Watermelon and l-arginine consumption improve serum lipid profile and reduce inflammation and oxidative stress by altering gene expression in rats fed an atherogenic diet

Nutr Res. 2018 Oct;58:46-54. doi: 10.1016/j.nutres.2018.06.008. Epub 2018 Jun 30.

Abstract

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.

Keywords: Antioxidants; Cardiovascular disease; Hepatic gene expression; Inflammation; Rat; Watermelon.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Anti-Inflammatory Agents / therapeutic use
  • Antioxidants / metabolism
  • Antioxidants / pharmacology*
  • Antioxidants / therapeutic use
  • Arginine / pharmacology*
  • Arginine / therapeutic use
  • Atherosclerosis / etiology
  • Atherosclerosis / metabolism
  • Atherosclerosis / pathology
  • C-Reactive Protein / metabolism
  • Cardiovascular Diseases / etiology
  • Cardiovascular Diseases / metabolism*
  • Cardiovascular Diseases / prevention & control
  • Citrulline / pharmacology
  • Citrulline / therapeutic use
  • Citrullus / chemistry*
  • Diet, Atherogenic
  • Dietary Supplements
  • Gene Expression
  • Gene Expression Regulation / drug effects*
  • Hydroxymethylglutaryl CoA Reductases / metabolism
  • Inflammation / blood
  • Inflammation / etiology
  • Inflammation / genetics
  • Inflammation / prevention & control
  • Lipid Metabolism / genetics
  • Lipids / blood*
  • Liver / metabolism
  • Male
  • NF-kappa B / metabolism
  • Oxidative Stress / drug effects
  • Plant Preparations / pharmacology
  • Plant Preparations / therapeutic use
  • Rats, Sprague-Dawley
  • Sterol Regulatory Element Binding Protein 2 / metabolism

Substances

  • Anti-Inflammatory Agents
  • Antioxidants
  • Lipids
  • NF-kappa B
  • Plant Preparations
  • Sterol Regulatory Element Binding Protein 2
  • Citrulline
  • C-Reactive Protein
  • Arginine
  • Hydroxymethylglutaryl CoA Reductases