Austdiol, fulvic acid and citromycetin derivatives from an endolichenic fungus, Myxotrichum sp.

A new austdiol analog myxodiol A (1), three novel fulvic acid derivatives myxotrichin A-C (2-4), and a new citromycetin analog myxotrichin D (5), were isolated from an endolichenic fungus Myxotrichum sp. inhabiting the lichen Cetraria islandica (L.) Ach. The structures of these compounds were elucidated unequivocally on the basis of comprehensive analysis of MS and NMR data. Compounds 2 and 5 displayed very weak cytotoxicity against human leukemia cell line K562, and compounds 1 showed very weak antifungal activity against Candida albicans (sc5314). (C) 2013 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved.