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Title: Watermelon, phytochemicals and health

Author
item Perkins Veazie, Penelope
item COLLINS, JULIE - EOSC, WILBURTON, OK
item WU, GUOYAO - TEXAS A&M
item Clevidence, Beverly

Submitted to: United States-Japan Cooperative Program in Natural Resources
Publication Type: Proceedings
Publication Acceptance Date: 7/1/2008
Publication Date: 9/24/2008
Citation: Perkins Veazie, P.M., Collins, J.K., Wu, G., Clevidence, B.A. 2008. Watermelon, phytochemicals, and health. Proceedings of the United States-Japan Cooperative Program in Natural Resources. 37th Annual Meeting, August 24-28, 2008, Chicago, Illinois. p. 138-139.

Interpretive Summary: Watermelon fruit contains the plant chemicals lycopene and citrulline, which may be helpful in preventing some chronic diseases. The amount of lycopene in watermelon is highly variable, but generally exceeds that of tomato. Citrulline is present in all parts of the fruit. Lycopene was found to be relatively stable in fresh cut watermelon, and could increase slightly in whole fruit held at room temperature. Seedless watermelon generally had more lycopene than seeded types, and lycopene was present in red fleshed fruit, with small amounts in orange fleshed watermelon, and none in yellow fleshed types. Subjects drinking six cups of watermelon juice per day had increased levels of arginine and lycopene content in their plasma. A diet enriched with citrulline/arginine or watermelon reduced glucose levels and improved aortic flexibility in an animal model study. The high amounts of lycopene in red fleshed watermelon may be useful in blocking free radical damage, while the citrulline may improve vascular health.

Technical Abstract: Watermelon fruit contains lycopene, a carotenoid pigment, and citrulline, an amino acid. These plant compounds may be helpful in preventing some chronic diseases. The amount of lycopene in watermelon ranges from 35 to 125 mg per kg of edible portion, and there is 2 to 4 mg per kg citrulline present in all parts of the fruit. Lycopene content and stability were evaluated over a range of germplasm and storage systems. Lycopene was found to be relatively stable in fresh cut watermelon, and could increase slightly in whole fruit held at room temperature. Seedless watermelon generally had more lycopene than seeded types, and lycopene was present in red fleshed fruit, with small amounts in orange fleshed watermelon, and none in yellow fleshed types. When subjects ingested 6 cups of watermelon juice daily, arginine and lycopene content in plasma were increased. Ingestion of watermelon or arginine/citrullline in Zucker diabetic fatty rats resulted in reduced glucose levels and improved aortic flexibility than controls. These results indicate that watermelon is a natural dietary source of lycopene and citrulline, and that these compounds are bioactive in humans.