The first bis-retrochalcone from Fissistigma latifolium.

Two novel chalconoids, [3-3'']bi-2-hydroxy-4,5,6-trimethoxydihydrochalcone (1) and 4,6-dimethoxy-2,5-quinodihydrochalcone (2), and twelve known compounds were isolated from the methanolic extract of Fissistigma latifolium (Dun.) Merr. The structures of all compounds were determined by spectroscopic methods. Of these, compounds 1, 2, and 2-hydroxy-4,5,6-trimethoxydihydrochalcone (10) belong to an uncommon group of chalconoids, the retrochalcones. Compound 1 is the first bis-retrochalcone to be reported, and compound 2 is a quinoretrochalcone. Furthermore, 2 showed activity against the MDA-MB-231 human breast cancer cell line with an IC (50) value of 7.1 µM.