Antihyperglycaemic activity of the stem-bark extract of Tamarindus indica L. on experimentally induced hyperglycaemic and normoglycaemic Wistar rats.

Diabetes is the most common endocrine disease and its prevalence is reaching epidemic proportion worldwide. In 2002, WHO Expert Committee on diabetes mellitus recommended an urgent and further evaluation of the folkloric methods of managing the disease. In response to this recommendation, several medicinal plants are currently being investigated for their hypoglycaemic activity and one of such plants is Tamarindus indica. Tamarindus indica is a slow growing tree that is resistant to strong winds and perennial. The stem-bark extract of the plant is used locally for the management of diabetes. The stem-bark extract of Tamarindus indica L. was investigated for its hypoglycemic action on experimentally induced hyperglycaemic Wistar rats using a single dose of alloxan monohydrate (150 mg kg(-1) IP). The oral LD50 of the extract was found to be greater than 5,000 mg kg(-1). Phytochemical screening revealed the presence of carbohydrates, glycosides, saponins, flavonoids, cardiac glycosides, tannins, alkaloids and triterpenes. The 1000 mg kg(-1) dose of the extract lowered the blood glucose level significantly (p < 0.05) at the 4th, 8th and 16th h. The 500 mg kg(-1) lowered the BGL significantly (p < 0.05) throughout the study. In the oral glucose load method the 1000 mg kg(-1) dose of the extract significantly (p < 0.05) lowered elevated blood glucose at the 3rd and 5th. The 500 mg kg(-1) lowered the blood glucose from the 1st to the 5th, while the 250 mg kg(-1) also lowered the blood glucose level but only significantly at the 5th h. The extract is practically non toxic when administered orally. The stem-bark extract of Tamarindus indica Linn significantly lowered elevated Blood Glucose concentration (BGL) in the experimental animal models, while the crude extract was able to prevent an elevation in BGL when used in the oral glucose load model.