Bioassay-guided isolation of antimutagenic naphthoquinones from Plumbago auriculata

Background Mutagen-induced genotoxicity plays a central role in carcinogenesis, highlighting the need for effective chemopreventive agents. Naphthoquinones, such as plumbagin, exhibit diverse biological activities; however, their antimutagenic potency at pharmacologically relevant concentrations remains poorly characterized. In this study, the acetone extract of Plumbago auriculata roots was subjected to bioassay-guided fractionation, yielding two known naphthoquinone derivatives: plumbagin and cis -isoshinanolone. Results Antimutagenic activity was evaluated using the Ames test with Salmonella typhimurium TA1535 against N -methyl- N -nitrosourea. The chloroform-soluble fraction (PAC) exhibited stronger activity than the residual fraction (PAAR), and purified plumbagin potently inhibited mutagen-induced revertant formation at nanomolar concentrations. No toxicity was observed at any of the tested doses. Conclusions These findings provide the first evidence that P. auriculata is a source of nanomolar-active antimutagenic naphthoquinones, highlighting their chemopreventive potential and expanding the biological relevance of quinone-type natural products beyond cytotoxicity.