1-1-diphenyl-2-picrylhydrazyl and genistin

A plastic composite support (PCS) bioreactor was implemented to evaluate the effects on isoflavone deglycosylation in black soymilk fermented by Rhizopus oligosporus NTU 5.. Evaluation for the optimal PCS for mycelia immobilisation was conducted, which led to the significant results that the most mycelium weight (0.237 g per PCS, P < 0.05) is held by an S-type PCS; therefore, it was selected for black soymilk fermentation. It was found that the PCS fermentation system without pH control exhibits better efficiency of isoflavone bioconversion (daidzin to daidzein, and genistin to genistein) than the one with pH control at pH 6.5. As for the long-run fermentation, those without pH control indeed accelerate the isoflavone bioconversion by continuously releasing β-glucosidase into soymilk. Deglycosylation can be completed in 8 to 24 h and sustained for at least 34 days as 26 batches. The non-pH-control fermentation system also exhibits the highest total phenolic content (ranged from 0.147 to 0.340 mg GAE mL(-1) sample) when compared to the pH-controlled and suspended ones. Meanwhile, the black soymilk from the 22nd batch with 8 h fermentation demonstrated the highest DPPH radical scavenging effect (54.7%).. A repeated-batch PCS fermentation system was established to accelerate the deglycosylation rate of isoflavone in black soymilk. © 2015 Society of Chemical Industry.

Topics: Antioxidants; beta-Glucosidase; Biphenyl Compounds; Fermentation; Food Handling; Genistein; Glycosides; Humans; Hydrogen-Ion Concentration; Isoflavones; Picrates; Rhizopus; Soy Milk

The present study describes the biotransformation of a commercially available crude extract of soy isoflavones, which contained significant amounts of the soy isoflavone glycosides daidzin and genistin, by recombinant

Topics: Antioxidants; Bacillus megaterium; Biotransformation; Biphenyl Compounds; Escherichia coli; Glycine max; Glycosides; Isoflavones; Monophenol Monooxygenase; Picrates

Isoflavonoids are thought to be the biologically active components in soy that play a role in the prevention of coronary heart disease and breast and prostate cancer. Mechanisms to explain how isoflavonoids mediate beneficial effects have not yet been clearly established. This study was undertaken to investigate the free radical-scavenging and antioxidant activities of various structure-related isoflavonoids including genistein, daidzein, biochanin A, and genistin in a cell-free and an endothelial cell model system. Electron spin resonance spectroscopy and spin trapping techniques were applied to evaluate the ability of isoflavonoids to scavenge hydroxyl, superoxide, nitric oxide, diphenylpicrylhydrazyl, galvinoxyl, and lipid-derived radicals. All isoflavonoids tested had no significant scavenging effects on the aforementioned radicals in concentrations up to 1.0 mM. However, at a physiologically achievable concentration of 5 nM, both genistein and daidzein slightly increased intracellular-reduced glutathione levels approximately by 10 and 30%, respectively, in human endothelial cells, whereas cellular alpha-tocopherol and uric acid remained unchanged by the isoflavonoid treatments. Present data indicate that free radical-scavenging activities of the isoflavonoids tested probably do not substantially contribute to their antioxidant properties. The ability of genistein and daidzein to increase cellular GSH (reduced glutathione) might be important for their action in biological system.

Topics: Anticarcinogenic Agents; Antioxidants; Biphenyl Compounds; Cells, Cultured; Chromatography, High Pressure Liquid; Electron Spin Resonance Spectroscopy; Endothelium, Vascular; Free Radical Scavengers; Genistein; Glutathione; Humans; Hydroxyl Radical; Isoflavones; Lipid Peroxidation; Nitric Oxide; Oxidants; Picrates; Superoxides; Uric Acid; Vitamin E