New pyranonaphthoquinone derivatives were synthesized and investigated for their activity against Trypanosoma brucei, Leishmania major, and Toxoplasma gondii parasites. The pentafluorophenyl derivative was efficacious against T. brucei with single digit micromolar EC50 values and against T. gondii with even sub-micromolar values. The 3-chloro-4,5-dimethoxyphenyl derivative showed an activity against amastigotes of Leishmania major parasites comparable to that of amphotericin B. In addition, antioxidant activities were observed for the bromophenyl derivatives, and their redox behavior was studied by cyclovoltammetry. Anti-parasitic and antioxidative activities of the new naphthoquinone derivatives appear uncorrelated.
Keywords: biological activity; lawsone; neglected tropical diseases; pyran.
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