Lanthanum Nanorods Deliver New Drug Candidate That Kills Parasitic Worms

A team of chemists and parasitologists at Zagazig University in Egypt has reported the development of a synthetic triazolopyrimidine compound that shows potent killing activity against Trichinella spiralis, the parasitic roundworm responsible for trichinellosis, a globally distributed foodborne disease. The work, published in The Science of Nature, combines green heterogeneous nanocatalysis with rigorous biological evaluation, offering a template for how advanced materials chemistry can accelerate the discovery of much-needed antiparasitic agents. The study was led by Yasmin A. Abd El-Latif and Radwa M. Said from the Department of Zoology, together with Doaa A. Elsayed and Abd-ElNasser A. Mohamed from the Department of Chemistry, all of the Faculty of Science at Zagazig University.

The motivation behind the research stems from a widening gap in the therapeutic arsenal against parasitic worms. Drugs such as albendazole and mebendazole remain the mainstay of treatment for trichinellosis and related nematode infections, but their limitations are increasingly well documented. Resistance concerns, incomplete efficacy against certain life stages of parasites, and adverse effects, including documented cases of albendazole-induced liver injury, have pushed researchers to explore novel heterocyclic scaffolds with different mechanisms of action. The emergence of drug resistance and the side effect profiles of currently available antiparasitic drugs, the authors note, necessitate the exploration of new chemical frameworks that could form the basis of next-generation anthelmintics.

The scaffold at the heart of the new study is the triazolopyrimidine, a fused bicyclic system that merges a 1,2,4-triazole ring with a pyrimidine ring. This class of nitrogen-rich heterocycles has attracted sustained attention in medicinal chemistry because it appears in compounds with antimicrobial, antiviral, anticancer, anti-inflammatory, and antiparasitic activities. Triazolopyrimidine derivatives have been investigated as inhibitors of DNA gyrase, cyclin-dependent kinases, and microtubule dynamics, and metal complexes of triazolopyrimidines have shown leishmanicidal and trypanocidal activity. Their structural rigidity, multiple hydrogen-bonding sites, and metabolic stability make them attractive pharmacophores, yet their synthesis has often required harsh conditions, long reaction times, and corrosive catalysts, which limits both scalability and environmental sustainability.

To address this synthetic bottleneck, the Egyptian team turned to lanthanum hydroxide nanorods, a rare-earth-based heterogeneous nanocatalyst. The researchers synthesized the La(OH)3 nanorods and subjected them to a thorough battery of characterization techniques, including X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and surface area analysis. These measurements confirmed the nanoscale dimensions, crystalline phase, rod-like morphology, and porous surface architecture of the material. Such one-dimensional lanthanum hydroxide nanostructures have previously found applications ranging from Claisen-Schmidt condensation catalysis to phosphate adsorption from water, and their basic surface sites make them well suited to promoting multicomponent condensation reactions under mild conditions.

Using these nanorods, the team prepared 6,8-diamino-5-(4-nitrophenyl)pyrido[3,2-e][1,2,4]triazolo[1,5-a]pyrimidine-7-carbonitrile, abbreviated DNP-Triazolopyrimidine, a highly functionalized fused heterocycle bearing an aminopyrido ring fused to the triazolopyrimidine core, two amino groups, a para-nitrophenyl substituent, and a nitrile function. The catalytic system demonstrated high efficiency, considerably reducing the reaction time while delivering a high product yield under mild reaction conditions. Compared with conventional approaches that may demand strong bases, elevated temperatures, or stoichiometric reagents, the heterogeneous nanocatalyst offers the additional practical advantage of easy separation from the reaction mixture, a hallmark of green chemistry that reduces waste and facilitates catalyst reuse. The final compound was structurally verified by FT-IR, proton nuclear magnetic resonance, and carbon-13 NMR spectroscopy, confirming the successful construction of the elaborate fused ring system.

With the compound in hand, the parasitology phase of the study began. The researchers evaluated DNP-Triazolopyrimidine in vitro against both the larval and adult stages of Trichinella spiralis, the two life stages most relevant to the pathology of trichinellosis. Adult worms inhabit the intestinal mucosa of the host, while larvae invade and encyst in skeletal muscle, so an effective drug candidate ideally must target both. The results were striking: the compound exhibited significant antiparasitic activity in a dose- and time-dependent manner, achieving complete larval mortality at concentrations of 10 and 20 micrograms per milliliter and complete adult-worm mortality at 20 micrograms per milliliter after 96 hours of exposure.

Quantitative analysis of the dose-response relationships revealed LC50 values, the concentrations lethal to half of the parasites, of 9.71 micrograms per milliliter for larvae and, notably, 3.16 micrograms per milliliter for adult worms. The lower LC50 for adults indicates that the intestinal stage of the parasite is particularly susceptible to the compound, an encouraging finding given that eliminating adult worms early in infection can prevent the subsequent establishment of muscle larvae and interrupt the parasite’s life cycle within the host. These potency figures compare favorably with many naturally derived and repurposed antiparasitic candidates previously tested against T. spiralis in vitro, positioning DNP-Triazolopyrimidine as a promising lead for further optimization.

To understand how the compound kills the parasites, the team turned to scanning electron microscopy, which revealed pronounced ultrastructural alterations in treated worms. The exposed cuticular surface of the nematodes suffered cuticular rupture, blebbing, vesicle formation, and loss of annulations, the characteristic transverse ridges of the nematode cuticle. The cuticle is far more than a passive skin; it is a metabolically active interface through which the worm absorbs nutrients, secretes immunomodulatory molecules, and defends itself against host immunity and drugs. Extensive damage to this tegumental barrier, as observed here, compromises osmotic balance, nutrient uptake, and immune evasion, providing a coherent mechanistic picture of nematode death consistent with surface-acting anthelmintic action.

Any prospective drug must spare host cells, so the researchers assessed the cytotoxicity of DNP-Triazolopyrimidine against WI-38 normal human fibroblast cells. The compound showed comparatively low cytotoxicity, with an IC50 of 51.61 plus or minus 2.9 micromolar, a concentration substantially above the levels that killed the parasites. This selectivity margin, while requiring confirmation in more cell types and in vivo models, suggests that the compound’s toxic effects are preferentially directed at the parasite rather than at mammalian tissue, a crucial property for a viable therapeutic candidate. Complementing the experimental data, the team performed in silico ADMET analysis, computational predictions of absorption, distribution, metabolism, excretion, and toxicity, which provided preliminary information on the pharmacokinetic and safety profile of DNP-Triazolopyrimidine and will guide medicinal chemists as they refine the scaffold.

The study, which received no external funding and was conducted with the support of Zagazig University’s Faculty of Science, illustrates a growing convergence between nanocatalysis and drug discovery. By demonstrating that inexpensive, recyclable lanthanum hydroxide nanorods can efficiently assemble a complex, biologically active heterocycle under mild conditions, the researchers have lowered a practical barrier that has historically slowed the exploration of triazolopyrimidine chemistry. At the same time, the potent in vitro activity against both larval and adult T. spiralis, the direct visualization of cuticular damage, and the encouraging selectivity over mammalian cells together argue that DNP-Triazolopyrimidine deserves further development. The path from an in vitro lead to a licensed medicine is long, requiring in vivo efficacy studies, detailed mechanism-of-action elucidation, and safety pharmacology, but this work provides a solid, technically well-documented starting point in the search for alternatives to a strained anthelmintic pharmacopoeia.

Subject of Research: Nanocatalytic synthesis of a triazolopyrimidine compound with in vitro antiparasitic activity against Trichinella spiralis

Article Title: An efficient nanocatalytic synthesis of a triazolopyrimidine carbonitrile with potent activity against Trichinella spiralis

Article References: El-Latif, Y. A. A., Elsayed, D. A., Mohamed, A.-E. A., & Said, R. M. (2026). An efficient nanocatalytic synthesis of a triazolopyrimidine carbonitrile with potent activity against Trichinella spiralis. The Science of Nature, 113(5), Article 111. https://doi.org/10.1007/s00114-026-02153-9

Image Credits: AI Generated

DOI: 10.1007/s00114-026-02153-9

Keywords: DNP-Triazolopyrimidine, La(OH)3 nanorods, heterogeneous nanocatalysis, Trichinella spiralis, trichinellosis, antiparasitic activity, lanthanum hydroxide, LC50, cuticular ultrastructure, WI-38 cytotoxicity, ADMET, medicinal chemistry