Five herbal drugs were obtained from a market in Nairobi and analyzed for anti-diabetic properties. Swiss albino rats were used as the animal model in the study. Metformin (500mg) was used as the positive control. The rats were induced with diabetes using alloxan. Thereafter, Fasting Blood Glucose (FBG) was carried out to confirm induction of diabetes. Rats induced with diabetes were then grouped into five groups, (n=5), corresponding to treatments with various herbal drugs: Commercial Diabetic formula®, Ganotech® herbal powder, Prunus africana herbal powder, Flax seeds herbal powder and Stevia rebudiana ground leaves powder. Herbal flax seeds at concentrations of 30, 40 and 50% recorded percentage blood glucose reduction of 44.9%, 9.4% and 31.1% respectively compared with the group administered with rat pellets only where the blood sugar increased by 9.5%. The group administered with metformin as positive control showed 75 % reduction of blood sugar. Stevia powder extract concentrations of 20, 30 and 40 % recorded 29.7, 32.7 and 66.7% reduction respectively compared to the group administered with water only which recorded a reduction of 30.3% compared to the group administered with 500 mg/Kg metformin which recorded a reduction of 64.3%..Aqueous and ethanolic extracts of Diabetic Formula® reduced the blood sugar by 56 and 44 % respectively while aqueous and ethanolic extract of Ganotech® herbal powder reduced the blood sugar by 61 and 72% respectively. The aqueous and ethanolic extracts of Prunus africana herbal treatment resulted in reduction of blood sugar by 21.71 and 38.5% respectively compared to the rats treated with the 5% DMSO which reduced by 24.0% and the group treated with 500mg/Kg metformin reduced blood sugar by 53.3%. The herbal drugs used in this study were found to be active against diabetes when compared to the commercial drug Metformin and should be exploited as possible alternative sources of medicine and dietary supplements for diabetes.
