5-hydroxytryptophan (NSC-92523) is the immediate precursor in the biosynthesis of SEROTONIN from tryptophan. It is used as an antiepileptic and antidepressant.

N-(p-Coumaroyl) Serotonin, a polyphenol isolated from the seeds of safflower, exhibits antioxidant, cardioprotective effects after ischemia, and antitumor activity. It may improve vascular distensibility and reduce cardiovascular risk. N-(p-Coumaroyl) Serotonin ameliorates atherosclerosis and distensibility of the aortic wall in vivo, and is commonly used in atherosclerosis research.