Kayser O, Kiderlen AF (2001): In vitro leishmanicidal activity of naturally occurring chalcones
Phytother. Res. 15 (2): 148-152.

A variety of chalcones have been shown to exhibit activity against Leishmania parasites. In contrast to synthetic or semisynthetic chalcones, only a few plant-derived compounds have been investigated. To provide a scientific rational for the antiprotozoal potency of plants used in ethnomedicine and containing chalcones, and in search for new antiprotozoal drugs, we have carried out a primary screening for in vitro leishmanicidal activity of 20 chalcones isolated from plants. The compounds were tested against extracellular promastigotes of Leishmania donovani, L. infantum, L. enriettii and L. major, and against intracellular amastigote L. donovani residing within murine macrophages. Against the extracellular Leishmania (L. donovani), most compounds were active with EC₅₀ values between 0.07 and 2.01 mg/mL. Some of these chalcones, 2',4'-dihydroxy-4-methoxychalcone, 2'-hydroxy-3,4-dimethoxychalcone and 2-hydroxy-4,4'-dimethoxychalcone also significantly inhibited the intracellular survival of L. donovani parasites with EC₅₀ values between 0.39 and 0.41 mg/mL. When tested against murine bone marrow-derived macrophages as mammalian host cell control, all compounds with antileishmanial activities also proved cytotoxic to various extents (EC₅₀ 0.19-2.06 mg/mL). Correlations between molecular structures and antileishmanial activity are discussed in detail. Selected compounds are illustrated with emphasis on their mode of action and potential for the development of selective antiprotozoal agents.