Entada rheedii phaseoloidin, protocatechuic acid and entadamide A against protozoal diseases: trypanosomiasis and leishmaniasis

Abstract

Background: African plant extracts and their isolated constituents remains a hot area for discovering novel drugs Aim: Entada rheedii Spreng. and its previously isolated major phytochemicals were evaluated for their antiprotozoal potency. Method: In vitro antiprotozoal activity against Trypanosoma brucei brucei, T. b. rhodesiense, T. cruzi and Leishmania infantum was determined, including cytotoxicity evaluation for the determination of selectivity. Results: The crude extract was inactive. Phaseoloidin exhibited pronounced activity against T. b. brucei, T. cruzi, T. b. rhodesiense, and L. infantum (IC50 of 9.70, 8.00, 7.83 and 6.96 μg/mL, respectively). Entadamide A showed pronounced activity against T. cruzi and L. infantum (IC50 of 8.98 and 10.77μg/mL, respectively). Protocatecheuic acid showed pronounced activity against T. b. brucei (IC50 of 8.12 μg/mL) and moderate activity against T. cruzi and T. b. rhodesiense (IC50 of 14.42, 12.23 μg/mL, respectively). All the active compounds exhibited low cytotoxicity score 2 (CC50˃13 μg/mL). Conclusion: The major phytochemicals of the African E. rheedii seeds were potent against sleeping sickness, Chagas disease, and leishmaniasis. They acted in their pure form rather than acting collectively in the crude extract.