Two new cytochalasins from the endophytic fungus Xylaria sp. GDGJ-77B.

Two new open-chain cytochalasins, xylarchalasins A and B (1 and 2), together with six known analogues (3-8), were isolated from the endophytic fungus Xylaria sp. GDGJ-77B from the Chinese medicinal plant Sophora tonkinensis. Their structures were elucidated on the basis of comprehensive spectroscopic analysis. Compound 2 displayed moderate antibacterial activities against Bacillus subtilis and Escherichia coli with MIC values of 25 and 12.5 µg/mL, respectively.

Cycloaspeptide H, a cyclopentapeptide from the endophytic fungus Penicillium virgatum.

One new cyclopentapeptide, cycloaspeptide H (1), featuring a serine residue, along with seven known compounds (2-8), was isolated from the endophytic fungus Penicillium virgatum GDGJ-227. The planar structure of 1 was elucidated by a comprehensive analysis of NMR and MS spectroscopic spectra, and the absolute configuration was determined by single-crystal X-ray diffraction (Cu Kα) analysis. Compounds 7 and 8 displayed antibacterial activities against Bacillus subtilis and Enterobacter aerogenes with MIC values ranging from 12.5 to 50 µg/mL.

Three new andrastin derivatives from the endophytic fungus Penicillium vulpinum.

Three new andrastin derivatives, 10-formyl andrastone A (1), 10-demethylated andrastone A (2) and andrastin G (3), together with four known andrastin analogues (4-7) were isolated from an endophytic fungus Penicillium vulpinum. Their structures were determined by 1 D, 2 D NMR, and the absolute configurations were further determined by experimental and calculated ECD spectra. Compound 5 exhibited significant antibacterial activity against Bacillus paratyphosus B with an MIC value of 6.25 µg·mL-1. Compounds 2 and 6 showed remarkable inhibitory activities against Bacillus megaterium with the MIC value of 6.25 µg·mL-1, respectively.