Hypoglycaemic Constituents of Stachytarpheta cayennensis Leaf

Abstract

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.

Pharmacological properties of the extract and some isolated compounds of Clausena lansium stem bark: Anti-trichomonal, antidiabetic, anti-inflammatory, hepatoprotective and antioxidant effects

“…Wollheim, Geneva, Switzerland generously provided INS-1 cells, an insulin releasing insulinoma cell line. Biological chemicals/media used for the INS-1 cell experiment were obtained as previously reported (Adebajo et al, 2007).…”

“…Insulin released into the medium was determined by a radioimmunoassay using rat insulin as standard, (mono-125 I-Tyr A 14 )-porcine insulin as the labelled compound and anti-insulin antibodies. Each extract/compound had been checked for noninterference with the insulin radioimmunoassay (Adebajo et al, 2007). The value of insulin release induced by 5.6 mmol/L glucose was taken as 100% (negative control) and the results of other test agents were expressed as percentage of this value.…”

Phenylethanoid glycosides from Stachytarpheta cayennensis (Rich.) Vahl, Verbenaceae, a traditional antimalarial medicinal plant

“…Lamiaceae and also the closely related Verbenaceae. Two of the isolated compounds, namely acteoside (2) and iso-acteoside (1) were already found in Stachytarpheta cayennensis before (Schapoval et al, 1998;Adebajo et al, 2007;Pereira et al, 2008), and acteoside also in Stachytarpheta glabra (Viccini et al, 2008), whereas the other phenylethanoid glycosides leucosceptoside A (3), martynoside (4) and jionoside D (5) were detected for the fi rst time in the genus Stachytarpheta.…”

Evaluation of Antihyperglycemic and Antihyperlipidemic Activity of Leaf Extracts of Breynia vitis-idaea in Alloxan Induced Diabetic Rats

“…1 The in creasing incidence of the disease worldwide may be due to sedentary life style, unhealthy diet, obesity and other predisposing risk factors. 2 It is projected to become of the world's main disablers and killers, as the number of people with diabetes multiplies worldwide. The disease has taken an ever increasing share of national and international healthcare budgets.…”