Traditional Medicinal Ranunculaceae Species from Romania and Their In Vitro Antioxidant, Antiproliferative, and Antiparasitic Potential

Several Ranunculaceae species are used in folk medicine to eliminate pathologies associated with oxidative stress as well as parasitic infections; however, a number of studies confirming their pharmacological properties is limited. In this study, 19 ethanolic extracts obtained from 16 Ranunculaceae species were assayed for in vitro antioxidant, antiproliferative, and antiparasitic potential. The maximum antioxidant potential in both oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays was observed for <i>Aconitum toxicum</i> extract [half-maximal inhibitory concentration (IC₅₀) 18.7 and 92.6 μg/mL]. Likewise, <i>Anemone transsilvanica</i> extract exerted the most promising antiproliferative activity against Caco-2 (IC₅₀ 46.9 μg/mL) and HT29 (IC₅₀ 70.2 μg/mL) cell lines in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, a dual antioxidant and cytotoxicity effect was demonstrated for <i>Aconitum moldavicum</i> and <i>Caltha palustris</i> extracts. Whilst the efficacy of extracts was modest against <i>Trypanosoma brucei</i> (IC₅₀ ranging from 88.8 to 269.3 µg/mL), several extracts exhibited high potency against <i>Leishmania infantum</i> promastigotes (<i>Aconitum vulparia</i> IC₅₀ 18.8 µg/mL). We also tested them against the clinically relevant intracellular stage and found extract of <i>A. vulparia</i> to be the most effective (IC₅₀ 29.0 ± 1.1 µg/mL). All tested extracts showed no or low toxicity against FHs 74Int normal cell line (IC₅₀ ranging from 152.9 to >512 µg/mL). In conclusion, we suggest the above-mentioned plant extracts as potential candidates for development of novel plant-based antioxidant and/or antiproliferative and/or antileishmanial compounds.