An Ethnomedicinal Survey of Antidiabetic Plants and Preliminary Evaluation of Antioxidant, Hypoglycemic Activity Maesa indica Leaves, a Folk Antidiabetic Plant of Manipur, India

Abstract

Background: Manipur is a small state of India, well known for its folk medicine. Folk medicine practitioners of the state use a number of plants to manage diabetes mellitus. Objective: This is an ethnomedicinal survey to find folk antidiabetic plants of the Thoubal district of Manipur, India. This study aimed to investigate the antioxidant and hypoglycemic potential of the chosen medicinal plant. Methods: An ethnomedicinal survey was carried out in Thoubal district, Manipur to find out antidiabetic plants regularly used by tribal/folk medicinal practitioners. Based on the information, Maesa indica leaves extracts (ethanol extract, MIE; ethyl acetate extract, MIEA; petroleum ether extract, MIPE) were further investigated for in vitro antioxidant and antidiabetic activity. Acute hypoglycemic activity (streptozotocin-induced diabetes model) was evaluated and NGOGTT tests were conducted to evaluate the hypoglycemic activity of Maesa indica leaves. Results: Ethnomedicinal survey revealed that folk medicinal practitioners regularly used 15 antidiabetic plants. Maesa indica is a plant of choice of folk medicinal practitioners. MIE was found to possess strong oxidative haemolysis inhibition, nitric oxide radical and DPPH radical scavenging effect with IC50 values of 54.5, 34.1 and 19.2 μg/mL, respectively. MIE inhibited α-glucosidase and α-amylase with IC50 values of 18.2 and 31.2 μg/mL, respectively. MIE and MIEA produced considerable hypoglycemic activity when tested through the NG-OGTT model. MIE (500 mg/kg, b.w.) asserted significant acute hypoglycemic activity by reducing blood glucose level after 1h, 2h, 3h, 5h, and 12h of drug administration in streptozotocin-induced diabetic rats. Conclusion: The present study showed that the ethanol extract of Maesa indica leaves possesses better activity compared to ethyl acetate and petroleum ether extract. This study also confirmed the ethnobotanical claim about traditional use of plant and antidiabetic potential of M. indica leaves.