Authors

K Doleckova²; H Hameed¹; R Nash³; P D Horrocks¹; H Price⁴;  ¹ Institute for Science and Technology in Medicine, Keele University, UK;  ² Keele University, School of Life Sciences, UK;  ³ PhytoQuest Ltd, UK;  ⁴ School of Life Sciences, Keele University, UK

Discussion

Trypanosoma evansi is a protozoan parasite causing surra, a debilitating veterinary disease, found worldwide and affecting a range of domestic livestock including cattle, horses and camels. The disease causes major socio-economic losses especially among pastoralists and farming populations, who heavily rely on their animals as a main source of income. Current treatments for surra have limited efficacy and can cause severe toxicity and the emergence of drug resistance to all available treatments highlight the need to identify new drugs.  

This work is part of our project on surra in Egyptian camels, financed by Newton-Mosharafa fund, with one of the aims to initiate work to develop new lead compounds against T. evansi parasite.

PhytoQuest library is a proprietary set of ca 1000 molecules from different chemical classes, isolated from temperate zone plants. It represents a novel source of potentially new biologically active compounds - typically, temperate zone plants have been overlooked in search of antiparasitic activities, unlike the plants from subtropical and tropical regions, which have been used in traditional medicine to cure parasitic diseases for centuries. 

We screened a subset of compounds from PhytoQuest library against culture adapted T. evansi using a phenotypic 72 h AlamarBlue assay with the aim to identify hit compounds, with high efficacy and selectivity. We obtained IC50 values for the hit compounds and determined cytotoxicity using the mammalian cell line HepG2 to ascertain parasite selectivity. In total, we screened 547 compounds, out of which we identified 12 compounds with IC50 values of ≤1 µM against T. evansi. 

In summary, we identified several promising natural products with the potential to be new chemical starting points for drug discovery efforts for surra disease.