Capsaicin, a Vanilloid Derivative, Modulates Arginine Kinase mRNA Expression in Trypanosoma evansi

Trypanosoma evansi, the causative agent of Surra, is a significant emerging zoonotic kinetoplastid protozoan parasite with wide host range and limited chemotherapeutic options. Arginine kinase is mainly responsible for providing metabolic plasticity and maintaining cellular homeostasis of trypanosome under adverse conditions.

This study investigated the in vitro anti-trypanosomal activity of Vanilloid derivative, Capsaicin against T. evansi and its effect on mRNA expression of arginine kinase enzyme in T. evansi. Herein, we determined the anti-trypanosomal activity of Capsaicin against T. evansi and its safety towards mammalian cells by estimating the selectivity index. From the dataset generated during the experiments, the IC₅₀ values of capsaicin was determined as 115 µM, respectively.

Cytotoxicity assays showed that Capsaicin exhibited moderate cytotoxicity against equine PBMC and Vero cells line with CC₅₀ value of 309.8 µM and 308.3 µM, respectively giving a selectivity index of around 2.68 at the therapeutic dose against T. evansi. Real-time PCR analysis revealed that Capsaicin showed significant alteration of mRNA expression of arginine kinase 1 gene at 24 and 48 h of exposure with IC₅₀ of drug.

The study suggests that Capsaicin may be a potential approach for treating T. evansi infections, warranting further in vivo investigations.