Anti- and pro-oxidant activity of rutin and quercetin derivatives

Bioactives from citrus food waste: types, extraction technologies and application

The Citrus fruits belong to the category where the groups of fruits are recognized to be an admirable repository of bioactive elements and phytochemical constituents, with strong biological potentials. The prominent use of Citrus fruits for nutrition as well as food processing has led to the release of a large amount of waste into the environment and surrounding, and it simultaneously burdens the nature and existence of many organisms including the human population. In order to rectify such consequences, the reuse of food waste from citrus for various advantageous effects. In this regard, the first part of the article primarily focussed on the various strategies available for the extraction of chemical elements from citrus waste and the remaining strand of the article focussed on the various bioactive compounds with special reference to their pharmacological as well as the medicinal benefits and future prospects.

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Acute Toxicity and Antioxidant and Antibacterial Activities of Kyllinga polyphylla Willd. ex Kunth, Cyperaceae Family

Kyllinga polyphylla Willd. ex Kunth. (KP) is a wild herb commonly distributed in the Mekong Delta, Vietnam. This study was carried out to evaluate the antibacterial and antioxidant activities and acute toxicity of KP before conducting studies at the in vivo level. All parts of KP had the free radical scavenging capacity of DPPH, in which the root methanol extract had the best antioxidant capacity (EC50 = 9.54 ± 0.37 μg/mL). Most of the extracts had a wide range of antibacterial spectra. The methanol and ethanol extracts (200 mg/mL) have ability to resist eight common bacterial strains (including Staphylococcus aureus, Listeria innocua, Bacillus subtilis, Bacillus cereus, Escherichia coli, Salmonella sp., Pseudomonas aeruginosa, and Enterococcus faecalis), which is equivalent to the antibacterial activity of amoxicillin and tetracycline at a concentration of 1 mg/mL. KP extracts did not cause death at a dose of 5000 mg/kg body weight and did not significantly change the biochemical, hematological, as well as histological structures of internal organs in toxicity-tested mice in comparison with the control. The research results showed that KP should be more interested in research that supports disease treatment, synthetic extraction of antibiotics, or other in vivo studies.

Antimicrobial, antioxidant activities, and total phenolic contents of Pycnanthus angolensis Sap and Cryptolepis sanguinolenta root extracts

The death of many people in tropical countries can be attributed to microbial infection, probably, because synthetic antibiotics are failing in the treatment of most microbial infections, attributed to the ability of the microorganisms to mutate and adapt to harsh conditions. This study evaluated, in vitro, the antimicrobial activities, antioxidant potentials, and the total phenolic as well as phytochemical contents of aqueous and ethanol extracts of the root of Cryptolepis sanguinolenta (Lindl.) and the crude sap of Pycnanthus angolensis (Welw) using selected standard bacteria strains (Staphylococcus aureus (ATCC 25,923), Staphylococcus saprophyticus (ATCC 15,305), Escherichia coli (ATCC 25,922), Salmonella typhi (ATCC 19,430), Pseudomonas aeruginosa (ATCC 27,853), and Proteus mirabilis (ATCC 49,565). The modified agar well diffusion method was used to evaluate the antimicrobial activities of the plant extracts. Chloramphenicol and tetracycline were used as positive controls. The extracts were screened for specific phytochemicals with total phenolic contents were determined using Folin Ciocalteu reagent test. The phytoconstituents observed were alkaloids, cardiac glycosides, and saponins in both Cryptolepis sanguinolenta and Pycnanthus angolensis. For the antimicrobial activities, all the test bacteria were susceptible to the crude sap of Pycnanthus angolensis except Proteus mirabilis. In the case of the Cryptolepis sanguinolenta, only S. aureus was susceptible to both aqueous and ethanol extracts. The total phenolic content, expressed in g/100 g GAE, recorded values of 55.427 ± 4.248 for the crude sap of Pycnanthus angolensis, and 11.642 ± 4.248 and 26.888 ± 4.248 for the aqueous and ethanol extracts of Cryptolepis sanguinolenta, respectively. It is concluded that Cryptolepis sanguinolenta and Pycnanthus angolensis are excellent candidates for further development of antimicrobial agents in the fight against microbial infections given the pressing need for novel efficacious agents.

Possible Side Effects of Polyphenols and Their Interactions with Medicines

Polyphenols are an important component of plant-derived food with a wide spectrum of beneficial effects on human health. For many years, they have aroused great interest, especially due to their antioxidant properties, which are used in the prevention and treatment of many diseases. Unfortunately, as with any chemical substance, depending on the conditions, dose, and interactions with the environment, it is possible for polyphenols to also exert harmful effects. This review presents a comprehensive current state of the knowledge on the negative impact of polyphenols on human health, describing the possible side effects of polyphenol intake, especially in the form of supplements. The review begins with a brief overview of the physiological role of polyphenols and their potential use in disease prevention, followed by the harmful effects of polyphenols which are exerted in particular situations. The individual chapters discuss the consequences of polyphenols’ ability to block iron uptake, which in some subpopulations can be harmful, as well as the possible inhibition of digestive enzymes, inhibition of intestinal microbiota, interactions of polyphenolic compounds with drugs, and impact on hormonal balance. Finally, the prooxidative activity of polyphenols as well as their mutagenic, carcinogenic, and genotoxic effects are presented. According to the authors, there is a need to raise public awareness about the possible side effects of polyphenols supplementation, especially in the case of vulnerable subpopulations.

A comprehensive review on medicinal plants possessing antioxidant potential

Many research studies have proposed that about two-thirds of the medicinal plant species of the world possess significant antioxidant potential. Antioxidants are very beneficial as they decrease oxidative stress (OS) in cells and hence play their role in management as well as treatment of numerous diseases like cancers, cardiovascular diseases, as well as many inflammatory illnesses. This review comprises the antioxidant potential of numerous parts of medicinal plants like leaves, stems, roots, seeds, fruits, as well as bark. Synthetic antioxidants named butylated hydroxyanisole (BHA) as well as butylated hydroxytoluene (BHT) are extensively employed in foods because of their role as food preservatives. Several natural antioxidants have better efficacy as compared to synthetic antioxidants. These medicinal plants include Geranium sanguineum L., Rheum ribes L., Diospyros abyssinica, Sargentodoxa cuneata Rehd. Et Wils, Pistacia lentiscus, Ficus microcarpa L. fil., Polyalthia cerasoides (Roxb.) Bedd, Cunn, Teucrium polium L., Crataeva nurvala Buch-Ham., Urtica dioica L., Dracocephalum moldavica L., Momordica Charantia L., Acacia auriculiformis A., Bidens pilosa Linn. The Lamiaceae species, Radiata, Leea indica, Pelargonium endlicherianum, Salvia officinalis L., and Uncaria tomentosa (Willd.) DC. The literature study disclosed more side effects of synthetic antioxidants (including food additives) in comparison with natural antioxidants and for prevention of many diseases.

K. Sagi S. Hypobaric hypoxia induced renal injury in rats: Prophylactic amelioration by quercetin supplementation

The present study aims at assessing the effect of hypobaric hypoxia induced renal damage and associated renal functions in male SD rats. Further, this study was extended to explore the protective efficacy of quercetin in ameliorating the functional impairment in kidneys of rats under hypobaric hypoxia. Rats were exposed to 7620m (25000 ft.) at 25°C ±2 in a simulated hypobaric hypoxia chamber for different time durations (0h,1h, 3h, 6h, 12h, 24h and 48h) in order to optimize the time at which maximum renal damage would occur. The rats were exposed to hypoxia for 12h duration was considered as the optimum time, due to significant increase in oxidative stress (ROS, MDA) and renal metabolites (creatinine, BUN and uric acid) with remarkable reduction (p<0.001) in antioxidants (GSH) in plasma, as compared to other tested durations. Moreover, these findings were in support with the histopathology analysis of renal tissues. For optimum quercetin dose selection, the rats were administered with different doses of quercetin (25mg, 50mg, 100mg and 200mg/Kg BW) for 12h at 7620 m, 25°C ±2, 1h prior to hypoxia exposure. Quercetin 50mg/kg BW was considered as the optimum dose at which significant (p<0.001) reduction in oxidative stress levels followed by reduction in creatinine and BUN levels were obtained in plasma of the rats compared to hypoxia control rats. Quercetin prophylaxis (50mg/kg BW) stabilized the HIF-1α protein expression followed by reduced VEGF protein expression along with reduced levels of LDH (p<0.001) in the kidneys of rats compared to hypoxia control. Histopathological observations further substantiated these findings in reducing the renal tissue injury. The study findings revealed that, quercetin prophylaxis abrogates the possibility of hypobaric hypoxia induced renal injury by reducing the oxidative stress in rats.

Medical physiological perspective to biochemical assays and GC-MS results of corn tassel

Corn tassel (Zea may L.) is rich in phenolic compounds including flavonoids and anthocyanins. The aim of this study is to consider the results of the contents of phenolics (TPC), flavonoids (TFC), flavonol (TF), anthocyanins (TAC), alfa-amylase inhibitory activity, and antioxidant activity including FRAP and metal chelating capabilities (MCC) as potential Antiviral and anti-Rheumatoid arthritis. Significantly high levels of antioxidant capacity, total flavonol and alfa-amylase inhibition were found in ethanolic extracts of corn tassels. It was found that their concentrations are TPC= 40 mg GA/g, TFC= 13 mg QE/g, TF= 45 mg R/g, and TAC= 8 mg cyanidin-3-glucoside/g based on dry extract. Additionally, the extracts showed relatively higher antioxidant activities due to metal chelating capabilities (MCC) were found to be 217 mg Fe2+/g dry extract. From the GC-MS analysis, corn tassel was found to be good source of arctigenin that has antiviral and anti- rheumatic properties. Further, the extracts of corn tassels showed significantly higher α-amylase inhibitory activity up to 90 %. Thus, it was concluded that extracts of corn tassels may be considered as pharmacological potential in rheumatoid and antiviral treatment.

Insights into the Small Molecule Targeting of Biologically Relevant G-Quadruplexes: An Overview of NMR and Crystal Structures

G-quadruplexes turned out to be important targets for the development of novel targeted anticancer/antiviral therapies. More than 3000 G-quadruplex small-molecule ligands have been described, with most of them exerting anticancer/antiviral activity by inducing telomeric damage and/or altering oncogene or viral gene expression in cancer cells and viruses, respectively. For some ligands, in-depth NMR and/or crystallographic studies were performed, providing detailed knowledge on their interactions with diverse G-quadruplex targets. Here, the PDB-deposited NMR and crystal structures of the complexes between telomeric, oncogenic or viral G-quadruplexes and small-molecule ligands, of both organic and metal-organic nature, have been summarized and described based on the G-quadruplex target, from telomeric DNA and RNA G-quadruplexes to DNA oncogenic G-quadruplexes, and finally to RNA viral G-quadruplexes. An overview of the structural details of these complexes is here provided to guide the design of novel ligands targeting more efficiently and selectively cancer- and virus-related G-quadruplex structures.

Excessive Consumption Hibiscus sabdariffa L. Increases Inflammation and Blood Pressure in Male Wistar Rats via High Antioxidant Capacity: The Preliminary Findings

Hibiscus sabdariffa L. (HSL) has high amounts of antioxidants and many beneficial effects in several pathologies. However, few studies describe the possible harmful effects of high concentrations of HSL. Here we evaluate the effect of excessive and chronic consumption of infusions with different percentages of HSL on some oxidative stress markers in serum, and the possible association with inflammation and increased systolic blood pressure (SBP), in healthy rats. A total of 32 male Wistar rats were used to form 4 groups with 8 animals each. Group 1 control (drinking tap water), group 2, 3 and 4, drinking water supplemented with 15, 30 and 60 g/L of HSL calyxes respectively. SBP was evaluated and determinations in serum of the NO₃⁻/NO₂⁻ ratio, glutathione (GSH), total antioxidant capacity (TAC), selenium (Se), TNF-α, IL-1α/IL-1F1, IL-1β, IL-10, extracellular superoxide dismutase (EcSOD), thioredoxin reductase (TrxR) and glutathione peroxidase (GPx) activities, were evaluated. The SBP (p = 0.01), GPx activity, GSH, TAC, Se, TNF-α and EcSOD activities (p ≤ 0.001) and IL-1α/IL-1F1, IL-1β, TrxR and NO₃⁻/NO₂⁻ (p ≤ 0.05), were increased but IL-10 (p < 0.001) was decreased in rats that consumed the 3 and 6% HSL infusions. The excessive and chronic consumption of HSL may increase the TAC that could lead to a proinflammatory state which is associated with hypertension.

High Throughput Screening for Bioactive Components of Berberis baluchistanica Ahrendt Root and Their Functional Potential Assessment

Berberis baluchistanica Ahrendt is a medicinal plant potentially known for the treatment of different diseases. The bioactive, antioxidant, nutritional components, and antimicrobial properties of crude ethanolic root extract of Berberis baluchistanica were evaluated in this study. The extract was analyzed for total phenolic, flavonoid, DPPH (2, 2-diphenyl-1-picryl-hydrazyl) scavenging ability, FRAP (ferric reducing antioxidant power), nutritional, and antimicrobial potentials. The alkaloids, tannins, cardiac glycosides, anthraquinones, coumarin, saponins, phenolics, flavonoids, steroids, and terpenoids were confirmed. The extract possessed DPPH radical inhibition with the IC50 of 1.125 mg/mL and FRAP % reduction activity with IC50 (0.912 mg/mL). Total phenolic $19.897\pm 4.8141\text{mg}$ GAE/g and flavonoid $12.9876\pm 0.8388\text{mg}$ QE/g contents were confirmed in the root. The extracts exhibit good antibacterial activity against a broad spectrum of food borne pathogens Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumoniae, Escherichia coli, and Staphylococcus aureus. The highest inhibitory activity was against Escherichia coli $23.30\pm 1.16\text{mm}$ and lowest against Klebsiella pneumoniae $7\pm 0.01\text{mm}$ . Furthermore, the presence of various phytochemical constituents (plant secondary metabolites) was also confirmed with gas chromatography and mass spectroscopy analysis. Results disclosed the occurrence of more than 70 compounds possessing various medicinal properties supporting the traditional uses of root of Berberis baluchistanica in various medical complications indigenously.

Castor Oil Plant (Ricinus communis L.) Leaves Improve Dexamethasone-Induced Muscle Atrophy via Nrf2 Activation

Skeletal muscle atrophy is characterized by reduced muscle function and size. Oxidative stress contributes to muscle atrophy but can be treated with antioxidants. This study investigated the antioxidant activity of a castor oil plant leaf (Ricinus communis L.) extract (RC) and its effects on muscle atrophy. Rutin was identified as the major compound among the thirty compounds identified in RC via LC-MS/MS and was found to inhibit dexamethasone (DEX)-induced muscle atrophy and mitochondrial oxidative stress. Rutin-rich RC showed DPPH and ABTS radical scavenging activities and efficiently reduced the DEX-induced myotube atrophy and mitochondrial oxidative damage in C2C12 cells. RC supplementation prevented the loss of muscle function and muscle mass in DEX-administered mice and ameliorated DEX-induced oxidative stress via Nrf2 signaling. Taken together, both RC and rutin ameliorated muscle atrophy and helped in maintaining redox homeostasis; hence, rutin-rich RC could be a promising functional food that is beneficial for muscle health.

The Impact of Quercetin and Its Methylated Derivatives 3-o-Methylquercetin and Rhamnazin in Lipopolysaccharide-Induced Inflammation in Porcine Intestinal Cells

Oxidative stress in the small intestine can lead to inflammation and barrier malfunction. The present study describes the effect of quercetin (Q), 3-o-methylquercetin (QM), and rhamnazin (R) on cell viability, paracellular permeability, production of intracellular reactive oxygen species (ROS), extracellular hydrogen peroxide (H₂O₂), and interleukin-6 (IL-6) after challenging jejunal cells (IPEC-J2) with different types (Salmonella enterica ser. Typhimurium, Escherichia coli O111:B4, and E. coli O127:B8) of lipopolysaccharides (LPS) applied in 10 µg/mL concentration. The intracellular ROS level increased after all LPS treatments, which could be decreased by all tested flavonoid compounds in 50 µM concentration. Extracellular H₂O₂ production significantly increased after Q and R treatment (50 µM). S. Typhimurium LPS could significantly increase IL-6 production of enterocytes, which could be alleviated by Q, QM, and R (50 µM) as well. Using fluorescein isothiocyanate dextran (FD4) tracer dye, we could demonstrate that S. Typhimurium LPS significantly increased the permeability of the cell layer. The simultaneous treatments of S. Typhimurium LPS and the flavonoid compounds showed no alteration in FD4 penetration compared to untreated cells. These results highlight that Q, QM, and R are promising substances that can be used to protect intestinal epithelial cells from the deteriorating effects of oxidative stress.

The effect of flavonoids on the reduction of cupric ions, the copper-driven Fenton reaction and copper-triggered haemolysis

Flavonoids are considered beneficial, but they may exhibit pro-oxidative effects likely due to metal reducing properties. For the first time, 24 structurally related flavonoids were compared for copper reduction, and modulation of the copper-triggered Fenton reaction and lysis of erythrocytes. The vast majority of flavonoids reduced cupric ions; their behaviour ranged from progressive gradual reduction through bell-shaped, neutral, to a blockade of spontaneous reduction. Similarly, different behaviours were observed with the Fenton reaction. Flavone was the only flavonoid that potentiated copper-triggered haemolysis (155 ± 81 % at twice the amount of Cu²⁺), while 18 flavonoids were at least partly protective in some concentrations. Only 5-hydroxyflavone did not reduce Cu²⁺ and behaved as an antioxidant in both assays (reduction of 60 ± 10 % and 88 ± 1%, respectively, at an equimolar ratio with Cu²⁺). In conclusion, relatively subtle structural differences resulted in very different anti/prooxidant behaviour depending on the model.

Quality Control Standardization, Contaminant Detection and In Vitro Antioxidant Activity of Prunus domestica Linn. Fruit

The increase in the use of herbal medicines has led to the implementation of more stern regulations in terms of quality variation and standardization. As medicinal plants are prone to quality variation acquired due to differences in geographical origin, collection, storage, and processing, it is essential to ensure the quality, efficacy, and biological activity of medicinal plants. This study aims to standardize the widely used fruit, i.e., Prunus domestica Linn., using evaluation techniques (microscopic, macroscopic, and physicochemical analyses), advanced instrumental (HPLC, HPTLC, and GC-MS for phytochemical, aflatoxins, pesticides, and heavy metals), biological, and toxicological techniques (microbial load and antioxidant activities). The results revealed a 6-8 cm fruit with smooth surface, delicious odor, and acidic taste (macroscopy), thin-walled epidermis devoid of cuticle and any kind of excrescences with the existence of xylem and phloem (microscopy), LOD (15.46 ± 2.24%), moisture content (13.27 ± 1.75%), the high extractive value of 24.71 ± 4.94% in water:methanol (1:1; v/v) and with ash values in the allowed limits (physicochemical properties), and the presence of numerous phytochemical classes such as alkaloids, flavonoids, carbohydrates, glycosides, saponins, etc. (phytochemical screening). Furthermore, no heavy metals (Pb, Hg, Cd, Ar), pesticides, ad microbial limits were detected beyond the permissible limits specified, as determined with AAS, GC-MS analysis, and microbial tests. The HPTLC was developed to characterize a complete phytochemical behavior for the components present in P. domestica fruit extract. The parameters utilized with the method used and the results observed for the prunus herein may render this method an effective tool for quality evaluation, standardization, and quality control of P. domestica fruit in research, industries, and market available food products of prunus.

Phytochemicals, Proximate Composition, Mineral Analysis and In Vitro Antioxidant Activity of Calligonum crinitum Boiss

Medicinal herbs are potential sources of biomolecules and their analogues that have great relevance in the preparation of modern medicines. Calligonum crinitum, a perennial shrub growing in the United Arab Emirates, has been utilized in the study to validate the therapeutic properties exploited in the traditional medicinal system of UAE. The phytochemical screening of the plant employing different solvents of methanolics and ethyl-acetates, expressed varied proportions of monosaccharides and carbohydrates along with tannins and saponins, which are high potency molecules for therapeutic applications. The presence of total phenol and flavonoid contents derived from methanolic extracts indicates antioxidant potentials and the defense mechanisms of the plant. Proximate and mineral nutrient analysis validates the significance of the extracts with a high amount of carbohydrates and proteins along with significantly high amounts of Zn, Fe, Mn, Ca, Mg and K involved in various metabolic reactions. Similarly, the ABTS radical scavenging activity varied significantly (p < 0.05) and ranged from 10 to 160 µg GAE/g in the methanolic extract. DPPH free radical scavenging activity exhibited a significantly high DPPH activity in methanolic extracts with free radical scavenging activity of 72%. Hydroxyl radicals scavenging activity was also found to be high in the Calligonum extracts along with SOD (49–83%, compared to the standard GAE 37–58%). Nitric oxide scavenging was also found to be high in the extracts, thereby decreasing the content of NO. Thus, our results confirm that the derived extracts have potential antioxidants, and this legitimizes their use in folkloric medicine. These results are highly significant as they can pave the way for future scientific validation of the traditional knowledge of this important medicinal plant.

Catharanthus roseus (L.) G. Don: A review of its ethnobotany, phytochemistry, ethnopharmacology and toxicities

ETHNOPHARMACOLOGICAL RELEVANCE

Catharanthus roseus (L.) G. Don is a well known medicinal plant belonging to family Apocynaceae that have been traditionally used as medicine since ancient times. C. roseus is a well-recognized herbal medicine due to its anticancer bisindole alkaloids (vinblastine (111), vincristine (112) and vindesine (121)). In the Ayurvedic system of medicine, different parts of C. roseus are used in folklore herbal medicine for treatment of many types of cancer, diabetes, stomach disorders, kidney, liver and cardiovascular diseases.

AIM OF THE STUDY

The main idea behind this communication is to update comprehensively and analyze critically the traditional applications, phytochemistry, pharmacological activities, and toxicity of various extracts and isolated compounds from C. roseus.

MATERIALS AND METHODS

The presented data covers scientific works on C. roseus published across the world between 1967 and 2021 was searched from various international publishing houses using search engines as well as several traditional texts like Ayurveda and relevant books. Collected data from different sources was comprehensively summarized/analyzed for ethnomedicinal uses, phytochemistry, analytical chemistry, biological activities and toxicity studies of C. roseus.

RESULTS AND DISCUSSION

C. roseus has a wide range of applications in the traditional system of medicine especially in cancer and diabetes. During phytochemical investigation, total of 344 compounds including monoterpene indole alkaloids (MIAs) (110), bisindole alkaloids (35), flavonoids (34), phenolic acids (9) and volatile constituents (156) have been reported in the various extracts and fractions of different plant parts of C. roseus. The extracts and isolated compounds of C. roseus have to exhibit many pharmacological activities such as anticancer/cytotoxic, antidiabetic, antimicrobial, antioxidant, larvicidal and pupicidal. The comparative toxicity of extracts and bioactive compounds investigated in dose dependent manner. The investigation of toxicity showed that the both extracts and isolated compounds are safe to a certain limit beyond that they cause adverse effects.

CONCLUSION

This review is a comprehensive, critically analyzed summarization of sufficient baseline information of selected topics in one place undertaken till date on C. roseus for future works and drug discovery. The phytochemical investigation including biosynthetic pathways showed that the MIAs and bisindole alkaloids are major and characteristic class of compounds in this plant. The present data confirm that the extracts/fractions and their isolated alkaloids especially vinblastine (111) and vincristine (112) have a potent anticancer/cytotoxic and antidiabetic property and there is a need for further study with particular attention to the mechanisms of anticancer activity. In biosynthesis pathways of alkaloids especially bisindole alkaloids, some enzymes and rearrangement are unexposed therefore it is required to draw special attention. It also focuses on attracting the attention of scientific communities about the widespread biological activities of this species for its better utilization prospects in the near future.

Revisiting the Oxidation of Flavonoids: Loss, Conservation or Enhancement of Their Antioxidant Properties

Flavonoids display a broad range of health-promoting bioactivities. Among these, their capacity to act as antioxidants has remained most prominent. The canonical reactive oxygen species (ROS)-scavenging mode of the antioxidant action of flavonoids relies on the high susceptibility of their phenolic moieties to undergo oxidation. As a consequence, upon reaction with ROS, the antioxidant capacity of flavonoids is severely compromised. Other phenol-compromising reactions, such as those involved in the biotransformation of flavonoids, can also markedly affect their antioxidant properties. In recent years, however, increasing evidence has indicated that, at least for some flavonoids, the oxidation of such residues can in fact markedly enhance their original antioxidant properties. In such apparent paradoxical cases, the antioxidant activity arises from the pro-oxidant and/or electrophilic character of some of their oxidation-derived metabolites and is exerted by activating the Nrf2–Keap1 pathway, which upregulates the cell’s endogenous antioxidant capacity, and/or, by preventing the activation of the pro-oxidant and pro-inflammatory NF-κB pathway. This review focuses on the effects that the oxidative and/or non-oxidative modification of the phenolic groups of flavonoids may have on the ability of the resulting metabolites to promote direct and/or indirect antioxidant actions. Considering the case of a metabolite resulting from the oxidation of quercetin, we offer a comprehensive description of the evidence that increasingly supports the concept that, in the case of certain flavonoids, the oxidation of phenolics emerges as a mechanism that markedly amplifies their original antioxidant properties. An overlooked topic of great phytomedicine potential is thus unraveled.

Effect of rutin on the physicochemical and gel characteristics of myofibrillar protein under oxidative stress

The effects of rutin (6, 30, and 150 μmol/g_pro ) on the physicochemical, structural properties and gel characteristics of myofibrillar protein (MP) under oxidative stress were investigated. The addition of rutin significantly promoted the formation of oxidized MP carbonyl derivatives and dimer tyrosine, but it cannot prevent the loss of sulfhydryl groups (-SH). With increasing rutin concentration, the hydrophobic area was gradually shielded and rutin acted as a quencher to reduce the fluorescence intensity of oxidized MP. Under the oxidative stress, rutin increased the particle size and aggravated the cleavage of protein molecules. SDS-polyacrylamide gel electrophoresis revealed that rutin further aggravated oxidized MP degradation and cross-linked form polymer which cross-linked with protein to the maximum extent at 150 μmol/g_pro rutin content. Moderate cross-linking between protein and rutin could improve the gel strength and water holding capacity (WHC) of oxidized MP gel. For rutin concentrations of 6 and 30 μmol/g_pro , the gels had denser network structures, as observed by scanning electron microscopy. PRACTICAL APPLICATIONS: Polyphenols of the type and dosage can change the properties of the product itself and optimize the quality of product processing. Certain polyphenols may promote the oxidation process of protein-rich products, but this does not affect the improvement of product quality. The application of natural polyphenols is the promising business direction in the development of Coregonus peled industry.

Hyphenated LC-ABTS•+ and LC-DAD-HRMS for simultaneous analysis and identification of antioxidant compounds in Astragalus emarginatus Labill. extracts

The compounds in leaf and stem extracts of Astragalus emarginatus Labill. (AEL), a plant species used in traditional Lebanese medicine, were investigated for antioxidant properties. First, the activity of various extracts was assessed using the Trolox equivalent antioxidant capacity, oxygen radical absorption capacity, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate assays. The extract obtained using 30% ethanol showed the greatest activity. The antioxidant compounds in this extract were screened using a hyphenated high-performance liquid chromatography-2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) radical (ABTS^·+) system before being separated by ultra-high-performance liquid chromatography and identified using high-resolution mass spectrometry and ultra-violet-visible diode array detection. Approximately 40 compounds were identified. Hydroxycinnamates (caffeic, ferulic, and p-coumaric acid derivatives) and flavonoids (quercetin, luteolin, apigenin, and isorhamnetin derivatives) were the two main categories of the identified compounds. The active compounds were identified as caffeic acid derivatives and quercetin glycosides. In addition, the catechol moiety was shown to be key to antioxidant activity. This study showed that AEL is a source of natural antioxidants, which may explain its medicinal use.

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Antioxidant activity of 30% ethanol extract from Astragalus emarginatus Labill was shown by an on-line HPLC-ABTS ^•+ assay.

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Caffeic acid derivatives and quercetin glycosides were responsible for antioxidant activity.

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Approximately forty compounds were tentatively identified using UHPLC-DAD-HRMS.

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Structure-activity investigations showed that the catechol moiety is central to the detected antioxidant activity.

Study of DNA Interaction and Cytotoxicity Activity of Oxidovanadium(V) Complexes with ONO Donor Schiff Base Ligands

Two new oxidovanadium(V) complexes, (HNEt3)[VVO2L] (1) and [(VVOL)2μ-O] (2), have been synthesized using a tridentate Schiff base ligand H2L [where H2L = 4-((E)-(2-hydroxy-5-nitrophenylimino)methyl)benzene-1,3-diol] and VO(acac)2 as starting metal precursor. The ligand and corresponding metal complexes are characterized by physicochemical (elemental analysis), spectroscopic (FT-IR, UV–Vis, and NMR), and spectrometric (ESI–MS) methods. X-ray crystallographic analysis indicates the anion in salt 1 features a distorted square-pyramidal geometry for the vanadium(V) center defined by imine-N, two phenoxide-O, and two oxido-O atoms. The interaction of the compounds with CT–DNA was studied through UV–Vis absorption titration and circular dichroism methods. The results indicated that complexes showed enhanced binding affinity towards DNA compared to the ligand molecule. Finally, the in vitro cytotoxicity studies of H2L, 1, and 2 were evaluated against colon cancer (HT-29) and mouse embryonic fibroblast (NIH-3T3) cell lines by MTT assay. The results demonstrated that the compounds manifested a cytotoxic potential comparable with clinically referred drugs and caused cell death by apoptosis.

Novel Insights into Corema album Berries: Vibrational Profile and Biological Activity

This study reports an evaluation of the biological properties of the edible berries from Corema album, an endemic shrub of the Portuguese coastline, aiming at its use as a nutraceutical. Different methanolic extracts were obtained from the pulp and seed of fresh berries: pulp extract, seed residue, and seed oil (extracted and characterized for the first time). For each of these, the antioxidant activity was assessed, by different methods, as well as the antimicrobial ability. Overall, the seeds were shown to be the most nutraceutical part of the berry since they showed higher antioxidant activity, while the pulp extract displayed a significant antimicrobial capacity against several clinically relevant bacterial strains. Furthermore, the extracts were fully characterized by complementary infrared and Raman spectroscopy, revealing the presence of phenolic acids, polysaccharides, sugars, and triterpenoids in the pulp, high content of unsaturated fatty acids in the seed oil, and significant amounts of phenolics and carotenoids in the seed residue. These results pave the way for a reliable correlation between chemical composition and biological activity, in edible fruit samples.

Structure - Functionality of lentil protein-polyphenol conjugates

Lentil protein isolate (LPI) was conjugated with plant polyphenols (quercetin, rutin, ellagic acid), and the structural and functional characteristics of the conjugates were determined in comparison with the proteins and pure polyphenols. The interaction between polyphenols and protein was achieved by a grafting method at pH 9.0 in the presence of atmospheric oxygen. Surface plasmon resonance measurements showed polyphenols' direct interaction with LPI, with the order of binding strength quercetin > ellagic acid > rutin. The degree of conjugation also followed the same order. Structural analysis of the conjugates was performed using FTIR, intrinsic fluorescence, and surface hydrophobicity. A significant improvement in DPPḢ radical scavenging and ferric reducing antioxidant power of the conjugates was observed compared to the polyphenols. However, there was a decrease in the surface activity of the conjugates compared to LPI. Such conjugation provides a novel way to combine the advantages of using plant protein and polyphenols in developing a novel food ingredient.

Plant cell cultures of Nordic berry species: Phenolic and carotenoid profiling and biological assessments

Plant cell cultures from cloudberry (CL), lingonberry (LI), stone berry (ST), arctic bramble (AB), and strawberry (SB) were studied in terms of their polyphenol and carotenoid composition, antioxidant activity, antihemolytic activity and cytotoxicity effects on cancerous cells. High-resolution mass spectrometry data showed that LI, presented the highest antioxidant activity, contained the highest contents of flavones, phenolic acids, lignans, and total carotenoids, while CL, ST and SB presented the opposite behavior. AB and SB presented the lowest FRAP and CUPRAC values, while AB and CL presented the lowest reducing power. SB presented the lowest antioxidant activity measured by single electron transfer assays and the lowest content of lignans, phenolic acids, and flavones. CL and LI decreased the viability of in vitro mammary gland adenocarcinoma while only LI decreased the viability of in vitro lung carcinoma and showed protective effects of human erythrocytes against mechanical hemolysis.

Traditional plants with antioxidant properties in clinical trials-A systematic review

There is a trend toward the use of natural substances present in plants and vegetables. In general, foods rich in antioxidants are complex matrices; therefore, understanding its absorption effects is extremely relevant to know its bioactive potential. Thus, this systematic review focused on clinical trials involving plants (or compounds) registered on the National List of Medicinal Plants of Interest to the Unified Health System (RENISUS) with antioxidant properties. Following the reporting guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyzes studies of interest indexed in the PubMed and ClinicalTrials.gov databases were analyzed. Of the 59 clinical trials found, Allium sativum and Curcuma longa are the plant species with the highest percentage of clinical research. Prevention/attenuation of oxidative stress was one of the main antioxidant mechanisms indicated in the studies. The most tested compounds of the RENISUS plants in clinical trials were curcumin and soy isoflavone. In this review, we selected studies in advanced stages that highlight plants' value in optimizing antioxidant status; however, even with high-quality studies, it is not prudent to overstate the clinical efficacy of these plants.

Nutraceuticals and Enteric Glial Cells

Until recently, glia were considered to be a structural support for neurons, however further investigations showed that glial cells are equally as important as neurons. Among many different types of glia, enteric glial cells (EGCs) found in the gastrointestinal tract, have been significantly underestimated, but proved to play an essential role in neuroprotection, immune system modulation and many other functions. They are also said to be remarkably altered in different physiopathological conditions. A nutraceutical is defined as any food substance or part of a food that provides medical or health benefits, including prevention and treatment of the disease. Following the description of these interesting peripheral glial cells and highlighting their role in physiological and pathological changes, this article reviews all the studies on the effects of nutraceuticals as modulators of their functions. Currently there are only a few studies available concerning the effects of nutraceuticals on EGCs. Most of them evaluated molecules with antioxidant properties in systemic conditions, whereas only a few studies have been performed using models of gastrointestinal disorders. Despite the scarcity of studies on the topic, all agree that nutraceuticals have the potential to be an interesting alternative in the prevention and/or treatment of enteric gliopathies (of systemic or local etiology) and their associated gastrointestinal conditions.

In vitro phenols bioaccessibility and antioxidant activity of goat milk yogurt fortified with Rhus coriaria leaf powder

Goat yogurt samples fortified with 20% (w/v) Rhus coriaria leaf powder were in vitro digested in order to evaluate the total phenolic content (TPC), antioxidant activity (AA), and bioaccessibility of phenolic compounds in the digestate. After digestion, TPC and AA values of the R. coriaria-fortified yogurts increased compared to the undigested yogurts (P < 0.001). In particular, TPC has increased about twice; whereas, AA values have increased about 10 and 6 times, for ABTS and FRAP assays, respectively. The bioaccessibility index was well above the 100% for all identified phenols; except for (-)-epicatechin (82.04%), rutin (51.51%), and gallic acid (5.42%). This different behavior highlighted that the bioaccessibility was modulated by both the yogurt-polyphenol complexes and phenol stability under digestion system. These findings can contribute to elucidate the influence of in vitro digestion on antioxidant capacity and polyphenols recovery infortified yogurts, and may help in the design of dairy products with better functional quality PRACTICAL APPLICATION: Rhus coriaria L. (Sumac) is a polyphenol-rich Mediterranean plant that may be used as functional ingredient to enrich fermented food such as yogurt. However, in fortified yogurts the evaluation of bioaccessibility, that is, the compounds released from the yogurt and stable in the digestive environment, thus able to exert their biological effects on the gastrointestinal system, is more important than the content of these compounds in the corresponding food. This study highlighted the phenolic content, antioxidant activity, and bioaccessibility of phenolic compounds in goat milk yogurt fortified with R. coriaria leaf powder after simulated gastro-pancreatic digestion.

Phytochemical composition and in vitro safety evaluation of Ziziphora clinopodioides Lam. ethanolic extract: Cytotoxicity, genotoxicity and mutagenicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

The application of the herb Ziziphora clinopodioides Lam. in folk medicine and as a food additive has been recommended due to its many claimed bioactivities. Regardless of the plant benefits, its safety considerations are largely unknown.

AIM OF THE STUDY

The aim of the present research was to determine the chemical compositions and cytotoxicity, genotoxicity, and mutagenicity potentials of the ethanolic extract of Ziziphora clinopdioides Lam. (EEZC).

MATERIALS AND METHODS

GC-MS and LC-MS analysis were used for chemical composition determination. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and trypan blue exclusion dye assays were used for cytotoxicity and the Comet assay was employed for genotoxicity assessment on human blood lymphocytes. Also, the Ames Salmonella/microsome test was carried out for the evaluation of mutagenicity.

RESULTS

Pulegone was the main component of the n-hexane fraction. Different phenolic acids and flavonoids were detected by LC-MS. The cytotoxicity study indicated a conspicuous decline in human lymphocyte viability ranging from 52% to 100% as showed by the MTT assay and 67% up to 100% by the trypan blue assay, at 1 and 10 mg/mL, respectively. The Comet assay results revealed a dose dependent genotoxicity, in so much as 90% and 98% of the cells were screened as damaged at concentrations of 5 and 10 mg/mL, respectively. An incidence rate of 8% and 13% of grade 4 damage was observed at 5 and 10 mg/mL, respectively. Additionally, the DNA damage index (DI) was elevated dose-dependently by a rising concentration of the extract, wherein the DI at 10 mg/mL concentration was 2.22, which was 22 times greater than that of negative control, and even more than positive control. The Ames test exhibited no signs of mutagenicity for neither Salmonella typhimurium TA98 nor TA100 strains, accompanied or unaccompanied by S9 metabolic activation.

CONCLUSION

Results indicated a dose-dependent cytotoxicity and genotoxicity potential of the EEZC on human lymphocytes, suggesting that this plant should be used with caution by consumers, even in the food and pharmaceutical industries. Since the plant usage in daily life continues to increase due to its ever growing phytotherapical and phytonutritional properties, it may pose a health risk by its high concentration's uptake. Although no mutagenicity of this extract was observed in this study, further research is recommended to clarify the mutagenic risks of this herb.

Flavonoids as natural phenolic compounds and their role in therapeutics: an overview

Background

Natural plants and plant-derived formulations have been used by mankind from the ancient period of time. For the past few years, many investigations elaborated the therapeutic potential of various secondary chemicals present in the plants. Literature revealed that the various secondary metabolites, viz. phenolics and flavonoids, are responsible for a variety of therapeutic action in humans.

Main body

In the present review, an attempt has been made to compile the exploration of natural phenolic compounds with major emphasis on flavonoids and their therapeutic potential too. Interestingly, long-term intake of many dietary foods (rich in phenolics) proved to be protective against the development and management of diabetes, cancer, osteoporosis, cardiovascular diseases and neurodegenerative diseases, etc.

Conclusion

This review presents an overview of flavonoid compounds to use them as a potential therapeutic alternative in various diseases and disorders. In addition, the present understanding of phenolics and flavonoids will serve as the basis for the next scientific studies.

The iron chelating activity of Gundelia tournefortii in iron overloaded experimental rats

ETHNOPHARMACOLOGICAL RELEVANCE

Gundelia tournefortii is a member of the Asteraceae (Compositae) family which is widely consumed as edible plant in the Eastern Mediterranean. In folkloric medicine, it is used for the treatment of various diseases and conditions, including pain, liver diseases, kidney stones and inflammations.

AIM OF THE STUDY

Recently, many commoners use this plant as adjuvant therapy for treating symptoms associated with liver diseases and thalassemia. Thus, the present study was conducted to evaluate, biochemically, the iron chelating activity of G. tournefortii methanolic extract in iron overloaded rats.

MATERIALS AND METHODS

Fifty Wister male rats were divided into five groups: one group was a healthy control, while iron overload was induced in the other four groups by 100 mg/kg iron-dextran. Of these, one group was left untreated as a control, while the other three groups were treated with 50 mg/kg deferoxamine, 100 mg/kg and 200 mg/kg of G. tournefortii methanolic extract, respectively. The total flavonoid and phenolic contents of the methanolic extract were estimated. The biochemical assessment was performed by measuring blood levels of iron, ferritin, liver biomarkers (ALT, ALP and AST), cardiac biomarkers (CPK and LDH) and lipid profile.

RESULTS

Not only the blood levels of iron, ferritin, liver biomarkers and cardiac biomarkers were reduced significantly by G. tournefortii methanolic extract, but also the lipid profile was improved. This clearly supports the chelating activity of G. tournefortii and its hepatoprotective and cardioprotective effects in iron overloaded rats.

CONCLUSIONS

This highlights the value of medicinal plants as alternative therapies for iron overload conditions such as thalassemia.

Natural Exogenous Antioxidant Defense against Changes in Human Skin Fibroblast Proteome Disturbed by UVA Radiation

Daily exposure of the skin to UVA radiation causes oxidative modifications to cellular components and biomolecules. These include proteins involved in the metabolism and cytoprotection of fibroblasts, and their modification can contribute to the disruption of cell function and the development of skin disorders. Therefore, there remains a need for highly active cytoprotective compounds with antioxidant properties. The purpose of this study was to investigate the effect of ascorbic acid on the activity of rutin against UVA-induced changes in the proteome of human fibroblasts. All analyses were carried out on fibroblasts cultured in a three-dimensional system exposed to UVA radiation and incubated with rutin and ascorbic acid. Their proteomic profile was analyzed using nano-HPLC, which revealed 150 proteins whose expression was significantly altered between treatment conditions. UVA radiation led to changes in the expression of 82 proteins. However, some of these changes were mitigated by rutin and ascorbic acid separately (23 and 25 proteins, respectively) and rutin and ascorbic acid together (23 proteins). UVA radiation has led to the upregulation of proteins involved in gene expression, catalytic processes and antioxidant pathways, and downregulation of proteins with binding activity. Nevertheless, rutin and ascorbic acid used separately or together have countered these changes to varying degrees. Moreover, rutin and ascorbic acid stimulated fibroblasts irradiated by UVA to increase the expression of the signalling molecules responsible for the opening of the transmembrane channels. In the context of the results obtained, the observed cytoprotective effect of the cooperation of rutin and ascorbic acid results not only from the overlapping properties of the compounds. The effect of rutin alone is probably inhibited by its limited bioavailability. Therefore, its interaction with ascorbic acid increases membrane penetration and improves the cytoprotective effect on skin fibroblasts.

Interplay between male reproductive system dysfunction and the therapeutic effect of flavonoids

Male infertility has affected many families around the world. However, due to the mechanism underlying male reproductive system dysfunction are not completely elucidated, the use of drugs for male reproductive system dysfunction treatment only insignificant higher pregnancy outcomes, low-quality evidence suggests that clinical pregnancy rates may increase. Therefore, the focus in the future will be on developing more viable treatment options to prevent or treatment of male reproductive system dysfunction and achieve the purpose of improving fertility. Interestingly, natural products, as the potential inhibitors for the treatment of male reproductive system dysfunction, have shown a good therapeutic effect. Among many natural products, flavonoids have been extensively investigated for the treatment of male reproductive system dysfunction, such as testicular structural disruption, spermatogenesis disturbance and sperm quality decline. Flavonoids have been reported to have antioxidant, anti-inflammatory, immune stimulating, anti-apoptotic, anticarcinogenic, anti-allergic and antiviral activities, investigating for the treatment of male reproductive system dysfunction. In this review, we evaluate the therapeutic effects of flavonoids on male reproductive system dysfunction under different cellular scenarios and summarize the therapeutic strategies of flavonoids based on the aforementioned retrospective analysis. In the end, we describe some perspective research areas relevant to the application of flavonoids in the treatment of male reproductive system dysfunction.

Effect of resveratrol and quercetin on the susceptibility of Escherichia coli to antibiotics

Activities of plant polyphenols (PPs), resveratrol and quercetin, alone or in combination with four conventional antibiotics against Escherichia coli have been investigated. In medium without antibiotics, both polyphenols caused a dose-dependent growth inhibition. However, pretreatment with resveratrol (40 and 100 μg ml^-1) and quercetin (40 μg ml^-1) reduced the bacteriostatic effect of kanamycin, streptomycin, cefotaxime and partially of ciprofloxacin. With few exceptions, both PPs also reduced the bactericidal effect of tested antibiotics. Paradoxically, low doses of PPs enhanced the bactericidal effect of kanamycin and partially ciprofloxacin. Compared to quercetin, resveratrol showed a weaker effect on the induction of antioxidant genes and the resistance of E. coli to the oxidative stress generated by hydrogen peroxide treatment. Both polyphenols at high doses reduced membrane potential. Altogether, these findings suggest that the decrease in the bactericidal effect of antibiotics by high doses of polyphenols is mostly due to bacteriostatic action of the latter. In the case of quercetin, the contribution of its antioxidant activity for antibiotic protection may be significant. There is a growing interest in the use of plant-derived compounds to enhance the toxicity of traditional antibiotics. This and other studies show that, under certain conditions, the use of polyphenols as adjuvants may not exert the expected therapeutic effect, but rather to decrease antimicrobial activity of antibiotics.

Anti-obesity efficacy of the selected high altitude Himalayan herbs: in vitro studies

Obesity is a serious health problem for all age groups and it also promotes Type 2 diabetes, cardiovascular diseases, cancer and hypertension. Herbs are used for the weight reduction from ancient times, therefore, 12 herbs viz. Betula utilis, Bunium periscum, Angelica glauce, Saussurea lappa, Podophyllum hexandrum, Bergenia ciliate, Rumex acetosa, Aconitum heterophyllum, Centella asiatica, Andrographis paniculata, Dactylorhiza hatagirea and Bauhina variegate were selected as per literature. Rumex acetosa roots showed the highest extraction rate (39.5%), while C. asiatica leaf showed lowest extraction rate (1.25%) as compared to other herbs. As well, S. lappa leaf extract (396.52 mg GAE/g), R. acetosa root extract (181.5 mg QE/g), and B. ciliate leaf extract (79.19%) showed significantly higher Total Phenolic Content, Total Flavonoid Content and antioxidant activity, respectively. Furthermore, lipase and amylase inhibition activity and IC50 value of herb extract were higher in S. lappa root extract (75.75%, 75.41% and 62.47, 61.37, respectively). Bauhina variegate leaf extract showed a significantly higher glucose level, percentage of glucose movement (1.446 mg/dL and 63.85%) and (0.938 mg/dL and 76.55%). Based upon these experiments, 5 herbs were selected and different formulations were prepared and out of these, F3 herb formulation showed higher lipase and amylase inhibition activity (81.75% and 70.66%) and therefore, F3 herbal formulation was selected for treatment of obesity.

Phytofabricated silver nanoparticles: Discovery of antibacterial targets against diabetic foot ulcer derived resistant bacterial isolates

The present study selected the predominant multi antibiotic-resistant diabetic foot ulcer (DFU) derived bacterial isolates such as Pseudomonas aeruginosa (PA), Escherichia coli (EC), Staphylococcus aureus (SA) and Bacillus subtilis (BS) and evaluated their response against the well-characterized Aerva lanata (AL) reduced multiple phytochemicals fabricated silver nanoparticles (AL-AgNPs). The overnight culture of DFU isolates was processed and subjected to various studies such as antimicrobial activity, growth kinetics, biofilm disruption, reactive oxygen species (ROS), membrane leakage, membrane permeability, and damage and genotoxicity. The molecular docking of AL phytochemicals was also performed with bacterial enzyme DNA gyrase. Interestingly, AL-AgNPs were produced the remarkable antibacterial effect against the resistant DFU isolates, which was closely similar to the effect of AL-AgNPs observed against the reference strains. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AL-AgNPs against the DFU isolates were found to be 5-15 μg/mL and 10-20 μg/mL, respectively. The AL-AgNPs were depicted a concentration-dependent growth inhibition of DFU bacterial isolates. The MIC and MBC of AL-AgNPs were effectively destroyed the preformed biofilms of DFU isolates. Furthermore, the MBC of AL-AgNPs was displayed the increased intracellular ROS accumulation, membrane leakage, permeability and damage, and genotoxicity in the DFU isolates. Additionally, the in silico study revealed that the AL phytochemicals were fitted over the binding pocket of the DNA gyrase B subunit. The observed results were confirmed that the negative impacts of the AL-AgNPs at the level of the membrane and intracellular components of DFU isolates.

Rutin Prevents LTA Induced Oxidative Changes in H9c2 Cells

Lipoteichoic acid (LTA), a component of Gram-positive bacteria cell walls is involved in infective endocarditis (IE), a life-threatening disease. We evaluated for the first time, whether flavonoid rutin (quercetin-3-rutinoside) can block LTA-induced pro-inflammatory response and reactive oxygen species (ROS) production, and reduction of antioxidant enzymes. We found that rutin suppresses LTA effects on the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, as well as the pro-inflammatory enzyme cyclooxygenase-2, preventing phosphorylation of the mitogen-activated protein kinases (MAPKs), p38, and c-Jun N-terminal kinase, and the increase of ROS production induced by LTA. Taken together, these findings suggest that rutin prevents oxidative damage, inflammation, and MAPKs activation induced by LTA. Rutin may exert a protective effect in IE. These data provide novel insights for future use of rutin to prevent the mechanisms of LTA-related pathogenesis, inflammatory processes, and antioxidant enzyme levels in diseases such as IE.

Evaluation of Anti-proliferative Effects of Barringtonia racemosa and Gallic Acid on Caco-2 Cells

Barringtonia racemosa leaf water extract (BLE) had been shown to have high gallic acid (GA) content and BLE has been postulated to have anti-proliferative effects towards colorectal cancer. This study aims to further investigate the mechanism underlying the anti-proliferative effect of BLE in Caco-2 cells and to determine if GA is responsible for the observed effects. Both BLE and GA inhibited Caco-2 cells in a dose-dependent manner. Cells exposed to IC₅₀ concentration of BLE and GA showed reduced antioxidant activities. GA-treated Caco-2 cells experienced higher oxidative stress compared to cells treated with BLE. Both BLE and GA significantly up-regulated the expression of SLC2A1. BLE but not GA, significantly down-regulated the expression of ADH4. Meanwhile, GA but not BLE, significantly up-regulated AKRIB10 and GLO1 but significantly down-regulated HAGH. Alterations in gene expression were coupled with changes in extracellular glucose and pyruvate levels. While BLE decreased intracellular pyruvate, GA did the opposite. Both intracellular and extracellular D-lactate were not affected by either BLE or GA. GA showed more pronounced effects on apoptosis while BLE irreversibly reduced cell percentage in the G0/G1 phase. In conclusion, this study demonstrates the multiple-actions of BLE against Caco-2 cells, potentially involving various polyphenolic compounds, including GA.

Battle between plants as antioxidants with free radicals in human body

Free radicals are constructed by natural physiological activities in the human cells as well as in the environment. They may be produced as a result of diet, smoking, exercise, inflammation, exposure to sunlight, air pollutants, stress, alcohol and drugs. Imbalanced redox status may lead to cellular oxidative stress, which can damage the cells of the body, resulting in an incidence of various diseases. If the endogenous antioxidants do not stop the production of reactive metabolites, they will be needed to bring about a balance in redox status. Natural antioxidants, for example plants, play an important part in this context. This paper seeks to report the available evidence about oxidative stress and the application of plants as antioxidant agents to fight free radicals in the human body. For this purpose, to better understand oxidative stress, the principles of free radical production, the role of free radicals in diseases, antioxidant defense mechanisms, and the role of herbs and diet in oxidative stress are discussed.

Accelerating healing of excisional wound with alginate hydrogel containing naringenin in rat model

Wounds have always been considered as one of the most common physical damages. Therefore, various researches have been conducted to find an appropriate method to improve wound healing process. Among various materials, since hydrogels have appropriate properties for wound healing, they are widely used for this purpose. In this study, to develop a potential wound dressing, different concentrations of naringenin (0%, 1%, 10% and 20%) were incorporated in alginate hydrogel followed by evaluating its characters such as morphology, swelling properties, weight loss, antibacterial activity, releasing profile of the naringenin, hemo-, and cytocompatibility. Finally, to evaluate the effect of developed hydrogels on wound healing, the full-thickness dermal wound model in rat was used. Our results provided that the prepared hydrogels have appropriate porosity (86.7 ± 5.3%) with the interconnected pores. Moreover, weight loss assessment confirmed that fabricated hydrogels have suitable biodegradability (about 89% after 14 days). MTT assay also revealed the positive effect of hydrogels on cell viabilities, and they have no toxicity effect on cells. In vivo study indicated that the prepared hydrogels had better wound closure than the gauze-treated wound (the control), and alginate/20% naringenin group had the best wound closure among other groups. All in all, this study concluded that alginate/naringenin hydrogel has positive effect on wound healing process, and it can be used to treat skin injuries in the clinic. Graphical abstract.

Phenolic Profile, Antioxidant and Anti-Proliferative Activities of Methanolic Extracts from Asclepias linaria Cav. Leaves

Asclepias linaria Cav. (Apocynaceae) is a shrubby plant endemic of Mexico which has been used in traditional medicine. However, the bioactive potential of this plant remains unexplored. In this study, the phenolic composition, antioxidant, and cytotoxic activities of A. linaria leaves were determined. In order to estimate the phenolic composition of the leaves, the total phenolic, flavonoid, and condensed tannins contents were determined. Furthermore, the antioxidant activity was measured by the scavenging activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) and 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulphonic acid] (ABTS^•+) radicals and the total antioxidant capacity. The phenolic compounds identified in the A. linaria leaves by ultra-performance liquid chromatography coupled to mass spectrometry (UPLC-MS) include phenolic acids, such as p-coumaric and ferulic acid, as well as flavonoids, such as rutin and quercetin. The leaves’ extracts of A. linaria showed a high scavenging activity of DPPH^• and ABTS^•+ radicals (IC₅₀ 0.12 ± 0.001 and 0.51 ± 0.003 µg/mL, respectively), high total antioxidant capacity values (99.77 ± 4.32 mg of ascorbic acid equivalents/g of dry tissue), and had a cytotoxic effect against K562 and HL60 hematologic neoplasia cells lines, but no toxicity towards the normal mononuclear cell line was observed. These results highlight the potential of A. linaria and could be considered as a possible alternative source of anticancer compounds.

Theoretical Study of the Antioxidant Activity of Quercetin Oxidation Products

It was recently shown that, when tested in cellular systems, quercetin oxidized products (Qox) have significantly better antioxidant activity than quercetin (Q) itself. The main Qox identified in the experiments are either 2,5,7,3',4'-pentahydroxy-3,4-flavandione (Fl) or its tautomer, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Bf). We have now performed a theoretical evaluation of different physicochemical properties using density functional theory (DFT) calculations on Q and its main Qox species. The most stable structures (for Q and Qox) were identified after a structural search on their potential energy surface. Since proton affinities (PAs) are much lower than the bond dissociation enthalpies (BDEs) of phenolic hydrogens, we consider that direct antioxidant activity in these species is mainly due to the sequential proton loss electron transfer (SPLET) mechanism. Moreover, our kinetic studies, according to transition state theory, show that Q is more favored by this mechanism. However, Qox have lower PAs than Q, suggesting that antioxidant activity by the SPLET mechanism should be a result of a balance between proclivity to transfer protons (which favors Qox) and the reaction kinetics of the conjugated base in the sequential electron transfer mechanism (which favors Q). Therefore, our results support the idea that Q is a better direct antioxidant than its oxidized derivatives due to its kinetically favored SPLET reactions. Moreover, our molecular docking calculations indicate a stabilizing interaction between either Q or Qox and the kelch-like ECH-associated protein-1 (Keap1), in the nuclear factor erythroid 2-related factor 2 (Nrf2)-binding site. This should favor the release of the Nrf2 factor, the master regulator of anti-oxidative responses, promoting the expression of the antioxidant responsive element (ARE)-dependent genes. Interestingly, the computed Keap1-metabolite interaction energy is most favored for the Bf compound, which in turn is the most stable oxidized tautomer, according to their computed energies. These results provide further support for the hypothesis that Qox species may be better indirect antioxidants than Q, reducing reactive oxygen species in animal cells by activating endogenous antioxidants.

Chemical Structure-Antioxidant Activity Relationship of Water-Based Enzymatic Polymerized Rutin and Its Wound Healing Potential

The flavonoid rutin (RU) is a known antioxidant substance of plant origin. Its potential application in pharmaceutical and cosmetic fields is, however, limited, due to its low water solubility. This limitation can be overcome by polymerization of the phenolic RU into polyrutin (PR). In this work, an enzymatic polymerization of RU was performed in water, without the addition of organic solvents. Further, the chemical structure of PR was investigated using 1H NMR, and FTIR spectroscopy. Size-exclusion chromatography (SEC) was used to determine the molecular weight of PR, while its acid/base character was studied by potentiometric charge titrations. Additionally, this work investigated the antioxidant and free radical scavenging potential of PR with respect to its chemical structure, based on its ability to (i) scavenge non biological stable free radicals (ABTS), (ii) scavenge biologically important oxidants, such as O2•, NO•, and OH•, and (iii) chelate Fe2+. The influence of PR on fibroblast and HaCaT cell viability was evaluated to confirm the applicability of water soluble PR for wound healing application.

Quercetin-induced inactivation and conformational alterations of alpha-2-macroglobulin: multi-spectroscopic and calorimetric study

Quercetin is a widely used bioflavonoid found in onions, grapes, berries and citrus fruits. Under certain conditions, quercetin acts as a pro-oxidant thereby generating reactive oxygen species and promoting the oxidation of molecules. Our study investigates the effect of quercetin on the structure and function of alpha-2-macroglobulin (α₂M) by employing various biophysical techniques and trypsin inhibitory assay. α₂M is the major antiproteinase present in the plasma of vertebrates. Results of activity assay indicated that α₂M loses its 56% of inhibitory activity on treatment with quercetin in the presence of light. UV spectroscopy reveals hyper chromaticity in absorption spectra of protein on interaction with quercetin suggesting structural change. The intrinsic fluorescence studies showed quenching of α₂M spectra in the presence of quercetin, and the mode of quenching was found to be static in nature. Synchronous fluorescence indicated the alteration in the microenvironment of tryptophan residues. CD and FTIR spectroscopy confirms concentration-dependent alterations in secondary structure of α₂M instigated by quercetin. The magnitude of binding constant, enthalpy change, entropy change and free energy change during the interaction process was determined by isothermal titration calorimetry. Hydrogen bonding and hydrophobic interaction were the main intermolecular forces involved during the process. This study identifies and signifies the damage induced by quercetin to α₂M due to its pro-oxidant action. Communicated by Ramaswamy H. Sarma.