Effects of red palm oil-supplementation on oxidative stress biomarkers in an experimental rat model

Abstract

Oxidative stress, in recent times appears to be a major underlying risk factor in the occurrence of various diseases such as cardiovascular disease (CVD) and ischemic heart disease (IHD). During oxidative stress, there is an imbalance between the production of reactive oxygen species (ROS) and antioxidant defence mechanisms in favour of ROS. This results in severe cellular damages in the heart, vascular membranes and other organs. Potential benefits of dietary supplements as one of the major quenching elements against oxidative stress have been highlighted. Thus, a growing interest has been stimulated in finding natural alternatives for the treatment and! or prevention of oxidative stress-mediated diseases. Red palm oil (RPO), refined from the tropical plant Elaeis guineensis was used in this study since it has captivated much attention in the health sector lately. The effects of RPO-supplementation on oxidative stress biomarkers as well as homocysteine, a cardiovascular disease risk factor in an oxidative stress-induced rat model were investigated in this in vivo study. All experiments were conducted for a period of six weeks. Male Wistar rats (120-150g) were randomly divided into six groups (n=5) where all the rats received a standard diet. Two groups (groups C, D) were supplemented with 0.175g RPO (7g RPO/kg chow) for four weeks whereas groups (groups E, F) were given 0.175g RPO (7g RPO/kg chow) supplementation for six weeks. Rats in control groups (groups A, B) were not given any RPO-supplementation. Groups B, 0, F were induced with oxidative stress by injection of 0.5ml (20IlM/100g of body weight) organic tertiary-butyl hydroperoxide. All parameters were determined using appropriate methods in plasma, serum and erythrocytes. Data were expressed as mean ± SEM. No significant differences were obtained between groups for total antioxidant capacity and glutathione peroxidase activity. Red palm oil supplementation significantly increased superoxide dismutase activity after 6 weeks consumption, total glutathione levels after 4 weeks consumption and homocysteine levels after four and six weeks consumption in rats not subjected to oxidative stress. Under oxidative stress conditions, malondialdehyde (MOA) level, a marker of oxidative stress related damage, significantly increased in rats receiving a standard diet. However, when RPO diet was supplemented for 4 and 6 weeks, MOA levels significantly decreased towards the value of normal controls. In conclusion, our findings suggest that RPO-supplementation could ameliorate antioxidant status in the body through its potential ability to increase some antioxidant enzymes activity. Similarly, it is suggested that RPO-supplementation could protect the rat against oxidative stress induced damage in diseased state.