Potential use of seaweed polysaccharides as prebiotics for management of metabolic syndrome: a review.

Seaweed polysaccharides (SPs) obtained from seaweeds are a class of functional prebiotics. SPs can regulate glucose and lipid anomalies, affect appetite, reduce inflammation and oxidative stress, and therefore have great potential for managing metabolic syndrome (MetS). SPs are poorly digested by the human gastrointestinal tract but are available to the gut microbiota to produce metabolites and exert a series of positive effects, which may be the mechanism by which SPs render their anti-MetS effects. This article reviews the potential of SPs as prebiotics in the management of MetS-related metabolic disturbances. The structure of SPs and studies related to the process of their degradation by gut bacteria and their therapeutic effects on MetS are highlighted. In summary, this review provides new perspectives on SPs as prebiotics to prevent and treat MetS.

The antioxidant and antihyperlipidemic activities of phosphorylated polysaccharide from Ulva pertusa.

Ulvan was the polysaccharide (U) from a large edible green algae Ulva pertusa. In this study, phosphorylated ulvan (PU) was prepared by the sodium trimetaphosphate -sodium tripolyphosphate method. Antioxidant and antihyperlipidemic effects of U and PU were investigated employing in vivo systems. The PU was confirmed by IR, 31P NMR and 13C NMR spectra. And in addition, we found that the PU3 group at the dose of 500 mg/kg showed stronger antioxidant activity. Compared with hyperlipidemia group, it significantly increased GSH-Px (34.29%; P < 0.01), SOD (20.04%; P < 0.01) and CAT (37.49%; P < 0.01). Treatment of hyperlipidemia mice with PU resulted in a significant decrease in TC, TG and LDL-C, and significant increase in HDL-C. The PU3 significantly increased HDL-C (33.70%; P < 0.01), decreased LDL-C (52.73%; P < 0.01) and TG (33.58%; P < 0.01) compared with hyperlipidemia group. The result showed that phosphorylation could improve hypolipidaemic and antioxidant activities in vivo. PU may be used as a drug for hyperlipidaemia treatment.

Antioxidant activity of purified ulvan in hyperlipidemic mice.

Several studies have reported that ulvan from the alga Ulva pertusa (Chlorophyta) exhibits substantial antioxidant and antihyperlipidemic activities; however, which group of heteropolysaccharides play roles in these activities remains unknown. In this study, three purified ulvan (PU1, PU2 and PU3) have been obtained by DEAE-Sepharose fast-flow column. The antioxidant activity was detected via the model of hyperlipidemic Kunming mice, including malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in liver. PU3, which possessed the highest uronic acid content (24.09%) and sulfate content (23.99%) as well as the lowest average molecular weight (83,094 Da), exhibited the stronger antioxidant activity than other examples. It significantly decreased MDA (29.2%; P < 0.05), increased SOD (36.4%; P < 0.05) and CAT (43.6%; P < 0.05) compared with hyperlipidemia group. In conclusion, PU3 may be potential sources of natural antioxidant to protecting against the liver damage of oxidative stress induced by cholesterol-rich diet.