藏药材诃子中3种α-葡萄糖苷酶抑制剂的分离与鉴定

Isolation and identification of threeα-glucosidase inhibitors from Terminalia chebula Retz.

通过超滤-高效液相色谱法筛选诃子提取物中具有α-葡萄糖苷酶抑制活性的化合物,采用大孔吸附树脂和半制备高效液相色谱对其进行富集和分离制备,1H NMR和13C NMR鉴定其化学结构,最后采用以4-硝基酚-α-D-吡喃葡萄糖苷(pNPG)为底物的酶抑制剂筛选模型检测目标化合物的活性。结果显示:诃子提取物中含有的3个主要成分具有潜在的α-葡萄糖苷酶抑制活性;经筛选,AB-8大孔树脂对目标化合物富集效果最好,富集后目标化合物的峰面积比分别达到29.6%、40.3%和21.9%;由半制备高效液相色谱对目标化合物进一步纯化后,得到纯度分别为96.6%、98.1%和96.4%的化合物1(27 mg)、2(35 mg)和3(22 mg);经1H NMR和13C NMR鉴定得出3个化合物分别为诃黎勒酸、诃子酸、鞣花酸;活性测试结果表明,3个化合物均具有良好的α-葡萄糖苷酶抑制作用,其中诃黎勒酸(IC50=39.2±0.7 mg/L)和诃子酸(IC50=35.8±0.4 mg/L)抑制活性大于阳性对照阿卡波糖(IC50=41.2±0.6 mg/L)。本试验为开发诃子中的α-葡萄糖苷酶抑制剂提供了科学依据。

In this study,the compounds withα-glucosidase inhibitory activity in the extract from Terminalia chebula were screened by ultrafiltration-HPLC,in addition,macroporous resin(MR)combined with semi-preparative HPLC were used to isolate the target compounds.The inhibitory effect of the compounds onα-glucosidase was determined by using 4-nortiphenyl-α-D-glucopyranoside(pNPG)as a substrate.The results showed that three components from T.chebula had potentialα-glucosidase inhibitory activities.It was found that AB-8 resin showed a ideal purifying profile,the peak area ratios of the target compounds raised at 29.6%,40.3%,21.9%respectively.After further purification by semi-preparative HPLC,compound 1(27 mg),2(35 mg)and 3(22 mg)with purity of 96.6%,98.1%and 96.4%were obtained.Finally,the three compounds were identified by 1H NMR and 13C NMR spectra as chebulagic acid,chebulinic acid and ellagic acid.The activity screening tests showed that the three compounds had strongα-glucosidase inhibitory activities,chebulagic acid(IC50=39.2±0.7 mg/L)and chebulinic acid(IC50=35.8±0.4 mg/L)showed greater activity than that of acarbose(IC50=41.2±0.6 mg/L).This study provided a scientific basis for the development ofα-glucosidase inhibitors in T.chebula.