Three new phenolic compounds from the lichen Thamnolia vermicularis and their antiproliferative effects in prostate cancer cells.

Three new phenolic compounds, thamnoliadepsides A (1), B (2), and thamnolic acid A (3), and seven known compounds, everninic acid (4), baeomycesic acid (5), β-orcinol (6), β-resorcylic acid (7), ethyl orsellinate (8), squamatic acid (9), and vermicularin (10), were isolated from the lichen Thamnolia vermicularis (Sw.) Ach. ex Schaerer. Their structures were determined based on spectroscopic analysis, including 2D-NMR experiments and HR-MS techniques. Compound 1 inhibited growth of prostate cancer cells and bonded to G-quadruplex DNA based on NMR determination.