Investigating the Effect of Silver, Chitosan, and Curcumin Nanoparticles on Blastocystis spp. and Comparing it With Metronidazole In Vitro

Background: Blastocystis is an anaerobic gastrointestinal protozoan that causes infections in humans and a wide range of animals. It was found that the host specificity and the pathogenic potential of different isolates are correlated with sequence variations in the SSU-rRNA gene. The identification of the organism at the species level is still an unclear challenge. The use of natural nature substances against infectious organisms has been promising, and the optimization of these substances in the direction of better delivery such as the form of nanoparticles (NPs) of natural substances has recently been considered. Objectives: The present study aimed to investigate the effect of silver, chitosan, and curcumin NPs on Blastocystis spp. and compare it with metronidazole in vitro conditions. Materials and Methods: The parasite was cultivated in Robinson’s medium and was then identified by polymerase chain reaction (PCR), and the subtype of the parasite was determined, which was subtype 3. Then, the methyl thiazolyl tetrazolium (MTT) test was performed to determine the toxicity level of the prepared drugs/substances using Caco2 cells. This study investigated the concentrations of silver NPs (10, 25, and 50 µg/mL), chitosan (75, 50, 25, and 12.5 µg/mL), and curcumin (250, 500, and 1000 µg/mL), and their effect on 24- and 48-hour time points after exposure to the parasite. Then, the final number of parasites was counted after staining with trypan blue by a Neubauer slide, and the values of IC50 and selectivity index (SI) were calculated for each substance. Results: Chitosan and curcumin NPs had SI of 2.04 and 13.15, respectively, which were more effective than metronidazole, and silver NP was 0.143. However, chitosan NP had the best antiparasitic effect. Based on the obtained results, chitosan and curcumin NPs were more effective against blastocystis than against metronidazole. Conclusion: Chitosan and curcumin NPs (liposomal curcumin) have a good inhibitory effect on blastocystis compared to metronidazole, but silver NP did not perform better than metronidazole.