Isoxanthohumol (2) and its 4'-O-monoacylated (3) and 7,4'-O-diacetylated (4) derivatives were synthesized and evaluated in vitro for their cytotoxic activity against several cancer cell lines of various origins: MCF-7 (breast), A549 (lung), MESSA (uterine sarcoma), LoVo (colon), drug-resistant human