Antioxidant Properties of Methanolic Extracts of some Nigerian Plants on Nutritionally-Stressed Rats

The antioxidant properties of methanolic extracts of six locally consumed plants in Nigeria were comparatively evaluated both in vitro and in vivo. The plants included V. amygdalina (bitter leaf); C. rubens (‘ebolo’); A. hybridus (‘tete’); J. tanjorensis (jatropha); G. africana (‘okazi’) and T. triangulare (water leaf). The in vitro study indicate that the DPPH radical scavenging activity was highest (p<0.05) in ebolo and water leaf. The proanthocyanidin content was significantly higher (p<0.05) in ebolo and tete. Jatropha extract has the highest phenolic content. Flavonoid content is significantly high (p<0.05) in jatropha and water leaf extracts. In vivo study of the effect of the extracts, on nutritionally stressed male albino rats, show that the liver and kidney tissues of rats fed the protein deficient diet (PDD) had significantly lower (p<0.05) superoxide dismutase (SOD), catalase (CAT), vitamin E, vitamin C levels and higher lipid peroxidation levels when compared with the control. However, supplementation of the PDD diet with the various extracts resulted in significantly higher (p<0.05) levels of SOD, CAT, vitamin E, vitamin C and reduced lipid peroxidation relative to the PDD group. Likewise, feeding of normal rats with the extracts resulted in higher levels of these parameters when compared with the control. The results suggest that the plant leaves possess varied degrees of antioxidant activity both in vitro and in vivo.