Synergic effects of some medicinal plants on anti-oxidant status and lipid peroxidation in diabetic rats

The leaves of Psidium guajava, Anacardium occidentale, Eucalyptus globulus and fruits of Xylopia aethiopica are used in the management of diabetes mellitus. Hence, the phytochemical constituents as well as the acute toxicity of the combined chloroform extracts (A. occidentale + E. globulus and P. guajava + X. aethiopica) and their effects (at graded doses of 100 and 250 mg/kg body weight each) on the concentration of malondialdahyde (MDA), activities of catalase (CAT), glutathione peroxidase (GPx) and superoxide dismutase (SOD) and concentration of vitamin C in diabetic and normal rats were investigated using standard methods. The phytochemical analyses of the four extracts showed the presence of terpenoids and fats and oil in all of them. Each of the combined extract was found to be non-toxic even at a dose as high as 5000 mg/kg body weight. The combined extracts at the tested doses significantly (p < 0.05) and dose-relatedly reduced the concentration of MDA, raised the activities of CAT, GPx and SOD as well as the concentration of vitamin C in the treated rats. The effects of the combined extracts (especially 250 mg/kg body weight of A. occidentale + E. globulus) were better than that of the standard anti-diabetic drug [glibenclamide (5 mg/kg body weight)]. The data of this investigation imply that the combined chloroform extracts of the leaves of A. occidentale, E. globulus, P. guajava and fruits of X. aethiopica may be preferentially used in the management and/or amelioration of diabetes mellitus and its associated complications. Key words: Anti-oxidants, diabetes mellitus, lipid peroxidation, Anacardium occidentale, Eucalyptus globulus, Psidium guajava and Xylopia aethiopica.