of the oil on Pityrosporum ovale is also indisputable and including TTO as the active ingredient has been highly beneficial for curing scalp dandruff. Expeditious antiviral activity is also considered as the promising characteristic suggested for this oil. Still, little information is available about feasibility of in vivo utilization.
New and detailed data are presented on the phytochemical composition of the volatile and non-volatile organic compounds of the Mediterranean endemic species Portenschlagiella ramosissima (Port.) Tutin. Both the essential oil and hydrosol were obtained from the air-dried plant by hydrodistillation and analyzed by gas chromatography-mass spectrometry. The volatile compounds from the fresh and air-dried plants and from the hydrosol were isolated for the first time by headspace solid-phase microextraction using two fibres of different polarity. The benzene derivative group was the predominant group in all samples, with myristicin being the most abundant component of all. The non-volatile compounds of the methanol extract were analyzed by ultra-high-performance liquid chromatography–high-resolution mass spectrometry with electrospray ionisation, and three flavonoid glycosides, one anthocyanidin glycoside, and lipid derivatives were detected. Both the chemical composition and biological activities of this plant have been described in a very limited number of publications, making it an interesting source for further study. The antiphytoviral activity of the essential oil and hydrosol showed that both extracts significantly reduced the number of lesions on the leaves of local host plants infected with tobacco mosaic virus. Moderate antiproliferative activity of the methanol extract was detected in three cancer cell lines, cervical cancer cell line, human colon cancer cell line and human osteosarcoma cell line, using the MTS-based cell proliferation assay. Based on the results, we highlight this plant as a new source of bioactive compounds and natural phytotherapeutic agent that deserves further investigation.
The outbreaks of plant pathogenic viruses and insect pests affect agricultural product supply chain systems. Environmentally friendly innovative technologies are provided accurate, practical, and acceptable means for surveillance by farmers. The bioactive compound applications are derived from plant essential oils with antiviral activities as well as integrating insect pest control and management are useful choices. Successful comprehensive planning, including material production systems, extraction techniques, quality testing, and product creation are essential for strategic and operational decision-making under current operation management trends of Agriculture 4.0. This information can potentially be used to impel today agriculture and set the directions for supports. The role of management and data analysis will meet the challenges of increasing populations and food security with the ultimate goal to achieve efficient and sustainable effectiveness for all participants in directing the world agricultural systems.
Essential oils (EOs) obtained from different parts of plants consist of diverse chemical constituents. Most of the essential oils are rich in monoterpenes, sesquiterpenes and phenylpropenes. The diversity of chemical constituents imparts several biological activities such as insecticidal, repellent, attractant, antifeedant, oviposition deterrent, disruption in growth regulation, fungicidal and antiviral to these essential oils. Traditionally, EOs are being utilised for management of insect pests both in field crops and storage. Mostly these essential oils are found to affect insects by inhibiting several enzymes such as acetylcholine esterages, Glutathion S-transferages and also octopaminergic nervous system. They do not show toxicity against the mammals and fishes, due to absence of target site in these organisms. A few essential oils are exempted from pesticide registration and are being used as seasoning agents in food and beverage products. Moreover, these EOs can be a potential “green pesticide” against agricultural pests and support to the organic food production. The main purpose of this review is to emphasize on biological activities of EOs. This comprehensive and critical review will be helpful for chemists to develop more candidates based on these moieties and also for plant protectionists to identify promising EOs as per the need.
Organoselenium and organotellurium compounds are not only interesting as intermediates for the synthesis of complex molecules but also for their biological properties. One of the strategies used to prepare a pharmacologically active organochalcogen compound involves using a natural molecule that is already active as a starting material in order to enhance the bioactivity of the final product. Such molecular hybrids are new semisynthetic bioactive organochalcogen compounds. In this chapter, we describe methodologies for the preparation of various semisynthetic bioactive organoselenium and organotellurium compounds, focusing on the scholarly works published between 1995 and 2019. Special emphasis has been given to organochalcogen derivatives that present antimicrobial, antioxidant, and anticancer activities.
There has been a growing interest in extracting essential oils from aromatic plants as potential sources of biorational pesticides. In the present study, essential oil emulsions of Satureja bakhtiarica (SEO), Oliveria decumbens (OEO), Trachyspermum ammi (TEO) and Zataria multiflora (ZEO) were prepared. Their major chemical compositions were characterized and their antiviral effects were evaluated against two important plant viruses: Cucumber mosaic virus (CMV) and Tobacco mosaic virus (TMV). SEO and ZEO indicated higher antiviral activity in comparison with OEO and TEO (p < 0.05). In systemic bioassay, the pre-treatment test of ZEO and SEO showed a reduced level of TMV accumulation in TMV-infected tobacco, with rates of 26.75% and 23.97%, respectively. Also, the two essential oils had mechanisms by which plant resistance acted against plant viruses. These mechanisms involved the activities of several defense-related enzymes (PAL and POD) and genes (ICS1, NPR1, and PR-1a). These results indicate that the essential oils of Zataria multiflora and Satureja bakhtiarica have the potential to be used as sources of effective antiviral agents and eco-friendly pesticide.
Two types of columns, three types of packings, and four levels of column height were considered to investigate how column and packings affected the separation in the vacuum fractional distillation process of raw tea tree ( Melaleuca alternifolia ) oil (TTO). This study discussed those effects on purity, yield, and overall discovery to select the most excellent operating conditions for enriching terpinen-4-ol. After the experiments, the essential oil was successfully separated into two fractions, in which the second one composed mostly the main TTO constituent, terpinen-4-ol. The best result was achieved by conducting the distillation on a 300-mm Hempel column filled with small Fenske helices (10 mm × 2 mm i.d.) at the system pressure of 60 mmHg. GC/MS analysis showed an almost 2.5-fold increase in the content of terpinen-4-ol, from 39.23% to 95.77% after fractionation. Meanwhile, there was 75% of terpinen-4-ol successfully recovered from its parental oil. Hence, the vacuum fraction distillation could be an effective method to enrich the terpinen-4-ol content in TTO.
After the understanding of the harm caused by unconsciously used antibiotics to humans, animals and nature, the interest in medicinal and aromatic plants has increased all over the world. For this reason, perhaps the first of the most remarkable and intense working subjects in the field of agriculture, veterinary medicine and food in the last two decades has been essential oils obtained from aromatic plants. It is also known by a number of different names such as aromatic-scented oils obtained from aromatic plants, essential oils, essential oils, herbal extracts and essential oils. The concept of essential oil has been preferred in the present book in order to set an example and to prevent misuse. The use of the concept of essential oil for the term essential oil also causes misunderstandings. Because the term essential oil will lead to the understanding of fatty acids such as linoleic and linolenic acid that cannot be synthesized in the body. Based on this understanding, this work has emerged as a result of the gathering of experts from different departments of different universities in Turkey (Field, Plant Protection, Animal Science, Veterinary Medicine, Food, Chemistry, Aquaculture). In the essential oils book, very extensive and comprehensive information about the cultivation, analysis and use of medicinal and aromatic plants in different sectors is presented in a way that includes the current literature. The work has been studied by academics at different levels.
We hope that it will contribute to students and all interested parties who want to benefit from essential oils.
The fast-developing transmissible antibiotic resistance among bacteria, especially spread because of antimicrobial abuse in farming, prompts researchers to find long-lasting molecules to contain infectious diseases. Here we describe the main alternative strategies for treating Gram-positives, Gram-negatives and MDR infections, highlighting the benefits and limits of each approach. Besides the well experimented bacteriocins and antimicrobial peptides, already in use as food preservatives, traditional compounds like cationic surfactants and plant essential oils will be analyzed for their potential in specific sectors. In parallel, the use of living organisms, probiotics and bacteriophages, will be examined underlining the possible risks for gut ecology. In addition, new promising natural molecules (rhamnolipids and exopolysaccharides) and very cutting-edge technologies such as bioengineered bacteriocins, metal nanoparticles (Me-NP) and quorum sensing inhibitors (QQ) will be described. The innovative aspect of the latter strategies is that attention is directed not on killing bugs but on preventing bacterial virulence: both rhamnolipids and Me-NP can control biofilm formation and disruption, whereas QQ also prevent toxin expression. Interestingly, some of the considered compounds are active also against fungi and viruses, sometimes behaving as immune-stimulators as well. Finally, considerations on the safety for humans and Earth ecosystems will be discussed.
Purpose:
This study is aimed at comparing the effects of Tea Tree Oil shampoo (TTO) with regular-lid shampoo on the treatment of meibomian gland dysfunction (MGD) signs and symptoms.
Design:
Double-masked randomized clinical trial METHODOLOGY: Forty patients with MGD were treated by daily lid scrubbing with TTO shampoo in one eye and regular-lid shampoo in the other one. Before treatment and then after 1 and 3 months, the effect on ocular surface symptoms, tear production and stability, and conjunctival and lid signs of the two eyes were compared.
Results:
Plugging and capping of meibomian gland orifices, foamy tear, glands expressibility, dry eye questionnaire score (DEQ5), and tear breakup time (TBUT) were improved more significantly in TTO shampoo treated eyes (capping P=0.050, plugging and glands expressibility P=0.001, others P<0.001). In spite of improvement in both eyes, scores of meibum quality, conjunctival hyperemia, corneal and conjunctival staining, and Schirmer1 test value showed no statistically significant difference between the eyes (P= 0.06, 0.187, 0.192, 0.19, respectively). Moreover, lid margin telangiectasia resolved only in TTO shampoo treated eyes (P<0.001). Trichiasis and distichiasis changed in neither groups (P=1.000). Furthermore, ocular surface irritation during scrubbing was more common with TTO shampoo (P=0.002).
Conclusion:
TTO shampoo was found to be more efficient than regular-lid shampoo in controlling MGD signs and symptoms although ocular surface irritation during its application was more frequent.
This study aims to assess the ability of vegetable oil of Pistacia lentiscus L. (lentiscus oil) in stimulating growth performance of broiler chickens and protecting them against coccidiosis. For this purpose, an in vitro test was first carried out to evaluate the destructive effect of this oil on Eimeria spp oocysts. On the other hand, an in vivo study was carried out to evaluate, once again, the capacity of the vegetable oil of Pistacia lentiscus L. in stimulating broilers growth performance and reducing the coccidiosis clinical signs. Thus, day old chicks were randomly divided into four equal groups: (1) uninfected and not-supplemented control (NI NS); (2) uninfected and supplemented (NI S); (3) infected and not supplemented (I NS); (4) infected and supplemented (IS). Each group was divided into three replicates containing each of them two subjects. The experimental groups (2 and 4) are supplemented with lentiscus oil by force-feeding at the rate of 1 mL per day from the 18th day until the end of the experiment. The chicks of the third and the fourth group are inoculated orally with sporulated oocysts (6.5 × 105 oocysts of Eimeria spp) on the day 20 of age. The results showed that lentiscus oil has an anticoccidial dose-dependent effect as shown by oocysts counting and released substances measurement at 273 nm. The growth performance of the (NI S) group was found better with an improvement percentage of 9.14% compared to the control (p < 0.05). Likewise, the weight gain of the (I S) group seems slightly higher than that of the control one (1316 g and 1235 g, respectively) (p < 0.05). In conclusion, the vegetable oil of Pistacia lentiscus L. has shown, not only, a promising growth effect in broiler chickens, but also, it seems to have a protective effect against coccidiosis sequels caused by Eimeria acervulina infection.
The purpose of the current study was to detect the effects of different levels of rosemary volatile oil (VO) supplemented to laying quail diets on performance, egg quality parameters, and egg yolk oxidative stability. In this study, a total of 105 laying quails (Coturnix coturnix Pharaoh) at the age of 6 weeks were used and 3 main groups were formed, each containing 35 quails. Also, each main group was separated into 5 replicates containing an equal number of quails. Quails were fed a control diet without rosemary VO or diets which were containing at different levels (200 or 400 mg/kg) of rosemary VO supplemented to the control diet. At the end of the study, which was continued for a total of 56 days, no significant difference was found in the feed intake, feed efficiency and egg weights among the control and experimental groups. The supplementation of rosemary VO at the levels of 200 and 400 mg/kg to the diets caused an increase in quails' egg production (P<0.01). However, there was no effect on the exterior and interior egg quality parameters. A significant decrease in malondialdehyde (MDA) levels in egg yolk were observed with both levels of rosemary VO at storage (+4 0C) for 7 (P<0.001) and 28 (P<0.01) days. Considering these data, it was concluded that rosemary VO can be supplemented to laying quail diets as a natural antioxidant without negatively affecting performance and egg quality parameters.
Recently, natural essential oils have been extensively studied for anti-bacterial application in foods due to their safety and high biological activity. Herein, Litsea cubeba essential oil (LC-EO) was applied as a natural anti-bacterial agent for exploring its anti-bacterial mechanism against Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7). The LC-EO could effectively inhibit the growth of EHEC O157:H7 and the minimal inhibitory concentration (MIC) was 0.5 mg/mL. In the study of anti-bacterial mechanism, the LC-EO was proved with good membrane penetration ability, which could destroy bacterial cell structure and disorder membrane permeability, thereby causing the leakage of intracellular organic matters. Furthermore, the inhibitory effects of LC-EO on physiological metabolism of EHEC O157:H7, including respiratory metabolism, enzyme activity, the replication of nucleic acid and the transcription level of main virulence genes (stx1, stx2, ehxA, eae), were also demonstrated in this study. Specially, the possible action mechanism of different components of LC-EO on bacterial genetic material was revealed deeply on molecular level by the molecular docking technology. Finally, the results of application evaluation indicated that the addition of LC-EO at MIC in different vegetable juices could maintain anti-bacterial rate above 99.9% for 4 days without remarkable influence on foods sensory quality. The information in this study provides the necessary theoretical foundation for extending the application of LC-EO in food preservation.
The sections in this article are
Introduction
Induced Local Defence by Means of Phytoalexins
Antibacterial and Antifungal Agents of Higher Plants
Secondary Metabolites from Higher Plants with Antiviral Properties
Conclusions
Salicylic acid (SA) is hypothesized to be an endogenous regulator of local and systemic disease resistance and an inducer of pathogenesis-related (PR) proteins among plants. High levels of PR proteins have been observed in an uninoculated amphidiploid hybrid of Nicotiana glutinosa X N. debneyi, which is highly resistant to tobacco mosaic virus (TMV). Fluorescence, UV, and mass spectral analysis established that the levels of SA in healthy N. glutinosa X N. debneyi leaves were 30 times greater than in N. tabacum 'Xanthi-nc' tobacco, which does not constitutively express PR proteins and is less resistant to TMV. Upon TMV-inoculation, SA levels increased at least 70-fold in leaves of Xanthinc but rose only slightly in the hybrid. Phloem exudates of N. glutinosa X N. debneyi contained at least 500 times more SA than those of Xanthi-nc. SA treatment caused the appearance of PR-1 protein in Xanthi-nc but did not affect constitutively high levels of PR-1 protein in N. glutinosa X N. debneyi. In contrast to Xanthi-nc tobacco, TMV-inoculated N. glutinosa X N. debneyi kept at 32 C accumulated more than 0.5 mug SA/g fresh weight, maintained high levels of PR proteins, and developed a hypersensitive response to TMV. PR proteins have previously been shown to accumulate in the lower leaves of healthy, flowering Xanthinc tobacco, which exhibited increased resistance to TMV. These developmentally induced increases in resistance and PR-1 proteins positively correlated with tissue levels of SA. These results affirm the regulatory role of SA in disease resistance and PR protein production.
Detailed GC and GC-MS analyses of oil of Melaleuca have identified several constituents not previously reported from Melaleuca alternifolia and clarified some earlier assignments. The range, mean, and coefficient of variation for the principle constituents in 800 typical samples are presented along with the compositions of several substandard oils. Isolation and storage procedures affecting the chemical composition of the oil are reported. Ethanolic extraction of mature leaves gave solutions suitable for direct injection into a gas chromatograph for the qualitative determination of tea tree oil. Comparison with conventional steam distillation showed that this technique was suitable for preliminary analysis of tea tree oil yield and quality.
The effect of mycolaminaran, aβ-1,3-glucan purified from the cytoplasm of Phytophthora megasperma, on initial infection by tobacco mosaic virus of Nicotiana species was tested. When mixed at 62−1,000 μg/ml with TMV inoculum and applied to Nicotiana tabacum Xanthi-nc', mycolaminaran reduced necrotic local lesion numbers by as much as 98%. In contrast, laminaran, a mannose-containing glucan derived from an alga, reduced infection by only 40−75%. Mycolaminaran did not reduce initial viral infection of Nicotiana rustica. This established that the polysaccharide inhibited infection but did not inactivate the virus (...)
Infectivity of the Ul strain of tobacco mosaic virus (TMV) was inhibited 40 to 50% by pre-incubation of the virus (5 /jg/ mL) with 3,7-dimethylquercetin (3,7-DMQ), 3,7,3'-trimethylquercetin (3,7,3'-TMQ), 3,7,4'-tnmethylquercetin (ayanin), or 3,7,3',4'-tetramethylquercetin (tetra-MQ) at 90 μg/mL. The infectivity of TMV RNA was unaffected by incubation with ayanin or tetra-MQ before inoculation. Tetra-MQ formed a stable complex with virions and reduced infectivity. Binding of tetra-MQ to virus particles decreased their recovery by ultracentrifugation. enhanced their decoration with polyclonal antiserum, and increased their sensitivity to RNase digestion. Specifically methylated quercetin compounds reduce infectivity by weakening virion subunit binding, exposing the viral RNA to attack by host RNases during mechanical inoculation.
SUMMARY Cross-protection reactions of two tobamoviruses, sunn-hemp mosaic virus (SHMV) and common tobacco mosaic virus (TMV-C), were investigated and compared. A mutant of SHMV (SHMV-n), produced by nitrous acid treatment, induced necrotic lesions in bean. SHMV protected completely against this mutant and against SHMV-n RNA. SHMV in bean protected only weakly, however, against TMV-C. To determine whether the coat protein of these viruses affected the ability to superinfect, RNA of each virus was encapsidated in the coat protein of the other. TMV-C RNA encapsidated in SHMV coat protein was five- to 27-fold less infectious on SHMV- infected bean leaves than TMV-C RNA re-encapsidated in TMV-C coat protein. When homologous or heterologous coat protein was added to inocula, infectivity for healthy plants was diminished markedly more by homologous protein, suggesting that extraneous homologous protein diminished infectivity by inhibiting viral uncoating. SHMV-n RNA encapsidated in TMV-C coat protein did not superinfect SHMV- infected bean leaves. Thus, although coat protein was shown to be a factor in cross- protection in some situations, other factors must also be involved.
The composition of the essential oil from the leaves and flowers of Monarda citriodora var. citriodora was analyzed by GC and GC/MS. Thymol was the dominant component in the oil from both the flowers (61.77%) and leaves (50.69%). The second most imprtant compound of the leaf oil was p-cymene, although yield from the flower oil was lower (4.19%). A more abundant component of the flower oil was γ-terpinene (13.30%), but only a trace of this was detected in the oil from leaves.
Volatile constituents of essential oils of eight different clones propagated from the Australian tea tree (Melaleuca alternifolia) were analyzed by gas chromatography and gas chromatography/mass spectrometry. The oils isolated by a simultaneous purging and solvent extraction method (SPE) contained high levels of monoterpenes, including α-thujene, sabinene, α-terpinene, γ-terpinene, 1,8-cineole, terpinolene, and limonene. The volatile composition of oils prepared by a simultaneous steam distillation and solvent extraction method (SDE) varied significantly among different clones. Six oils contained 1,8-cineole as the major constituent, whereas two oils had terpinen-4-ol as the major component of the SDE samples. More compounds were found in SDE samples than in SPE samples. A principal component analysis on volatile compositions of eight oils conducted by computer indicated that sabinene and α-thujene in SPE samples and terpinen-4-ol and α-terpinene in SDE samples are highly correlated with each other.
Steam distilled volatile oil from marjoram (Origanum majorana L.) was evaluated for its antibacterial and antifungal activities. A range of 25 bacterial and five fungal species was used in this study, and included animal and plant pathogens, food poisoning bacteria and mycotoxigenic fungi. The oil exerted considerable inhibitory powers against several of the bacteria, with the food-poisoning bacterium Staphylococcus aureus being least affected. The most susceptible organisms were Beneckea natriegens, Erwinia carotovora and Moraxella sp. Of the fungi tested, Aspergillus niger proved the most susceptible to marjoram oil.
Fifty plant essential oils were examined for their antibacterial properties against 25 genera of bacteria. Four concentrations of each oil were tested using an agar diffusion technique. The ten most inhibitory oils were thyme, cinnamon, bay, clove, almond (bitter), lovage, pimento, marjoram, angelica and nutmeg. The most comprehensively inhibitory extracts were angelica (against 25 genera), bay (24), cinnamon (23), clove (23), thyme (23), almond (bitter) (22), marjoram (22), pimento (22), geranium (21) and lovage (20).
Based on the fact that Chenopodium amaranticolor extracts showed inhibitory activity against tobacco mosaic virus (TMV) and Ehrlich tumour (EA), tests were carried out to investigate whether the antiviral and antitumoral activity were caused by the same compounds. When the extract was purified by CM Sephadex C-25 column, after precipitation with 90% ammonium sulphate, twenty active fractions against TMV and two pools of fractions active against EA were obtained. Only one fraction with high absorbance values at 260 and 280 nm was able to inhibit both TMV and EA. When the extract was purified by Bio Gel P-60 column two active fractions against TMV and EA were obtained, suggesting that they were contained in the 0.01 M fraction of the CM Sephadex column. It is suggested that C. amaranticolor leaf extract contained at least two protein-like substances manifesting antiviral and antitumoral activity.
Control of Spaerothecafulginea on cucurbits with an oil extracted from Australian Tea tree
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Flavonoids inhibit infectivity of Tobacco Mosaic Virus Screening of plants for biological activity 11. Antiviral avtiuity
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Antibacterial and antioxidant properties of the volatile oil of Monarda citriodora var. citriodora. In preparation Composition of the essential oil from the leaves andjlowers ofMonarda citriodoravar
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Antifungal activity of the essential oil of Mytus communis var microphylla. Herba Hung
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Antqungal substance in the oil ofAnise Antibacterial properties of plant essential oils
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Raskin,EndogenuussalycylicacidleDelscorrelatewithaccumulation of pathogenesis-related proteins and virus resistance in tobacco
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Antiviral activity of a Rosmurinus officinalis L. extract. Mitt
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