Pro-oxidant Effects of Repeatedly Heated Sunflower Oil and the Possible Ameliorative Potential of Elaeodendron transvaalense Leaf Powder in Sprague Dawley Rats

Abstract

Repeated heating of cooking oils induces the overproduction of reactive oxygen species with an overwhelmed cellular antioxidant defense system, resulting in oxidative stress, the known cause of cardiovascular diseases. Elaeodendron transvaalense is a medicinal plant believed to have phytochemicals that help ameliorate the effects of oxidative stress. This study investigated the pro-oxidant effects of repeatedly heated sunflower oil and the possible ameliorative potential of Elaeodendron transvaalense leaf powder in Sprague Dawley rats. Four groups of male Sprague Dawley rats were fed for 4-weeks a standard diet supplemented without (a) control or with (b) 15% (w/w) repeatedly heated sunflower oil (RHSO), (c) 15% (w/w) non-heated sunflower oil, (d) 15% (w/w) RHSO and 1.5% ETLP. Endogenous antioxidants: Catalase and SOD activities were observed to rise significantly (p <0.05) in Group 2 when compared to Group 1 and Group 3 respectively. A significant decline in the SOD and catalase activities was observed in group 4 fed RHSO + ETLP. No significant differences were observed in the body, liver, and kidney weights of Group 2 when compared with Groups 1, 3 and 4 respectively, and no significant differences were observed when comparing Group 4 to Groups 1, 2 and 3. The levels of Lipid profiles; Low-density Lipoproteins (LDL), Total cholesterol (TC), and Triglycerides (TG) were observed to rise significantly (p <0.05) in Group 2 when compared to Group 1 and 3, while their significant (p <0.05) decline was observed in Group 4 fed with RHSO + ETLP. The levels of HDL showed no significant difference across all groups because the p-values for the difference between groups exceeded the null hypothesis (p <0.05). The findings of this experiment indicate the possible ameliorative potential of ETLP observed in the significantly (p <0.05) reduced SOD and catalase activities. A significant (p <0.05) decline in the TC, TG, and LDL to desirable levels further indicated the ameliorative effects.