Synthesis and Comparative Evaluation of Polymethoxy Substituted 1,4-Naphthoquinones and their Acetyl- O -glucosides as Cytotoxic Agents

Abstract

Twenty five hydroxy-, chloro- and methoxy derivatives of natural and synthetic naphthazarins and their acetylated O-glycosides were synthesized. Targeted compounds were screened as cytotoxic agents on mouse Ehrlich ascites carcinoma cells using MTT test. Chloro- and methoxy-substituted naphthoquinones as well as naphthoquinone O-acetylglucosides were the most potent with IC₅₀ in low micromolar concentration range. Glucosidation of hydroxynaphthoquinones was shown to enhance cytotoxicity, whereas methoxylation yielded both more active and less active derivatives depending on the number and position of methoxy groups. Evaluation using a phenotypic sea urchin embryo assay suggested that naphthazarins exerted their cytotoxic effects through tubulin-unrelated mechanism.