Watermelon (Citrullus lanatus) is rich in L-citrulline, an L-arginine precursor that may reduce cardiovascular disease risk. The purpose of this study was to compare the effects of watermelon powder and L-arginine on lipid profiles, antioxidant capacity, and inflammation in rats fed an atherogenic diet. We hypothesized that watermelon and L-arginine would increase antioxidant capacity and reduce blood lipids and inflammation by modulating hepatic gene expression. Male Sprague-Dawley rats aged 21 days (N = 32) were assigned to 3 groups and fed diets containing watermelon powder (0.5% wt/wt), L-arginine (0.3% as 0.36% L-arginine HCl wt/wt), or a control diet for 9 weeks. Watermelon and L-arginine supplementation improved lipid profiles by lowering serum concentrations of triglycerides, total cholesterol, and low-density lipoprotein cholesterol (P <.050). Serum concentrations of C-reactive protein were significantly lower (P <.050) in the watermelon and L-arginine groups. Rats in the watermelon and L-arginine groups showed reduced oxidative stress, increased total antioxidant capacity, and higher concentrations of superoxide dismutase and glutathione S-transferase (P <.050). Concentrations of aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase were lower (P <.050) in the watermelon and L-arginine groups. Watermelon and L-arginine consumption upregulated hepatic gene expression of endothelial nitric oxide synthase and downregulated expression of fatty acid synthase, 3-hydroxy-3-methylglutaryl-CoA reductase, sterol regulatory element-binding protein 1, sterol regulatory element-binding protein 2, cyclooxygenase-2, and nuclear factor–κB p65 (P <.050). The results support the hypothesis that watermelon and arginine improve cardiovascular disease risk factors including lipid profile, antioxidant capacity, and inflammation by altering relevant gene expression.
- Cardiovascular disease
- Hepatic gene expression