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A novel 20-norpimarane glucoside, xylopimarane (1), together with the known sphaeropsidin C (2) and clonostachydiol (3), was isolated from the fungus Xylaria sp. BCC 4297. Compound 1 exhibited cytotoxicity to cancer cell lines KB, MCF-7, and NCI-H187 with respective IC(50) values of 1.0, 13, and 65 μM.

Two new triterpenes, 17(21)-hopene-6alpha,12beta-diol (1) and 17(21)-hopen-12beta-ol (2), the known 17(21)-hopen-6alpha-ol (zeorinin, 3), and two new biarylic dihydronaphthopyrones, aschernaphthopyrones A (4) and B (5), were isolated from the scale insect pathogenic fungus Aschersonia paraphysata BCC 11964. Hopene 1 and aschernaphthopyrone A (4) exhibited antimalarial activity with IC(50) values of 15 and 7.3 microM, respectively.

Cordybislactone (3), a new stereoisomer of the 14-membered bislactone clonostachydiol, together with its open ring analog (4), was isolated from the hopper pathogenic fungus Cordyceps sp. BCC 49294. The relative and absolute configurations of 3 were determined by chemical derivatizations, including the modified Mosher's method. The stereochemistry of clonostachydiol was determined using the natural compound isolated from Xylaria sp. BCC 4297. The result revealed that the absolute configuration of clonostachydiol, previously determined by synthesis, should be revised to its enantiomer.

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Two new ascochlorin derivatives, nectchlorins A (1) and B (2), together with eight known compounds (3-10), were isolated from cultures of the leafhopper pathogen Microcera sp. BCC 17074. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The absolute configuration of 2 was determined by application of the modified Mosher's method. The absolute configuration of LL-Z 1272α epoxide (9), which is a plausible biosynthetic precursor of ascochlorins, was established by chemical correlations. Cytotoxic activities of these ascochlorin derivatives were evaluated.