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Six new dibenzo[b,e]oxepinone metabolites, chaetones A-F (1-6), as well as three known compounds, 1-hydroxy-6-methyl-8-hydroxymethylxanthone (7), citreorosein (8), and emodin (9), were obtained from a freshwater-derived fungal strain Chaetomium sp. YMF 1.02105. Their structures were established on the basis of extensive spectroscopic data analysis and comparison with spectroscopic data reported. Compounds 1-6 are further additions to the small group of dibenzo[b,e]oxepinones represented by arugosins A-H. Compounds 1-7 were tested for their cytotoxic activities against A549, Raji, HepG2, MCF-7, and HL-60 cell lines. The results showed that compound 3 had significant cytotoxicity with IC50 values of 1.2, 1.8, 1.9, 2.3, and 1.6 µg/mL, respectively, against the five cancer cell lines. All compounds showed modest antimicrobial activity against Staphylococcus aureus (ATCC 6538) in standard disk assays., (Georg Thieme Verlag KG Stuttgart · New York.)

Three new dihydrodibenzoxepins 7,8-dihydro-5-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[ B,F]oxepin (1), 7,8-dihydro-4-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[ B,F]oxepin (2), and 7,8-dihydro-3-hydroxy-12,13-methylenedioxy-11-methoxyldibenz[ B,F]oxepin (3), were isolated from Bulbophyllum kwangtungense Schlecht, along with three known compounds, cumulatin (4), densiflorol A (5) and plicatol B (6). Their structures were established by a combination of 1D and 2D NMR spectroscopic techniques. All new compounds (1-3) and the known compound densiflorol A (5) exhibited anti-tumor activities against HeLa and K562 human tumor cell lines.