Antihyperglycaemic activity of the methanol extract from leaves of Eremophila maculata (Scrophulariaceae) in streptozotocin-induced diabetic rats

Abstract

Abstract Objectives This study was designed to evaluate the antihyperglycaemic activity of the methanol leaf extract of Eremophila maculata (EMM) both in vitro and in vivo. Methods The antihyperglycaemic activity was assessed in vitro using differentiated 3T3-L1 adipocytes, whereas in-vivo effect was evaluated in streptozotocin-induced diabetic rats. Chemical profiling of EMM was done using LC-ESI-MS techniques. Molecular modelling experiments of the identified compounds were performed using C-Docker protocol. Key findings Eremophila maculata slightly enhanced cellular glucose uptake and utilization in vitro by 3.92% relative to the untreated control. A stronger in-vivo effect was observed for EMM and its dichloromethane fraction. A pronounced elevation in serum insulin by 88.89 and 66.67%, respectively, accompanied by an apparent decline in fasting blood glucose (FBG) level by 65.60 and 70.37% comparable to streptozotocin-induced diabetic rats was observed. This effect was stronger than that of the reference drug glibenclamide (GLB). Chemical profiling of EMM revealed that leucoseptoside A, verbascoside, syringaresinol-4-O-β-D-glucopyranoside, pinoresinol-4-O-β-D-glucopyranoside and pinoresinol-4-O-[6″-O-(E)-feruloyl]-β-D-glucopyranoside are the major compounds. Molecular modelling showed that martynoside, verbascoside and phillygenin exhibited the highest inhibition to human pancreatic α-amylase (HPA), maltase glucoamylase (MGAM) and aldose reductase (AR), respectively. Conclusion Eremophila maculata offers an interesting relatively safer antihyperglycaemic candidate comparable to synthetic analogues.