Three types with six new carboline alkaloids, trigonostemonines A-F (1- 6), were isolated from the roots and stems of Trigonostemon lii. Their structures were elucidated by spectroscopic analyses. It is the first time that beta-carboline alkaloids have been reported in Trigonostemon species. Trigonostemonine F (6) exhibited moderate cytotoxic activity against HL-60 with an IC (50) value of 16 microM.
Georg Thieme Verlag KG Stuttgart.New York.