A New Bibenzyl-phenanthrene Derivative from Dendrobium signatum and its Cytotoxic Activity.

From the whole plant of Dendrobium signatum, a new bibenzyl-dihydrophenanthrene derivative, named dendrosignatol was isolated, together with the known compounds 3,4-dihydroxy-3,4'-dimethoxybibenzyl, dendrocandin B, dendrocandin I and dendrofalconerol A. The structure of the new compound was elucidated through analysis of its spectroscopic and mass spectrometric data. All of the isolates showed appreciable cytotoxic activity against three human cancer cell lines, including MDA-23 1, HepG2 and HT-29 cells.