Polyphenol composition and antioxidant capacity from different extracts of Aster scaber

Polyphenol Profile and In Vitro Antioxidant and Enzyme Inhibitory Activities of Different Solvent Extracts of Highland Barley Bran

Five different solvent extracts of highland barley bran were analyzed and compared for their polyphenol profile, antioxidant activity, and α-glucosidase and α-amylase inhibitory activities. The highland barley bran acetone extract had the highest total phenolic content, total flavonoid content, and antioxidant capacity. It was followed by the methanol and ethanol extracts, while n-butanol and ethyl acetate extracts exhibited lower measured values. Diosmetin, luteolin, protocatechuic acid, vanillic acid, ferulic acid, phlorogucinol, diosmin, isoquercitrin, catechin, and isovitexin were among the most abundant phenolic compounds identified in different solvent extracts, and their concentrations varied according to the solvent used. The highest α-glucosidase and α-amylase inhibitory activity were observed in the ethyl acetate extract of highland barley bran, followed by the acetone and methanol extracts. In contrast, n-butanol and ethanol extracts exhibited lower measured values. The different solvent extracts were effective inhibitors for α-glucosidase and α-amylase with activity reaching to 34.45-94.32% and 22.08-35.92% of that of positive control acarbose, respectively. There were obvious correlations between the phenolic content and composition of different solvent extracts and their in vitro antioxidant activity, α-glucosidase inhibition activity and α-amylase inhibition activity. Black barley bran is an excellent natural raw material for developing polyphenol-rich functional foods and shows good antioxidant and hypoglycemic potential to benefit human health.

Antioxidant Activity of Oxygen Evolving Enhancer Protein 1 Purified from Capsosiphon fulvescens

This study was conducted to determine the antioxidant activity of a protein purified from Capsosiphon fulvescens. The purification steps included sodium acetate (pH 6) extraction and diethylaminoethyl-cellulose, reversed phase Shodex C4P-50 column chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that the molecular weight of the purified protein was 33 kDa. The N-terminus and partial peptide amino acid sequence of this protein was identical to the sequence of oxygen evolving enhancer (OEE) 1 protein. The antioxidant activity of the OEE 1 was determined in vitro using a scavenging test with 4 types of reactive oxygen species (ROS), including the 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl radical, superoxide anion, and hydrogen peroxide (H2 O2 ). OEE 1 had higher H2 O2 scavenging activity, which proved to be the result of enzymatic antioxidants rather than nonenzymatic antioxidants. In addition, OEE 1 showed less H2 O2 -mediated ROS formation in HepG2 cells. In conclusion, this study demonstrates that OEE 1 purified from C. fulvescens is an excellent antioxidant.

Selenium, putrescine, and cadmium influence health-promoting phytochemicals and molecular-level effects on turnip (Brassica rapa ssp. rapa)

The effects of selenium, putrescine, and cadmium on the contents of glucosinolates, total phenolics, flavonoids, carotenoids, chlorophyll, anthocyanin, malondialdehyde, hydrogen peroxide, and antioxidant capacities as well as gene regulation of phenolics, flavonoids, carotenoids, and glucosinolates biosynthesis were investigated in turnip plants. Selenium dioxide (SeO2) treatment significantly induced the amount of gluconasturtiin, glucobrassicanapin, glucoallysin, glucobrassicin, 4-methoxyglucobrassicin, and 4-hydroxyglucobrassicin. Cadmium chloride (CdCl2)- and putrescine-treated plants had considerably enhanced gluconasturtiin and 4-hydroxyglucobrassicin levels, respectively. Total phenolic and flavonoid content as well as antioxidant capacities were significantly increased in SeO2-treated plants. Lutein was higher in control plants followed by, in decreasing order, SeO2-, putrescine-, and CdCl2-treated plants. The chlorophyll content was significantly decreased and anthocyanin, MDA, and H2O2 levels were significantly increased with CdCl2 treatment. Moreover, plants treated with selenium and cadmium showed significant induction of genes related to glucosinolate, phenolic, and carotenoid biosynthesis. These results demonstrated that SeO2 significantly increased the contents of health-promoting compounds and enhanced the antioxidant capacities of turnip plants.