Three antibacterial naphthoquinone analogues from cultured mycobiont of lichen Astrothelium sp

A new naphthoquinone compound named 7-hydroxyl-8-methoxyltrypethelone 3 together with two known compounds trypethelone 1 and trypethelone methyl ether 2 was isolated from cultured mycobiont of Astrothelium sp. The structures were elucidated by 1D and 2D NMR spectroscopic analysis as well as comparison with those reported in literatures. Compound 1 displayed significant antibacterial activity against Bacillus subtilis (ATCC 6633), and showed modest antibacterial activity against Staphylococcus aureus col (MRSA) (CGMCC 1.2465), while compounds 2 and 3 showed modest antibacterial activity against Enterococcus faecalis 850E (CGMCC 1.2135) and S. aureus col (MRSA) (CGMCC 1.2465).