Thielavin B methyl ester: a cytotoxic benzoate trimer from an unidentified fungus (MSX 55526) from the Order Sordariales

Tetrahedron Lett. 2011 Nov 2;52(44):5733-5735. doi: 10.1016/j.tetlet.2011.08.125.


As part of our ongoing investigation of filamentous fungi for anticancer leads, an active fungal extract was identified from the Mycosynthetix library (MSX 55526; from the Order Sordariales). Bioactivity-directed fractionation yielded the known ergosterol peroxide (2) and 5α,8α-epidioxyergosta-6,9(11),22-trien-3β-ol(3), and a new benzoate trimer, termed thielavin B methyl ester (1). The structure elucidation of 1 was facilitated by the use of HRMS coupled to an APPI (atmospheric pressure photoionization) source. Compound 1 proved to be moderately active against a panel of three cancer cell lines.