Antidiabetic and antioxidant effects of methanol extract and fractions of Glyphaea brevis (Spreng.) Monachino in alloxan-induced diabetic rats

Background: Glyphaea brevis, which has been reported to show considerable antibacterial, anti inflammatory, and antioxidant activities, was mentioned as a recipe for diabetes in our recent ethnomedicinal survey.

Objective: The present study investigated antidiabetic and antioxidant activities of methanol extract and fractions of Glyphaea brevis.

Methods: Antioxidant activity was evaluated by the total phenolic content (TPC), total flavonoid content (TFC) and DPPH assay. The antidiabetic effect of leaf extracts was evaluated on alloxan-induced diabetic rats. Solvent fractions were evaluated for in vitro α-amylase inhibitory activity using 3, 5-dinitrosalicylic acid assay.

Results: The TPC and TFC values of Glyphaea brevis leaf extract and its solvent fractions were comparable to that of gallic acid and quercetin included in the study as standard drugs. The ethyl acetate fraction had the highest DPPH radical-scavenging activity. The methanol leaf extract (1g/kg bw.) produced a significant antidiabetic activity (p<0.05) on day seven. Histopathological studies of the pancreas of the diabetic rats treated with G. brevis leaf extract showed comparable regeneration to glibenclamide-administered rats at of 1 mg/kg body weight. Solvent fractions effectively inhibited α-amylase.

Conclusion: Our study provides justification for the use of Glyphaea brevis leaf traditionally to manage diabetes. The polyphenolic constituents in the plant may be responsible for the antidiabetic and antioxidant effects.