Prophylactic Effect of Ethanol Extract of Azadirachta indica Leaf in Streptozotocin-induced Diabetic Rats

Background: Medicinal plants are now becoming indispensable in the treatment and management of many ailments. The unaffordability, unavailability and adverse effects of conventional therapy in the treatment and management of many diseases have geared keen interest in the use of herbal medicine. This work was carried out to investigate the prophylactic effect of the ethanol extract of Azadirachta indica leaf in streptozotocin-induced diabetic rats.

Methods: A total of one hundred (100) rats were randomized into four (4) groups (n=25) and used for the study. Each group of 25 rats was sub-divided into five (5) groups (n=5). The sub-groups comprise: Group A-normal control that was not treated, group B-100 mg/kg body weight of metformin and groups C to E - graded doses (100 mg/kg, 200 mg/kg and 400 mg/kg body weight) of the ethanol leaf extracts of A. indica leaves. The standard drug and the extracts were consecutively administered to groups B-E for 7, 14, 21 and 28 days before the induction of diabetes. Diabetes was induced intraperitoneally using 50 mg/kg bodyweight of streptozotocin.

Results: The groups that were administered 100, 200 and 400 mg/kg bw of ethanol extract of A. indica showed a significant (p<0.05) increase in their weight after 21 and 28 days of pre-treatment compared with the control group that was not treated. The graded doses of the extract also have a remarkable effect in the fasting blood glucose levels which was made visible by the significant (p<0.05) reduction recorded in the fasting blood glucose levels compared with the control group that was not pre-treated and the group pre-treated with metformin.

Conclusion: The results obtained in this research suggest that ethanol extract of A. indica has the potential to protect against diabetes by delaying its onset. However, the longer the period of pre-treatment, the better the condition of the animals pre-treated as well as the protection as can be seen from the results of the weight and fasting blood glucose levels.