Abstract

 The chemical investigation on the fruiting bodies of white rot fungus Ganoderma tropicum(Jungh.) Bres. led to the isolation of ten natural compounds by column chromatography on silica gel and sephadex LH-20. Their structures were elucidated by nuclear magnetic resonance (NMR) analysis as well as comparison with those reported in the literatures. Compounds 1-10 were isolated for the first time from this fungus. The bioassay of cytotoxic activities of seven compounds was evaluated against five human tumor cell lines HL-60, SMMC-7721, A-549, MCF-7 and SW-480. Compound jacareubin (1) displayed obvious cytotoxic activities on HL-60, SMMC-7721, A-549, MCF-7 and SW-480 with IC₅₀values of 7.49, 9.04, 4.44, 21.61 and 14.02 μmol.L^-1, respectively. Compound 22E-7α-methoxy-5α,6α-epoxyergosta-8(14),22-dien-3β-ol (9) also exhibited definite cytotoxic activities on HL-60, MCF-7 and SW-480. The discovery of cytotoxic compounds exhibited potential effect on anti-tumor of G. tropicum.

Key words: Ganoderma tropicum, chemical constituents, cytotoxic activities.