Total synthesis and bioactivity of unique flavone desmosdumotin B and its analogs

The first total synthesis of a unique flavone natural product, desmosdumotin B (1), was accomplished. Furthermore, three novel flavonoids, 6-8, and a novel chalcone, 9, were synthesized. The new compounds were evaluated as in vitro inhibitors of human cancer cell growth. The synthetic 1 showed significant cytotoxic activity against a multi-drug resistant cell line (KB-VIN) with an ED50 value of 2.0 microg/mL compared to >40 microg/mL against the parental KB cell line. Flavone 7 displayed selective activity against 1A9 ovarian carcinoma with an ED50 value of 0.7 microg/mL. Selected 1-analogs and synthetic intermediates were also screened for antitumor-promoting effects as inhibitors of EBV-EA activation. Among them, trihydroxyacetophenone derivatives 11 and 14 showed good activity.