In vitro antitrypanosomal activity of synthesized nitrofurantoin-triazole hybrids against Trypanosoma species causing animal African trypanosomosis

Abstract

Animal African trypanosomosis (AAT) is a disease caused by Trypanosoma brucei brucei, T. vivax, T. evansi and T. congolense which are mainly transmitted by tsetse flies (maybe the family/genus scientific name for the tsetse flies here?). Synthetic trypanocidal drugs are used to control AAT but have reduced efficacy due to emergence of drug resistant trypanosomes. Therefore, there is a need for the continued development of new safe and effective drugs. The aim of this study was to evaluate the in vitro anti-trypanosomal activity of novel nitrofurantoin compounds against trypanosomes (Trypanosoma brucei brucei, T. evansi and T. congolense) causing AAT. This study assessed previously synthesized nineteen nitrofurantoin-triazole (NFT-TZ) hybrids against animal trypanosomes and evaluated their cytotoxicity using Madin-Darby bovine kidney cells. The n-alkyl sub-series hybrids, 8 (IC₅₀ 0.09 ± 0.02 μM; SI 686.45) and 9 (IC₅₀ 0.07 ± 0.04 μM; SI 849.31) had the highest anti-trypanosomal activity against T. b. brucei. On the contrary, the nonyl 6 (IC₅₀ 0.12 ± 0.06 μM; SI 504.57) and nitrobenzyl 18 (IC₅₀ 0.11 ± 0.03 μM; SI 211.07) displayed the highest trypanocidal activity against T. evansi. The nonyl hybrid 6 (IC₅₀ 0.02 ± 0.01 μM; SI 6328.76) was also detected alongside the undecyl 8 (IC₅₀ 0.02 ± 0.01 μM; SI 3454.36) and 3-bromobenzyl 19 (IC₅₀ 0.02 ± 0.01 μM; SI 2360.41) as the most potent hybrids against T. congolense. These hybrids had weak toxicity effects on the mammalian cells and highly selective submicromolar antiparasitic action efficacy directed towards the trypanosomes, hence they can be regarded as potential trypanocidal leads for further in vivo investigation.