Studies On Composition, Bioactivity Of Tea Polysaccharides From 69 Varieties And Structure Of Tea Polysaccharides With Lower Bioactivity

The composition and bioactivity of tea polysaccharides of 69 varieties were studied, relatively higher and lower bioactivity representative breeds were selected. Monosaccharides composition, molecular weight, spectral signature of ultraviolet spectrum and infrared spectrum of the tea polysaccharide were analyzed based on the lower bioactivity representative variety NO.13.1. 69 tea varieties were collected, picking standard was a bud with three leaves. The samples were fixed by steam. After water-extraction and being precipitated by ethanol, the tea polysaccharides of different breeds were obtained. The extraction rate of tea polysaccharides and the contents of neutral sugar, uronic acid, protein, polyphenol of each crude polysaccharide were analyzed, and the scavenging rate of·OH, O₂^-·by tea polysaccharides of 69 varieties were compared. The results showed that: there were very significant differences of extraction rate of tea polysaccharides and the contents of neutral sugar, uronic acid, protein, polyphenol of each crude polysaccharide among 69 breeds, it illustrated that the breeds diversity of tea polysaccharides was clear. Meanwhile, there was a very significant difference of scavenging rate of·OH, O₂^-·by tea polysaccharides of different varieties. NO.31, NO.54, NO.57 were selected as the higher bioactivity representative varieties, and NO.13 was the lower bioactivity representative variety based on cluster analysis of scavenging rate of·OH, O₂^-·by tea polysaccharides of 69 varieties.2. NO.13, the lower bioactivity representative breed, was selected as research objects. The crude tea polysaccharides was extracted, and four main fractions TPS1, TPS2, TPS3, TPS4 were isolated from crude tea polysaccharides by DEAE-52 cellulose column.TPS2 was separated by Sephadex G-150 column chromatography into TPS2-1 and TPS2-2. Monosaccharide Composition, molar ratio, spectral signature of ultraviolet spectrum of TPS1, TPS2, TPS3, TPS4, TPS2-2 were analyzed, the molecular weight and spectral signature of infrared spectrum of TPS2-2 were analyzed. Gas chromatography analysis showed that TPS1, TPS2, TPS3, TPS4 were composed of rhamnose, ribose, arabinose, glucose, galactose; TPS2-2 was composed of rhamnose, arabinose, glucose, galactose, monosaccharide molar ratio was: 0.43∶1.34∶0.30∶1.67, and the main components were arabinose and galactose. The molecular weight and distribution of TPS2-2 were determined by gel permeation chromatography and laser light scattering (GPC-LLS), its molecular weight (Mw) was 34410, number-average molecular weight ( Mn) was 32810, Breadth Parameter of Molecular Weight Distribution (Mw/Mn) was 1.049. UV and IR spectrum analysis showed that the tea polysaccharides was a polysaccharide-protein conjugate withβ-pyran.