Structural characterization and anti-photoaging activity of a polysaccharide from Sargassum fusiforme.

In this study, a purified algal polysaccharide (P1) was isolated from Sargassum fusiforme and its structural characteristics and anti-photoaging activity were studied. Results showed that P1 had a molecular weight of 289 kDa and was mainly composed of mannuronic acid, guluronic acid and fucose with molar ratio of 7.67:2.35:1.00. The backbone of P1 was →4)-ß-ManA-(1→4)-α-GulA-(1→4)-ß-ManA-(1→4)-ß-ManA-(1→4)-α-GulA-(1→4)-ß-ManA-(1→3,4)-ß-ManA-(1→ with a terminal group of α-Fucp-(1→ linked to O-3 position of →3,4)-ß-ManA-(1→. In addition, P1 could inhibit the expressions of MMPs (MMP-1, MMP-3 and MMP-9) in the UVB-irradiated HaCaT cells, indicating that P1 could reduce collagen loss caused by UVB irradiation. It also reduced the contents of ROS and inflammatory factors (TNF-α, IL-6 and IL-1ß), indicating that P1 could reduce the oxidative stress and inflammation response. Thus, Sargassum fusiforme polysaccharide P1 could be used as a potential functional food to relieve skin photoaging.

Prebiotic supplementation (beta-glucan and inulin) attenuates circadian misalignment induced by shifted light-dark cycle in mice by modulating circadian gene expression.

Circadian rhythm governs multiple behavioural and physiological processes and its disruption is closely associated with various pathological conditions. In this study, the effects of dietary intervention by prebiotics including beta-glucan and inulin on attenuating circadian desynchrony in C57BL/6J mice subjected to weekly shifted light-dark cycle under a high fat diet was investigated. Using RT-qPCR and rhythmicity analysis, our study revealed that beta-glucan (0.2 g/day) and inulin (0.2 g/day) modulated the expression and phase of circadian-clock genes, explicitly reversed the phase delay of Period 1 and Period 3 in the hypothalamus, and reversed the phase delay of Period 2 in the liver of the mice. In the shifted mouse group, inulin also exhibited its reversal effects on the phase advance of Brain and muscle-Arnt-like 1 in the hypothalamus. These findings indicated that prebiotic supplementation can be a novel dietary approach for attenuating circadian misalignment.