Total synthesis and bioactivity of the marine alkaloid pityriacitrin and some of its derivatives

Abstract We report herein the chemical synthesis and biological evaluation of β-carboline alkaloid pityriacitrin and some of its new derivatives. Using tryptophan or 5-hydroxytryptophan and 5-substituted indole-3-glyoxals as the starting materials, pityriacitrin and some of its derivatives were synthesized via the acid-catalyzed Pictet–Spengler reaction and fully characterized by 1 H and 13 C NMR, mass spectroscopy and IR determinations. Biological studies revealed that pityriacitrin has a weak antiproliferative activity against a panel of breast and prostate cancer cell lines, whereas some of its derivatives exhibited stronger and potent activity, which was associated with induction of both cell apoptosis and necrosis.