文摘
Two new degraded diterpenoids, trigohowilols A (1) and B (2), four new heterodimers, trigohowilols C鈥揊 (3鈥?b>6), one new homodimer, trigohowilol G (7), and three known degraded diterpenoids (8鈥?b>10) were isolated from the methanol extract of the stems of Trigonostemon howii. Compounds 1鈥?b>7 were evaluated for their cytotoxic activity against five human tumor cell lines by an MTT assay, and trigohowilols E (5) and F (6) exhibited inhibitory activity with IC50 values ranging from 2.33 to 12.57 渭M. Moreover, compounds 1鈥?b>6 showed weak antimicrobial activities (MIC values: 6.25鈥?5 渭g/mL) against Staphylococcus aureus, Pseudomonas aeruginosa, MRSA 92#, and MRSA 98# using a 2-fold dilution method.