Effect of microencapsulated watermelon (Citrullus Lanatus) rind on flow-mediated dilation and tissue oxygen saturation of young adults

BACKGROUND/OBJECTIVES: Watermelon rind (usually discarded by consumers) presents a high L-citrulline content. Given that Lcitrulline is involved in nitric oxide (NO) synthesis, a crucial molecule that regulates vascular function, this study aimed to evaluate the effect of microencapsulated watermelon rind (MWR) on endothelial function and tissue oxygen saturation (StO(2)) assessed by flow-mediated dilation (FMD) and near-infrared spectroscopy, respectively. Plasma L-arginine and L-citrulline were also evaluated. SUBJECT/METHODS: Eleven participants ingested 30 g of MWR (containing 4 g of L-citrulline) and a placebo. Before and 30, 60, 90, and 120 min after ingestion, StO(2) parameters were assessed, whereas FMD and plasma amino acids were analyzed 60 and 120 min after ingestion. RESULTS: The FMD improved 60 min after MWR without changes in StO(2) parameters. Absolute plasma L-citrulline and relative change from baseline in plasma L-arginine increased 60 min after MWR ingestion. CONCLUSION: A single dose of microencapsulated watermelon rind containing 4 g of L-citrulline seems adequate to improve FMD response, but not StO(2) parameters in healthy adults.

Automated summary

The study found that ingestion of microencapsulated watermelon rind containing 4 g of L-citrulline can improve endothelial function in healthy adults. However, it does not have an effect on tissue oxygen saturation.