In Vitro and In Silico Evaluation of the Efficacy and Safety of a Ghanaian Herbal Medicine for the Treatment of Onchocerciasis and African Trypanosomiasis

Background This study investigated the anti-onchocercal and antitrypanosomal properties of a Ghanaian herbal medicine (NTD-O2) and its medicinal plant constituents, Xylopia aethiopica fruits and Bambusa vulgaris leaves, with the aim of addressing the therapeutic potential and safety of a herbal medicine against Onchocerciasis and Animal African Trypanosomiasis in Ghana. Methods Extracts from NTD-O2 and the medicinal plants were tested against Onchocerca ochengi and Trypanosoma brucei brucei in vitro . Bioassay-guided fractionation, spectroscopic and spectrometric techniques identified bioactive compounds, while in silico methods explored their possible mechanisms of action. Results NTD-O2 extracts achieved 100% inhibition of adult male O. ochengi worm motility, with moderate activity against adult female worms. Additionally, the extracts demonstrated promising antitrypanosomal activity (IC ₅₀  = 9.44 µg/mL and 10.68 µg/mL) against the positive control, diminazene aceturate (IC ₅₀  = 0.13 ± 0.02 µg/mL). The active compound found in the NTD-O2 extract was bis(4-methylheptyl) phthalate. On the contrary, the compounds isolated from X. aethiopica – ent-kaur-16-en-19-oic acid, xylopic acid, and ent-kaur-16-en-15-one-19-oic acid – and the long chain carbonyl compounds from B. vulgaris were inactive (IC ₅₀  = > 100 ± 0.46 µg/mL). These results were corroborated by in silico analysis. Conclusion The findings highlight significant variability in the chemical composition and bioactivity of the herbal medicine NTD-O2 and its plant constituents. Given the health risks linked to the ingestion of phthalate derivatives, it is essential to conduct regular assessments of the quality and safety of herbal medicines to ensure consumer protection.