Antiparasitic Activities of Plants From the Traditional Senegalese Pharmacopoeia: Isolation of Antitrypanosomal and Antileishmanial Ellagic Acid Derivatives From Terminalia Avicennioides.

Parasitic diseases such as trypanosomiasis and leishmaniasis pose significant health challenges in Africa. The Senegalese Pharmacopoeia, known for its many medicinal plants with anti-infectious properties, can be a source of antiparasitic natural products. This study aimed to evaluate the in vitro antiparasitic activities of 33 methanolic extracts from 24 ethnopharmacologically selected plants against Trypanosoma brucei brucei (Tbb) and Leishmania mexicana mexicana (Lmm), as well as their cytotoxic activities on WI-38 cells. The most promising plant species were Balanites aegyptiaca, Eucalyptus camaldulensis, Vachellia nilotica and four Combretaceae species. In a second step, antitrypanosomal and antileishmanial compounds were isolated by preparative high-performance liquid chromatography from one of the most active plant extracts, Terminalia avicennioides leaves. Four ellagic acid derivatives were identified by nuclear magnetic resonance (1D & 2D) and high-resolution electrospray ionization-tandem mass spectrometry (HR-ESI-MS/MS) as 3,4,3-tri-O-methylellagic acid (2), 3,4,5-O-trimethyl-3',4'-O,O-methylideneflavellagic acid (3), hexamethylcoruleoellagic acid (4) and pentamethylflavellagic acid (5). In addition, HR-ESI-MS/MS-based dereplication analysis was performed to putatively identify compounds in active cyclohexane and dichloromethane sub-extracts. Pentamethylflavellagic acid (5) showed the most promising activity against Tbb (half-maximal inhibitory concentration = 6.20 µM). This is the first time that these compounds have been isolated from T. avicennioides and evaluated for their antitrypanosomal and antileishmanial activities.