Rapid HPLC-UV method for quantification of l-citrulline in watermelon and its potential role on smooth muscle relaxation markers

► For the first time a simple HPLC-UV method was developed for l-citrulline. ► l-Citrulline was quantified directly without derivatisation from the watermelons. ► l-Citrulline containing watermelon extracts help in smooth muscle relaxation. ► Results indicated the potential role of watermelon extracts at cellular level.