Lupeol acetate isolated from L. fruit as a template for the synthesis of -alkyl-arylsulfonamide derivatives and their synergistic effects with metronidazole against .

Pentacyclic triterpenes are found in a great variety of natural products and constitute an organic template for the development of new derivative compounds with therapeutic applications. In the present work, lupeol acetate isolated from L. fruit was used as a template for the synthesis of novel -alkyl-arylsulfonamide derivatives, and their synergistic effects with metronidazole against strains of were tested. A library of 18 derivatives was synthesized. Ten compounds exhibited an IC < 100 μM against a metronidazole-sensitive strain of . Only seven of these compounds (, , -) also showed activity against metronidazole-resistant strains. The compounds (-cyclohexyl--chlorobenzenesulfonamidolupeol acetate) and (-cyclohexyl--nitrobenzenesulfonamidolupeol acetate) exhibited a similar IC against both susceptible and resistant strains and enhanced the efficacy of metronidazole in a partial and total synergistic way, respectively. These data provided evidence of the trichomonicidal effect of -alkyl-arylsulfonamide derivatives of lupeol acetate, representing highly promising novel antiparasitic agents.