Gymnotheca chinensis Decne (G chinensis), as one of the endemic genera of seed plants in China, is a perennial herb of the family Saururaceae. The whole plants of G. chinensis have long been used as a traditional herbal medicine to treat contusions and strains.

Prof. DING Li-Sheng’s group of Chengdu Institute of Biology CAS engaged in an ongoing research program to isolate and determine novel structures of secondary metabolites from medicinal endemic plants of southwestern China, and sequentially performed a phytochemical study on G. chinensis. As a result, two novel degraded lignans, gymnothedelignans A and B were isolated. Their structures were established by means of spectroscopic analysis including one and two-dimensional NMR spectroscopy, and the absolute configurations of gymnothedelignans A and B were determined by X-ray diffraction analysis.

Gymnothedelignans A and B represented a rare 2/5 epoxy benzocycloheptanone degraded lignan skeleton, which was first discovered from nature. These novel compounds were tested for cytotoxic activity against the HCT116, HCT15, A549, MCF-7 and HepG2 cancer cell lines, with the CellTiter-Glo® luminescent cell viability assay. The results of the cell viability assay indicated that this kind of degraded lignan exhibited no detectable cytotoxicity against the tested cancer cells. More results have been published in Tetrahedron Letters.