基于偏最小二乘法分析枇杷叶提取物中α-葡萄糖苷酶抑制剂

Analysis ofα-glucosidase Inhibitors in Loquat Leaf Extracts Based on Partial Least Squares Method

为快速筛选枇杷叶(Eriobotrya japonica)提取物中的α-葡萄糖苷酶抑制剂,本研究基于组效分析法探究有效组分与酶抑制活性间的关系,揭示其关键活性组分。通过测定不同产地的枇杷叶提取物对α-葡萄糖苷酶的抑制效果,采用超高效液相色谱-质谱联用(UPLC-MS)对其进行成分分析,运用偏最小二乘回归分析法分析活性,并通过分子对接进行验证。结果表明,10种提取物能有效抑制α-葡萄糖苷酶,IC_(50)值为1.31~2.65μg·mL^(-1),且抑制活性强于阳性对照阿卡波糖(IC_(50)为81.98μg·mL^(-1)),其中产自陕西省汉中市的野生枇杷叶提取物的抑制效果最佳,IC_(50)为1.31μg·mL^(-1),对α-葡萄糖苷酶呈竞争型抑制。10批样品的UPLC-MS特征指纹图谱中有16个共有峰,其中有6个共有峰的回归系数与抑制活性呈正相关,变量重要性较大,贡献度较高。通过与二级质谱、数据库及标准品比对,明确其中4个成分分别为科罗索酸、科罗索酸甲酯、奎宁酸和nerolido-3-α-L-rhamnopyranosyl(1→4)-α-L-rhamnopyranosyl(1→2)-[α-L-rhamnopyranosyl(1→6)]-β-D-glucopyranoside。进一步的分子对接结果表明,上述4种活性成分与α-葡萄糖苷酶对接的结合能小于-6.0 kcal·mol^(-1),其中科罗索酸的结合能最低(-8.9 kcal·mol^(-1)),主要通过氢键作用于酶活性中心。本研究结果为后续应用枇杷叶提取物开发降血糖药物提供了研究思路。

To explore theα-glucosidase inhibitors in Eriobotrya japonica extracts,this study examines and reveals the main active components ofα-glucosidase inhibitors based on the link between their active ingredients and the enzyme inhibition activity.Extracts from habitat specific loquat leaf were obtained using ultra-high performance liquid chromatography-mass spectrometry,and the inhibitory effect of glucosidase was investigated.Partial least squares regression analysis was used to determine its activity,which was then confirmed by molecular docking.All ten extracts were effectiveα-glucosidase inhibitors with IC_(50)values ranging from 1.31μg·mL^(-1)to 2.65μg·mL^(-1),which were stronger than the positive control acarbose(IC_(50)was 81.98μg·mL^(-1)).The wild loquat leaves from Hanzhong and Shanxi province showed the strongest inhibitory effect with an IC_(50)value of 1.31μg·mL^(-1)and competitive inhibition ofα-glucosidase.A total of 16 shared peaks were identified in the UPLC-MS characteristic fingerprint profiles of 10 batches of samples,of which 6 shared peaks showed a positive correlation between the regression coefficients and the inhibitory activity,with greater variable importance and greater contribution to inhibitory activity.The four components were identified as corosolic acid,methyl corosoate,quinic acid,and nerolido-3-α-L-rhamnopyranosyl(1→4)-α-L-rhamnopyranosyl(1→2)-[α-Lrhamnopyranosyl(1→6)]-β-D-glucopyranoside through comparison with secondary mass spectrometry,databases,and standards.Further molecular docking results show that the binding energy toα-glucosidase of four active ingredients was less than-6.0 kcal·mol^(-1),and the binding energy of Corosolic acid was the lowest(-8.9 kcal·mol^(-1)),which mainly acts on the enzyme activity center through hydrogen bonds.This study investigatedα-glucosidase inhibitors in loquat leaf,which may help to develop hypoglycemic drugs from natural sources.