Prenyl bibenzyls isolated from Chinese liverwort Radula amoena and their cytotoxic activities

Abstract Six previously undescribed prenyl bibenzyls Radulamoenins A–F ( 1 – 6 ) and eleven known analogues ( 7 – 17 ) were isolated from the Chinese liverwort Radula amoena Herzog. Their structures were determined based on the analysis of their spectroscopic data and electronic circular dichroism (ECD) calculations. Cytotoxicity tests of all the isolated compounds showed that 2-carbomethoxy-3,5dihydroxystilbene ( 7 ) and 3,5-dihydroxybibenzyl ( 8 ) exhibited moderate cytotoxic activities against a panel of human cancer cell lines.