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

• Published in: Journal of natural products (Washington, D.C.) Vol. 79; no. 4; pp. 894 - 898
• Main Authors: Mudalungu, Cynthia M, Richter, Christian, Wittstein, Kathrin, Abdalla, Muna Ali, Matasyoh, Josphat C, Stadler, Marc, Süssmuth, Roderich D
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society and American Society of Pharmacognosy 22.04.2016; Amer Chemical Soc
• Subjects: Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antineoplastic Agents - chemistry; Antineoplastic Agents - isolation & purification; Antineoplastic Agents - pharmacology; Bacillus subtilis; Bacillus subtilis - drug effects; Basidiomycetes; Chemistry, Medicinal; Diterpenes - chemistry; Diterpenes - isolation & purification; Diterpenes - pharmacology; Drug Screening Assays, Antitumor; Female; Glycosides - chemistry; Glycosides - isolation & purification; Glycosides - pharmacology; Humans; Life Sciences & Biomedicine; MCF-7 Cells; Methicillin Resistance - drug effects; Mice; Molecular Structure; Nuclear Magnetic Resonance, Biomolecular; Pharmacology & Pharmacy; Plant Sciences; Science & Technology; Staphylococcus aureus; Staphylococcus aureus - drug effects; METABOLITES; DITERPENOIDS; BIOSYNTHESIS; BIOLOGICAL-ACTIVITY; ERINACINES; MYCELIA; A-F; CULTURES
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/acs.jnatprod.5b00950

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.