Chiral separation and absolute configurations of two pairs of racemic polyprenylated benzophenones from Hypericum sampsonii.

(±) Sampsonins A–B ( 1 – 2 ), two pairs of racemic polyprenylated benzophenones, were isolated from the aerial parts of Hypericum sampsonii and successfully separated by chiral HPLC column. Their structures were elucidated by spectroscopic analyses, X-ray diffraction analysis, and quantum chemical calculation of ECD method. Besides, the plausible biogenetic pathways of 1 – 2 were proposed, and all of them were evaluated for RXRα transcriptional-inhibitory activities and cytotoxicity against HeLa cells. [ABSTRACT FROM AUTHOR]