Shivraj Hariram Nile

Carotenoids from fruits and vegetables: Chemistry, analysis, occurrence, bioavailability and biological activities

Fruits and vegetables are generally considered as important contributors to a healthy diet and their intake is extremely helpful to reduce the risk of specific diseases like cancers, cardiovascular diseases, neural tube defects, and cataracts. Bioactive constituents from fruits and vegetables, such as carotenoids, folic acid and dietary fiber appear to play important roles in the prevention of these diseases. Carotenoids and their derivatives are versatile isoprenoids and play a vital role in plants and animals, starting from cellular antioxidant to gene regulation and so their importance at cellular and molecular level is well established. The most significant aspect of carotenoids in our diet is the antioxidant and provitamin A activity, and also the color that they impart to our food. The composition and bioavailability of carotenoids in food are significantly influenced by processing and other post-harvest technologies. This review discusses the theoretical aspects and recent developments in structural properties, biosynthesis and enhancement, processing, methods of analysis, composition in fruits and vegetables, and bioaccessibility and bioavailability of carotenoids. Additionally, future research challenges in this context are identified.

In Vitro Evaluation of Selected Benzimidazole Derivatives as an Antioxidant and Xanthine Oxidase Inhibitors

2‐Aryl‐1‐arylmethyl‐1H‐benzimidazole derivatives having different side chains on the structure were examined in vitro for their antioxidant abilities by 2,2‐diphenyl‐1‐picryl hydrazine radical scavenging activity, reducing ability, OH radical scavenging activity, inhibition of polyphenol oxidase and xanthine oxidase. Overall, with few exceptions, all the 2‐aryl‐1‐arylmethyl‐1H‐benzimidazoles showed moderate biological activity with all parameters examined. The 2‐aryl‐1‐arylmethyl‐1H‐benzimidazoles were found to be reactive toward 2,2‐diphenyl‐1‐picryl hydrazine radical and had considerable reducing ability, with significant xanthine oxidase inhibition. With few exceptions, all the compounds under study were found to possess moderate‐to‐poor OH radical scavenging activity and inhibited polyphenol oxidase significantly. These findings suggest that these 2‐aryl‐1‐arylmethyl‐1H‐benzimidazoles can be considered as potential antioxidant and xanthine oxidase inhibitory agents, those might be further, explored for the design of lead antioxidant and antigout drug candidates using in vivo trials.

Antioxidant, α-glucosidase and xanthine oxidase inhibitory activity of bioactive compounds from maize (Zea mays L.).

Chemical investigations into maize (Zea mays L.) kernels yielded phenolic compounds, which were structurally established using chromatographic and spectroscopic methods. The isolated phenolic compounds from maize kernel were examined in vitro for their antioxidant abilities by DPPH (2,2‐diphenyl‐1‐picryl hydrazine) radical, OH radical scavenging activity, and reducing ability, along with α‐glucosidase and xanthine oxidase (XO) inhibition. The isolated maize phenolics revealed significant xanthine oxidase and α‐glucosidase inhibitory activity to that of allopurinol and acarbose in vitro and in vivo, respectively. The kinetics study with xanthine oxidase revealed competitive type of inhibition by isolated maize vanillic acid (M2), ferulic acid (M5), 3′‐methoxyhirsutrin (M7), and peonidin‐3‐glucoside (M10) as compared to control allopurinol. Overall, with few exceptions, all the phenolic compounds from maize kernel revealed significant biological activities with all parameters examined. Also, the phenolic compounds from maize were found to be more reactive toward DPPH radical and had considerable reducing ability and OH radical scavenging activity. These findings suggest that maize kernel phenolic compounds can be considered as potential antioxidant, α‐glucosidase, and XO inhibitory agents those might be further explored for the design of lead antioxidant, antidiabetic and antigout drug candidates using in vivo trials.

Total phenolics, antioxidant and xanthine oxidase inhibitory activity of three colored onions (Allium cepa L.)

Methanolic extracts from bulbs of three onion (Allium cepa L.) varieties: red (Pusa Red), white (Pusa White Round), and yellow (Arka Pitamber) and the CHCl 3, Et 2O, EtOAc, and n-BuOH fractions obtained from those extracts were investigated for their total phenolics and antioxidant activity. The antioxidant activity measurements, expressed as total antioxidant status (TAS), were 5.2–50.18, 2.2–35.6 and 3.5–42.2 mg ml−1 for red, white and yellow onion bulb extracts, respectively, as compared to trolox (IC 50, 40.2 mg ml−1). The total phenolic content of the samples was 62–186, 56–156 and 68–165 mg GAE ml−1 for red, white and yellow onion bulb extracts, respectively, with all solvents. There was a positive correlation between the total phenolic content and antioxidant activity for MeOH extracts and EtOAc fractions (R2=0.96, 0.8 respectively). Of the selected colored onion bulbs the red onion (IC 50=14.2 μg ml−1) revealed more potent xanthine oxidase inhibitory activity to those of yellow (IC 50=15.5 μg ml−1) and white onion (IC 50=17.0 μg ml−1) in vitro and as compared to control allopurinol (IC 50=10.5 μg ml−1). The kinetic study by xanthine oxidase revealed that the white and yellow onion extracts were non-competitive inhibitors, as Km values were constant, while Vmax consequently decreased with increased inhibitor concentration. In the red onion extract there was an increase in Km values while Vmax remained constant at all extract concentrations, thus confirming a competitive type of inhibition by the Lineweaver–Burk equation. These findings suggest that these onion varieties can be considered as potential sources of antioxidants and XO inhibitory agents.

Polyphenolic Contents and Antioxidant Properties of Different Grape (V. vinifera, V. labrusca, and V. hybrid) Cultivars

The polyphenolic contents and the antioxidant activity of the skins and pulps of different grape cultivars were estimated using HPLC and DPPH antioxidant assay, respectively. The phenolics and flavonoids identified were quercetin, kaempferol, caffeic acid, p-coumaric acid, cinnamic acid, and (−)-epicatechin. The total phenolic contents were found to be the highest in the grape skin of Flouxa (>400 mg/100 g), followed by Campbell Early and Tamnara (>300 mg/100 g), and then by Red Globe and Ruby Seedless (>250 mg/100 g), and the total phenolic content was the lowest in Italia and Delaware (<60 mg/100 g). The antioxidant activities of the grape extracts varied from 12.5% (Ruby Seedless) to 60.2% (Hongiseul) for skins, whereas the antioxidant activities of the grape extracts varied from 35.4% (Campbell Early) to 84.5% (Hongiseul) for pulps. The grape pulps have stronger antioxidant activities than those of the grape skins. Our results suggest that the phenolic and flavonoid contents in extracts of grape skins and pulps showed statistically significant correlations with the free radical scavenging activity.

Folates: Chemistry, analysis, occurrence, biofortification and bioavailability

Folates (Vitamin B9) include both naturally occurring folates and synthetic folic acid used in fortified foods and dietary supplements. Folate deficiency causes severe abnormalities in one-carbon metabolism can result chronic diseases and developmental disorders, including neural tube defects. Mammalian cells cannot synthesize folates de novo; therefore, diet and dietary supplements are the only way to attain daily folate requirements. In the last decade, significant advancements have been made to enhance the folate content of rice, tomato, common bean and lettuce by using genetic engineering approaches. Strategies have been developed to improve the stability of folate pool in plants. Folate deglutamylation through food processing and thermal treatment has the potential to enhance the bioavailability of folate. This review highlights the recent developments in biosynthesis, composition, bioavailability, enhanced production by elicitation and metabolic engineering, and methods of analysis of folate in food. Additionally, future perspectives in this context are identified. Detailed knowledge of folate biosynthesis, degradation and salvage are the prime requirements to efficiently engineer the plants for the enhancement of overall folate content. Similarly, consumption of a folate-rich diet with enhanced bioavailability is the best way to maintain optimum folate levels in the body.

Synthesis, biological evaluation, and molecular docking of N-{3-[3-(9-methyl-9H-carbazol-3-yl)-acryloyl]-phenyl}-benzamide/amide derivatives as xanthine oxidase and tyrosinase inhibitors

Claisen-Schmidt condensation of 3-formyl-9-methylcarbazole with various amides of 3-aminoacetophenone afforded N-{3-[3-(9-methyl-9H-carbazol-3-yl)-acryloyl]-phenyl}-benzamide/amide derivatives. All compounds were investigated for their in vitro xanthine oxidase (XO), tyrosinase and melanin production inhibitory activity. Most of the target compounds had more potent XO inhibitory activity than the standard drug (IC(50) = 4.3-5.6 μM). Interestingly, compound 7q bearing cyclopropyl ring was found to be the most potent inhibitor of XO (IC(50) = 4.3 μM). Molecular modelling study gave an insight into its binding modes with XO. Compounds 7a, 7d, 7e, 7g, and 7k were found to be potent inhibitors of tyrosinase (IC(50) = 14.01-17.52 μM). These results suggest the possible use of these compounds for the design and development of novel XO and tyrosinase inhibitors.

Effect of different exposed lights on quercetin and quercetin glucoside content in onion (Allium cepa L.)

Quercetin and quercetin glucosides are the major flavonols present in onion (Allium cepa L.) and are predominantly present as quercetin, quercetin-3,4′-diglucoside and quercetin-4′-glucoside. Effect of different light wavelengths on onion after harvest and storage, with fluorescent, blue, red and ultra violet light influenced the quercetin and quercetin glucosides profile. In a peeled onion, all the light treatments elevated quercetin content in bulb. Among them, particularly fluorescent light effect was more eminent which stimulates the maximum synthesis of quercetin in onion. In case of whole onion bulb, skin and pulp showed different responses to light treatment, respectively. The pulp had the highest quercetin glucosides under blue light, whereas the lowest under fluorescent light. Onion skin showed nearly opposite pattern as compared to the pulp. In particular, light treatment proved to be a better way to increase the level of quercetin content in onions which might be utilized for industrial production of bioactive compounds from onion and onion waste products.

HPTLC analysis, antioxidant, anti-inflammatory and antiproliferative activities of Arisaema tortuosum tuber extract

Abstract Context: Oxidative stress and inflammation are related to several chronic diseases including cancer and atherosclerosis. Arisaema tortuosum (Wall.) Schott (Araceae) is an Indian folk medicinal herb traditionally used for treatment of various diseases related to inflammation and stress. Objective: This study was carried out for HPTLC analysis and evaluation of antioxidant, anti-inflammatory and antiproliferative activities of a methanol extract of A. tortuosum tuber. Materials and methods: The antioxidant activities of methanol extract of A. tortuosum tuber (1 mg/mL) were evaluated by DPPH, ABTS and FRAP assays and anti-inflammatory effects by diene-conjugate and β-glucuronidase assays, with in vitro tumor growth inhibition on HeLa cancer cells. The results for antioxidant and anti-inflammatory effects were compared using Trolox and salicylic acid as reference compounds, respectively. Results: The TLC and HPTLC analysis showed the presence of quercetin, rutin, luteolin and lectin (Rf values 0.97, 0.53, 0.59 and 1.58, respectively). The methanol fraction of tuber exhibit higher activity in each antioxidant system with a special attention for DPPH (IC50 = 852 μg/mL), ABTS (IC50 = 532 μg/mL), and FRAP (IC50 = 458 μg/mL), as compared with Trolox as standard, with a remarkable amount of phenolics (86.2 mg/100 g) and flavonoids (175.5 mg/100 g), along with potent anti-inflammatory activity indicated by diene-conjugate (86.20%) and β-glucuronidase (92.92%) inhibition, as compared with salicylic acid as reference compound. The antiproliferative activity at 100 mg/mL was 88% inhibition with HeLa cells. The inhibition of HeLa cell proliferation was greatest (p < 0.001) with the 100 mg/mL A. tortuosum tuber extract treatments and least with the 25 mg/mL dose. Discussion and conclusion: Our results suggested that A. tortuosum tuber might be used as a promising and potent antioxidant, anti-inflammatory, and antiproliferative agent and might be used for standardization of potential drug after successful isolation and characterization of bioactive compounds.

Optimized and comparative antioxidant assays and its applications in herbal and synthetic drug analysis as an antioxidants.

Drug development in the recent times often relies on use of natural and synthetic drugs that are promising candidates as therapeutic agents for prevention of diseases and disorders. They possess different chemical structures with wide range of therapeutic activities. Many natural and synthetic drugs act as antioxidant agents in various metabolic processes. Increasing epidemiological, clinical and experimental studies have shown that intake of antioxidants drugs provide protection against various disorders and diseases related to oxidative stress. The factors responsible for this oxidative stress are mainly free radicals, reactive nitrogen species (RNS) and reactive oxygen species (ROS). The antioxidant drugs act as free radical scavenging, reducing and metal chelating substances; Antioxidants also show inhibition of various metabolic enzymes and factors responsible for inflammation. The present paper reviews different In vitro assays for determination of antioxidant activities (Table 1). The basic assays include DDPH assay, OH Scavenging assay, Reducing activity assay, TEAC assay, FCR assay, PRTC assay, ABTS assay, FRAP assay, ORAC assay, Ferric thiocynate assay, TRAP assay, Chemiluminescence assay, NBT assay, CUPRAC Assay.