No abstract

No abstract

Naphthoquinones are among the most active natural products obtained from plants and microorganisms. Naphthoquinones exert their biological activities through pleiotropic mechanisms that include reactivity against cell nucleophiles, generation of reactive oxygen species (ROS), and inhibition of proteins. Here, we report a mechanistic antiproliferative study performed in the yeast Saccharomyces cerevisiae for several derivatives of three important natural naphthoquinones: lawsone, juglone, and β-lapachone. We have found that (i) the free hydroxyl group of lawsone and juglone modulates toxicity; (ii) lawsone and juglone derivatives differ in their mechanisms of action, with ROS generation being more important for the former; and (iii) a subset of derivatives possess the capability to disrupt mitochondrial function, with β-lapachones being the most potent compounds in this respect. In addition, we have cross-compared yeast results with antibacterial and antitumor activities. We discuss the relationship between the mechanistic findings, the antiproliferative activities, and the physicochemical properties of the naphthoquinones.

β-Lapachone (β-lap) is a promising antitumoral agent. DNA base oxidation and alkylation are among the expected damages by β-lap. Herein, we have explored the role that the homologous recombination pathway (HR), a critical DNA repair process in Saccharomyces cerevisiae, has in the cytotoxic profile of β-lap. We have further compared β-lap to the closely related compound menadione and the well-known alkylating agent methyl methanesulfonate (MMS). Surprisingly, we found that β-lap does not trigger HR, as seen for (i) the mutant sensitivity profiles, (ii) concentration-dependent arrest profiles, (iii) absence of nuclear DNA repair factories, and (iv) frequency of recombination between direct repeats.

No abstract