Abstract
Parasitic diseases represent a significant global public health concern. Two clinically important parasites of high prevalence rates are Trichinella spiralis and Strongyloides stercoralis. However, the limitations of currently used nematocidal drugs highlight the urgent need for novel treatment approaches. The present study investigated the in vitro nematocidal activity of methanol extracts from Amphipterygium adstringens, Artemisia ludoviciana, Cymbopogon citratus, Heterotheca inuloides, Jatropha dioica, Justicia spicigera, Larrea tridentata, Mimosa tenuiflora, Psacalium decompositum, Ruta chalepensis, Semialarium mexicanum, and Smilax aspera against T. spiralis L1 and S. venezuelensis L3 (model for S. stercoralis). Most of the plants showed antiparasitic activity, but R. chalepensis crude methanol extract showed the most potent nematocidal activity against both parasites, with a mean lethal concentration (LC(50)) of 28.2 µg/mL and a selectivity index (SI) of 22.4 for T. spiralis and an LC(50) of 244.8 µg/mL and SI of 2.58 for S. venezuelensis. This extract was further separated into n-hexane, chloroform, and methanol partitions by continuous Soxhlet extractions. The n-hexane partition demonstrated the strongest activity against both parasites, with an LC(50) of 147.6 µg/mL and an SI of 7.77 against T. spiralis and an LC(50) of 39.2 µg/mL and an SI of 3.77 against S. venezuelensis. LC-MS/MS analysis identified coumarins as the main chemical class (53%), and chalepin represented this partition's most abundant compound (29.9%). Overall, this study confirmed the antiparasitic potential of medicinal plants commonly used in Mexico. In addition, it highlights the possibility of obtaining bioactive compounds from plants like R. chalepensis, or the other plants evaluated in this study, as novel treatments against parasitic diseases.