The amino-acid [[citrulline]] was first extracted from watermelon and analyzed.<ref>{{cite journal
| author = Wada, M.
| title = Über Citrullin, eine neue Aminosäure im Presssaft der Wassermelone, Citrullus vulgaris Schrad.
| journal = Biochem. Zeit.
| volume = 224
| issue =
| page = 420
| year = 1930
| doi = }}</ref> Watermelons contain a significant amount of citrulline and after consumption of several kilograms, an elevated concentration is measured in the [[blood plasma]]; this could be mistaken for [[citrullinaemia]] or other [[urea cycle]] disorders.<ref>{{cite journal
| author = H. Mandel, N. Levy, S. Izkovitch, S. H. Korman
| title = Elevated plasma citrulline and arginine due to consumption of Citrullus vulgaris (watermelon)
| journal = Berichte der deutschen chemischen Gesellschaft
