Chemical composition, antimicrobial and antimycobacterial activities of Aristolochia triangularis Cham. from Brazil

Three diterpenes (1, 4, 5), four lignans (2, 6, 7a, 7b), one sequiterpene (3) and one alkaloid (8) were isolated from an acidic ether fraction of Aristolochia triangularis Cham. native from Brazil. The compounds were identified as: ent-Kaur-16-en-19-al (1), zuonin B (2), nerolidol (3), (−)-Kaur-16-en-19-oic acid (4), ent-Kauran-16β,17-diol (5), dihydrocubebin (6), a mixture of α and β-cubebin (7a + 7b) and aristolactam BII (8). The methanol extract, fractions and the isolated substances were evaluated to check their antimicrobial/antimycobacterial activity against bacteria (14 strains), fungi (9 strains) and mycobacteria (3 strains). Shigella sonnei was highly susceptible to (−)-Kaur-16-en-19-oic acid (4), which showed a potency similar to the antibacterial substance chloramphenicol (MICs at