Comparative efficacy and safety investigation of eight antidiabetic herbal products distributed within South- Western Nigeria

Herbal preparations, often promoted as being natural and completely safe, are gaining popularity in the management of diabetes mellitus, despite lack of scientific data to confirm their efficacy and safety claims. This study investigated efficacy and safety of eight commercial antidiabetic herbal products. Antidiabetic activities were investigated in streptozotocin-induced diabetic rats at doses based on their labelled recommended dosages using metformin as reference drug. Body weights, blood glucose level (BGL), haematogical and biochemical parameters as well as histopathology of the kidney and lungs were assessed by standard procedures. All the samples demonstrated weight reduction (p<0.05), with accompanying BGL decrease ranging from 21.9 ±1.71 to 73.9 ±1.42% which was significant (p < 0.01) in three samples, when compared with metformin (37.9 ±7.41%). Of all the hematological indices, only WBC, platelet and eosinophil were affected by two of the samples, while for the biochemical parameters only alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels were increased (p<0.05) by one of the samples. Varied histopathological damages were observed with the liver, lungs and kidney tissues of treated groups. Hypoglycaemic activities were confirmed in all the samples, however, their deleterious effects on the liver, kidney and lungs calls for caution in their consumption.