β-carboline alkaloids from Trigonostemon filipes and Trigonostemon lii

Six β-carboline alkaloids including three new ones, trifilines A-C (1–3) were isolated from Trigonostemon filipes, along with a new β-carboline alkaloid, trigonoine C (7) isolated from Trigonostemon lii. Their structures were elucidated by extensive spectroscopic techniques. Trifilines A (1) and B (2) showed weak anti-HIV-1 activity with EC50 values of 54.61 µg/mL and 9.75 µg/mL, along with TI (Therapeutic index) values of 1.52 and 1.42, respectively. This is the first time to report the chemical constituents of Trigonostemon filipes. [graphic not available: see fulltext]