Cytotoxicity of derivatives of oncocalyxone A from Auxemma oncocalyx Taub

Abstract

Oncocalyxone A (1) (rel-8α-hydroxy-5-hydroxymethyl-2-methoxy-8aβ-methyl-7,8,8a,9- tetrahydro-1,4-anthracenedione) is a 1,4-anthracenedione that has been shown to be cytotoxic to human tumor cells and to be DNA reactive. Three derivatives of 1 obtained by chlorination (6- chloro-oncocalyxone A, 2) and acetylation (11-O-acetyloncocalyxone A, 3; 8,11-O- diacetyloncocalyxone A, 4) were found to be less cytotoxic and less DNA reactive in human leukemia cells. These derivatives were less polar compounds with modifications that may have hindered binding of the compound to DNA.