Antioxidant activity evaluation of dietary phytochemicals using Saccharomyces cerevisiae as a model

In Vitro Analysis of Selected Antioxidant and Biological Properties of the Extract from Large-Fruited Cranberry Fruits

This study investigated the in vitro antioxidant and biological properties of ethanol extracts obtained from the fruits of the highbush cranberry. The produced extracts exhibited a high content of polyphenols (1041.9 mg 100 g d.m.-1) and a high antioxidant activity (2271.2 mg TE g 100 d.m.-1 using the DPPH method, 1781.5 mg TE g 100 d.m.-1 using the ABTS method), as well as a substantial amount of vitamin C (418.2 mg 100 g d.m.-1). These extracts also demonstrated significant in vitro biological activity. Studies conducted on the Saccharomyces cerevisiae cellular model revealed the strong antioxidant effects of the extract, attributed to a significant reduction in the levels of reactive oxygen species (ROS) within the cells, confirming the utility of the extracts in mitigating oxidative stress. Moreover, inhibitory properties were demonstrated against factors activating metabolic processes characteristic of inflammatory conditions. It was observed that the cranberry extract inhibits the activity of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) non-selectively. Additionally, the extract was found to be a highly active inhibitor of acetylcholinesterase (AChE), potentially suggesting the applicability of this extract in the prevention of neurodegenerative diseases, including Alzheimer's disease.

Evaluation of Physicochemical and Microbial Properties of Extracts from Wine Lees Waste of Matelica’s Verdicchio and Their Applications in Novel Cosmetic Products

Wine lees are sediments deposited on the walls and bottom of barrels resulting from wine fermentation and mainly consist of yeasts. Saccharomyces cerevisiae extracts, rich in beneficial components for the skin, have already been used in cosmesis, while wine lees have not been well exploited by the cosmetics industry yet. The aim of this work was the full characterization of the wine lees from Verdicchio’s wine, with the aim to exploit it as a beneficial ingredient in new cosmetic products. After mapping the microbial composition of the sample waste, the parameters for the sonication extraction process were optimized and the physicochemical properties of the extract were analyzed. The efficiency of the aqueous extraction—and in particular the yeast cell lysis necessary for the release of proteins from the cell—was assessed by evaluating cell shape and size, and protein release, under scanning electron microscopy (SEM), dynamic light scattering (DLS) and Bradford’s protein assays. Thus, the total phenol content and antioxidant capacity of the supernatant recovered from native and sonicated lees were determined by Folin–Ciocalteu’s and spectrophotometric assays, respectively. To quantify the heavy metals and highlight the presence of microelements beneficial for the skin, inductively coupled plasma-mass spectrometry (ICP-MS) was applied. In vitro metabolic activity and cytotoxicity were tested on both HaCat keratinocytes and human gingival fibroblasts, showing that wine lees are safe for skin’s cells. The results show that sonicated lees appear to be more interesting than native ones as a consequence of the release of the active ingredients from the cells. Due to the high antioxidant capacity, content of beneficial elements for skin and an appropriate microbiologic profile, wine lees were included in five new solid cosmetic products and tested for challenge test, compatibility with human skin, sensory analysis, trans epidermal water loss (TEWL) and sebometry.

Invited review: Rumen modifiers in today's dairy rations

Our aim was to review feed additives that have a potential ruminal mechanism of action when fed to dairy cattle. We discuss how additives can influence ruminal fermentation stoichiometry through electron transfer mechanisms, particularly the production and usage of dihydrogen. Lactate accumulation should be avoided, especially when acidogenic conditions suppress ruminal neutral detergent fiber digestibility or lead to subclinical acidosis. Yeast products and other probiotics are purported to influence lactate uptake, but growing evidence also supports that yeast products influence expression of gut epithelial genes promoting barrier function and resulting inflammatory responses by the host to various stresses. We also have summarized methane-suppressing additives for potential usage in dairy rations. We focused on those with potential to decrease methane production without decreasing fiber digestibility or milk production. We identified some mitigating factors that need to be addressed more fully in future research. Growth factors such as branched-chain volatile fatty acids also are part of crucial cross-feeding among groups of microbes, particularly to optimize fiber digestibility in the rumen. Our developments of mechanisms of action for various rumen-active modifiers should help nutrition advisors anticipate when a benefit in field conditions is more likely.

Evaluation of The Antioxidant Capacity of Food Products: Methods, Applications and Limitations

Assays of total antioxidant capacity (TAC) are popular in the analysis of food products. This review presents the most popular assays of TAC and their limitations, databases of TAC of food products, their application in clinical studies, and the effect of processing on the TAC of food. The importance of sample preparation for TAC assays and striking effects of digestion in the gastrointestinal tract on the TAC of food are discussed. Critical opinions on the validity of food TAC assays are considered. It is concluded that TAC methods can be useful as screening assays for food quality control and as low-cost, high-throughput tools used to discover potential antioxidant sources and follow changes in the content of antioxidants during food processing. However, effects revealed by TAC assays should be followed and explained using more specific methods.

Comparative study of the antioxidant activity of the essential oils of five plants against the H2O2 induced stress in Saccharomyces cerevisiae

The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H₂O₂ (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H₂O₂. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H₂O₂ only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress.

Antioxidant Phytochemicals for the Prevention of Fluoride-Induced Oxidative Stress and Apoptosis: a Review

Fluorosis is a major public health problem globally. The non-availability of specific treatment and the irreversible nature of dental and skeletal lesions poses a challenge in the management of fluorosis. Oxidative stress is known to be one of the most important mechanisms of fluoride toxicity. Fluoride promotes the accumulation of reactive oxygen species by inhibiting the activity of antioxidant enzymes, resulting in the excessive production of reactive oxygen species at the cellular level which further leads to activation of cell death processes such as apoptosis. Phytochemicals that act as antioxidants have the potential to protect cells from oxidative stress. Evidence confirms that clinical symptoms of fluorosis can be mitigated to some extent or prevented by long-term intake of antioxidants and plant products. The primary purpose of this review is to examine recent findings that focus on the amelioration of fluoride-induced oxidative stress and apoptosis by natural and synthetic phytochemicals and their molecular mechanisms of action.

Oxidative stress alleviating potential of galactan exopolysaccharide from Weissella confusa KR780676 in yeast model system

In the present study, galactan exopolysaccharide (EPS) from Weissella confusa KR780676 was evaluated for its potential to alleviate oxidative stress using in vitro assays and in vivo studies in Saccharomyces cerevisiae (wild type) and its antioxidant (sod1∆, sod2∆, tsa1∆, cta2∆ and ctt1∆), anti-apoptotic (pep4∆ and fis1∆) and anti-aging (sod2∆, tsa1∆ and ctt1∆)) isogenic gene deletion mutants. Galactan exhibited strong DPPH and nitric oxide scavenging activity with an IC₅₀ value of 450 and 138 µg/mL respectively. In the yeast mutant model, oxidative stress generated by H₂O₂ was extensively scavenged by galactan in the medium as confirmed using spot assays followed by fluorescencent DCF-DA staining and microscopic studies. Galactan treatment resulted in reduction in the ROS generated in the yeast mutant cells as demonstrated by decreased fluorescence intensity. Furthermore, galactan exhibited protection against oxidative damage through H₂O₂ -induced apoptosis inhibition in the yeast mutant strains (pep4∆ and fis1∆) leading to increased survival rate by neutralizing the oxidative stress. In the chronological life span assay, WT cells treated with galactan EPS showed 8% increase in viability whereas sod2∆ mutant showed 10–15% increase indicating pronounced anti-aging effects. Galactan from W. confusa KR780676 has immense potential to be used as a natural antioxidant for nutraceutical, pharmaceutical and food technological applications. As per our knowledge, this is the first report on in-depth assessment of in vivo antioxidant properties of a bacterial EPS in a yeast deletion model system.

On the Role of the Carboxyl Group to the Protective Effect of o-dihydroxybenzoic Acids to Saccharomyces cerevisiae Cells upon Induced Oxidative Stress

In the present work, the role of the carboxyl group of o-dihydroxybenzoic acids (pyrocatechuic, 2,3-diOH-BA and protocatechuic, 3,4-diOH-BA) on the protection against induced oxidative stress in Saccharomyces cerevisiae was examined. Catechol (3,4-diOH-B) was included for comparison. Cell survival, antioxidant enzyme activities, and TBARS level were used to evaluate the efficiency upon the stress induced by H₂O₂ or cumene hydroperoxide. Theoretical calculation of atomic charge values, dipole moment, and a set of indices relevant to the redox properties of the compounds was also carried out in the liquid phase (water). Irrespective of the oxidant used, 2,3-diOH-BA required by far the lowest concentration (3–5 μM) to facilitate cell survival. The two acids did not activate catalase but reduced superoxide dismutase activity (3,4-diOH-BA>2,3-diOH-BA). TBARS assay showed an antioxidant effect only when H₂O₂ was used; equal activity for the two acids and inferior to that of 3,4-diOH B. Overall, theoretical and experimental findings suggest that the 2,3-diOH-BA high activity should be governed by metal chelation. In the case of 3,4-diOH BA, radical scavenging increases, and chelation capacity decreases. The lack of carboxyl moiety (3,4-diOH B) improves to radical scavenging, interaction with lipophilic free radicals, and antioxidant enzymes. The present study adds to our knowledge of the antioxidant mechanism of dietary phenols in biological systems.

Bioactive compounds of parsley (Petroselinum crispum), chives (Allium schoenoprasum L) and their mixture (Brazilian cheiro-verde) as promising antioxidant and anti-cholesterol oxidation agents in a food system

This study determined the bioactive composition and antioxidant potential of parsley, chives and their mixture (Brazilian cheiro-verde). Additionally, the effect of these herbs against cholesterol oxidation in grilled sardines (Sardinella brasiliensis) was also investigated. Ultra-high Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometry (UHPLC-ESI-MS) analyses revealed the presence of phenolic acids (caffeic, chlorogenic, and ferulic acids) and flavonoids (apigenin, kaempferol, catechin) in the herbs. Higher levels of phenolics (2.10 ± 0.02 mg GAE/g) and carotenoids (205.95 ± 0.17 µg/g) were determined in parsley extracts. Moreover, parsley also presented higher antioxidant capacity by DPPH (59.21 ± 0.07 %) and ORAC (109.94 ± 18.7 µM TE/g) than the other herbs. In vivo analyses demonstrated that the herbs' extracts decreased the damage on Saccharomyces cerevisiae cells exposed to H₂O₂, except the chives extract at 10 μg/mL. Higher levels of cholesterol oxidation products (COPs) were determined after grilling. The total COPs increased from 61.8 ± 0.7 (raw fish) to 139.7 ± 10.1 µg/g (control). However, the addition of herbs effectively reduced cholesterol oxides formation, this effect was more pronounced in fish containing 4% parsley and 4% cheiro-verde. Promising results were found for cheiro-verde; however, it did not present synergic antioxidant effects.

Natural Cinnamic Acid Derivatives: A Comprehensive Study on Structural, Anti/Pro-Oxidant, and Environmental Impacts

Cinnamic acid (CA), p-coumaric acid (4-hydroxycinnamic acid, 4-HCA), caffeic acid (3,4-vdihydroxycinnamic acid, 3,4-dHCA), and 3,4,5-trihydroxycinnamic acid (3,4,5-tHCA) were studied for their structural, anti-/pro-oxidant properties and biodegradability. The FT-IR, FT-Raman, UV/Vis, ¹H and ¹³C NMR, and quantum chemical calculations in B3LYP/6-311++G** were performed to study the effect on number and position of hydroxyl group in the ring on the molecular structure of molecules. The antioxidant properties of the derivatives were examined using DPPH^● and HO^● radicals scavenging assays, ferric ion reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), inhibition of linoleic acid oxidation, as well as the biological antioxidant assay with Saccharomyces cerevisiae. Moreover, the pro-oxidant activity of compounds in Trolox oxidation assay was estimated. The effect of the derivatives on environment on the basis of increasing the carbon and nitrogen compounds transformation processes occurring in biological wastewater treatment was studied.

Antioxidant properties and phenolic composition of "Composed Yerba Mate"

Yerba mate contains bioactive compounds, and is widely consumed as a decoction beverage in several Southern American countries. At present, the consumption of mate with added herbal blends and flavors, called "composed yerba mate", has increased; however, no studies on the antioxidant characteristics of these products have been published. In this sense, the main objective was to assess the antioxidant characteristics of "composed yerba mate" compared to "traditional yerba mate", in the form it is traditionally consumed. Total polyphenols content ranged from 15 to 45 mg/g GAE in all decoctions analyzed. Seventeen phenolic compounds were identified and quantified by HPLC-DAD-MS/MS, mainly belonging to the caffeoylquinic acids group. The antioxidant capacity was measured using in vitro assays, Ferric reducing ability of plasma (FRAP) and Trolox equivalent antioxidant capacity (TEAC), and with Saccharomyces cerevisiae as the in vivo model organism. All decoctions displayed antioxidant activity and were capable of rescuing yeast cells between 10.68 and 18.38% from oxidative stress. Multiple regression analysis showed a high correlation between phenolic composition and activity of samples, where different compounds indicate a significant contribution to the observed activity. Significant differences were found in the content, profile and antioxidant activity of polyphenols when "traditional yerba mate" and "composed yerba mate" were compared. In some cases, the antioxidant capacity was similar or higher in composed yerba mate; while the rest displayed lower biological activity. Based on these findings, it would be possible to assume that the addition of herb mixtures modifies the antioxidant and biological properties of mate.

Supplementary Information

The online version contains supplementary material available at (10.1007/s13197-020-04961-x).

Antioxidant action and enzyme activity modulation by bioaccessible polyphenols from jambolan (Syzygium cumini (L.) Skeels)

Jambolan is rich in antioxidant polyphenols; however, the bioactivity of these compounds remains poorly investigated. We compared changes in polyphenols and antioxidant capacity by ABTS and FRAP assays of jambolan pulp during in vitro digestion and chemical extraction and evaluated the effects of these changes on oxidative stress in wild and mutant Saccharomyces cerevisiae. Digestion and chemical extraction were performed with enzyme saline solutions, deionized water, and 50% (v/v) aqueous acetone solution. Caffeic, quinic, gallic, and ellagic acids, isomers of myricetin, catechin, and anthocyanins are bioaccessible during gastric digestion. In the duodenum, flavonoids and proanthocyanidins remained stable when the pH changed from acidic to neutral/alkaline, whereas anthocyanins were degraded when exposed to pH 7. In the colon, anthocyanins were not identified. The antioxidant activity of bioaccessible fractions is correlated with non-anthocyanin flavonoids and proanthocyanidins, reflected in the modulation of antioxidant enzymes of S. cerevisiae. The digestion process favors the release of bio-polyphenols from jambolan with preventive, scavenger, and reparative antioxidant action. They also stimulate the production and activity of Sod and Cat, strengthening the endogenous antioxidant system.

Comparison of Antioxidant and Antibacterial Activities of Camellia Oil From Hainan With Camellia Oil From Guangxi, Olive Oil, and Peanut Oil

Background/Aim: Camellia oil from Hainan (SY) is a unique vegetable oil in Hainan, China, due to the geographical environment and oil extraction only through simple physical treatments. To compare SY with camellia oil from Guangxi (SC), olive oil (GL), and peanut oil (HS), this study analyzed the antioxidant and antibacterial activity of four vegetable oils.

Methods: Using Gallic acid, BHT as the control, Saccharomyces cerevisiae as the model organism, the antioxidant activities of vegetable oils were measured in vitro and in vivo, and the antibacterial activity was measured with the minimum inhibitory concentration (MIC) method.

Results: The major contents of SY, SC, and HS were oleic Acid; the major content of GL was squalene. The highest total flavonoids content of SY was 39.50 ± 0.41 mg RE/g DW; and the highest total phenolic content of SC was 47.05 ± 0.72 mg GAE/g DW. SY exhibited the strongest scavenging activity of hydroxyl radical (HO·) and superoxide anions (O2-·), the IC₅₀ value were 2.06 mg/mL, 0.62 mg/mL, respectively; and SC showed the strongest DPPH· and ABTS· scavenging activity and the reducing abilities. SY showed excellent effect on survival rate, protection rate, flavonoids uptake of S. cerevisiae cells, decreased MDA content and ROS level, inhibited CAT, POD, and GR enzyme activity. The absorption of SC total phenols was the highest by cells. The activity showed GL had a broad-spectrum antibacterial activity.

Conclusion: Thus, SY shows potential antioxidant activity and provides an important reference value for people to choose edible vegetable oils.

Toxicological assessment of a bioactive extract from Triplaris gardneriana Wedd. seeds using alternative models

The Triplaris gardneriana Wedd. seeds extract has great therapeutic potential due to numerous biological activities such as antioxidant, antibacterial and anti-inflammatory, which are associated with phenolic content. Although this herbal preparation has shown many benefits, recently their toxicity profile has begun to be explored. In this present study, the toxic effects of T. gardneriana seeds ethanolic extract (EETg) on biological systems of different taxonomical groups and levels of complexity (from cell culture to lower vertebrates) were assessed, through a variety of viability and toxicological assays. It was found that EETg did not impair the Saccharomyces cerevisiae growth at the highest tested concentration (200 µg/mL), and no toxicant evidence was observed in Aedes aegypti larvae or in Drosophila melanogaster adult stage. Contrarily, the extract reduced the viability of undifferentiated Caco-2 cells (250 µg/mL, 40% of viable cells), but did not affect differentiated ones. The embryotoxicity in Danio rerio model showed a LC₅₀ of 7.41 mg/L (95% confidence interval, 4.78 - 11.49 mg/L). EETg did not show signs of toxicity in the majority of the models used, but lethality and malformations in zebrafish embryos occurred. Further analyses are needed to better understand the selective toxicity mechanism of EETg on zebrafish, as well as whether the toxic effects happen in higher vertebrates.

Antifungal activity of an allicin derivative against Penicillium expansum via induction of oxidative stress

The application of natural preservatives has become an attractive method for controlling postharvest decay of fruits and vegetables. Allicin, the main active ingredient of allium plants, has broad-spectrum antifungal activity. However, the unstable properties of allicin limit its wide application. In this study, 1-[(R)-ethylsulfinyl]sulfanylethane, a structurally stable derivative of allicin, was used to explore its antifungal activity and potential mechanism on the expansion of Penicillium expansum. We demonstrated the antifungal activity of 1-[(R)-ethylsulfinyl]sulfanylethane through in vitro antifungal experiments. At the concentration is 2 mg/L, 1-[((R)-ethylsulfinyl]sulfanyl]ethane can completely inhibit spore germination and mycelial growth, whereas the concentration of allicin needs to reach 16 mg/L. Fungal Biochemical assay indicated that decrease of mitochondrial membrane potential, overgeneration of reactive oxygen species, decrease of adenosine triphosphate and glutathione content, increase of superoxide dismutase, catalase, and malondialdehyde content. The results revealed that 1-[(R)-ethylsulfinyl]sulfanylethane induced mitochondrial dysfunction and oxidative stress in P. expansum. Due to its excellent antifungal activity, 1-[((R)-ethylsulfinyl]sulfanyl]ethane might be developed as a substitute for fungicides against P. expansum in postharvest fruit storage.

Anxiety Therapeutic Interventions of β-Caryophyllene: A Laboratory-Based Study

The bicyclic sesquiterpene β-caryophyllene (BCP) has diverse biological activities, including antioxidant, anti-inflammatory, antidiabetic, and analgesic effects. This study evaluates anxiolytic, toxicity, and antioxidant effects of BCP using in vitro and in vivo test models. The anxiolytic effects were tested in Swiss albino mice ( Mus musculus) by applying the elevated plus-maze, rota-rod, light and dark, and hiding sphere models, while the toxicity was evaluated by brine shrimp ( Artemia salina) lethality bioassay. Additionally, the antioxidant capacity was tested by using 2,2-diphenyl-1-picrylhydrazyl radical, 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic acid hydroxyl radical scavenging, and the Saccharomyces cerevisiae test model. The results suggest that BCP exerted a dose-dependent anxiolytic-like effect on the experimental animals. It did not show toxicity in A. salina at 24 hours. BCP showed a concentration-dependent free-radical-scavenging capacity, similar to the standard antioxidant Trolox. It also showed protective and repair capacities against hydrogen peroxide-induced damaging effects in isogenic and wild-type S. cerevisiae strains. Taken together, BCP exerted antioxidant and protective effects, which can be targeted to treat neurological diseases and disorders such as anxiety.

Thermoplastic microfluidic bioreactors with integrated electrodes to study tumor treating fields on yeast cells

Tumor-treating fields (TTFields) are alternating electrical fields of intermediate frequency and low intensity that can slow or inhibit tumor growth by disrupting mitosis division of cancerous cells through cell cycle proteins. In this work, for the first time, an in-house fabricated cyclo-olefin polymer made microfluidic bioreactors are integrated with Cr/Au interdigitated electrodes to test TTFields on yeast cells with fluorescent protein:Nop56 gene. A small gap between electrodes (50 μm) allows small voltages (<150 mV) to be applied on the cells; hence, uninsulated gold electrodes are used in the non-faradaic region without causing any electrochemical reaction at the electrode-medium interface. Electrochemical modeling as well as impedance characterization and analysis of the electrodes are done using four different cell nutrient media. The experiments with yeast cells are done with 150 mV, 150 kHz and 30 mV, 200 kHz sinusoidal signals to generate electrical field magnitudes of 6.58 V/cm and 1.33 V/cm, respectively. In the high electrical field experiment, the cells go through electroporation. In the experiment with the low electrical field magnitude for TTFields, the cells have prolonged mitosis from typical 80-90 min to 200-300 min. Our results confirm the validity of the electrochemical model and the importance of applying a correct magnitude of the electrical field. Compared to the so far reported alternatives with insulated electrodes, the here developed thermoplastic microfluidic bioreactors with uninsulated electrodes provide a new, versatile, and durable platform for in vitro cell studies toward the improvement of anti-cancer therapies including personalized treatment.

Triplaris gardneriana seeds extract exhibits in vitro anti-inflammatory properties in human neutrophils after oxidative treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Triplaris gardneriana Wedd. (Polygonaceae family) is a plant species from Brazilian semiarid region which is used in local traditional medicine for the treatment of inflammatory conditions such as hemorrhoids.

AIM OF THE STUDY

In this study, the in vitro anti-inflammatory activity of different concentrations of ethanolic extract from T. gardneriana seeds (EETg) was performed in order to contribute to the knowledge about etnomedicinal use of this plant species.

MATERIALS AND METHODS

The anti-inflammatory properties were evaluated through different approaches, such as in vitro protein anti-denaturation test, scavenging of reactive oxygen species (ROS) and myeloperoxidase (MPO) inhibition in human neutrophils activated by phorbol-12-myristate-13-acetate (PMA). Besides that, molecular docking was performed to provide new insights about the interaction between the major phenolic components in the plant extract and MPO.

RESULTS

EETg was characterized showing a total phenol content of 153.5 ± 6.3 μg gallic acid equivalent/mg extract, ability to remove hydrogen peroxide (H₂O₂) in a concentration-dependent manner and had a spectroscopic profile which suggests the presence of hydroxyl groups. EETg was able to prevent protein denaturation ranging from 40.17 to 75.09%. The extract, at 10 and 20 μg/mL, was able to modulate neutrophils pro-inflammatory functions, such as degranulation and burst respiratory. In both assays, the EETg had anti-inflammatory effect comparable to nonsteroidal anti-inflammatory drugs. Among the main phenolic compounds of EETg, quercitrin, quercetin and catechin showed the highest binding affinity in silico to MPO.

CONCLUSION

This study demonstrated, for the first time, that the anti-inflammatory effect of T. gardneriana seeds occurs due to its modulatory effect on human neutrophil degranulation and free-radical scavenging activity.

Proteomic Analysis of Saccharomyces cerevisiae Response to Oxidative Stress Mediated by Cocoa Polyphenols Extract

The present study addressed the protective effects against oxidative stress (OS) of a cocoa powder extract (CPEX) on the protein expression profile of S. cerevisiae. A proteomic analysis was performed after culture preincubation with CPEX either without stress (−OS) or under stress conditions (+OS) (5 mM of H₂O₂). LC-MS/MS identified 33 differentially expressed proteins (–OS: 14, +OS: 19) that were included By Gene Ontology analysis in biological processes: biosynthesis of amino acids, carbohydrate metabolism and reactive oxygen species metabolic process. In a gene-knockout strains study, eight proteins were identified as putative candidates for being involved in the protective mechanism of cocoa polyphenols against OS induced by H₂O₂. CPEX was able to exert its antioxidant activity in yeast mainly through the regulation of: (a) amino acids metabolism proteins by modulating the production of molecules with known antioxidant roles; (b) stress-responsive protein Yhb1, but we were unable to fully understand its down-regulation; (c) protein Prb1, which can act by clipping Histone H3 N-terminal tails that are related to cellular resistance to DNA damaging agents.

Proteomic analysis of Saccharomyces cerevisiae to study the effects of red wine polyphenols on oxidative stress

Understanding the molecular mechanisms underlying the "French paradox" has contributed to a growing interest in the investigation of the biological activity of red wine polyphenols (RWP). The main goal of this research is to provide valuable information on how RWP could exert their biological action at the cellular level. So, we report a proteomic analysis of S. cerevisiae exposed to both pro-oxidant (H₂O₂) and antioxidant (wine) agents. Cellular proteome analysis shows that RWP modify the level of certain proteins. Under both normal conditions (Wine treatment) and oxidative stress situations (Wine + H₂O₂ treatment), the proteins involved in the metabolism and biosynthesis of biomolecules were down-regulated, while one ribosomal protein was up-regulated, probably performing its ribosome-independent functions, and so contributing to the stress defense system. Considering this action mechanism, we suggest that RWP may be acting as mild pro-oxidants and, therefore, exerting a hormetic effect that leads to the strengthening of cells' antioxidant capacity.

Onion skin extract as a protective agent against oxidative stress in Saccharomyces cerevisiae induced by cadmium

Onion skin extract is a source of bioactive compounds demonstrating a high antioxidant activity. The purpose of this research was to investigate the effect of onion skin extract at the level of oxidative stress markers in Saccharomyces cerevisiae exposed to cadmium. The generation of reactive oxygen species (ROS), antioxidant enzymes activity, total content of glutathione, and the level of lipid peroxidation in yeast cells were determined. Research showed that onion skin extract protected the yeast cells from the occurrence of oxidative stress induced by cadmium. Cells treated with onion skin extract and cadmium were characterized by lower generation of ROS, antioxidant enzymes activity, lipid peroxidation, and higher level of glutathione content than cells treated with cadmium only. However, the protective effect was dependent on the onion skin extract concentration in yeast medium. PRACTICAL APPLICATIONS: The presented studies are of comprehensive character regarding antioxidant properties of the onion skin extract, using Saccharomyces cerevisiae as a model organism. The research results give the opportunity to conduct further research on the use of onion skin extract in functional food or dietary supplements production, as a cellular protector against negative consequence of oxidative stress. It should also be mentioned that the major research material was onion skin which is a troublesome waste material for onion producers. Consequently, the study result will, to a certain extent provide an opportunity to increase interest in the problem of rational use of the waste material, according to a sustainable development idea.

Antioxidant Activity Evaluation of Dietary Flavonoid Hyperoside Using Saccharomyces Cerevisiae as a Model

Oxidative stress leads to various diseases, including diabetes, cardiovascular diseases, neurodegenerative diseases, and even cancer. The dietary flavonol glycoside, hyperoside (quercetin-3-O-galactoside), exerts health benefits by preventing oxidative damage. To further understand its antioxidative defence mechanisms, we systemically investigated the regulation of hyperoside on oxidative damage induced by hydrogen peroxide, carbon tetrachloride, and cadmium in Saccharomyces cerevisiae. Hyperoside significantly increased cell viability, decreased lipid peroxidation, and lowered intracellular reactive oxygen species (ROS) levels in the wild-type strain (WT) and mutants gtt1∆ and gtt2∆. However, the strain with ctt1∆ showed variable cell viability and intracellular ROS-scavenging ability in response to the hyperoside treatment upon the stimulation of H₂O₂ and CCl₄. In addition, hyperoside did not confer viability tolerance or intercellular ROS in CdSO₄-induced stress to strains of sod1∆ and gsh1∆. The results suggest that the antioxidative reactions of hyperoside in S. cerevisiae depend on the intercellular ROS detoxification system.

Evaluation of in vivo antioxidant potential of Syzygium jambos (L.) Alston and Terminalia citrina Roxb. towards oxidative stress response in Saccharomyces cerevisiae

Excessive production and restricted elimination of free radicals like superoxide, hydroxyl radical (^·OH), anion radical (O₂ ^·-), and non-radical hydrogen peroxide (H₂O₂) are related to the development of cancer, arteriosclerosis, arthritis and neurodegenerative diseases. According to a report of World Health Organisation, about 80% of the population living in the developing countries predominantly depends on the traditional medicine for their primary healthcare. Plants possess innate ability to synthesize a wide variety of enzymatic and non-enzymatic antioxidants capable of attenuating ROS-induced oxidative damage. The ethanolic leaf extracts of Syzygium jambos L. and Terminalia citrina Roxb. exhibited a significant in vitro antioxidant activity when compared with natural antioxidant, ascorbic acid. The extracts also provided strong cellular protection against the damaging effects of H₂O₂ induced oxidative stress in the mutant strains (tsa1Δ and sod1Δ) of Saccharomyces cerevisiae. The GC-MS analysis of the leaf extracts revealed the presence of phytoconstituents majorly constituting of terpenes, vitamin and fatty acids contributing to the antioxidant property. The plant extracts may serve as a potential source of exogenous antioxidants to combat the undesirable effects of oxidative stress.

QSAR Study on Antioxidant Tripeptides and the Antioxidant Activity of the Designed Tripeptides in Free Radical Systems

In this study, quantitative structure-activity relationship (QSAR) models were determined based on 91 antioxidant tripeptides. We firstly adopted the stepwise regression (SWR) method for selecting key variables without autocorrelation and then utilized multiple linear regression (MLR), support vector machine (SVM), random forest (RF), and partial least square regression (PLS) to develop predictive QSAR models based on the screened variables. The results demonstrated that all the established models have good reliability (R²_train > 0.86, Q²_train > 0.70) and relatively good predictability (R²_test > 0.88). The contribution of amino acid residues was calculated from the stepwise regression combined with multiple linear regression (SWR-MLR) method model that shows Trp, Tyr, or Cys at C-terminus is favorable for antioxidant activity of tripeptides. Nineteen antioxidant tripeptides were designed based on SWR-MLR models, and the antioxidant activity of these tripeptides were evaluated using three antioxidant assays in free radical systems (1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, trolox equivalent antioxidant capacity assay, and the ferric reducing antioxidant power assay). The experimental antioxidant activities of these tripeptides were higher than the calculated/predicted activity values of the QSAR models. The QSAR models established can be used to identify and screen novel antioxidant tripeptides with high activity.