1240724-47-3Relevant articles and documents
Terpene conjugates of the Nigella sativa seed-oil constituent thymoquinone with enhanced efficacy in cancer cells
Effenberger, Katharina,Breyer, Sandra,Schobert, Rainer
experimental part, p. 129 - 139 (2010/04/23)
Thymoquinone (TQ; 1) is a weak anticancer constituent of black seed oil. Derivatives bearing terpene-terminated 6-alkyl residues were tested in cells of human HL-60 leukemia, 518A2 melanoma, multidrug-resistant KB-V1/Vbl cervix, and MCF-7/Topo breast carcinomas, as well as in non-malignant human foreskin fibroblasts. Derivatives with a short four-atom spacer between quinone and cyclic monoterpene moieties were more antiproliferative than analogues with longer spacers. 6-(Menthoxybutyryl) thymoquinone (3a) exhibited single-digit micromolar IC50 (72 h) values in all four cell lines. It was seven times more active than TQ (1) in 518A2 melanoma cells and four times in KB-V1/Vbl cervix carcinoma cells, while only half as toxic in the fibroblasts. Compound 3a was also not a substrate for the Pgp and BCRP drug transporters of the resistant cancer cells. The caryophyllyl and germacryl conjugates 3e and 3f specifically inhibited the growth of the resistant MCF-7 breast carcinoma cells. Conjugation of TQ with the triterpene betulinic acid via the OH group as in 3g led to a loss in activity, while conjugation via the carboxylic acid afforded compound 4 with nanomolar IC50 (72 h) activity against HL-60 cells. All anticancer-active derivatives of TQ (1) induced apoptosis associated with DNA laddering, a decrease in mitochondrial membrane potential and a slight increase in reactive oxygen species.
