Evaluation of the Anti-Diabetic Potential of the Methanol Extracts of Aloe camperi, Meriandra dianthera and a Polyherb

The objective of the study was to evaluate the anti-diabetic activities of methanol extracts of Aloe camperi (AC), Meriandra dianthera (MD) and a polyherbal drug (PH) in diabetes induced Wistar albino rats. A single dose of alloxan monohydrate (150 mg/kg, i.p.) was used to induce diabetes mellitus (DM). Diabetes was confirmed by the elevated blood glucose levels determined after 72 h of induction. Animals with mean fasting blood glucose (FBG) level more than 200 mg/dl were recruited for the experiment. The herbal extracts at doses of 200 and 400 mg/kg and standard drugmetformin (5 mg/kg) were administered orally to the diabetic rats for 21 days and the FBG level was estimated on 0, 7, 14 and 21 days. The herbal extracts showed dose-dependent fall in FBG levels and the result exhibited very significant (P < 0.001) decreases in FBG level by the end of the experimental day as compared to the diabetic control. The highest antihyperglycemic effect was observed by MD extract at 400 mg/kg and was comparable to the standard drug. Oral glucose tolerance test (OGTT) was also conducted on normal rats and thus glucose at 2 g/kg per body weight was loaded via oral gavage to all groups 30 min after extract administration. All the groups showed significant increase (P < 0.01 or P < 0.05) in FBG level at 30 min following glucose loading. The hyperglycemia with glucose challenge was significantly brought down (P < 0.001) by all herbal extracts at 60 and 120 min relative to the negative control. Moreover, acute oral toxicity tests was conducted based on the protocols of OECD-425 and thus the LD50 of the herbal extracts was estimated to be greater than 2000 mg/kg. Statistical analysis was performed using One-Way ANOVA followed by Dunnett’s test for multiple comparisons, and values of P < 0.05 were considered as statistically significant.