石榴皮多糖的提取及组成、体外降脂活性研究

Study on the extraction and composition of pomegranate peel polysaccharide and hypolipidemic activity in vitro

以石榴皮为原料,通过响应面试验对内部沸腾法提取石榴皮多糖(polysaccharides from pomegranate peel,PPP)的工艺进行了优化,对PPP的单糖组成进行分析,并以PPP对胆固醇酯酶、胰脂肪酶的抑制作用,体外结合胆酸盐的能力为指标,评价PPP的体外降脂能力。结果表明,PPP的最佳提取条件为乙醇体积分数91%,液料比42∶1(mL∶g),提取时间62 min,提取温度96℃,在此条件下,PPP的得率为(16.32±0.21)%(n=3);高效液相色谱结果表明,PPP主要由岩藻糖、半乳糖醛酸、阿拉伯糖组成,除此之外还含有少量的甘露糖、鼠李糖、葡萄糖醛酸、葡萄糖、木糖和半乳糖。PPP对胆固醇酯酶和胰脂肪酶均具有明显的抑制作用,IC 50值(半抑制浓度)分别为25.00、9.46 mg/mL,抑制类型分别为非竞争性抑制和竞争性抑制;对甘氨胆酸钠和牛磺胆酸钠的最大结合率分别为40.09%和34.90%。该研究表明,PPP具有一定的体外降脂能力,可为进一步开发降脂功能食品奠定基础。

This study aimed to prepare crude polysaccharides from pomegranate peel(PPP)and to study its monosaccharide composition and hypolipidemic activity in vitro.To obtain the optimal extraction conditions of polysaccharides from pomegranate peel by the inner ebullition method,response surface tests were used to optimize the extraction process.The monosaccharide composition of PPP was analyzed by HPLC.The hypolipidemic activity of PPP in vitro was evaluated by the inhibitory effect on cholesterol esterase,pancreatic lipase,and the ability of binding cholate.Results showed that the optimal extraction conditions of PPP were as follows:91%of ethanol concentration,42∶1(mL∶g)of liquid-solid ratio,62 min of extraction time,and extraction temperature of 96℃.Under these conditions,the yield of PPP was(16.32±0.21)%(n=3).HPLC results showed that the PPP mainly consisted of fucose,galacturonic acid,arabinose and monosaccharides,besides contained a small amount of mannose,rhamnose,glucuronic acid,glucose,xylose and galactose.PPP had significant inhibitory effects on cholesterol esterase and pancreatic lipase with IC 50(inhibitory concentration)values of 25.00 mg/mL and 9.46 mg/mL,respectively.The inhibitory types were non-competitive inhibition and competitive inhibition,respectively.The maximum binding rates of sodium glycocholate and sodium taurocholate were 40.09%and 34.90%,respectively.These results indicated that pomegranate peel polysaccharide had hypolipidemic activity in vitro,which could provide a theoretical basis for the further development of lipid-lowering functional foods.