Identification of anthocyanin compositions in black seed coated Korean adzuki bean (Vigna angularis) by NMR and UPLC-Q-Orbitrap-MS/MS and screening for their antioxidant properties using different solvent systems.

The aim of the present research was to investigate the antioxidant properties and anthocyanin profiles in the black seed coated adzuki bean (Vigna angularis, Geomguseul cultivar). The acidic 60% methanol extract (40 µg/mL) contains the highest total phenolic and flavonoid contents (486 ± 3 mg GAE/100 g; 314 ± 10 mg CE/100 g) with potent antioxidant properties (trolox equivalent 1272 ± 26 and 662 ± 24 mg TE/100 g) against ABTS and DPPH radicals compared to other methanol-water ratios (20, 40, 80, and 100%). Ten anthocyanin components were identified in this extract including delphinidin-3,5-O-digalactoside (1), delphinidin-3,5-O-diglucoside (2), delphinidin-3-O-galactoside (3), delphinidin-3-O-glucoside (4), delphinidin-3-O-rutinoside (5), delphinidin-3-O-(p-coumaroyl)glucoside (6), cyanidin-3-O-glucoside (7), petunidin-3-O-galactoside (8), petunidin-3-O-glucoside (9) and petunidin-3-O-(p-coumaroyl)glucoside (10) via NMR spectroscopy and UPLC-Q-Orbitrap-MS/MS analysis. The key anthocyanins 3 and 4 of delphinidin type were isolated by reversed phase C-18 MPLC. Our results indicate that the anthocyanin profiles as well as the high phenolic and flavonoid contents are important factors determining the antioxidant effects of black adzuki bean.

Effects of black adzuki bean (Vigna angularis) extract on proliferation and differentiation of 3T3-L1 preadipocytes into mature adipocytes.

The aim of this work was to investigate the effects of black adzuki bean (BAB) extract on adipocytes, and to elucidate the cellular mechanisms. In order to examine the proliferation of preadipocytes and differentiating adipocytes, cell viability and DNA content were measured over a period of time. Lipid accumulation during cell differentiation and the molecular mechanisms underlying the effects of BAB on the transcriptional factors involved, with their anti-adipogenic effects, were also identified. We observed that BAB exhibits anti-adipogenic effects through the inhibition of proliferation, thereby lowering mRNA expression of C/EBPß and suppressing adipogenesis during the early stage of differentiation. This, in turn, resulted in a reduction of TG accumulation in a dose- and time-dependent manner. Treating the cells with BAB not only suppressed the adipogenesis-associated key transcription factors PPARγ and C/EBPα but also significantly decreased the mRNA expression of GLUT4, FABP4, LPL and adiponectin. The expression of lipolytic genes like ATGL and HSL were higher in the treatment group than in the control. Overall, the black adzuki bean extract demonstrated an anti-adipogenic property, which makes it a potential dietary supplement for attenuation of obesity.