Polymethoxylated xanthones from the herb of Centaurium erythraea with strong antimutagenic properties in Salmonella typhimurium.

Two methoxylated xanthone derivatives, eustomin and demethyleustomin, were isolated from the aerial parts of Centaurium erythraea Rafn. Both compounds were identified by spectral analysis. They showed strong antimutagenic properties in Salmonella typhimurium strains TA98, TA100, and TA102, when tested against 2-nitrofluorene, 2-aminoanthracene, ethyl methanesulfonate, and nalidixic acid. The bioantimutagenic character of the compounds was supported by the strong effects shown in post-treatment experiments as well as by results obtained with rec A- mutants of E. coli and Bacillus subtilis. From this it follows that the xanthone derivatives probably interfere mainly with the process of post-replication repair.