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Antioxidant and antiradical activity of flavonoids
Abstract
The relationship between the structure of 42 flavonoids and their antioxidant and antiradical activities was elucidated by heat-induced oxidation in a beta-carotene and linoleic acid system and by the 1,1-diphenyl-2-picrylhydrazyl decoloration test. From seven structurally divergent groups of flavonoids, only flavonols with a free hydroxyl group at the C-3 position of the flavonoid skeleton showed high inhibitory activity to beta-carotene oxidation. Antiradical activity depended on the presence of a flavonol structure or free hydroxyl group at the C-4' position. The effect of the 4'-hydroxyl was strongly modified by other structural features, such as the presence of free hydroxyls at C-3 and/or C-3' and a C2-C3 double bond.
... They have enormous health effects and have played significant roles in successful medical treatments [320]. Flavonoids are widespread bioactive molecules in plants with antioxidant properties and scavenging ability of free radicals [321]. Flavonoids can scavenge different reactive oxygen and nitrogen species [321]. ...
... Flavonoids are widespread bioactive molecules in plants with antioxidant properties and scavenging ability of free radicals [321]. Flavonoids can scavenge different reactive oxygen and nitrogen species [321]. The number of free hydroxyl groups, the presence of an orthohydroxylation on the B-ring of a flavonoid molecule, and the presence of a 3-hydroxyl group or a C2-C3 double bond in the C-ring are usually listed as a reasons of antioxidant activity of flavonoids [321]. ...
... Flavonoids can scavenge different reactive oxygen and nitrogen species [321]. The number of free hydroxyl groups, the presence of an orthohydroxylation on the B-ring of a flavonoid molecule, and the presence of a 3-hydroxyl group or a C2-C3 double bond in the C-ring are usually listed as a reasons of antioxidant activity of flavonoids [321]. The antioxidants, anti-cancer-causing properties, anti-inflammatory, anti-mutagens, and the ability to control major enzyme functions of flavonoids have miscellaneous reciprocal biochemical associated with various diseases including cancer, atherosclerosis, and Alzheimer's disease. ...
... This excellent antioxidant capacity may be due to the high content of phenolic components, particularly in polar extracts/fractions, which appear to be efficient hydrogen and electron donors, and due to their ideal structural chemistry, Additionally, as a biological activity requires the consideration of chemical synergy, we should not ignore the presence of other small phenolic compounds (Khiya et al., 2021), as well as to the presence of major components known for their anti-oxidant power such hydroxybenzoic acid derivatives (gallic acid, protocatechuic acid, salicylic acid), cinnamic acid derivatives (o-coumaric acid, trans-ferulic acid, chlorogenic acid) (Razzaghi-Asl et al., 2013), flavonoids and its derivatives (kaempferol, quercetin) (Burda & Oleszek, 2001). ...
The present study aimed to evaluate the phytochemical composition and the antioxidant potential of the crude extract and its various fractions which are n-hexane, chloroform, ethyl acetate, and n-butanol of the aerial part of Erodium guttatum (E. guttatum). Total flavonoid and phenolic content have been estimated using the trichloroaluminum colorimetric and Folin-Ciocalteu method. The phytochemical profile was investigated in various polar (ethyl acetate) and nonpolar (chloroform) fractions, using LC-MS/MS technique. The antioxidant activities were also assessed using in vitro assays such as the DPPH, ABTS, FRAP, SNP and Phenanthroline. The obtained results showed that the ethyl acetate fraction had the highest phenolic and flavonoid content (332.76 ± 1.10 µg GAE/mg and 192.07± 1.26 µg QE/mg), respectively. Moreover, LC-MS/MS analysis of the chloroform and ethyl acetate fractions revealed the presence of 16 and 14 compounds, respectively, the main compounds in the chloroform fraction being shikimic acid (13.708 mg/g), hesperidin (0.356 mg/g), isoquercitrin (0.282 mg/g). and in the ethyl acetate fraction, shikimic acid (3.989 mg/g), quercetin 3-xyloside (2.082 mg/g), and gallic acid (0.881 mg/g). The Antioxidant studies revealed that the ethyl acetate fraction exhibited significantly superior activity with IC50 of 2.37±0.02 µg/ml and 1.49±0.02 µg/ml against DPPH and ABTS radicals, respectively. Additionally, the fraction showed A0.5 values of 2.98±0.07µg/ml, 3.62±0.15µg/ml, and 1.23±0.01 µg/ml against FRAP, SNP and Phenanthroline, respectively. E. guttatum may serve as a promising resource for antioxidants, warranting further exploration of its potential in medicine or as a dietary supplement due to its components with potential pharmacological benefits.
... Reaction progress was followed by UV-vis spectrophotometry and measuring the absorbance at 515 nm in cycles for 15 min. Radical consumption was expressed as percentage of antiradical activity (ARA) (Fig. 3, inset) as proposed by Burda and Oleszek [33] and calculated according to the following equation (Eqn 8): ...
A simple and direct arylation of sesamol with aryl halides by a photoinduced reaction is reported. Five 6-arylsesamol derivatives were synthesized in order to evaluate possible changes in their antioxidant properties as a function of the C6 aryl substituent nature. Extension of the procedure to the reaction with o-dihalobenzenes leads to the synthesis of ring-closure products bearing a tetracyclic aromatic condensed ring system, although in lower overall yields (~45 %). The antioxidant activity of the synthetic derivatives towards 1,1-diphenyl-2-picrylhydrazyl radical was determined taking sesamol as the reference compound. In addition, the relationship between the antiradical activities of these molecules against this radical and the bond dissociation energies of their phenolic O–H group was calculated using computational chemistry methods.
... 23 The activity of these enzymes is regulated by a person's diet, genetics and environment, underscoring their significance for the longevity and health of cells. 24 Various types of Antioxidants have been described in Figure 2. ...
The use of green-synthesized nanoparticles has emerged as a promising avenue for enhancing antioxidant activity in various applications, including medicine, environmental protection and food preservation. This review provides a comprehensive overview of the role of nanotechnology in antioxidant activity, focusing on the green synthesis of nanoparticles using plant-based extracts. The paper begins by discussing the types of antioxidants, categorizing them into enzymatic, non-enzymatic and synthetic compounds and highlighting their mechanisms of action in scavenging free radicals. Various antioxidant assay methods, including DPPH, ABTS and FRAP, are examined for their effectiveness in evaluating antioxidant potential. The review also delves into the role of medicinal plants in the green synthesis of nanoparticles, detailing how bioactive compounds in plant extracts contribute to the reduction and stabilization of metal ions into nanoparticles. The types of green synthesized nanoparticles covered include silver, gold, titanium oxide, starch, iron oxide, zinc oxide, copper, cerium oxide, nickel oxide, selenium, platinum and palladium, each with unique properties that influence their antioxidant activity. The interaction between these nanoparticles and free radicals, as well as their potential synergistic effects with other antioxidants, is discussed. Finally, the review highlights the benefits of using green synthesis methods over conventional chemical synthesis, emphasizing sustainability, cost-effectiveness and the reduced environmental impact. This work underscores the growing potential of green-synthesized nanoparticles as powerful antioxidant agents, offering new insights into their applications and future directions in both scientific research and industrial innovation.
... Following incubation in the darkness at 25 °C for 30 min, the absorbance was measured at 517 nm using spectrophotometer (Biotek Power Wave XS2, USA), with ethanol serving for baseline correction. The absorbance was expressed as the percentage of inhibition and was calculated using the equation (Burda, Oleszek, 2001): ...
Belonging to the Alismataceae family, Echinodorus macrophyllus, known in Brazil as “chapéu de couro”, is popular in the food industry, where it is used in teas and infusions. The objective of this study was to evaluate the active chemical compounds in the powder of E. macrophyllus leaves extracted by two different methods (Soxhlet [SXT] and ultrasound-assisted extraction [UAE]), quantify the total phenolic compound (TPC) and total flavonoid (TFC) content, and evaluate the antioxidant potential and larvicidal activity. The SXT extraction was the most efficient (6.05% yield). Analysis by thin-layer chromatography (TLC) and high-performance liquid chromatography with a diode array detector (HPLC-DAD) evidenced the presence of cinnamic acid derivatives, flavones, and flavanones in the extracts. The TPC was higher in the SXT extract (7.71±0.05 µg GAE/mL). However, there was no significant difference in TFC. The SXT extract exhibited greater antioxidant potential according to the ferric reducing antioxidant power (FRAP) method (IC50=3.37±0.45 µg/mL), while the UAE extract showed higher activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50=42.16±5.79 µg/mL). Both extracts were nontoxic to Artemia salina, suggesting the potential health benefits of this plant, which is rich in phenolic compounds and diverse pharmacological properties.
... In contrast, the ability to scavenge these radicals may also be influenced by other structural components found in various types of polyphenols [56]. As an example, Flavonoids, a well-known type of polyphenols, contain a 3-OH group which involves in neutralizing the impact of free radicals [57]. As stated earlier, polyphenols possess the ability to impede the production of RNS and ROS by disrupting the function of the enzymes responsible for their creation. ...
Exercise is one of the most important activities for every individual due to its proven health beneficials. Several investigations have highlighted the advantageous impacts of aerobic exercise, largely attributed to its capacity to enhance the body’s capability to defend against threats against oxidative stress. The information currently accessible suggests that adding regular aerobic exercise to a daily routine greatly decreases the chances of developing serious cancer and passing away. An unevenness in the levels of free radicals and the body’s antioxidant defenses, made up of enzyme and non-enzyme antioxidants, results in oxidative pressure. Generally, an imbalance in the levels of oxidative stress triggers the creation of harmful reactive oxygen or nitrogen compounds, causing the development or progression of numerous ailments, including cancer. The equilibrium between pro-oxidant and antioxidant substances is a direct indicator of this imbalance. Green tea and its derivatives are rich sources of bioactive substances such as flavonoids and polyphenols which possess antioxidant abilities. Moreover, modulation of epigenetic targets as well as inflammatory pathways including ERK1/2 and NF-κB are other proposed mechanisms for its antioxidant activity. Recent studies demonstrate the promise of green tea as an antioxidant, showing its ability to decrease the likelihood of developing cancer by impacting actions like cell growth, blood vessel formation, and spread of cancer cells. This summary will concentrate on the complex network of different pathways related to physical activity and consumption of green tea. In particular, the focus of this research will be on examining how oxidative stress contributes to health and investigating the potential antioxidant properties of green tea, and the interconnected relationship between exercise and green tea in the treatment of cancer. Elucidation of these different pathways would help scientists for development of better therapeutic targets and further increase of current anticancer agents efficiency.
... Milk thistle fruit extract, silymarin, has been extensively used as a hepatoprotective agent. 5 In vitro experimental studies have shown that the individual flavonolignans isolated from silymarin, such as silybins A and B, isosilybin A, silychristin A, silydianin, and 2,3-dehydrosilybins A and B (DHS), exert significant biological effects, 6 including antioxidant, 7,8 immunomodulatory, 9 hepatoprotective, 10 antiviral, 11,12 and antiproliferative and anticancer activities. 13−15 Similarly, quercetin (QCT), a flavonol commonly found in citrus fruits, onion, berries, and green tea, has been investigated in several experimental studies for its potential therapeutic benefits in various types of cancer, and its anticancer effects have been confirmed in some clinical trials. ...
Flavonoids are naturally occurring compounds found in fruits, vegetables, and other plant-based foods, and they are known for their health benefits, such as UV protection, antioxidant, anti-inflammatory, and antiproliferative properties. This study investigates whether flavonoids, such as quercetin and 2,3-dehydrosilybin, can act as photoactivatable carbon monoxide (CO)-releasing molecules under physiological conditions. CO has been recently recognized as an important signaling molecule. Here, we show that upon direct irradiation, CO was released from both flavonoids in PBS with chemical yields of up to 0.23 equiv, which increased to almost unity by sensitized photooxygenation involving singlet oxygen. Photoreleased CO reduced cellular toxicity caused by high flavonol concentrations, partially restored mitochondrial respiration, reduced superoxide production induced by rotenone and high flavonol levels, and influenced the G0/G1 and G2/M phases of the cell cycle, showing antiproliferative effects. The findings highlight the potential of quercetin and 2,3-dehydrosilybin as CO-photoreleasing molecules with chemopreventive and therapeutic implications in human pathology and suggest their possible roles in plant biology.
... To date, the specific mechanisms by which flavonoids influence aging remain unclear, but they may involve the following mechanisms: Firstly, flavonoids could inhibit the formation of the senescence-associated secretory phenotype (SASP) and selectively eliminate senescent cells, thereby mitigating the aging process [33][34][35]. Secondly, due to the structural basis of flavonoids, they possess direct antioxidant activity which could directly scavenge ROS and upregulate antioxidant responses through the transcription factor NRF2 (Nuclear factor erythroid 2-related factor 2), which enhances proteasome activity and maintaining proteostasis to delay the aging process [36,37]. Thirdly, flavonoids could inhibit the release of pro-inflammatory cytokines and reduce inflammation by modulating the MAPK and NF-κB signaling pathways [38,39]. ...
Background
Flavonoids are believed to have potential anti-aging effects due to their anti-inflammatory and antioxidant properties. However, the effectiveness of dietary flavonoids and their subclasses in delaying aging has yet to be confirmed. Our study intends to examine relationship between them.
Methods
Data from three survey cycles (2007–2008, 2009–2010, and 2017–2018) of the National Health and Nutrition Examination Survey (NHANES) was used to investigate the relationship between PhenoAgeAccel and dietary flavonoid intake. Weighted linear regression was conducted to evaluate the relationship between dietary flavonoid intake and PhenoAgeAccel, and the dose-response relationship was investigated by limited cubic spline (RCS) analysis. Mixed effects were explored using weighted quantile sum (WQS) regression. Further, the subgroup analyses were also conducted.
Results
A total of 5391 participants were included, after multivariable adjustments, a negative association was found with total dietary flavonoid, flavan-3-ols, flavanone, flavones and flavonols with a β (95% CI) of -0.87 ( -1.61, -0.13), -0.83 (-1.95, -0.08), -1.18 (-1.98, -0.39), -1.64 (-2.52, -0.77) and − 1.18 (-1.98, -0.39) for the higher quintile compared to the lowest quintile. The RCS analysis show a non-linear relationship between flavan-3-ols (P for nonlinear = 0.024), flavanones (P for nonlinear = 0.005), flavones (P for nonlinear < 0.001), flavonols (P for nonlinear < 0.001) and total flavonoid intake (P for nonlinear < 0.001) and PhenoAgeAccel. WQS regression indicated that flavones had the primary effect on the mixture exposures (52.72%). Finally, the subgroup analysis indicated that participants without chronic kidney disease are more likely to benefit from dietary flavanone and flavone intake in mitigating aging, while the benefits of flavanone intake are more significant in participants with a lower body mass index.
Conclusion
Our study suggested that dietary flavonoid intake is negatively associated with accelerating aging in adults of American, and the most influential ones are flavones, flavanones, flavan-3-ols and flavonols.
... Furthermore, it combines elements that help replenish vitamin E in cell membranes by donating reducing equivalents with vitamin E. Vitamin C transfers an electron to the lipid radical, changing it into the ascorbate radical, which halts the lipid peroxidation chain process [32,46].Vitamin C is an antioxidant with therapeutic capabilities that also plays a role in multiple metabolic processes, wound healing, osteogenesis, detoxification, iron absorption, collagen production, and preventing blood clotting [47,48]. The DPPH is one of the most trustworthy free radicals and is frequently used to evaluate the radical scavenger properties of natural foods [49]. A quick and simple technique to manually examine the antioxidant content is to use the DPPH test method. ...
... Alkaloids primarily act as feeding deterrents and toxins to insects and other herbivores, in many cases by directly interacting with molecular targets within the nervous system (W ink, 2000). Flavonoids are a secondary metabolite of plants and the most abundant polyphenols in the human diet (Burda and Oleszek, 2001). Cyclo oxygenase (COX) are lipid metabolising enzymes that catalyse the oxygenation of polyunsaturated fatty acids (PUFA), preferably Extraction of Phytochemical Constituents from the Leaves of Vitex trifolia in the Inhibition of Lipoxygenase, Cyclooxygenase... arachidonicacid (AA), to form the prostanoids, which are potent cell-signalling molecules associated with the initiation, maintenance and resolution of inflammatory processes (Charlier and Michaux, 2003). ...
Background: Herbal medicines are often used to stimulate the immune system in an attempt to prevent disease, as well as to induce specific cures. The use of phyto medicines is becoming more scientifically based, with increasing emphasis placed on proven product safety and efficacy. Methods: In the present study, the leaves of Vitex trifolia were extracted with distilled water, 1M Na2CO3 and 70% methanol. The extracted contents were screened to identify the presence of various phytochemicals. The contents of Na2CO3 and methanol were filtered, centrifuged and the supernatant was collected. The supernatant of Na2CO3 extract was collected and the alkaloid layer was separated in a separating funnel using alcohol. The contents were analysed for thin layer chromatography and phytochemical constituents. Result: Thin layer chromatography was performed at 360 nm the Rf value were 0.953, 0.230, 0.184, 0.153, 0.123 and in 240 nm Rf values 0.953, 0.338, 0.184, 0.153, 0.123 were obtained. The methanol extract was condensed at 40oC and dissolved in chloroform. Rf at 360 nm of 0.714, 0.396, 0.158 and at 240 nm with Rf values 0.714, 0.492, 0.349. The activity of extracts on Xanthine oxidase, tyrosinase and cyclooxygenase were estimated and the inhibition percentage of all the three was calculated as 59.34, 61.23, 71.02 and 51 respectively. The values obtained with flavanoid extracts for the same set of enzymes were 70.22, 81.48, 94.8 and 74.36 respectively. In this study, inhibition properties of flavanoid extracts were greater than that of alkaloid extracts.
... Для определения антиоксидантной активности использовали реакцию со стабильным свободным радикалом 2,2-дифенил-1-пикрил гидразилом (DPPH) [9]. К 1 мл исследуемого раствора добавляли 3 мл раствора DPPH в спирте этиловом 95%-ном с концентрацией 5 мг/100 мл. ...
Цель - исследовать фенольные соединения и антиоксидантную активность сухого водного экстракта побегов первого года малины обыкновенной - Rubus idaeus (L.). В качестве объектов исследования выступали образцы побегов первого года малины, заготовленные на территории Ильинского района Пермского края в ельнике травяном в июне 2019 года. Молодые побеги длиною до 30 см срезали и высушивали воздушно-теневым способом. Анализ фенольных соединений проводили на жидкостном хроматографе марки Agilent 1100 Series HPLC. Для определения антиоксидантной активности использовали реакцию со стабильным свободным радикалом 2,2-дифенил-1-пикрилгидразилом (DPPH). В результате хроматографического исследования в сухом водном экстракте побегов малины обыкновенной первого года было идентифицировано 12 веществ фенольной природы. В наибольшем количестве в сухом экстракте побегов малины содержится эллаговая, бензойная, ванилиновая кислоты, ванилин и флавоноид гиперозид. Сухой водный экстракт побегов малины обыкновенной проявляет выраженную антиоксидантную активность (IC50 – 43,86 мкг/мл). Данный показатель превышает активность настоя плодов шиповника в пересчете на сухой остаток (IC50– 76,75 мкг/мл), но уступает по выраженности антиоксидантного действия субстанции аскорбиновой кислоты (IC50 - 9,46 мкг/мл). Сухой водный экстракт побегов малины первого года можно рекомендовать для дальнейших исследований антиоксидантной и других видов фармакологической активности.
Purpose - to make a research of phenolic compounds and antioxidative activity of dry aqueous extract of Rubus idaeus (L.) one-year shoots. The objects of the research were the samples of one-year shoots of red raspberry - Rubus idaeus (L.). Raspberry shoots were collected on the territory of the Ilyinsky district of the Perm Region in an herbaceous-spruce forest in June 2019. Young one-year shoots, up to 30 centimeters in length, were cut and dried with the shade drying method. Phenolic compounds were analyzed with a liquid chromatograph Agilent 1100 Series HPLC. Antioxidative activity was determined by using a stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) reaction. As a result of the chromatographic research, 12 substances of phenolic nature were identified in a dry aqueous extract of the red raspberry one-year shoots. The most substances in the raspberry shoots dry extract are: ellagic acid, benzoic acid, vanillic acid, vanillin and the flavonoid hyperoside. Dry aqueous extract of red raspberry one-year shoots shows significant antioxidative activity (IC50 – 43.86 μg/ml). This index is above the activity of the sweet-brier fruits infusion in terms of dry residue (IC50 – 75.76 μg/ml), but is inferior to the substance of ascorbic acid in the severity of the anti-oxidant action (IC50 - 9.46 μg/ml). Dry aqueous extract of raspberry one-year shoots can be recommended for further researches of antioxidative activity and other types of pharmacological activity.
... Results in photomicrograph 1 represents the extremally very small cubic particles of vitamin C. The inverse relationship between decreasing the particle size and increasing the surface area, may increase the surface chelating sites and consequently the antioxidant activity of the vitamin [29]. DPPH assay is one of the most reliable, straightforward and rapid methods for determining the antioxidant and radical scavenger levels in natural foods [30]. Results of the current study represented in (Fig. 2). ...
The current study examines the effects of vitamin C nanoparticles on fish health as well as the acute and long-term toxic effects of Fe²⁺ and Mn²⁺ combination on Nile tilapia, Oreochromis niloticus. The metal mixture under study has a detected 96-hour LC50 of 2.7% TU (Toxic unit). Fish were divided into four groups: Group 1, which served as the control group; Groups 2, 3, and 4 were exposed to 20% of the 96-hour LC50 for 30 days and fed on a conventional diet. Fish of Group 3 were supplemented with 20% vitamin C while fish of Group 4 were supplemented with 20% vitamin C as nanoparticles. The metals, levels in tissues of the liver and gills were examined, as well as the biochemical markers of metabolic processes in blood plasma. Fish from Group 2 displayed noticeable deteriorating conditions, followed by those from Group 3, whereas fish from Group 4 demonstrated noticeable good conditions across all examined criteria. Results showed that, while vitamin C nanoparticle proved to be more efficient, both vitamin C and its nanoparticles supplements had a positive impact on reducing the harmful effects of the studied metal mixture by chelating metal ions and scavenging free radicals.
... There are two main effects of these two groups. First, these two groups affect the ionic domains around ArOH in flavonoids, which further increases the formation of unpaired ArO • and ArO − and promotes the scavenging of free radicals by hydrogen supply and electron transfer (Burda & Oleszek, 2001). Second, these two groups can affect the electrons around the radicals and promote the formation of ROO − (Bors, Heller, Michel, & Saran, 1990;Gulcin, 2020) (Fig. 2D). ...
Fruits contain numerous polyphenols in the form of conjugates, which exhibit low antioxidant activity. Probiotic fermentation is a strategy to improve the antioxidant activity of these conjugated polyphenols by modifying their structure. However, the mechanisms underlying the effects of functional groups and derivatizations on the antioxidative activities of polyphenols and the antioxidation enhancement by probiotic biotransformation haven't been comprehensively explored. This review aimed to explore the structure–antioxidant activity relationships of four functional groups and three derivatizations in flavonoids and phenolic acids. Further, the review elucidated the antioxidant mechanisms underlying the biotransformation of flavonoids and phenolic acids as glycoside, methylated, and ester conjugates by probiotic biotransformation. Deglycosylation, demethylation, and hydrolysis catalyzed by enzymes produced by Bifidobacterium and Lactobacillus facilitated the conversion of conjugated polyphenols into flavonoids and phenolic acids with hydrolyzed forms and highly active functional groups, thereby increasing hydrogen supply and electron transfer capacity to enhance the antioxidant activity.
... wa flavonon, keberadaan gugus 4-okso pada ikatan 2-3 pada cincin C tidak memperlihatkan keberadaan ikatan ganda, yang berakibat pada kemungkinan kehilangan elektron dalam struktur senyawa flavonon. Hal ini mungkin terjadi sebagai respons terhadap kebutuhan senyawa untuk menstabilkan dirinya sendiri dengan cara menerima elektron dari donor hidrogen.(Burda dan Oleszek, 2001).ekstrak etanol buah kelor (Moringa oleifera Lamk.) asal kabupaten pinrang kecamatan suppa memiliki aktivitas antioksidan dengan nilai IC50 1183,0914 μg/ml. dan Kemampuan aktivitas antioksidan ekstrak etanol buah kelor (Moringa oleifera Lamk.) yaitu 0.00224 kali dari aktivitas antioksidan asam askorbat dengan nilai IC50 sebesar 2,6616 μg ...
Antioxidants are chemical compounds that can provide one or more electrons to free radicals, so that these free radicals can be reduced. This research aims to determine the antioxidant activity of ethanol extract of Moringa fruit (Moringa oelifera Lamk.) from Suppa District, Pinrang Regency using the DPPH method. Moringa fruit simplicia is extracted using 70% ethanol by maceration. Testing for antioxidant activity against free radicals was analyzed using a visible spectrophotometer at a wavelength of 515 nm. The results of the analysis show that the antioxidant activity of the ethanol extract of Moringa fruit (Moringa oleifera Lamk.) from Pinrang Regency, Suppa District has an IC50 value of 1183.0914 μg/mL.
... This is probably due to the specific properties of quercetin, and its derivatives such as the increased hydrophilicity of its glycosides, which modifies the distribution coefficients between the lipid and aqueous phases. 9 Given the promising antioxidant activity of quercetin derivatives, extensive research has been conducted, for example on the synthesis and antioxidant activity of quercetin complexes with copper and magnesium, 10,11 as well as studies on synthesis and antioxidant, and antibacterial activities of the alkyl quercetin derivatives. 12 In addition, the important role of quercetin in age-associated diseases [13][14][15] as well as its role as a potential inhibitor of COVID-19, is discovered and demonstrated by Khaerunnisa et al. in 2020. ...
The Dynamic Light Scattering (DLS) measurements have been performed on quercetin with dioctyl sodium sulfosuccinate (Aerosol OT, AOT), Triton X-100 in 1,4-dioxane, as well as on the solutions containing water in the core of suitable reversed micelles; the water amount was calculated using the relation R = [H 2 O]/[surfactant], defining the ratio of water to surfactant concentration. The amount of quercetin in the studied systems as well as the effects of the water presence on the size of the micelles and diffusion effects were discussed. A significant effect of the research was the determination of the maximum amount of water that can be introduced into the AOT micelles in the studied systems.
... Gallic acid, a major antioxidant and anticancer commercial standard [54], was identified only in PA-C-3SV and was 131.61. Three molecules found exclusively in PP-P-3SV, Trans-cinnamic acid (1.31), 5-hydroxy-Plants 2024, 13, 1802 9 of 32 4 ′ -methoxyflavone (0.31), and 4-hydroxy-3-(3-oxo-1-phenylbutyl)coumarin (15.48), are known for their strong antioxidant properties [56]. These molecules are estimated to be responsible for the observed antioxidant activity (10.54 µg/mL) in this extract. ...
Various parts of the Pinaceae species, a traditional plant, have potential health benefits and exhibit antibacterial, anti-cancer, and antioxidant activities. This study aims to investigate the biochemical properties of both petal (P) and core (C) fractions from pinecones of P. halepensis (PA), P. brutia (PB), and P. pinea (PP). Pinecones were manually separated into P and C, which were then milled to investigate maceration with solvents of increasing polarity: cyclohexane (1SV), ethyl acetate (2SV), and methanol (3SV) at 20 °C. Spectrophotometry was utilized to quantify the total phenolic content (TPC) and to assess bioactivities. Gas chromatography with mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) were employed to identify the chemical composition. 3SV extracts demonstrated the highest TPC and a significant anti–oxidant potential. PA-P-3SV exhibited the highest TPC (460.66 mg GAE/g DW) and PP-P-3SV displayed the best IC50 (10.54 µg/mL) against DPPH. 1SV and 2SV extracts showed interesting anticancer activity against Hela and HepG2 cells. No significant toxic effect of P and C extracts from pinecones was observed on HEK-293 cells. GC-MS analysis unveiled 46 volatile compounds, of which 32 were detected for the first time in these species. HPLC analysis identified 38 compounds, of which 27 were not previously detected in these species. This study highlights the significant potential of pinecones as a rich source of bioactive compounds.
... Quercetin displayed lower recovery compared to its glycoside form quercitrin, suggesting that the presence of sugar increases flavonoid stability. It was previously demonstrated that glycosylation on position 3 in the C ring can lower their ability to release hydrogen, which lowers their pharmacological activity [15]. Recovery of the flavanone hesperetin was similar in all extraction procedures ( Figure 5A). ...
Propolis has gained popularity in recent years as a potential preventive and therapeutic agent due to its numerous health benefits, which include immune system boosting, blood pressure lowering, allergy treatment, and skin disease treatment. The pharmacological activity of propolis is primarily attributed to phenolics and their interactions with other compounds. Given that phenols account for most of propolis’s biological activity, various extraction methods are being developed. The resin–wax composition of the propolis matrix necessitates the development of an extraction procedure capable of breaking matrix–phenol bonds while maintaining phenol stability. Therefore, the aim of this study was to assess the stability of two major groups of phenolic compounds, flavonoids and phenolic acids, in propolis methanol/water 50/50 (v/v) extracts obtained after ultrasound-assisted extraction (USE) under different extraction parameters (extraction time and pH) and heat reflux extraction (HRE). The methodology involved varying the USE parameters, including extraction time (5, 10, and 15 min) and pH (2 and 7), followed by analysis using liquid chromatography–tandem mass spectrometry (LC-MS/MS) to quantify phenolic recoveries. Results revealed that benzoic acid and chlorogenic acid derivatives demonstrated excellent stability across all ultrasound extraction procedures. The recoveries of flavonoids were highly diverse, with luteolin, quercitrin, and hesperetin being the most stable. Overall, neutral pH improved flavonoid recovery, whereas phenolic acids remained more stable at pH = 2. The most important optimization parameter was USE time, and it was discovered that 15 min of ultrasound resulted in the best recoveries for most of the phenols tested, implying that phenols bind strongly to the propolis matrix and require ultrasound to break the bond. However, the high variability in phenol extraction and recovery after spiking the propolis sample shows that no single extraction method can produce the highest yield of all phenols tested. As a result, when working with a complex matrix like propolis, the extraction techniques and procedures for each phenol need to be optimized.
... For gallic acid as a reference standard, Orhan and Üstün (2011) have determined 91% inhibition only at a concentration of 500 μg/mL or 92% at 1000 μg/mL. The antioxidant activity of the extract can also be attributed to other polyphenolic components such as flavonoids, phenolic acids or phenolic diterpenes (Pietta et al., 1998;Velioglu et al., 1998;Burda and Oleszek, 2001;Cervellati et al., 2002;Živković et al., 2010). The main components of the sweet chestnut leaf extract (Table 2) lead to the conclusion that in the case of neutralization of the stable DPPH radical, quercetin and gallic acid were largely responsible for the antiradical activity of the extract, given their abundance. ...
The aim of this work was to examine the polyphenol content in Castanea sativa leaf extracts and to determine their antioxidant and antigenotoxic effect. The antioxidant activity of extracts and main components were determined by the application of spectophotometric and electronic spin resonance methods of capturing DPPH, superoxide and hydroxyl radical. The antigenotoxic effect was evaluated with genotoxic mycotoxins – aflatoxin B1 (AFB1) and ochratoxin A (OTA). Castanea leaf extract contained 6.74% of total polyphenols. Castanea extract was the richest in tannins and flavonoids (gallic and ellagic acid derivatives). Castanea leaf extract showed the ability to neutralize DPPH radicals (IC50 = 1.87 μg/mL). Similar results were also identified by testing the capture of hydroxyl and superoxide radicals. The strong antioxidant activity of the dominant components, that indicate phenolic acids as the ingredients that contribute the most to the antioxidant and antigenotoxic effect of castanea leaf extract, was also found. Genotoxic suppression of AFB1 and OTA was established by a comet test, establishing a significant reduction in tail, tail intensity and tail torque in leukocytes co-treated with mycotoxins and different concentrations of extracts. Our findings emphasize the potential of C. sativa to prevent genotoxics and also its antioxidant effects.
... According to a review by Pietta (2000), flavonoids exhibit antioxidant properties by inhibiting the formation of Reactive Oxygen Species (ROS) and scavenging them. Additionally, a study by Burda and Oleszek (2001) demonstrated the high antioxidant activities of certain flavonols that have free hydroxyl groups at the C-3 position. These data suggest that flavonoids are correlated with antioxidant activities, as flavonoids themselves may be the source of antioxidant activities. ...
Soybeans contain flavonoids and anthocyanins that are associated with health benefits related to antioxidant activities. In this study, the total flavonoid content (TFC), total anthocyanin content (TAC), and the relative antioxidant activities (AOA) of selected Philippine soybean genotypes were screened in order to select and recommend promising genotypes that may be used for further breeding and varietal development. Using the aluminum trichloride method, the genotypes POP 1-44 (TFC = 0.619 g/100 g), PHL 29272 (TFC = 0.616 g/100 g), and Tiwala 6 (TFC = 0.608 g/100 g) were determined to have the highest calculated TFC values. pH differential and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays distinguished all three black-seeded soybean genotypes PHL 29272 (TAC = 177.010 mg/100 g; AOA = 24.476%), PHL 29502 (TAC = 143.750 mg/100 g; AOA = 25.745%), and PHL 29552 (TAC = 123.572 mg/100 g; AOA = 29.297%) with the highest anthocyanin contents and relative antioxidant activities. Genotype PHL 29272 was consistently found among those with the highest results for the three tests. Significant correlations (α = 0.05) were found between flavonoid content and antioxidant activity (p < 0.0001), and between anthocyanin content and antioxidant activity (p < 0.0001). In conclusion, the study was able to identify genotypes that can be recommended as the most suitable candidates for soybean breeding activities.
... In a methanolic DPPH solution, scavenging free radical potentials were examined (Burda and Oleszek, 2001). The added substance's scavenging efficiency is indicated by the degree of decolorization in the solution. ...
Bajakah Tampala extracted with ethanol was indicated to contain phenolic and flavonoids. So far, the ethanol extract of Bajakah Tampala wood has only been analyzed for its antioxidant activity. Whereas flavonoids not only act as antioxidants but also play a role in inhibiting -amylase which is related to antidiabetic properties. The ethanol extract of Bajakah Tampala wood has never been used as a fortificant in honey. The purpose of this study was to determine the levels of phenols, flavonoids, antioxidant activity, and inhibitory activity of α-amylase from the ethanol extract of Bajakah Tampala Wood (EEBTW) at various solvent concentrations. In addition, to investigate the effect of adding EEBTW to Kapok honey on its bioactivity. This study was conducted using Post Test Only Group Design that was applied to 1% fortification of the three extracts in Kapok honey. Extraction used three concentrations of ethanol (70%, 80%, and 90%). Parameters tested in the study were total phenol, total flavonoid, antioxidant activity, and % inhibition of α-amylase. The result showed the higher the ethanol concentration, the lower the total phenolic, flavonoid, % DPPH scavenging activity, and α-amylase inhibition. The addition of 1% EEBKT has synergism with brown honey in increasing phenol, antioxidant activity, and % inhibition of α-amylase. EEBTW has the potential as an antidiabetic candidate and Kapok honey with EEBTW has the potential as functional honey
... Therefore, the impact of methoxyl groups on antiradical properties seems interesting. The slight antioxidant activity for hesperetin indicates the interaction of methoxyl substituted in a certain position on antioxidant activity [26,27]. ...
Chemokines, also known as chemotactic cytokines, stimulate the migration of immune cells. These molecules play a key role in the pathogenesis of inflammation leading to atherosclerosis, neurodegenerative disorders, rheumatoid arthritis, insulin-resistant diabetes, and cancer. Moreover , they take part in inflammatory bowel disease (IBD). The main objective of our research was to determine the activity of methyl-derivatives of flavanone, namely, 2 ′-methylflavanone (5B), 3 ′-methylflavanone (6B), 4 ′-methylflavanone (7B), and 6-methylflavanone (8B), on the releasing of selected cytokines by RAW264.7 macrophages activated by LPS. We determined the concentration of chemokines belonging to the CC chemokine family, namely, MCP-1, MIP-1β, RANTES, and eotaxin, using the Bio-Plex Magnetic Luminex Assay and the Bio-PlexTM 200 System. Among the tested compounds, only 5B and 6B had the strongest effect on inhibiting the examined chemokines' release by macrophages. Therefore, 5B and 6B appear to be potentially useful in the prevention of diseases associated with the inflammatory process.
... The pure solvent was used as a blank for the experiment. The percentage of DPPH inhibition was calculated using the following equation (Equation (4)) by Burda and Oleszek [92]: % DPPH inhibition = [1 − (Aa/Ab)] × 100 (4) The Aa refers to the absorbance of the sample and Ab to the absorbance of the DPPH solution. The calculation of EC 50 (effective concentration to discolor 50% of the DPPH solution) was carried out using the probits method of analysis [93]. ...
Synthetic dyes are persistent organic environmental pollutants that can cause extensive damage to living beings and to the ecosystem as a whole. Cost-effective, sustainable, and efficient strategies to deal with this type of pollution are necessary as it commonly resists conventional water treatment methods. Silver nanoparticles (AgNPs) synthesized using the aqueous extract from the leaves, stem, and fruits of Leucaena leucocephala (Leucena) were produced and characterized through UV–vis, TEM, EDS, SDL, XPS, XRD, and zeta potential, and they proved to be able to promote adsorption to remediate methylene blue and tartrazine pollution in water. The nanoremediation was performed and did not require direct exposure to sunlight or any special lamp or a specific reduction agent. The AgNPs produced using the extract from the leaves exhibited the best performance in nanoremediation and also presented antioxidant activity that surpassed the one from butylated hydroxytoluene (BHT). Consequently, it is an interesting nanotool to use in dye nanoremediation and/or as an antioxidant nanostructure.
... It has also been proven in this study that the antioxidant activity of flavonoids is independent of their solubility, as the more hydrophobic quercetin had a better hydroperoxides formation inhibition than the hydrophilic glycoside rutin. Hence, their antioxidant activity was attributed to both the presence of the C3 hydroxyl group, and the metal chelation potency of the complex formed by the C4 and C3 keto group and hydroxyl group, respectively [217]. In another structural activity relationship report, it was revealed that 3 1 , 4 1 -dihydroxy catechin in the β-ring, 2,3 unsaturated alongside the oxo functional group at the position four in the C-ring of the flavonoids, hyperoxides, and myricetin have been attributed to the antioxidant potency of the flavonoid [218]. ...
Polyphenols, as secondary metabolites ubiquitous in plant sources, have emerged as pivotal bioactive compounds with far-reaching implications for human health. Plant polyphenols exhibit direct or indirect associations with biomolecules capable of modulating diverse physiological pathways. Due to their inherent abundance and structural diversity, polyphenols have garnered substantial attention from both the scientific and clinical communities. The review begins by providing an in-depth analysis of the chemical intricacies of polyphenols, shedding light on their structural diversity and the implications of such diversity on their biological activities. Subsequently, an exploration of the dietary origins of polyphenols elucidates the natural plant-based sources that contribute to their global availability. The discussion extends to the bioavailability and metabolism of polyphenols within the human body, unraveling the complex journey from ingestion to systemic effects. A central focus of the review is dedicated to unravelling the antioxidant effects of polyphenols, highlighting their role in combating oxidative stress and associated health conditions. The comprehensive analysis encompasses their impact on diverse health concerns such as hypertension, allergies, aging, and chronic diseases like heart stroke and diabetes. Insights into the global beneficial effects of polyphenols further underscore their potential as preventive and therapeutic agents. This review article critically examines the multifaceted aspects of dietary polyphenols, encompassing their chemistry, dietary origins, bioavailability/metabolism dynamics, and profound antioxidant effects. The synthesis of information presented herein aims to provide a valuable resource for researchers, clinicians, and health enthusiasts, fostering a deeper understanding of the intricate relationship between polyphenols and human health.
... Flavonoids constitute a significant portion of the metabolites in plant content and contain more than six thousand nutrients developed in various plants. Numerous studies have been conducted on the antioxidant, anti-allergic, anticancer, antimicrobial, and antiviral properties of flavonoids and their remarkable pharmacological components (Araujo et al., 2014;Li et al., 2014;Kim et al., 2011;Burda & Oleszek, 2001;Ramos, 2007). ...
Isorhamnetin (3’-methylquercetin) is an important flavonoid produced as a secondary metabolite from medicinal and aromatic plants due to its pharmacological and therapeutic properties. Thus far, the anticancer, antiallergic, antiinflammatory, antioxidant, antiviral, and antimicrobial properties of isorhamnetin have been evaluated in indirect studies conducted with isorhamnetin found in plant extracts or essential oils or direct studies performed with pure isorhamnetin. However, this is the first study in the literature on the antifungal activity of 97% pure isorhamnetin against C. tropicalis, C. albicans, C. krusei, and C. parapsilosis using two assays including agar dilution and broth microdilution methods. This study showed that isorhamnetin has a significant inhibitory effect against all Candida species used. The minimum inhibitory concentration (MIC) value of isorhamnetin against C. tropicalis, C. albicans, C. krusei, and C. parapsilosis was 1.875 mg/mL, the same for all yeast strains. These results have opened a new horizon regarding the usability of isorhamnetin as a pharmacological therapeutic antifungal agent.
... Compounds in aglycones form showed a similar increase in antioxidant properties and have been known to have higher antioxidant activities than their glycosides (de Araújo et al. 2013). Burda and Oleszek (2001) suggested that a free C-3 hydroxyl group of flavonols is responsible for the strong inhibition of oxidation in heterogeneous systems. Comparison of the antioxidant activity of flavonol aglycones with the activity of their glycosides or methyl derivatives showed that blocking the C-3 hydroxyl group led to a complete loss of antioxidant activity, whereas glycosylation or methylation of other flavonol hydroxyl groups did not lead to such an effect. ...
Bark residues from Douglas fir are an abundant resource that is currently used primarily in low-value energy recovery or is landfilled. Bark extractives are rich in diverse compounds like terpenes, fatty acids, phenols, and sugars with potential uses in a variety of high value applications. The study explores the potential of enzymatic hydrolysis to improve phenolic compounds from Douglas fir bark. It also assesses differences in chemical composition among rhytidome, phloem, and comingled bark fractions from an industrial waste pile. Phloem fractions exhibit higher yields of extractives, rhytidome fractions have elevated lignin levels, while the comingled fraction lies between the two except in ash content which was higher than in the separated fractions. Fungal decay tests with Gloeophyllum trabeum and Coniophora puteana on extract treated wood suggest potential for growth inhibition in extracts, about 58–31 % and 30–7% mass loss (in average) respectively, but due to high mass loss at low concentrations an enzymatic modification approach seems crucial for enhanced inhibition. Growth responses in whole-cell fermentation approach display variability depending on the participating microorganisms. Enzymatic hydrolysis with beta-glucosidase improved the antioxidant properties of bark extracts and holds promise for altering the chemical composition and enhancing bioactivity.
... Their abilities to attach to biologic polymers, including enzymes, hormone carriers, and DNA, chelate transition metal ions like Fe 2+ , Cu 2+ , Zn 2+ , and Mg 2+ , catalyze electron transport and scavenge free radicals are well-established [9]. Research on the structure-relationship has shown that the presence of an ortho-dihydroxyl group on the B-ring, one or more free hydroxyl groups, a C2-C3 double bond in the C-ring, or a 3-hydroxyl group are among the structural factors that influence the antiradical activities [10,11]. Current research increasingly emphasizes their transition metal chelation capabilities and direct interaction with some enzymes and blood/vascular cells, which may play key roles in their influence on humans. ...
Hibiscetin, a major bioactive ingredient of Hibiscus sabdariffa, exhibits numerous pharmacological actions and five metal-chelating sites. Since flavonoids play a vital role in scavenging or reducing the toxicity of redox-active metal ions, the chelation of Fe²⁺ cation by the flavonoid Hibiscetin was examined using the DFT method carried out at the M06-2X/6-311+G(d, p)/LANL2DZ level of theory in the aqueous phase. All the complexed species derived from neutral and deprotonated ligand forms were considered. The results show that the oxygen atoms of the di-deprotonated catechol moiety at the C-7 and C-8 positions of Hibiscetin interact best with the Fe²⁺ ion among the possible chelation sites on Hibiscetin. The stability of the most stable complex, HIB-[7-8] -Fe²⁺, was validated by Frontier molecular orbital, Natural bond orbital, and natural population reports. The topological analysis indicated the electrostatic interaction between the oxygen atoms of Hibiscetin and the metal ion in the complex. The investigation of the radical scavenging capabilities in gas, water, and benzene media proved the superior antioxidant activity of the most stable complex of Hibiscetin and Fe²⁺ ion when compared to parent flavonoid. The hydrogen atom transfer (HAT), single-electron transfer followed by proton transfer (SET-PT), and sequential proton-loss electron transfer (SPLET) mechanisms were studied, and the HAT mechanism was found to be the most effective radical scavenging mechanism in the gas and non-polar solvent and the SPLET mechanism in the polar solvent. The best site for radical attack is identified to be 4'-OH.
Research background. Dandelion flowers have a very short shelf life. The canning process is known not only to stabilize foods and preserve their nutritional content at a high level but also to significantly extend their shelf life. For this reason, canned dandelion flowers are thought to be beneficial for both consumers and the gastronomy sector. Experimental approach. In this study, fresh dandelion (Taraxacum officinale L.) flowers were canned using sucrose syrups with varying degrees of Brix (°Bx) (20 and 30) as filling mediums and stored at 25 °C for 30 days. A total of 56 phytochemicals were identified using LC-MS/MS, while in vitro antioxidant activities (DPPH and CUPRAC) and total phenolic content (TPC) were analyzed in both the canned flowers and the filling mediums at different storage intervals (10th, 20th, and 30th days). Results and conclusions. The antioxidant activities of fresh dandelion flowers were 89.625 % and 0.804 mmol Trolox equivalents per gram (mmol Trolox Eq/g), respectively. The lowest DPPH (41.453 %) and CUPRAC (0.328 mmol Trolox Eq/g) activities were observed on the 20th day in samples stored in the 30 ºBx filling medium. TPC in fresh flowers was measured at 367.409 mg gallic acid equivalents per gram of extract (mg GAE/g extract). The highest TPC levels in canned flowers were recorded in samples taken on the 10th day for both ºBx filling mediums. Using LC-MS/MS analysis, 24 phytochemicals were identified in fresh flowers, including quinic acid, luteolin, siranoside, chlorogenic acid, fumaric acid, caffeic acid, protocatechuic acid, quercetin, cosmosiin, isoquercitrin, and apigenin. A decrease in the polyphenol content of canned flowers was observed during storage. The results indicate that canning dandelion flowers in a 30 ºBx syrup medium and storing them for 20 days was effective in preserving their phenolic components and antioxidant capacity. Novelty and scientific contribution. In the scientific literature, numerous studies focus on extending the shelf life of fruits and vegetables through the canning method. However, this study fills a gap in the literature by successfully applying the canning technique to edible flowers for the first time. Furthermore, the findings of this study contribute to future research on the potential commercialization of canned dandelion flowers as a consumer food product.
Olive fruit is a key component of the Mediterranean diet. Olive mill wastewater (OMWW) is the main byproduct of the olive oil extraction process. It contains high amounts of polyphenols with interesting socio-economic and health benefits. The study aims to examine the impact of Hydroxytyrosol-rich-olive mill wastewater (HT-OMWW) on retinal neurodegeneration in diet-induced diabetic retinopathy (DR) rat model like human Psammomys obesus (P. obesus). Animals were divided into four groups. Two groups were fed a high-calorie diet (HCD), one untreated (D) and the other receiving HT-OMWW (20 mg/kg body weight) (D+), and two other groups served as controls (C and C+) fed a low-calorie diet. Throughout the study, body weight and glycemia were assessed. Outer and inner retina cell types were scrutinized using immunohistochemistry in different stages. Our results showed that the extract was rich in phenols with antioxidant activity. The major compound identified was Hydroxytyrosol, which has demonstrated anti-obesity and hypoglycemic effects. Furthermore, long-term administration of HT-OMWW exhibited radical enhancements in retinal thickness and cell density with reduced cone-photoreceptor damage in diabetic animals in 5 and 7 months. The treatment has also attenuated bipolar, amacrine and ganglion cell loss in 5 and 7-month diabetic P. obesus. These results confirm that P. obesus is a valuable HCD-induced diabetes model for evaluating DR features and indicate the efficacy of HT-OMWW administration as a therapeutic intervention for DR, specifically in protecting the retina against neurodegenerative processes. HT-OMWW could be implemented in the socio-economic integration approach via its valorization as a nutraceutical for DR treatment.
Ready-to-drink (RTD) wedang uwuh is herbal beverage product innovations that are practical and healthy but perishable because it is vulnerable to microorganisms. This research aim to determining the shelf-life of RTD wedang uwuh. Wedang Uwuh that has been brewed and packaged in 200mL glass bottles was used in this study. Product analysis was conducted on color, antioxidant activity, and total microbes quality parameters of RTD wedang uwuh. A complete randomized design was used as experimental design, with temperatures treatment of 5 ± 2°C, 25 ± 2°C, 45 ± 2°C for 28 days of storage and observations every 7 days. This study plays a crucial role in sustainable agriculture because wedang uwuh is a traditional Indonesian herbal drink. Research on its storage life helps in determining optimal preservation techniques and ensuring the beverage retains its nutritional. By extending the shelf life of wedang uwuh, producers can minimize spoilage, reducing the overall environmental impact and conserving resources. The estimated shelf-life of RTD wedang uwuh is calculated using the Accelerated Shelf-Life Testing measurement method. The shelf-life of RTD wedang uwuh based on the color–lightness ( L *) parameter 30.143 days at 5°C; 29.892 days at 25°C; and 29.758 days at 45°C.
The fat oxidation is a major cause of quality degradation in various processed food products. Oxidation can occur through reactions with diradical triplet oxygen or nonradical singlet oxygen, which may be formed from triplet oxygen in the presence of sensitizers and light. Erythrosine, a common food colorant, is a photosensitizer due to its conjugated double bonds. This study investigates the antioxidant and antiphotooxidant activities of the Medan Barangan banana fruit and its potential to enhance the oxidative stability of food products, particularly in the linoleic acid system. Key methods include extraction and activity testing of various banana extracts: hexanes (HE), hexanes acetone sequential (HASE), and hexanes acetone ethanol sequential (HAESE). Results show all extracts possess reducing power and DPPH radical scavenging activities, with HAESE demonstrating the highest efficacy. Additionally, HAESE exhibits significant singlet oxygen quenching, reducing linoleic acid peroxide formation in the presence of erythrosine. These findings suggest potential applications of Medan Barangan banana in food preservation, contributing to more sustainable agricultural practices by utilizing local agricultural commodities.
Rheumatoid Arthritis (RA) is a persistent inflammatory autoimmune illness that damages bones by causing joint discomfort, edema, and stiffness. In RA, inflammatory cell infiltration and synovial hyperplasia lead to the generation of proinflammatory cytokines like TNF-α and IL-1. To find phytochemical substances utilised in RA treatment, SciELO, Virtual Health Library, and PubMed databases were searched for rheumatoid arthritis, herbal remedies, and medicinal plants. One of the predominant transcription factors is NF-κB, in regulating inflammatory response. Translocation of active NF-κB into the nucleus leads to gene transcription that produces proinflammatory cytokines. Oxidative stress changes transcription factors, which affects inflammatory gene expression. Phytochemicals have treated various diseases, blocking NF-κB translocation mitigates proinflammatory cascade activation (Withanolides, Gugglosterone, Epigallocatechin-3-gallate, O-glucosylcimifugin, Andrographolide, Curcuminoids, and Resveratrol), Flavonoids (Quercetin, Hesperidin, Kaempferol, Liquirin). Their therapeutic potential aids in creating safe and effective medicines for NF-κB-driven immune-inflammatory disorders like RA. This study emphasises the involvement of NF-κB in a series of events of inflammation, highlighting the role of phytochemicals in regulating its activity. It also discusses the effectiveness of polyphenols in relieving RA by blocking the signalling pathways and suggests a further study to support their usage.
Pummelo is the largest fruit in the citrus family and has thick rind, unique flavour and other biochemical characteristics depending on the genotypes. The consumer preference mostly tends towards fruits with thin rind for easy separation of segments coupled with negligible bitterness. The present study was carried out on two pummelo hybrid progenies planted during August 2016 at Indian Institute of Horticultural Research(IIHR), Bengaluru, Karnataka, India. The morphological and biochemical characterization of 102 pummelo hybrids generated from two different cross combinations was conducted with special emphasis on economic traits (low in bitterness and thin rind). Among the progenies, two hybrid combinations, the fruit weight ranged from 0.72 to 2.62 kg in Acc.12 x Acc.19 with rind thickness ranging from 0.92 to 3.16 cm, while in Acc.3 x Acc.19, the fruit weight ranged from 0.61 to 2.41 kg with rind thickness ranging from 1.08 to 2.88 cm. The mean TSS was 8.80 and 9.02° B across two different cross combinations, respectively. The average titratable acidity ranged from 1.35 to 1.38 % and total flavonoid content of 13.71 and 11.44 mg catechin eqv.100 g-1 in the two hybrid progenies. Based on biochemical traits and sensory evaluations, the elite progenies H17–3, H17–5 and H17–9 from the first cross (Acc.12 x Acc.19) as well as H23–4 and H23–11 from the second cross (Acc.3 x Acc.19), were selected for their low bitterness and high TSS. These selections show potential as valuable breeding stock or new hybrids for commercial cultivation.
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Dietary polyphenols (DPs) have garnered growing interest because of their potent functional properties and health benefits. Nevertheless, the antioxidant capabilities of these substances are compromised by their multifarious structural compositions. Furthermore, most DPs are hydrophobic and unstable when subjected to light, heat, and varying pH conditions, restricting their practical application. Delivery systems based on the interactions of DPs with food constituents such as proteins, polypeptides, polysaccharides, and metal ions are being created as a viable option to improve the functional activities and bioavailability of DPs. In this review, the latest discoveries on the dietary sources, structure-antioxidant activity relationships, and interactions with nutrients of DPs are discussed. It also innovatively highlights the application progress of polyphenols and their green nutraceutical delivery systems. The conclusion drawn is that the various action sites and structures of DPs are beneficial for predicting and designing polyphenols with enhanced antioxidant attributes. The metal complexation of polyphenols and green encapsulation systems display promising outcomes for stabilizing DPs during food processing and in vivo digestion. In the future, more novel targeted delivery systems of DPs for nutrient fortification and intervention should be developed. To expand their usage in customized food products, they should meet the requirements of specific populations for personalized food and nutrition.
Background
Flavonoids are believed to have potential anti-aging effects due to their anti-inflammatory and antioxidant properties. However, the effectiveness of dietary flavonoids and their subclasses in delaying aging has yet to be confirmed. Our study intends to examine relationship between them.
Methods
Data from three survey cycles (2007–2008, 2009–2010, and 2017–2018) of the National Health and Nutrition Examination Survey (NHANES) was used to investigate the relationship between PhenoAgeAccel and dietary flavonoid intake. Weighted linear regression was conducted to evaluate the relationship between dietary flavonoid intake and PhenoAgeAccel, and the dose-response relationship was investigated by limited cubic spline (RCS) analysis. Mixed effects were explored using weighted quantile sum (WQS) regression. Further, the subgroup analyses were also conducted.
Results
A total of 5391 participants were included, after multivariable adjustments, a negative association was found with total dietary flavonoid, flavan-3-ols, flavanone, flavones and flavonols with a β (95% CI) of -0.87 ( -1.61, -0.13), -0.83 (-1.95, -0.08), -1.18 (-1.98, -0.39), -1.64 (-2.52, -0.77) and − 1.18 (-1.98, -0.39) for the higher quintile compared to the lowest quintile. The RCS analysis show a non-linear relationship between flavan-3-ols (P for nonlinear = 0.024), flavanones (P for nonlinear = 0.005), flavones (P for nonlinear < 0.001), flavonols (P for nonlinear < 0.001) and total flavonoid intake (P for nonlinear < 0.001) and PhenoAgeAccel. WQS regression indicated that flavones had the primary effect on the mixture exposures (52.72%). Finally, the subgroup analysis indicated that participants without chronic kidney disease are more likely to benefit from dietary flavanone and flavone intake in mitigating aging, while the benefits of flavanone intake are more significant in participants with a lower body mass index.
Conclusion
Our study suggested that dietary flavonoid intake is negatively associated with accelerating aging in adults of American, and the most influential ones are flavones, flavanones, flavan-3-ols and flavonols.
Phyllanthus Engleri an annual plant of the kingdom Plantae is one of the most popular traditional herbal medicines, and its fruits are used to cure a wide range of illnesses, including fever, stomachaches, kidney cancer, and digestive disorders. Phyllanthus Engleri contains various phytochemicals, with screening mainly identifying constituents like flavonoids, phenols, saponins, alkaloid, Tannins etc. These compounds contribute to plants potential medicinal properties. Among their many advantageous qualities are their anti-inflammatory, anti-mutation, anti-carcinogenic, and ability to regulate key cellular enzyme functions. Phenols often contribute to the medicinal properties of plants. Alkaloids are another class of compound found in various plants. According to preliminary research, Phyllanthus Engleri may also be useful in treating cancer, diabetes, hypertension, and a host of other illnesses. However more research is required to confirm its efficacy and safety for specific medical applications including liver treatment. Conducting research on Urolithic with Phyllanthus Engleri because their gap in the existing studies, and previous research has specifically explored the nephroprotective potential of Phyllanthus Engleri extract which could potentially lead to development of nephroprotectivity treatments or therapies using this extract.
The Chemistry inside Spices & Herbs: Research and Development brings comprehensive information about the chemistry of spices and herbs with a focus on recent research in this field. Experts in phytochemistry have contributed chapters with the aim to give the reader deep knowledge about phytochemical constituents in herbal plants and their benefits. These in-depth reviews cover the biochemistry and biotechnology of spices and herbs, herbal medicines, biologically active compounds and their role in therapeutics among other topics. Chapters which highlight natural drugs and their role in different diseases and special plants of clinical significance are also included. Volume 4 covers these topics: the potential use of Indian spices in managing viral infections, the chemical, functional, and nutritional properties of Coriander, traditional uses, chemical components, and pharmacological properties of Sphaeranthus indicus, Copaiba oleoresins phytochemisty and the pharmacological properties of oils from Copaifera species. Additionally, the pharmacognostic profile of Nardostachys jatamansi is discussed, along with insights into the medicinal herb Bush Onion (Afrostyrax lepidophyllus) and its nutritional and medicinal values. Various aspects of plant essential oils, including their chemistry, extraction methods, and medicinal properties, and plant proteases are also covered in detail. This book is an ideal resource for scholars (in life sciences, phytomedicine and natural product chemistry) and general readers who want to understand the importance of herbs, spices and traditional medicine in pharmaceutical R & D and clinical research.
This study aimed to strengthen the antioxidant defenses against the toxic effect of mercury, by administering a synthetic antioxidant (vitamin E) and a natural product rich in antioxidant compounds (virgin olive oil) to rabbits. Hepatic and renal biomarker levels, cortisol and testosterone synthesis, mercury concentration, relative weight of organs, and tissue architecture were studied. The results showed a significant decrease in the plasma alkaline phosphatase (ALP), plasma aspartate aminotransferase (AST), serum alanine aminotransferase (ALT), plasma testosterone levels, and relative weight of the liver, testes, and adrenal in the mercury treated group (group M), while the other indices were significantly increased in the m-group compared to the control (group C). However, the group treated with olive oil combined with mercury (group O) showed a significant decrease in the ALP, AST, ALT, testosterone levels, and adrenal relative weight, while plasma creatinine, uric acid levels, mercury concentration in organs, and the kidney relative weight were significantly increased. Vitamin E supplementation (group E) led to a significant decrease in the ALP, testosterone levels, and adrenal relative weight, a significant increase was observed in plasma levels of triglycerides, creatinine, and uric acid. Histological sections of the liver, kidney, testis, and adrenal of group M showed severe tissue damage, while the other groups showed less important tissue alterations demonstrating that supplementation with natural or synthetic antioxidants can protect against the toxicity of heavy metals such as mercury, improving the health of rabbits.
This study was aimed to determine the effect of young and old leaves on the quality of soyogik leaf (Saurauia bracteosa DC.) herbal tea. Soyogik leaf herbal tea was made by drying it in an oven at 50˚C for 150 minutes, then testing for phytochemical screening, free radical scavenging activity, and quality standard. Phytochemical screening showed that young and old soyogik leaves contained triterpenoids, flavonoids, saponins and tannins. The antioxidant test results showed that free radical scavenging activity of young soyogik leaves (70.637%) were higher than that of old soyogik leaves (70.204%). Soyogik leaf herbal tea from young leaves had the best quality with the criteria of water content 7.664%; ash content 6.344%; acid insoluble ash content 0.077%; crude fiber 15.36%; metal contamination Pb (0.22 mg/kg), Cd (<0.00009 mg/kg), As (0.15 mg/kg); color with value L = 63.5, a* = 44.8, and b* = 71.2; and the aroma/smell and taste somewhat liked by the panelists. The overall results obtained show that soyogik leaves have potential as herbal teas and the degree of aging can affect the quality of soyogik leaf herbal teas. Keywords: herbal tea, soyogik, Saurauia bracteosa DC., antioxidants, quality ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh daun muda dan daun tua terhadap kualitas mutu teh herbal daun soyogik (Saurauia bracteosa DC.). Pembuatan teh herbal daun soyogik dilakukan dengan pengeringan oven pada suhu 50˚C selama 150 menit, kemudian dilakukan skrining fitokimia, pengujian aktifitas penangkal radikal bebas, dan uji standar mutu. Skrining fitokimia menunjukkan bahwa daun soyogik muda dan tua mengandung triterpenoid, flavonoid, saponin dan tanin. Hasil pengujian antioksidan menunjukkan bahwa aktivitas penangkal radikal bebas daun soyogik muda (70,637%) lebih tinggi dibandingkan dengan daun soyogik tua (70,204%). Teh herbal daun soyogik dari daun muda mempunyai kualitas paling baik dengan kriteria kadar air 7,664%; kadar abu 6,344%; kadar abu tak larut asam 0,077%; serat kasar 15,36%; cemaran logam Pb (0,22 mg/kg), Cd (<0,00009 mg/kg), As (0,15 mg/kg); warna dengan nilai L = 63,5 a* = 44,8, dan b* = 71,2; dan aroma/bau serta rasa yang agak disukai oleh panelis. Keseluruhan hasil yang diperoleh menunjukkan bahwa daun soyogik dapat berpotensi sebagai teh herbal dan tingkat ketuaan daun dapat mempengaruhi kualitas teh herbal daun soyogik. Kata kunci: teh herbal, soyogik, Saurauia bracteosa DC., antioksidan, kualitas mutu
Research has been carried out on the antioxidant activity and inhibition of the α-amylase enzyme extract and fractions of sugar palm fronds and their potential as nanoemulsions. The research stages include preparation, extraction, fractionation, determination of total phenolic content, flavonoids, condensed tannins, scavenging activity of DPPH free radicals and ABTS cation radicals, inhibition of the α-amylase enzyme, nanoemulsion formulation and nanoemulsion characterization. The yield of the resulting extract was 5.46% with the highest fractionation yield in the water fraction (FA) (34.71%) and the lowest in the n-hexane (FNH) fraction (3.50%). The ethyl acetate (FEA) fraction has total phenolic content (176.91 µg/mL), flavonoid content (17.64 µg/mL) and condensed tannin (7.34 µg/mL), DPPH free radical scavenging activity (90 .55%), ABTS cation radicals (99.15%), as well as inhibition of the α-amylase enzyme (84.77%) with the highest value. Formulation 1 has the smallest nanoemulsion size, namely 13.58 nm with a polydispersity index of 0.017. The conclusion of this research is that palm frond extracts and fractions have antioxidant activity and inhibition of the ????-amylase enzyme and have potential as nanoemulsions. Keywords: Sugar palm fronds, antioxidants, ????-amylase enzyme, nanoemulsion ABSTRAK Telah dilakukan penelitian tentang aktivitas antioksidan dan penghambatan enzim α-amilase ekstrak dan fraksi pelepah aren serta potensinya sebagai nanoemulsi. Tahapan penelitian meliputi preparasi, ekstraksi, fraksinasi, penentuan kandungan total fenolik, flavonoid, tanin terkondensasi, aktivitas penangkal radikal bebas DPPH dan radikal kation ABTS, penghambatan enzim α-amilase, formulasi nanoemulsi dan karakterisasi nanoemulsi. Rendemen ekstrak yang dihasilkan sebesar 5,46% dengan rendemen hasil fraksinasi tertinggi pada fraksi air (FA) (34,71%) dan terendah pada fraksi n-heksana (FNH) (3,50%). Fraksi etil asetat (FEA) memiliki kandungan total fenolik (176,91 µg/mL), flavonoid (17,64 µg/mL) dan tanin terkondensasi (7,34 µg/mL), aktivitas penangkal radikal bebas DPPH (90,55%), radikal kation ABTS (99,15%), serta penghambatan enzim α-amilase (84,77%) dengan nilai tertinggi. Formulasi 1 memiliki ukuran nanoemulsi terkecil yaitu sebesar 13,58 nm dengan indeks polidispersitas sebesar 0,017. Kesimpulan hasil penelitian ini adalah ekstrak dan fraksi pelepah aren memiliki aktivitas antioksidan dan penghambatan enzim ????-amilase serta berpotensi sebagai nanoemulsi. Kata kunci: Pelepah aren, antioksidan, enzim ????-amilase, nanoemulsi
In the seeds of bird's foot trefoil (Lotus corniculatus L.) the presence of quercetin- and kaempferol heterosides was found. Eight crystalline compounds and one chromatographically homogeneous fraction were obtained from the flavonoid mixture using column chromatography on polyamide and cellulose. By means of TL-chromatography, elemental analysis and UV-spectrometry seven of the isolated compounds were identified to be quercetin, quercetin 3-arabopyranoside (guajaverin), quercetin 3-galactoside, quercetin 3-rhamnoside, kaempferol 3,7-diglucoside, kaempferol 3,7-dirhamnoside kaempferol 3-glucosyl-7-rhamnoside and two remaining ones were only partly characterized a snearer indefinite kaempferol heterosides.
Five compounds having an isoflavone structure were isolated from the tops of red clover (Trifolium pratense). On the basis of spectral (UV, MS) and chromatographic (TLC, HPLC) analyses the compounds were identified as biochanin A, formononetin, pratensein, genistein and daidzein. Biochanin A and formononetin - two main clover estrogens - were obtained in crystalline forms in the amounts of 50 mg and 15 mg, respectively (per 250 g of D. W.). Homogenous fractions of pratensein, genistein, and daidzein were also obtained. The obtained standards were used as markers for peak identification in HPLC. The presented method of isoflavone isolation is simple and quick. It allows for the simple isolation of a mixture of crude isoflavone aglycones which may be used in qualitative and semi-quantitative (TLC) analyses. The individual standards are obtained through column chromatography and may be used for quantitative analyses.
Four dominant flavonoid compounds in crystal form were isolated from flowers of Medicago lupulina L. and identified as laricytrin (3'-metoxy-3,4',5,5'7-pentahydroxyflavone), and its three glycosides: 5'-O-β-D-glucoside, 3,5'-O-β-D-diglucoside and 3,5',7-0-β-D-triglucoside. The described monoglucoside is a new compound, isolated for the first time from plant material. The remaining three flavonoid constituents appear only in trace amounts characterized as heterosides of kaempferol, quercetin and myricetin with 0-glycoside bounded in the position 3.
Flavonoids occurring in Vernonia amygdalina leaves have been studied. Three flavones were identified with chemical and spectroscopic techniques. They were identified as luteolin, luteolin 7-O-beta-glucuronoside, and luteolin 7-O-beta-glucoside. The most abundant compound was luteolin 7-O-beta-glucuronoside. The antioxidant activity of the three flavones was determined by measuring the coupled oxidation of beta-carotene and linoleic acid. It was shown that luteolin was a significantly more potent antioxidant than the synthetic antioxidant butylated hydroxytoluene (BHT) at the same concentration (15 mg/L). The two glycosides showed similar activities but significantly lower activities than luteolin or BHT.
Six flavonoids have been isolated and identified in buckwheat grain. These are rutin, orientin, vitexin, quercetin, isovitexin, and isoorientin. Rutin and isovitexin are the only flavonoid components of buckwheat seeds while hulls contain all six identified compounds. The total flavonoid concentration in the seeds was 18.8 and in the hulls 74 mg/100 g of dry matter. Dehulling the grain by using different temperature regimes resulted in drastic reductions of the total flavonoid concentration in the grain (by 75% of the control) and smaller but significant (15-20%) reduction in the hulls.
Natural antioxidants in foods may be from (a) endogenous compounds in one or more components of the food; (b) substances formed from reactions during processing; and (c) food additives isolated from natural sources. Most natural antioxidants are from plants. Most plants contain compounds that possess antioxidant activity. They are polyphenolics that occur in all parts of the plant - wood, bark, stems, leaves, fruit, roots, flowers, pollen and seeds. The antioxidant activities in these plants range from extremely slight to very great. Natural antioxidants may function (a) as reducing agents, (b) as free radical scavengers, (c) as complexers of pro-oxidant metals, and (d) as quenchers of the formation of singlet oxygen. The most common natural antioxidants are flavonoids (flavanols, isoflavones, flavones, catchins, flavanones), cinnamic acid derivatives, coumarins, tocopherols, and polyfunctional organic acids. The antioxidants of plants are phenolics. Some form complexes with metals. However, the major value is in their primary antioxidant activity (i.e., as free radical acceptors and as chain breakers.)
Six flavonoids have been isolated and identified in buckwheat grain. These are rutin, orientin, vitexin, quercetin, isovitexin, and isoorientin. Rutin and isovitexin are the only flavonoid components of buckwheat seeds while hulls contain all six identified compounds. The total flavonoid concentration in the seeds was 18.8 and in the hulls 74 mg/100 g of dry matter. Dehulling the grain by using different temperature regimes resulted in drastic reductions of the total flavonoid concentration in the grain (by 75% of the control) and smaller but significant (15-20%) reduction in the hulls.
The conformational behavior, molecular geometry and electronic structure of quercetin were investigated using the semiempirical AM1 and PM3 methods. Results reveal that quercetin has a nonplanar molecular structure, with cross-conjugation occurring at the C ring. Calculations were also performed for quercetin radical species at the OH groups, showing the presence of three radicals in a narrow range of energy. An interpretation of the antioxidative process mechanism, exerted by quercetin as a free radical scavenger, relies on two isoenergetic radicals with extended electronic delocalization between adjacent rings, also having cross-conjugated systems and being affected by the experimental environment influencing their relative order.
This study was aimed at evaluating the antioxidant effectiveness of α-tocopherol and its water-soluble analogue, Trolox, in different lipid systems. The oxidative stability of lipids in bulk and emulsion systems at 37 °C decreased in the order corn oil triglycerides > methyl linoleate > linoleic acid. In both bulk and emulsified linoleic acid, Trolox was a better inhibitor of hydroperoxide formation and decomposition than α-tocopherol. However, in bulk methyl linoleate and corn oil triglycerides, although Trolox was a better inhibitor of hydroperoxide formation, in emulsions, α-tocopherol was a better inhibitor of both the formation and decomposition of hydroperoxides. In emulsified methyl linoleate and corn oil, the partition coefficients of Trolox between lipids and water at high concentrations were not affected by Tween 20, and the antioxidant activity of Trolox decreased because it partitioned into the water phase and Tween 20 micelles. In contrast, in linoleic acid emulsified with Tween 20, the formation of mixed micelles of linoleic acid and Tween 20 increased the percentage of Trolox in the water phase and Trolox was more effective as an antioxidant than α-tocopherol because it diffused in the water phase and into mixed micelles. The physical states of lipid systems affect the distribution of antioxidants and thus significantly influence their antioxidant behavior. Because linoleic acid has unique physical properties in aqueous micelles, it may not be a valid substrate for evaluating food antioxidants. Keywords: Antioxidants; α-tocopherol; Trolox; partitioning; partition coefficient; linoleic acid; methyl linoleate; corn oil triglycerides; emulsion; mechanism; interfacial oxidation; hydroperoxides; hexanal
The antioxidant activity of selected representatives of flavonoids, coumarins, and cinnamic acids was examined by measuring their protective action toward linoleic acid peroxidation in micelles of sodium dodecyl sulfate in buffer solution, pH 7.4. Results are expressed as relative antioxidant efficiency (RAE), defined as the ratio of the antioxidant efficiency (AE) of the tested compound to that of α-tocopherol. The best RAE values were observed for flavonoids, followed by coumarins and cinnamic acids. From the results, within each class of compounds a structure−activity relationship can be deduced. Keywords: Antioxidant; flavonoids; coumarins; cinnamic acids and esters; relative antioxidant efficiency (RAE); lipid peroxyl radicals; α-tocopherol
Spectral, acid-base, and redox properties of the phenoxyl radicals derived from 3,4-dihydroxybenzene derivatives and selected flavonoids were studied by pulse radiolysis of aqueous solutions. From the pH-dependent changes in the phenoxyl spectra, the dissociation constants were derived. The pK(a), values for the deprotonation of the 3'-OH group in the catechin (pK(a) = 4.6) and rutin (pK(a) = 4.3) radicals are similar to the pK(a) value of the 3,4-dihydroxybenzoate radicals, pK(a) = 4.2, which is expected from their similar electronic structures. Deprotonation of 5- and 7-OH in the catechin and rutin and of 5-OH in the hesperidin radicals has no effect on the radical spectra, which is explained by the inefficient coupling of the A-ring of the flavonoid radicals with the unpaired electron. Because of favorable reduction potentials of the phenoxyl radicals, E(7) = 0.56-0.7 V vs NHE, flavonoids may act as efficient antioxidants of alkylperoxyl and superoxide/hydroperoxyl radicals. The ac kinetic conductivity method was developed for the measurements of the low reaction rate constants of the superoxide radical reactions with flavonoids and phenols in aqueous solutions at pH 10. The rates of the superoxide radical reactions with flavonoids, k = 3 X 10(2)-5.1 X 10(4) M(-1) s(-1), depend on the redox properties and the charge of the flavonoids. The highest rates are measured for the oxidation of quercetin and rutin, whereas the lowest are those for the B-ring monosubstituted derivatives, with substantially higher redox potentials. Uncharged catechin at pH 7 reacts at k = 6.6 X 10(4) M(-1) s(-1), whereas the rate at pH 10, where catechin is doubly negatively charged, is approximately 4 times lower, k = 1.8 x 10(4) M(-1) s(-1). The activation parameters of the oxidation of rutin and trolox at pH 10 and methyl gallate at pH 7 were determined in an attempt to understand why the rates of the superoxide reactions are low despite high driving forces of Delta E greater than or equal to 0.4 V. Low activation enthalpies, Delta H-double dagger = 2.3-3.6 kcal/mol, and negative activation entropies, Delta S-double dagger = -25-28 cal/(mol K), point to an inner-sphere electron-transfer mechanism.
This chapter discusses the fluorescence measurements of incorporation and hydrolysis of tocopherol and tocopheryl esters in biomembranes. The hydrolysis of nonfluorescent esterified chromanols can be studied by the appearance and increase of the intensity of fluorescence emitted by chromanols produced in the course of deesterification reactions. Excitation at 303 rather than 292 nm should be used to minimize the interference of protein fluorescence. The sensitivity of the assay is determined by the minimum amounts of chromanols producing a distinct fluorescence increment in the presence of a given concentration of membrane protein. Preliminary calibration by addition of standard amounts of chromanols to membrane suspensions allows obtaining the rates of hydrolysis of esterified chromanols. The chapter summarizes the data on the hydrolysis rates of α-T acetate, α-stearate, linoleate, phosphate, and 2,2,5,7,8-pentamethylchromane acetate (C1 acetate) in suspensions of rat liver mitochondria and microsomes at three different temperatures. The de-esterification rates depend on the chemical nature of the ester and the incubation temperature, and they differ significantly in microsomes, mitochondria, and, particularly, in blood serum.
Ginkgo biloba extract is known to be efficient in diseases associated with free radical generation. This study compares the in vitro effect of some constituents of Ginkgo against lipid peroxidation and cell necrosis of isolated rat hepatocytes, and against superoxide anion which is generally implicated in cell damages.
The antioxidant and prooxidant behavior of flavonoids and the related activity-structure relationships were investigated in this study using the oxygen radical absorbance capacity assay. Three different reactive species were used in the assay: 2,2'-azobis(2-amidino-propane) dihydrochloride, a peroxyl radical generator; Cu(2+)-H2O2, mainly a hydroxyl radical generator; and Cu2+, a transition metal. Flavonoids including flavones, isoflavones, and flavanones acted as antioxidants against peroxyl and hydroxyl radicals and served as prooxidants in the presence of Cu2+. Both the antioxidant and the copper-initiated prooxidant activities of a flavonoid depend upon the number of hydroxyl substitutions in its backbone structure, which has neither antioxidant nor prooxidant action. In general, the more hydroxyl substitutions, the stronger the antioxidant and prooxidant activities. The flavonoids that contain multiple hydroxyl substitutions showed antiperoxyl radical activities several times stronger than Trolox, an alpha-to copherol analogue. The single hydroxyl substitution at position 5 provides no activity, whereas the di-OH substitution at 3' and 4' is particularly important to the peroxyl radical absorbing activity of a flavonoid. The conjugation between rings A and B does not affect the antioxidant activity but is very important for the copper-initiated prooxidant action of a flavonoid. The O-methylation of the hydroxyl substitutions inactivates both the antioxidant and the prooxidant activities of the flavonoids.
Since reactive oxygen radicals play an important role in carcinogenesis and other human disease states, antioxidants present in consumable fruits, vegetables, and beverages have received considerable attention as cancer chemopreventive agents. Thus, in order to identify antioxidants in plant extracts, test materials were assessed for potential to scavenge stable 1,2-diphenyl-2-picrylhydrazyl (DPPH) free radicals, reduce TPA-induced free radical formation in cultured HL-60 human leukemia cells, and inhibit responses observed with a xanthine/xanthine oxidase assay system. Approximately 700 plant extracts were evaluated, and 28 were found to be active in the DPPH free radical scavenging assay. Based on secondary analyses performed to assess inhibition of 7,12-dimethylbenz(a)anthracene-induced preneoplastic lesion formation with a mouse mammary organ culture model, Chorizanthe diffusa Benth. (Polygonaceae), Mezoneuron cucullatum Roxb. (Leguminosae), Cerbera manghas L. (Apocynaceae) and Daphniphyllum calycinum Benth. (Daphniphyllaceae) were selected and subjected to bioassay-guided fractionation. 5,7,3',5'-Tetrahydroxy-8,4'-dimethoxyflavonol, 5,8,4'-trihydroxy-7,3'-dimethoxyflavonol, 5,3',4'-trihydroxy-7-methoxyflavonol, and 6,3',4'-trihydroxy-7-methoxyflavonol were identified as active principles from C. diffusa. Piceatannol, trans-resveratrol, apigenin and scirpusin A were found as the active principles of M. cucullatum, olivil, (-)-carinol, and (+)-cycloolivil were active principles from C. manghas, and 5,6,7,4'-tetrahydroxyflavone 3-O-rutinoside and kaempferol 3-O-neohesperidoside were active principles from D. calycinum. Of these substances, the hydroxystilbenes piceatannol and transresveratrol have thus far been shown to inhibit carcinogen-induced preneoplastic lesion formation in the mouse mammary gland organ culture model.
An ethyl acetate-soluble extract of Chorizanthe diffusa was found to exhibit significant antioxidant activity, as judged by scavenging stable 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radicals and inhibition of 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced free radical formation with cultured HL-60 cells. Bioassay-directed fractionation of this extract using the DPPH antioxidant assay as a monitor led to the isolation of five structurally related flavonoids (1-5), including the novel compound 5,8,3',4',5'-pentahydroxy-3, 7-dimethoxyflavone (1). Isolates 1-5 demonstrated varying degrees of antioxidant or antimutagenic activity. Two of the compounds, 5,7,3', 4'-tetrahydroxy-3-methoxyflavone (2) and quercetin (4), were subsequently found to inhibit carcinogen-induced preneoplastic lesions in a mouse mammary organ culture model. Inhibitory activity of this type is known to correlate with cancer chemopreventive effects in full-term models of tumorigenesis.
Chromatography of biflavanones from Garcinia kola fruit
- S Burda
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Burda, S.; Oleszek, W.; Igile, G. O. Chromatography of
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Flavonoids from needles of Pinus silvestris as a markers of chemical biogenesis of pine
- W Oleszek
- A Stochmal
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- A M Simonet
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Antioxidant activity of R-tocopherol and trolox in different lipid substrates: bulk oils vs oil-inwater emulsions Semiempirical molecular modeling into quercetin reactive site: structural , conformational, and electronic features
- S Huang
- W Hopia
- A Schwarz
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Dietary flavonoids as plasma antioxidants on lipid peroxidation: Significance of metabolic conversion In Antioxidant Food Supplements in Human Health Received for review November 27 Revised manuscript received
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and cinnamic acids as antioxi-dants in a micellar system Structure-activity relation-ship
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Flavonoids as antioxidants
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Screening of phenolics and flavonoids for antioxidant activity
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