Modulatory effect of methanolic extract of Vernonia amygdalina (MEVA) on tert-butyl hydroperoxide-induced erythrocyte haemolysis.

Reactive oxygen species (ROS) have been implicated in the aetiology of several pathological and degenerative diseases. The protective effect of natural products possessing antioxidant properties has played a crucial role in ameliorating these deleterious effects. This study investigated the chemoprotective properties of the methanolic extract of Vernonia amygdalina (MEVA) in an experimental model of tert-butyl hydroperoxide (t-BHP)-induced human erythrocyte lysis in vitro. Haemolysis was induced by incubating erythrocytes with t-BHP (2 and 3 mM) in vitro. Samples of erythrocyte suspensions were removed at different intervals over a 6-h period, and the degree of haemolysis was measured. The anti-haemolytic effect of MEVA at 25-150 µg ml(-1) concentrations on the samples were assessed and compared with Triton X-100. Administration of t-BHP at 2- and 3-mM concentrations significantly (p < 0.05) induced erythrocyte lysis by 37.5% and 31.4%, respectively. The addition of MEVA, however, reduced t-BHP-induced erythrocyte lysis significantly (p < 0.05) by 39.3%, 48.4%, 67.3% and 73.4% at 25, 50, 100 and 150 µg ml(-1) concentrations, respectively. MEVA likewise protected against t-BHP-induced lipid peroxidation significantly (p < 0.05) at 100 and 150 µg ml(-1) by the fourth hour and non-significantly (p > 0.05) at all concentrations by the sixth hour. The reduced glutathione level was, however, increased with the administration of t-BHP, while a delayed addition of MEVA had no protective effect on the t-BHP-induced cell lysis. These findings therefore suggest that MEVA may have protective antioxidant properties, making it suitable for incorporation into food and drug products.

Antilipemic and hypocholesteremic activities of Globimetula braunii in rats.

Antilipemic/hypocholestermic activities of the methanolic extracts of Globimetula braunii were studied in the tissues of normo and hypercholesteremic rats. Hypercholesteremia was induced in the rats by feeding with dietary cholesterol at a dose of 40 mg/kg body weight. A significant increase (p<0.05) was observed in the body and the visceral organs relative weights in all the groups. There was a significant decrease in HDL-cholesterol and a significant increase in the levels of LDL, total cholesterol and triglycerides in hypercholesteremic rats when compared to normo rats. Administration of the methanolic extracts restored the elevated levels of serum lipids to normal. The methanolic extracts of G. braunii produced a significant (p<0.05) decrease in the levels of total cholesterol, triglyceride, LDL-cholesterol and lipid peroxidation of the extract treated group compared to hypercholesteremic control. There was a significant (p<0.05) increase in the levels of HDL-cholesterol as compared to hypercholesteremic control. The results obtained from this study are indications of the antilipemic and hypocholestermic activities of G. braunii as well as its cardio-protective potential in normo and hypercholesteremia conditions.