HYPOGLYCAEMIC EFFECTS OF NIGERIAN ZINGIBER OFFICINALE RHIZOME ON EXPERIMENTAL DIABETIC RATS

The aqueous extract of Zingiber officinale Roscoe (Zingiberaceae) rhizome was studied in Streptozotocin (STZ) and Glucose-induced diabetic rats to evaluate its hypoglycaemic activity. The aqueous extract was administered intraperitoneally at 2g/kg, 4g/kg and 8g/kg. The hypoglycaemic effect produced by the extract in STZ induced diabetic rates and glucose-induced hyperglycaemia were found to be shown 30 min after drug administration having high significant value as compared to diabetic control rats. However, there is no significant change with increase in dose between 4 and 8g/kg in STZ diabetic rats. When compared to chlopromide (45mg/kg), the aqueous extract if ginger at 2g/kg was of equal potency. Hypoglycaemic effect was also observed in glucose-induced hyperglycaemia when 4kg/kg of ginger extract was used under the same conditions. The results of this study indicate that the acute dose of aqueous extract of Nigerian cultivated Zingiber officinale rhizome exhibited hypoglycaemic activity. Key Words: Anti-diabetic effects, Zingiber officinale, Ginger, hypoglycaemic agent, STZ induced diabetic, Glucose-induced hyperglycaemia. [Nig. J. Nat. Prod. And Med. Vol.6 2002: 33-3

Constituents of Nymphaea lotus linn.

Nine are known amino acids (alanine, tyrosine, phenyl alanine, valine, threonine, arginine, leucine, D and L-isoleucine and aspartic acid), 2 alkanoic acids in form of butanoic acids and its ã- hydroxyl isomer, a dipeptide (serine-arginine) as well as a rare compound named 2-amino-7-methyl octanoic acid were isolated from Nymphaea lotus. Keywords: Nymphaea lotus, Nymphaeaceae, amino acidsNigerian Journal of Natural Products and Medicine Vol. 11 2007 pp. 83-8

Hypoglycaemic constituents of Stachytarpheta cayennensis leaf

The aqueous infusion (tea) of Stachytarpheta cayennensis leaves is used ethnomedically in Peru, Nigeria and other tropical countries for the management of diabetes. Oral administration (p. o.) of aqueous (125 mg/kg) and methanolic (2000 mg/kg) extracts of the leaves to alloxan-diabetic rats showed significant blood glucose reductions by 43 and 53%, respectively, at the end of a 4 hour period similar to the strong effect of glibenclamide (5 mg/kg, P. O.). The methanolic extract was successively partitioned into ethyl acetate, butanol and water fractions, and the same test showed that the butanol fraction (2000 mg/kg) had the highest (50%) hypoglycaemic activity at 4 hours after oral administration. It was also the most active fraction when tested in vitro [insulin release from an insulin secreting cell line (INS-1)] and was also active in normal rats and rats made hyperglycaemic by a glucose load. Its activity was comparable to that of glibenclamide (positive control) in these models. This active butanol fraction was subjected to chromatographic subfractionation; some subfractions reduced hyperglycaemia in alloxan-diabetic rats to 60 and 78% and induced insulin release from the INS-1 cells; other subfractions, however, gave hyperglycaemic activities IN VIVO and inhibition of insulin release from the INS-1 cells. Three major compounds of the butanol fraction were isolated and characterised as 6beta-hydroxyipolamide, ipolamide and isoverbascoside; they increased insulin secretion from INS-1 cells to 125, 128 and 127%, respectively, whereas glibenclamide increased insulin secretion to 157%. The results justify the ethnomedical use of the plant in the management of diabetes and suggest that the butanol fraction and some of its isolated constituents mediate their actions primarily by stimulating insulin release directly