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[摘要]
目的对茶叶中的水溶性中性多糖(NTPS)和酸性多糖(ATPS)进行分离,以探讨不同结构的茶多糖的降血糖活性?方法采用弱碱性的大孔阴离子交换树脂D 315分离出两种带不同电荷的茶多糖NTPS和ATPS,采用气相色谱和离子色谱分析其单糖组成,并采用DEAE-Sepharose FF对其作进一步分离,通过HPGPC法分析其分离产物主要级分的相对分子质量?通过四氧嘧啶ip造成高血糖模型,连续ig茶多糖12 d,对比研究两种茶多糖的降血糖活性?结果NTPS和ATPS都是杂聚糖?NTPS以中性糖为主,含质量分数为6.82%半乳糖醛酸,中性糖部分主要由半乳糖组成;ATPS以酸性糖为主,含质量分数为33.02%半乳糖醛酸,中性糖部分主要由鼠李糖?阿拉伯糖和半乳糖组成?两种茶多糖相对分子质量均小于3×104?NTPS?ATPS按照200和400 m g/kg.d的剂量连续给四氧嘧啶糖尿病小鼠ig 12 d,发现都能抑制四氧嘧啶糖尿病小鼠血糖的升高?结论首次采用D 315阴离子交换树脂从茶叶中分离出了不同结构的多糖NTPS和ATPS,两种多糖都有很好的降血糖效果?
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[Abstract]
Objective To isolate water-soluble neutral polysaccharides(NTPS)and acidic polysaceha-rides(ATPS)fram tea,investigatet heirhy poglycemic effects,and elucidate the relationship between structure and activity.Methods Weak base macroporous anion-exchange resin D315 wfls used to isolate two kinds of tea polysaccharides NTPS and ATPS based on electric charge of tea polysaccharides.Their monosaccharide compositions were analyzed by gas chromatography and ionchromatography.NTPS and ATPS were further isolated by DEAE-SepharoseF F.Molecular weights of the main fractions were analyzed by HPGPC.The model of diabetic mellitus was established by ipalIoxan in mice.The blood samples were collected with tail vein puncture to determine blood glucose.The hypoglycemie activity between neutral and acidic polysaccharides was compared afterig tea polysaccharides for 12d successively.Results Both NTPS and ATPS were heteropolysaccharides.NTPS was mainly composed of netltral polyssccharide and ira main monopolysaccharl如WB.SD-galactoae.NTPS contalned 6.82%galacturonic acid.Whereas,ATPS was mainly composed of acidic polysaccharide and contained 33.02%D-galactose,whose neutral polysaccharide was mostly L-rhamnose,D-arabinose and D-galactose.The molecular weights of both two kinds of tea polysaccharides were less than 3x104.Continuousig administration of NTPS and ATPS E200 and 400mg/(kg·d)for 12 d was found to depress glucose increases in anoxan-dependent diabetic model mice.Conclusion TWO different structures of tea D0I vsaccharides NTPS and ATPS are isolated byanion-exchange resin D315 firstly.Both tea polysaccharides show good hypoglycemic effect.
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