Bibenzyl Derivatives from Radula voluta (An Ecuadorian Liverwort): Bioprospecting for Antiprotozoal Properties.

Phytochemical investigation of Radula voluta, a liverwort species collected in the Ecuadorian Amazon, led to the isolation of four known bibenzyl derivatives: 2-prenyl-3,5-dihydroxy-bibenzyl (1), 2-geranyl-3,5-dihydroxybibenzyl (2), 2,2-dimethyl-5-phenethyl-2H-chromen-7-ol (3), and radulanin L (4). Structural elucidation was achieved through extensive NMR and MS analyses, supported by comparison with previously reported data. Compounds 1 and 4 are reported for the first time in R. voluta. The crude extract and isolated compounds were evaluated for their in vitro antiprotozoal activity against Trypanosoma cruzi, Leishmania amazonensis, Leishmania donovani, Naegleria fowleri, and Acanthamoeba castellanii Neff. Among the isolated compounds, bibenzyls 2 and 4 exhibited the most potent activity across multiple protozoan strains. Cytotoxicity was assessed against murine macrophages (J774A.1), obtaining moderate-low toxicities against compounds 1 and 3. These findings highlight the pharmacological value of liverwort-derived bibenzyls and support further research on R. voluta as a promising source of antiparasitic leads.