Plant extracts are an important raw material for the development of new drugs. Rumex obtusifolius L., popularly known as 'bitter dock', has significant pharmacological properties. This study evaluated the in vitro antitrypanosomal activity of aqueous, hydroethanolic and ethanolic extracts from the leaf and roots of R. obtusifolius L. against Trypanosoma evansi, as well as their antibacterial activity against Escherichia coli and Streptococcus aureus. Antitrypanosomal assays were performed using extract concentrations of 0.5%, 1% and 2% and analysed by flow cytometry (necrosis). The antimicrobial activity was assessed at 1-100 mg/mL. Cytotoxicity was evaluated in mammalian cells for extracts active against T. evansi. The hydroethanolic and ethanolic leaf extracts exhibited significant anti-T. evansi activity, inducing necrosis rates of 64.6% and 63.7%, respectively. Besides, treatment with the ethanolic leaf extract (2%) of R. obtusifolius reduced cell viability to 14.3% after 24 h, whereas the hydroethanolic extract (2%) exhibited lower cytotoxicity, with cell viability remaining at approximately 65%-70%. None of the extracts exhibited antibacterial activity. In addition, our findings demonstrate a previously unreported pharmacological property of R. obtusifolius: the antitrypanosomal activity of its hydroethanolic and ethanolic extracts against T. evansi. Nevertheless, further studies are required to elucidate the mechanisms of action and to confirm a possible in vivo antitrypanosomal efficacy of these extracts.
Borges et al. (2026) studied this question.