In the present study, two new cyclic bisbibenzyls(1, 2) co-occuring with a known compound, isoplagiochins C(3) were isolated from Hebertus dicranus. The structures were determined mainly by extensive 1D and 2D NMR experiments, and the absolute configurations of 1 and 2 were established by the circular dichroism spectrum. Furthermore, all these three rare compounds were tested in vitro for inhibitory activity against the growth of human cancer cell lines(A549, HCT116, MDA-MB-231, and BEL7404) by the MTT assay, and compound 2 exhibited moderately inhibitory activity with IC50 values ranging from 13.89 to 31.62 ?mol·L-1. In conclusion, our results provided a basis for future development and modification of these compounds for cancer therapy.
