A new indole alkaloid named bufobutarginine (1), along with three known bufotenines, namely, serotonin (2), bufotenidine (3), and bufotenine (4), were isolated from the water extract of toad venom. Their structures were elucidated by spectral methods. This is the first time that arginine has been found to be involved in the biosynthesis of bufotenines in parotid of toad. The cytotoxic activities of these compounds have been assayed against A375 and A549 cell lines by the MTT method; however, they showed no cytotoxic activities.
