Mutagenicity of Natural Anthraquinones from Rubia tinctorum in the Drosophila Wing Spot Test

Mutagenicity of anthraquinone aglycones from Rubia tinctorum L. (Rubiaceae) was examined using the somatic mutation and recombination test in Drosophila melanogaster. Larvae heterozygous for recessive wing trichome mutations, multiple wing hairs (mwh), and flare (flr3) were exposed to test compounds and wings of emerged mwh/flr3 females were inspected for the presence of phenotypically mutant mosaic spots. No significant increase in the frequency of mutant spots was observed after the treatment of Drosophila larvae with pure alizarin, xanthopurpurin, and lucidin, or with the crude mixture of anthraquinone aglycones. In contrast, the naphthohydroquinone mollugin induced mainly single spots that can originate either from somatic mutation or from mitotic recombination. Twin spots, consisting of both the mwh and flr3 subclones and originating exclusively from mitotic recombination, were also enhanced, but the increase was only marginally significant. We suggest that mollugin exhibits both the mutagenic and recombinagenic activities.