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Laxitextines A and B, Cyathane Xylosides from the Tropical Fungus Laxitextum incrustatum

2016; American Chemical Society; Volume: 79; Issue: 4 Linguagem: Inglês

10.1021/acs.jnatprod.5b00950

1520-6025

Cynthia M. Mudalungu, Christian Richter, Kathrin Wittstein, Muna Ali Abdalla, Josphat C. Matasyoh, Marc Stadler, Roderich D. Süßmuth,

Plant Pathogens and Fungal Diseases

Bioassay-guided fractionation of the mycelial extract of a basidiomycete culture collected in Kenya led to the isolation of two new cyathane diterpenoids named laxitextines A (1) and B (2). The producer strain was characterized by detailed taxonomic studies based on rDNA using the 5.8S gene region, the internal transcribed spacer 2 (ITS2), and part of the large subunit that identified the fungus as Laxitextum incrustatum. The structures of 1 and 2 were elucidated by NMR spectroscopic and mass spectrometric analyses. Both compounds exhibited moderate activities against Gram-positive bacteria Bacillus subtilis (DSM 10), Staphylococcus aureus (DSM 346), and methicillin-resistant Staph. aureus (DSM 1182). The two compounds also showed variable antiproliferative activities against mouse fibroblast (L929) and selected human cell lines (breast cancer MCF-7, epidermoid carcinoma A431, and umbilical vein endothelial HUVEC). The IC50 values with respect to the MCF-7 cell line for compounds 1 and 2 were 2.3 and 2.0 μM, respectively.