Investigation of bioactive compounds and their correlation with the antioxidant capacity in different functional vinegars.

There are complex and diverse substances in traditional vinegars, some of which have been identified as biologically active factors, but the variety of functional compounds is currently restricted. In this study, it was aimed to determine the bioactive compounds in 10 typical functional vinegars. The findings shown that total flavonoids (0.21-7.19 mg rutin equivalent/mL), total phenolics (0.36-3.20 mg gallic acid equivalent/mL), and antioxidant activities (DPPH: 3.17-47.63 mmol trolox equivalent/L, ABTS: 6.85-178.29 mmol trolox equivalent/L) varied among different functional vinegars. In addition, the concentrations of the polysaccharides (1.17-44.87 mg glucose equivalent/mL) and total saponins (0.67-12.46 mg oleanic acid equivalent/mL) were determined, which might play key role for the function of tested vinegars. A total of 8 organic acids, 7 polyphenol compounds and 124 volatile compounds were measured and tentatively identified. The protocatechuic acid (4.81-485.72 mg/L), chlorogenic acid (2.69-7.52 mg/L), and epicatechin (1.18-97.42 mg/L) were important polyphenol compounds in the functional vinegars. Redundancy analysis indicated that tartaric acid, oxalic acid and chlorogenic acid were significantly positively correlated with antioxidant capacity. Various physiologically active ingredients including cyclo (Pro-Leu), cyclo (Phe-Pro), cyclo (Phe-Val), cyclo (Pro-Val), 1-monopalmitin and 1-eicosanol were firstly detected in functional vinegars. Principle component analysis revealed that volatiles profile of bergamot Monascus aromatic vinegar and Hengshun honey vinegar exhibited distinctive differences from other eight vinegar samples. Moreover, the partial least squares regression analysis demonstrated that 11 volatile compounds were positively correlated with the antioxidant activity of vinegars, which suggested these compounds might be important functional substances in tested vinegars. This study explored several new functionally active compounds in different functional vinegars, which could widen the knowledge of bioactive factor in vinegars and provide new ideas for further development of functional vinegar beverages.

Hyperoside protects human primary melanocytes against H2O2-induced oxidative damage.

Cuscutae semen has been shown to have beneficial effects in the treatment of vitiligo, recorded in the Chinese Pharmacopoeia, whereas the effects of its constituent compounds remains to be elucidated. Using a tetrazolium bromide assay, the present study found that hyperoside (0.5­200 µg/ml) significantly increased the viability of human melanocytes in a time­ and dose­dependent manner. The present study used a cell model of hydrogen peroxide (H2O2)­induced oxidative damage to examine the effect of hyperoside on human primary melanocytes. The results demonstrated that hyperoside pretreatment for 2 h decreased cell apoptosis from 54.03±9.11 to 17.46±3.10% in the H2O2­injured melanocytes. The levels of oxidative stress in the mitochondrial membrane potential of the melanocytes increased following hyperoside pretreatment. The mRNA and protein levels of B­cell lymphoma­2/Bcl­2­associated X protein and caspase 3 were regulated by hyperoside, and phosphoinositide 3­kinase/AKT and mitogen­activated protein kinase signaling were also mediated by hyperoside. In conclusion, the results of the present study demonstrated that hyperoside protected the human primary melanocytes against oxidative damage.