Structural characterization, antioxidant and antibacterial activity of three pectin polysaccharides from blueberry.

In this study, three pectin polysaccharides BP1, BP2 and BP3, were purified from blueberries. The weight-average molecular weight (Mw) of BP1, BP2, and BP3 were detected to be 9.027 × 104, 9.313 × 104, and 1.223 × 106 Da, respectively. The structures of the three pectin polysaccharides were characterized and compared based on the results of molecular weight, monosaccharide composition, GC-MS and NMR analysis. Structural characterization revealed that BP1, BP2, and BP3 all contain homogalacturonan (HG) and rhamnogalacturonan I (RG-I) domains, and the rhamnose residues in RG-I domains are substituted at C-4 with side chains such as araban and galactosan. BP2 had the highest degree of esterification and HG domain ratio, followed by BP3 and BP1. In addition, BP1, BP2 and BP3 showed great antioxidant and antibacterial activities, and could destroy the cell membrane of Staphylococcus aureus and Escherichia coli. Moreover, the better DPPH and ABTS free radical scavenging and antibacterial activities of BP1 and BP2 than BP3 might be related to their lower molecular weight. The results of this study will provide essential information for the structure-activity relationship of pectin polysaccharides and research basis for development and application of blueberry pectin polysaccharides.

Effects of high hydrostatic pressure on the binding capacity, interaction, and antioxidant activity of the binding products of cyanidin-3-glucoside and blueberry pectin.

In this study, the effects of high hydrostatic pressure (HP) treatment on the binding capacity, interaction, and antioxidant activity of the binding products of blueberry pectin (BP) and cyanidin-3-glucoside (C3G) were assessed. HP was found to significantly improve the adsorption between C3G and BP. After binding, the C3G concentration was found to be the highest (382.1 ± 13.2 µg/mg for BP) when using a C3G-BP mass ratio of 1:2, a pressure of 400 MPa, and a holding time of 15 min. HP processing decreased particle size and altered the characteristics of C3G-BP complexes. The main binding form of the complexes before HP treatment was pectin-wrapped C3G by hydrogen bond interaction, while HP caused charged groups in pectin to be more exposed and improve the electrostatic interaction between C3G and BP. The antioxidant activity results showed that the presence of BP could protect the ferric-reducing antioxidant power of C3G after HP treatment.

Schisantherin A alleviated alcohol-induced liver injury by the regulation of alcohol metabolism and NF-kB pathway.

Schisantherin A (SinA), one of the most abundant active ingredients of Schisandra chinensis, was reported to protect and benefit the liver, however, its effect on alcohol-induced liver injury (ALI) was still not clear. In the present study, an ALI mice model was induced by feeding mice an alcohol-containing liquid diet for four weeks. Then, 100 mg/kg or 200 mg/kg SinA was administered to mice every day by gavage for the last two weeks. Histopathological analysis showed that alcohol-induced liver lipid vacuoles were reduced by SinA. The activities of aspartate aminotransferase (AST, 61.90 ± 14.65 vs. 93.65 ± 20.50, 50.46 ± 13.21 vs. 93.65 ± 20.50) and alanine transaminase (ALT, 41.29 ± 9.20 vs. 64.04 ± 18.13, 36.52 ± 7.71 vs. 64.04 ± 18.13) in the serum of ALI mice were significantly reduced by 100 mg/kg or 200 mg/kg SinA when compared with control mice. Alcohol-induced oxidative stress and the inflammatory response in the liver were suppressed by SinA in a dose-dependent manner. Meanwhile, treatment with SinA decreased alcohol dehydrogenase (ADH) activity and increased acetaldehyde dehydrogenase (ALDH) activity in ALI mice. Alcohol-induced upregulation of CYP2E1 and CYP1A2 in the liver was inhibited by SinA. Further, SinA suppressed activation of the NF-kB pathway in ALI mice. In conclusion, our findings demonstrate that SinA is able to protect against ALI, and this may be, at least in part, caused by regulation of alcohol metabolism and the NF-kB pathway. Our data suggest a therapeutic potential of SinA in the treatment of ALI.