Anti-HIV agents 45 and antitumor agents 205. Two new sesquiterpenes, leitneridanins A and B, and the cytotoxic and anti-HIV principles from Leitneriafloridana

Two new sesquiterpenes, leitneridanin A (1) and leitneridanin B (2), and se ven known compounds, lirioresinol B, (-)-pinoresinal, (+)-lariciresinol, qu assimarin (3), simalikalactone D (4), 1-methoxycanthinone (5), and 5-methox ycanthinone (6), were isolated from Leitneria floridana. Their structures w ere identified on the basis of spectral data. In vitro biological evaluatio n showed that 5 is a potent anti-HIV agent (EC50 0.26 mug/mL; TI > 39) and that 3-6 suppressed the growth of a panel of human tumor cell lines (KB, A- 549, HCT-8, CAKI-1, MCF-7, and SK-MEL-2). Compounds 3 and 4 were significan tly active, with ED50 values in the range of 0.26-0.012 mug/mL.