Xanthones from the cultured lichen mycobionts of Pyrenula japonica and Pyrenula pseudobufonia

Cultures of the spore-derived mycobionts of the Asian lichen Pyrenula japon ica and the North American species P. pseudobufonia gave two xanthones, 1,5 ,8-trihydroxy-3-methylxanthone and 1,8-dihydroxy-5-methoxy-3-methylxanthone along with the known 1,7-dihydroxy-3-methylxanthone. Their structures were determined by spectroscopic methods. This is the first instance of the iso lation of xanthones with a methyl group at C-3 from lichen mycobionts. (C) 1999 Elsevier Science Ltd. All rights reserved.