Cytotoxic and anti-HIV-1 constituents of Gardenia obtusifolia and their modified compounds

Abstract

5α-Cycloart-24-ene-3,23-dione (1), 5α-cycloart-24-ene-3,16,23-trione (2) and methyl 3,4-seco-cycloart-4(28),24-diene-29-hydroxy-23-oxo-3-oate (3), together with five known flavones 5,7,4′-trihydroxy-3,8-dimethoxyflavone (4), 5,7,4′-trihydroxy-3,8,3′-tri-methoxyflavone (5), 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone (6), 5,4′-dihydroxy-3,6,7,8-tetramethoxyflavone (7) and 5,3′-dihydroxy-3,6,7,8,4′-pentamethoxyflavone (8) have been isolated from the leaves and twigs of Gardenia obtusifolia. The structures were assigned on the basis of spectroscopic methods. Compounds 3-8 and some of the modified compounds showed significant cytotoxic activities in several mammalian cell lines, especially 8 and its diacetate 21 which exhibited potent cytotoxicities (compound 8: P-388 0.05μg/mL, KB 0.09μg/mL, BCA-1 0.63μg/mL, Lu-1 0.09μg/mL, ASK 0.70μg/mL; its diacetate: P-388 0.27μg/mL, KB 0.06μg/mL, BCA-1 0.53μg/mL, Lu-1 0.49μg/mL). It was also found that 5, 8 and 21 showed antimitotic acitivity in the ASK assay. Compounds 2, 4, 6, 7 and some of the modified compounds displayed interesting anti-HIV activity in the syncytium assay, but were inactive or exhibited weak activity in the HIV-1 RT assay; while compound 3 was found to be active in the HIV-1 RT assay (99.9 % inhibition at 200μg/mL), but cytotoxic in the syncytium assay. © 2002 Elsevier Science Ltd. All rights reserved.