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 (LC₅₀) of 28.2 µg/mL and a selectivity index (SI) of 22.4 for T. spiralis and an LC₅₀ 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 LC₅₀ of 147.6 µg/mL and an SI of 7.77 against T. spiralis and an LC₅₀ 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.

Background: Schistosomiasis impacts over 230 million people globally, with 251.4 million needing treatment. The disease causes intestinal and urinary symptoms, such as hepatic fibrosis, hepatomegaly, splenomegaly, and bladder calcifications. While praziquantel (PZQ) is the primary treatment, its effectiveness against juvenile stages (schistosomula) is limited, highlighting the need for new therapeutic agents, repurposed drugs, or reformulated compounds. Existing microscopy methods for assessing schistosomula viability are labor-intensive, subjective, and time-consuming. Methods: An artificial intelligence (AI)-assisted culture system using YOLOv5 was developed to evaluate compounds against Schistosoma mansoni schistosomula. The AI model, based on object detection, was trained on 4390 images distinguishing between healthy and damaged schistosomula. The system was externally validated against human counters, and a small-scale assay was performed to demonstrate its potential for larger-scale assays in the future. Results: The AI model exhibited high accuracy, achieving a mean average precision (mAP) of 0.966 (96.6%) and effectively differentiating between healthy and damaged schistosomula. External validation demonstrated significantly improved accuracy and counting time compared to human counters. A small-scale assay was conducted to validate the system, identifying 28 potential compounds with schistosomicidal activity against schistosomula in vitro and providing their preliminary LC₅₀ values. Conclusions: This AI-powered method significantly improves accuracy and time efficiency compared to traditional microscopy. It enables the evaluation of compounds for potential schistosomiasis drugs without the need for dyes or specialized equipment, facilitating more efficient drug assessment.

Parasitic diseases constitute a significant challenge to global public health, with Strongyloides stercoralis 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 Ruta chalepensis, was evaluated against larval and adult stages of Strongyloides venezuelensis (model for S. stercoralis). 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.

Background: Strongyloidiasis, a parasitic infection, presents a significant public health challenge in tropical regions due to the limited repertoire of effective treatments. The screening of chemical libraries against the therapeutically relevant third-stage larvae (L3) of the model parasite Strongyloides venezuelensis yielded meager success rates. This situation is reminiscent of Gram-negative bacteria, where drug entry is a limiting factor. Methods: Here, we set out to determine whether similar barriers are in place and establish whether structural and property requirements exist for anti-strongyloides drug discovery. We focused on dyes as their uptake and effects on viability can be independently assessed in the multicellular parasite, thus providing a means to study the possibility of similar entry rules. We tested different dyes in in vitro assays on L3s. Results: We found that staining was necessary to reduce parasite viability, with some dyes achieving anti-strongyloides effects at concentrations similar to those of the reference drug, ivermectin (IV). Some dyes also showed activity against female adults at concentrations well below that of ivermectin. Unfortunately, the most potent dye, Methylene Blue, was unable to prevent the infection in a preliminary in vivo mouse model assay, presumably due to fast dye clearance. Structural analysis showed that positive charges facilitated the access of the compounds to the L3 tissue, thus providing a structural tool for the introduction of activity. For female adults, low globularity is additionally required. As a proof of concept, we added a positive charge to an inactive compound of one of our chemical libraries and re-determined the activity. Conclusions: These findings allow us to establish structural rules for parasite entry that could be of interest for future drug screening or drug development campaigns. These rules might also be applicable to other related parasites.

Background/Objectives: Microtubule-targeting agents represent a pillar of cancer chemotherapy; however, their clinical utility is constrained by significant toxicity, pharmacokinetic instability, and susceptibility to multidrug resistance transporters. This study aimed to explore the impact of replacing substituted phenyl rings with a naphthalene moiety in sulfonamide-based colchicine-site ligands, with the goal of identifying new antiproliferative candidates with improved profiles. Methods: We designed, synthesized, and evaluated a library of 35 naphthalene sulfonamides bearing varied aryl groups and sulfonamide nitrogen substituents. We assessed the antiproliferative activity against multiple cancer cell lines. Mechanistic studies, including fluorescence microscopy, cell cycle analysis, and cell death assays, were performed to evaluate the effect of these compounds on microtubule polymerization dynamics and cell fate. Molecular docking and in silico pharmacokinetic profiling were carried out to support the proposed binding mode at the colchicine site and to assess drug-likeness. Results: Exclusively, compounds bearing a trimethoxyphenyl group showed antiproliferative activity in the submicromolar range, thus identifying it as a structural requirement. The most potent compound (2) reached double-digit nanomolar IC₅₀ values (67–104 nM) across multiple cancer cell lines. Microscopy confirmed intracellular disruption of microtubule polymerization. Unlike colchicine, these compounds did not induce canonical mitotic arrest but instead triggered apoptotic cell death. In silico analyses supported binding at the colchicine site and revealed favorable predicted pharmacokinetic properties. Conclusions: The naphthalene sulfonamides described herein demonstrate potent antiproliferative activity through a distinct mechanism compared to colchicine, and their favorable in silico profiles position them as promising candidates for further development as antitumor agents.