Structural Characterization and In Vitro Antioxidant, Hypoglycemic and Hypolipemic Activities of a Natural Polysaccharide from Liupao Tea

This study extracted and purified a natural polysaccharide (TPS-5) that has a molecular weight of 48.289 kDa from Liupao tea, a typical dark tea with many benefits to human health. TPS-5 was characterized as a pectin-type acidic polysaccharide. It has a backbone composed of -> 2,4)- alpha- L-Rhap-(1) -> 4)- alpha- D-GalAp-(1) ->, with a branch composed of -> 5)- alpha- L-Ara(1 -> 5,3)- alpha- L-Ara-(1 -> 3)- beta- D-Gal-(1 -> 3,6)- beta- D-Galp-(1) ->. The in vitro biological activity evaluation illustrated that TPS-5 has free radical scavenging, ferric-ion-reducing, digestive enzyme inhibitory, and bile-salt-binding abilities. These results suggest that TPS-5 from Liupao tea has potential applications in functional foods or medicinal products.