Constituents of the moss Polytrichum commune.

Two unusual flavonones coupled with styryl units, communins A (1) and B (2), and a new benzonaphthoxanthenone, ohioensin H (3), together with 11 known compounds, were isolated from the moss Polytrichum commune. The structures of 1-3 were assigned by spectroscopic data interpretation. The new compounds were evaluated for cytotoxicity against a small panel of cancer cell lines.