Hypoglycaemic Effects of Hypoxis Hemerocallidea (Fisch. and C. A. Mey.) Corm 'African Potato' Methanolic Extract in Rats

This study was designed to examine the hypoglycaemic effects of methanolic extract of Hypoxis hemerocallidea (family: Hypoxidaceae) corm (commonly known as 'African Potato') in normal (normoglycaemic) and in streptozotocin-induced diabetic (hyperglycaemic) rats. Adult, male Wistar rats (Rattus norvegicus) weighing 250-300 g were used. 1, 2, 4, 8 and 24 hours after oral administration of graded doses of African Potato methanolic extract (APME, 100-800 mg/kg p.o.) into the rats, blood samples were taken from the tail veins of the rats, and blood glucose concentrations were determined by using Bayer's Glucometer EliteÒ and blood glucose strips. Glibenclamide (5 mg/kg p.o.) was used as reference antidiabetic drug for comparison. Following acute treatment, relatively moderate to high doses of APME (100-800 mg/kg p.o.) produced dose dependent, significant (p<0.05-0.001) reductions in the blood glucose concentrations of both normal and diabetic rats. The plant extract-induced maximal reductions in the blood glucose concentrations of normal and diabetic rats were found to be 35.07% and 55.32% respectively. Glibenclamide (5 mg/kg p.o.) also produced significant (p<0.01-0.001) reductions in the blood glucose concentrations of normal and diabetic rats. Glibenclamide induced maximal reductions in the blood glucose concentrations of normal and diabetic rats were found to be 46.27% and 68.71% respectively. Although 'African Potato' is less potent than glibenclamide as an antidiabetic agent, the results of this experimental study indicate that the herb possesses hypoglycaemic activity, and thus, lend credence to the suggested folkloric use of ‘African Potato’ in the management of adult-onset diabetes mellitus in some communities of South Africa.