Antibacterial and antioxidant xanthones and benzophenone from Garcinia smeathmannii

摘要

A new prenylated xanthone, 1,3,5,8-tetrahydroxy-2-(3-methybut-2-enyl)-4-(3,7-dimethylocta-2,6-dienyl) xanthone (1), and a new benzophenone (2), together with fourknown xanthone derivatives, cheffouxanthone (3), smeathxanthone A (4), smeathxanthoneB (5), ananixanthone (6), and two pentacyclic triterpenes, epi-friedelinol (7) and friedelin (8),were isolated from the stem bark of Garcinia smeathmannii. The structures of thecompounds were elucidated on the basis of 1D and 2D NMR experiments, and compound 2was further characterized and confirmed by single X-ray analysis. Compounds 1, 2, and 3exhibited the most prominent Garcinia activity against gram-positive Enterococcus faecaliswith minimal inhibitory concentration values of 8, 8, and 2 μg/mL, respectively, whilecompounds 1, 3, 4, and 6 showed the capacity to scavenge free radicals.