Recent Updates on Free Radicals Scavenging Flavonoids: An Overview

Selective Structural Derivatization of Flavonoid Acetamides Significantly Impacts Their Bioavailability and Antioxidant Properties

Flavonoids show abundant favorable physicochemical and drug related properties, leading to substantial biological applications which are limited by undesirable properties such as poor solubility, high polarity, low bioavailability, and enzymatic degradations. Chemical modification with bioisosteres can be used to address some of these challenges. We report the synthesis and characterization of partial flavonoid acetamide derivatives from quercetin, apigenin and luteolin and the evaluation of their structure-activity relationships based on antioxidant, bioavailability, drug likeness, and toxicity properties. The sequential synthesis was achieved with 76.67-87.23% yield; the structures of the compounds were confirmed using ¹H & ¹³C NMR characterizations. The purity of each compound was determined by HPLC while the molecular weights were determined by mass spectrometry. The % bioavailability was determined using the dialysis tubing procedure and the values were in the range 15.97-38.12%. The antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay and expressed as the IC₅₀ values which were in the range 31.52-198.41 µM. The drug likeness and the toxicity properties of compounds 4, 5, 7, 11 and 15 were predicted using computational tools and showed satisfactory results. A structure-activity relationship evaluation reveals that hydroxyl and methylene groups attached on the 2-phenylchromen-4-one structure of the flavonoid play a colossal role in the overall antioxidant and bioavailability properties. The improved bioavailability and excellent drug relevance and toxicity properties present flavonoid acetamide derivatives as prospective drug candidates for further evaluations.

Transcriptome analysis of perennial ryegrass reveals the regulatory role of Aspergillus aculeatus under salt stress

Perennial ryegrass (Lolium perenne) is an important turf grass and forage grass with moderately tolerant to salinity stress. Aspergillus aculeatus has been documented to involved in salt stress response of perennial ryegrass, while the A. aculeatus-mediated molecular mechanisms are unclear. Therefore, to investigate the molecular mechanisms underlying A. aculeatus-mediated salt tolerance, the comprehensive transcriptome analysis of the perennial ryegrass roots was performed. Twelve cDNA libraries from roots were constructed after 12 h of plant-fungus cocultivation under 300 mM salt stress concentrations. A total of 21,915 differentially expressed genes (DEGs) were identified through pairwise comparisons. Enrichment analysis revealed that potentially important A. aculeatus-induced salt responsive genes belonging to specific categories, such as hormonal metabolism (auxin and salicylic acid metabolism related genes), secondary metabolism (flavonoid's metabolism related genes) and transcription factors (MYB, HSF and AP2/EREBP family). In addition, weighted gene co-expression network analysis (WGCNA) showed that blue and black modules were significantly positively correlated with the peroxidase activity and proline content, then the hub genes within these two modules were further identified. Taken together, we found the categories of A. aculeatus-induced salt responsive genes, revealing underlying fungus-induced molecular mechanisms of salt stress response in perennial ryegrass roots. Besides, fungus-induced salt-tolerant hub genes represent a foundation for further exploring the molecular mechanisms.

The protective effect of chrysin against oxidative stress and organ toxicity in rats exposed to propetamphos

The aim of this study was to investigate the protective efficacy of chrysin against propetamphos exposure. For this purpose, 2 to 3-month-old 40 male Wistar Albino rats were used. These animals were randomly assigned to four groups. The animals in the control group received the vehicle substance (corn oil) alone. Groups 2, 3 and 4 were administered with 50 mg/kg.bw/day of chrysin (in corn oil), 10 mg/kg.bw/day of propetamphos (in corn oil), and 10 mg/kg.bw/day of propetamphos plus 50 mg/kg.bw/day of chrysin, respectively, for 28 days. Some oxidative stress/lipid peroxidation parameters (MDA, SOD, CAT, GSH-Px, NO, glutathione) and serum biochemical parameters (triglyceride, cholesterol, creatinine, BUN, creatine phosphokinase, ALT, ALP and pseudocholinesterase) were analyzed in tissue/blood samples. Also, histopathological findings were observed. According to the data obtained, no significant alteration had occurred in these parameters and the histological findings in the group given chrysin alone, when compared to the control group. Significant unfavorable alterations were detected in the oxidative stress/lipid peroxidation/antioxidant status parameters, all biochemical parameters and histopathological findings of the group that received propetamphos alone. In the group that was given both chrysin and propetamphos, remedial/recovery alterations were observed in the oxidative stress/lipid peroxidation/antioxidant status values, serum biochemical parameters and histopathological findings, such that the values and histopathological findings showed partly similarity to those of the control group. In result, it is suggested that chrysin may provide protection against propetamphos exposure and propetamphos-induced organ damage in rats at a certain level.

Zingiber roseum Rosc. rhizome: A rich source of hepatoprotective polyphenols

Zingiber roseum is native to Bangladesh and widely used in folk medicine. This present study was designed to assess the ameliorative potential of Zingiber roseum rhizome extract in carbon tetrachloride (CCl₄) induced hepatotoxicity in mice model. Seven phenolic compounds were identified and quantified by HPLC analysis in the plant extract, including quercetin, myricetin, catechin hydrate, trans-ferulic acid, trans-cinnamic acid, (-) epicatechin, and rosmarinic acid. Hepatotoxicity was induced by administrating a single intraperitoneal injection of CCl₄ (10 mL/kg) on 7th day of treatment. The results revealed that plant extract at all doses (100, 200 and 400 mg/kg) significantly reduced (p < 0.05) the elevated serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) concentrations, and these effects were comparable to that of standard drug silymarin. Histopathological examination also revealed the evidence of recovery from CCL₄ induced cellular damage when pretreated with Z. roseum rhizome extract. The in-vivo hepatoprotective effects were further investigated by the in-silico study of the aforementioned compounds with liver-protective enzymes such as superoxide dismutase (SOD), peroxiredoxin, and catalase. The strong binding affinities (ranging from -7.3359 to -9.111 KCal/mol) between the phenolic compounds (except trans-cinnamic acid) and oxidative stress enzymes inhibit ROS production during metabolism. The compounds were also found non-toxic in computational prediction, and a series of biological activities like antioxidant, anticarcinogen, cardio-protectant, hepato-protectant have been detected.

Anacardium humile St. Hil as a novel source of antioxidant, antiglycation and α-amylase inhibitors molecules with potential for management of oxidative stress and diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

The substantial increase in diabetes cases worldwide has been a major public health problem, and the use of medicinal plants can be considered an interesting alternative to control the disease and its complications. Anacardium humile St. Hill. (Anacardiaceae) is a typical plant from the Brazilian savanna, popularly known for its antidiarrheal, expectorant, antidiabetic and anti-inflammatory properties, however, few studies have fully described its biological properties. This study aimed to investigate in vitro and ex vivo the antioxidant and antiglycation potential of A. humile ethanolic extract, its organic fractions and three isolated molecules (quercetin, catechin and gallic acid), their capacity to inhibit the glycolytic enzyme α-amylase, as well as their cytotoxic effects against RAW264.7 macrophages.

MATERIAL AND METHODS

The ethanolic extract of A. humile, its organic fractions and three isolated molecules (catechin, quercetin and gallic acid) were tested for their antioxidant (ORAC, FRAP and DPPH) and antiglycation (BSA/Fructose, BSA/Methylglyoxal, Arginine/Methylglyoxal and Lysine/Methylglyoxal) capacities, and also for its potential to inhibit the enzyme α-amylase. Additionally, bioactive compounds present in the A. humile leaves fractions were elucidated by an HPLC-ESIMS/MS analysis.

RESULTS

The analysis showed relevant antioxidant activity of DCM (1264.85 ± 76.90 μM Trolox eq/g ORAC; 216.71 ± 1.04 μM Trolox eq/g FRAP and 3.03 ± 0.08 IC₅₀ μg/mL IC₅₀ DPPH) and EtOAc (1300.11 ± 33.04 ORAC, 236.21 ± 23.86 FRAP and 3.03 ± 0.14 μg/mL IC₅₀ DPPH) fractions and also of the isolated molecules, mainly gallic acid (1291.19 ± 8.41 μM Trolox eq/g ORAC, 1103.52 ± 31.48 μM Trolox eq/g FRAP and 0.78 ± 0.11 μg/mL IC₅₀ DPPH). Concerning the antiglycation activity, all samples inhibited over 88% in the BSA-FRU method. In the BSA-MGO and ARG-MGO methods, the Hex, DCM, EtOAc fractions and the isolated molecule catechin stood out. However, in the LYS-MGO model, only the isolated molecules showed significant results. In α-amylase assay, all fractions, for exception Hex, presented notable inhibition capacity with low IC₅₀ values, especially DCM, EtOAc, ButOH and H₂O (IC₅₀ 0.56 ± 0.10, 0.84 ± 0.01, 0.74 ± 0.03 and 0.79 ± 0.06 μg/mL, respectively). Tests using hepatic tissue showed a notorious capacity of the DCM, AcOEt and ButOH fractions, as well as of the isolated molecules to inhibit lipid peroxidation and ROS production, and also to preserve thiol groups. Molecules of great antioxidant potential were found in our samples, such as kaempferol, quercetin, catechin, gallic acid and luteolin.

CONCLUSION

A. humile extract and its organic fractions showed promising antioxidant and antiglycation potential and a prominent capacity to inhibit the α-amylase enzyme. Hence, this study presents new results and stimulates further research to elucidate the biological properties of A. humile and its capacity to manage DM and its complications.

Bioactive Compounds for Skin Health: A Review

Human skin is continually changing. The condition of the skin largely depends on the individual’s overall state of health. A balanced diet plays an important role in the proper functioning of the human body, including the skin. The present study draws attention to bioactive substances, i.e., vitamins, minerals, fatty acids, polyphenols, and carotenoids, with a particular focus on their effects on the condition of the skin. The aim of the study was to review the literature on the effects of bioactive substances on skin parameters such as elasticity, firmness, wrinkles, senile dryness, hydration and color, and to define their role in the process of skin ageing.

Glycosyltransferase OsUGT90A1 helps protect the plasma membrane during chilling stress in rice

Due to its subtropical origins, rice (Oryza sativa) is sensitive to low-temperature stress. In this study, we identify LOC_Os04g24110, annotated to encode the UDP-glycosyltransferase enzyme UGT90A1, as a gene associated with the low-temperature seedling survivability (LTSS) quantitative trait locus qLTSS4-1. Differences between haplotypes in the control region of OsUGT90A1 correlate with chilling tolerance phenotypes, and reflect differential expression between tolerant and sensitive accessions rather than differences in protein sequences. Expression of OsUGT90A1 is initially enhanced by low temperature, and its overexpression helps to maintain membrane integrity during cold stress and promotes leaf growth during stress recovery, which are correlated with reduced levels of reactive oxygen species due to increased activities of antioxidant enzymes. In addition, overexpression of OsUGT90A1 in Arabidopsis improves freezing survival and tolerance to salt stress, again correlated with enhanced activities of antioxidant enzymes. Overexpression of OsUGT90A1 in rice decreases root lengths in 3-week-old seedlings while gene-knockout increases the length, indicating that its differential expression may affect phytohormone activities. We conclude that higher OsUGT90A1 expression in chilling-tolerant accessions helps to maintain cell membrane integrity as an abiotic stress-tolerance mechanism that prepares plants for the resumption of growth and development during subsequent stress recovery.

Improving shelf-life of raw pork and pork meatballs by starfruit (Averrhoa carambola) powder supplementation

The study was conducted to evaluate the effect of starfruit (Averrhoa carambola) powder on the storage stability of both raw minced pork and cooked pork meatballs. Starfruit powder was incorporated to raw minced pork as well as pork meatball mixture at the rate of 1.0%,1.5% and 2.0% based on w/w basis. Samples with starfruit powder had lowered Thiobarbituric acid reactive substances (TBARS) value and improved microbiological quality of the product was observed, when stored at refrigeration temperature (4±1°C) for a period of 21 days. The product had better physico-chemical properties, desirable textural properties and enhanced sensorial characteristics. All these attributes lead to enhancement of the overall acceptability of the treated product. It indicated that starfruit powder can successfully be utilized as additives to raw pork and pork meatball mixtures to obtain products having improved shelf-life and can act as functional foods.

The role of myricetin from Rhodomyrtus tomentosa (Aiton) Hassk fruits on downregulation of FcɛRI-mediated mast cell activation

Rhodomyrtus tomentosa was reported to contain various bioactive metabolites, especially phenolic compounds. In the present study, the suppressive activity of phenolic compound from R. tomentosa fruits on mast cell activation was investigated in vitro. The result showed that myricetin was isolated from R. tomentosa fruits and its characterization was identified by nuclear magnetic resonance spectroscopy. Notably, myricetin was found to be effective in inhibition of mast cell degranulation by attenuating the release of β-hexosaminidase and the elevation of intracellular calcium. Moreover, myricetin exhibited inhibitory effect on the production of IL-4 and Tumor necrosis factor alpha (TNF-α) in a concentration-dependent manner. Furthermore, high antioxidant activity of myricetin due to scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ABTS⁺ radicals was also evidenced. Notably, the activation of FcɛRI-mediated signaling molecules including Syk, PLCγ, and NF-κB was also suppressed by myricetin treatment. Accordingly, myricetin from R. tomentosa fruits could be suggested as a functional food for the amelioration of allergic diseases. PRACTICAL APPLICATIONS: Polyphenol have been shown to exert various biological activities and health beneficial effects. Results from the present study revealed that myricetin from R. tomentosa fruits possesses the inhibitory effect on allergic response in mast cells. Therefore, myricetin from R. tomentosa fruits could be developed as a functional ingredient for the amelioration of allergic diseases.

Antihyperlipidemic and Antioxidant Effects of Averrhoa Carambola Extract in High-Fat Diet-Fed Rats

The present study explored the antihyperlipidemic potential of a standardized methanolic extract of Averrhoa carambola (A. carambola) leaf (MEACL) in high-fat diet (HFD)-fed rats. The standardized MEACL was orally administered at different doses (250, 500, and 1000 mg/kg) to HFD-induced hyperlipidemic rats for five weeks. Serum lipid profile, body weight changes, body mass index (BMI), daily food intake, relative organ weight, and histology of the liver were evaluated. In addition, the effect of MEACL on HMG-CoA reductase and pancreatic lipase activities as well as hepatic and fecal lipids was demonstrated. MEACL supplementation reduced serum lipids in HFD-fed rats in a dose-dependent manner. Histopathological scores revealed that 1000 mg/kg MEACL restored the damage to liver tissue in hyperlipidemic rats. MEACL decreased the body mass index (BMI), atherogenic index, and hepatic cholesterol and triglycerides and increased fecal cholesterol and bile acids in HFD-fed rats. Also, MEACL ameliorated lipid peroxidation and improved antioxidant defenses in the liver of HFD-fed rats. Furthermore, HMG-CoA reductase and lipase were suppressed by MEACL. In conclusion, this study shows the potential effect of MEACL to ameliorate hyperlipidemia and oxidative stress in HFD-fed rats. It prevented hepatic lipid accumulation and exerted an inhibitory effect on HMG-CoA reductase and lipase.

Diversity of active constituents in Cichorium endivia and Cynara cornigera extracts

The present study attempts to explore the phytochemical constituents of different extracts from Cynara cornigera and Cichorium endivia plant materials. The two species studied are native in Egypt. Five different solvents, viz., aqueous, methylene chloride, petroleum ether, ethyl acetate, and n-butanol were used. Phytochemical analysis revealed the presence of phenols, flavonoids, sterols (stigmasterol and beta-sitosterol), terpenes (α-amyrin, ursolic and oleanolic acid), and hydrocarbons (n-alkane), the latter found in low amount. The ethyl acetate and water extracts of C. cornigera root showed lower mass fractions of phenolic compounds ranged from 20 to 81 g/100 g, and higher amounts in ethyl acetate extract of the inflorescences and butanol extract of the root where values ranged from 195 to 399 g/100 g. The β-sitosterol and stigmasterol were present in all plant extracts. Oleanolic and ursolic acids were detected in roots, leaves and inflorescences of C. cornigera and in C. endivia shoot. The ethyl acetate extracts from C. cornigera leaf and inflorescence attained higher chemical diversity than the other extracts. Alternatively, sterols and triterpenes were the major constituents. The high chemical diversity of active constituents justifies the future potential use of the two species at commercial level.

Nutritional Characterization of Shoots and Other Edible Products of an Edible Bamboo - Dendrocalamus hamiltonii

Dendrocalamus hamiltonii is a locally available variety of multipurpose bamboo which is mainly cultivated as wood substitute, fodder and edible shoots used for making pickles. As this is a predominant species of bamboo popular with the masses, therefore, an effort was made to evaluate its shoots for quality parameters. Results showed that it contained 91.06 % moisture, 0.81% ash, 0.29% fat and 1.50% fiber. Edible bamboo shoots need to be processed and utilized immediately due to their seasonal availability and short shelf life. Some edible products such as preserve, candy, chutney, nuggets, cracker (papad) and chukh were prepared which were then analyzed for nutritional and organoleptic evaluation. The results revealed that prepared formulations were nutritionally rich and acceptable by sensory scores. Such an activities are bound to provide livelihood opportunities to the local population thereby, exploring the value of bamboo resource as underutilized health food.

Quality and shelf life evaluation of pork nuggets incorporated with fermented bamboo shoot (Bambusa polymorpha) mince

Pork nuggets were processed by incorporating fermented bamboo shoot mince and their physico-chemical, microbiological and sensory characteristics were evaluated during 35 day storage at refrigeration temperature (4±1 °C). Addition of fermented bamboo shoot significantly affects the pH, moisture, protein, fat, fiber, instrumental color values and texture profiles of nuggets, especially at 6% and 8% addition levels. Nuggets with 6% and 8% FBSM had significantly lower TBARS values at the end of the storage period (i.e. 0.39 and 0.33 mg malonaldehyde/kg respectively) compared to the control (0.84 mg malonaldehyde/kg). Bamboo shoot addition significantly improved the microbial and sensory qualities of the pork nuggets. Incorporation of fermented bamboo shoot at 8% level increased the shelf life of pork nuggets by at least two weeks i.e. from 21 days to 35 days at 4±1 °C compared to the control.