Eremophila maculata Muell, Spotted Emu Bush or Native Fuchsia, is a well-known member of family Scrophulariaceae. It was popular among the Australians as an effective cure of cold sores; however, nowadays it is cultivated as an ornamental plant worldwide [1]. The biological assessment of E. maculata has not been fully explored. Thus, the foregoing study aimed to evaluate the antidiabetic activity of E. maculata leaves methanol extract (EMM) in vivo according to Pari et al. 2000 [2]. Herein, diabetes was induced in the rats by a single intraperitoneal injection of streptozotocin (STZ) in saline (60 mg/kg b.w.).
The administration of glibenclamide or E MM to STZ-diabetic rats elicited significant declines in fasting blood glucose level (FBG) by 28.57 and 65.60%, respectively associated with a marked increase in serum insulin level by 22.22 and 88.89%, respectively. A detailed phytochemical investigation of EMM resulted in the isolation and identification of six lignans. Among them a rare naturally-occurring lignan glycoside namely pinoresinol 4-O-[6''-O-(E)-feruloyl]-β-D-glucopyranoside was isolated from the nature for the second time in addition to pinoresinol 4-O-β-D-glucopyranoside. The antidiabetic activity was explained by virtual docking of the major compounds to the main sites on both human α-glucosidase and aldose reductase. Pinoresinol 4-O-β-D-glucopyranoside showed a relevant binding mode in the aldose reductase active sites with a binding energy equals -57.93 Kcal/mol. It was concluded that EMM exhibited a marked in vivo antidiabetic activity that could be attributed to its polyphenolics and lignans.
References:
[1] Singab A, Youssef F, Ashour M, Wink M. The genus Eremophila (Scrophulariaceae): An ethnobotanical, biological, and phytochemical review. J Pharm Pharmacol 2013; 65: 1239 – 1279
[2] Pari L, Umamaheswari J. Antihyperglycemic activity of Musa sapientum flowers: effect on lipid peroxidation in alloxan diabetic rats. Phytother Res 2000; 14: 136 – 138
