Antiparasitic Activity of Chalepensin and Graveoline Isolated from Ruta chalepensis L.: In Vitro Evaluation Against Strongyloides venezuelensis

Parasitic diseases constitute a significant challenge to global public health, with <i>Strongyloides stercoralis</i> ranking among the most prevalent and clinically significant parasites. The limitations of current nematocidal therapies highlight an urgent need for novel treatment strategies. In this study, the nematocidal activity of chalepensin and graveoline, two compounds isolated from <i>Ruta chalepensis</i>, was evaluated against larval and adult stages of <i>Strongyloides venezuelensis</i> (model for <i>S. stercoralis</i>). The in vitro efficacy of these compounds was assessed on third-stage infective larvae (L3) and adult parthenogenetic females at various time points, while cytotoxicity was determined using Vero cells to calculate selectivity indices (SI). Both compounds showed good antiparasitic activity, but chalepensin exhibited superior nematocidal activity compared to graveoline, with an LC₅₀ of 3.9 µg/mL and an SI of 990 for L3, and an LC₅₀ of 16.8 µg/mL and an SI of 200 for adult females at 72 h. Morphological analysis via scanning electron microscopy in adult females revealed that graveoline induced mostly cuticle detachment, while chalepensin caused protuberances across the parasite body. These findings suggest that both compounds possess promising antiparasitic potential, with chalepensin emerging as a particularly potent candidate for further exploration.