The effects of Xenorhabdus and Photorhabdus bacterial secondary Leishmania tropica and determination of the bioactive compounds

Objective: Determination of the bioactivity of bacterial secondary metabolites obtained from bacteria belonging to the genera Xenorhabdus and Photorhabdus against human protozoan parasites Acanthamoeba castellanii and Leismania tropica. Material and Methods: The antiprotozoal activity of 5 Photorhabdus and 22 Xenorhabdus wild-type bacteria were investigated in bioactivity experiments. Then promotor exchanged mutants belonging to the some bioactive species with the highest activity were generated so that specific genes in these bacteria induced with L-arabinose could be used to demonstrate the activity of the corresponding secondary metabolite. Purification of these substances was also carried out using the XAD resin method. Results: Among the tested bacteria, Xenorhabdus species displayed high antiprotozoal activity against both protozoal parasites. No activity was observed in Photorhabdus species. Experiments with mutant bacteria revealed that the antiprotozoal bioactive compounds were fabclavins, xenocoumacins, xenorhabdins and PAX peptides. Conclusion: The data indicate that these determined antiprotozoal compounds have great potential in the development of new, alternative and effective drugs in the suppression of human parasites in the future. Keywords: Leismania tropica, Acanthamoeba castellanii, Xenorhabdus, Photorhabdus, Secondary metabolites, Antiprotozoal substances