# Effectiveness of Thymol-Loaded Chitosan Nanoparticles Against Toxocara Vitulorum Infective Larvae In Vitro

## TL;DR

This study shows that thymol-loaded chitosan nanoparticles can effectively kill infective larvae of Toxocara vitulorum in a lab setting.

## Contribution

The novel contribution is the development and testing of thymol-loaded chitosan nanoparticles as a potential antiparasitic agent.

## Key findings

- TC NPs caused oxidative stress and morphological damage in larvae.
- Larvae exposed to TC NPs showed increased malondialdehyde, catalase, and nitric oxide levels.
- TC NPs at lower concentrations exhibited significant larvicidal activity.

## Abstract

This study assessed the impact of different concentrations of thymol-loaded chitosan nanoparticles (TC NPs) on the physiological condition and surface morphology of Toxocara vitulorum infective larvae in vitro.

Thymol-loaded chitosan nanoparticles were produced utilizing the emulsion-ionic gelation process with sodium tripolyphosphate and then freeze dried. UV-Vis, XRD, TEM, and DLS were used to analyze optical, structural, and size properties, as well as encapsulation efficiency and loading capacity. Toxocara vitulorum worms were gathered from buffaloes, and female worms were employed to extract and hatch eggs in the laboratory. The larvae were exposed to different concentrations of thymol, chitosan NPs, and TC NPs (0, 1000, 2000, 3000, 4000, and 5000 µg/mL) and were kept at 37 °C for 24 h Trypan blue staining and scanning electron microscopy were used to assess the toxicity and larvicidal activity of TC NPs at various doses. The oxidative stress indicators (GSH, MDA, CAT, and NO) were evaluated in treated larvae.

The exposed larvae to TC NPs had an increase in malondialdehyde, catalase and nitric oxide levels, while a depletion in glutathione concentration. Light microscopy analysis indicated that the exposed larvae lost their coiling habit, exhibiting many holes and wrinkles. Moreover, scanning electron microscopy revealed morphological changes in the larvae’s body wall, including numerous erosional and fissured regions, along with both small and large blebs resulting from exposure to TC NPs.

TC NPs at environmentally relevant doses demonstrated considerable antihelminthic action against Toxocara vitulorum infective larvae, establishing a successful model for parasite control research.