Comparative Study of the Effect of Sophora alopecuroides Plant Extract on Trichomonas vaginalis Parasite In Vitro

Background: Trichomoniasis caused by Trichomonas vaginalis is considered one of the most important worldwide non-viral sexually transmitted infections. The remaining clinical symptoms of the disease after treatment with metronidazole confirm the presence of metronidazole-resistant strains. Objectives: Therefore, the present study aimed to investigate the inhibitory effect of the extract of the root and leaf of the Sophora alopecuroides plant on the growth and inhibition of the growth of T. vaginalis parasite. Methods: Aqueous and alcoholic extracts of S. alopecuroides plant roots and leaves with concentrations of 0.5, 1, 2, 4, and 5 mg/mL, as well as metronidazole were exposed to 105 parasites and mouse macrophage cells in 24 and 48 hours. To determine the toxicity of the extract on the cells, mice peritoneal cells were used for the 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-2H-tetrazolium bromide test. The half-maximal inhibitory concentration and 50% cytotoxic concentration values were evaluated by PRISM GraphPad software, and analysis of variance and t test were employed for statistical comparisons by SPSS-23. Results: The aqueous-alkaline compounds of the root of the S. alopecuroides plant demonstrated a promising effect on inhibiting parasite growth, but the therapeutic index of the aqueous extract of its leaves was less effective than the rest of the extracts and metronidazole. After 24 hours, at a concentration of 2.5%, the aqueous extract of the root had the most effect with 69.4%, and the aqueous extract of the leaf had the least effect with 34.68% of growth inhibition. However, none of the extracts had a greater inhibitory effect than metronidazole, but after 48 hours, the effect of the extract caused more inhibition due to time. Conclusion: Overall, the aqueous and alcoholic extracts of the leaves and roots of the S. alopecuroides plant had suitable anti-trichomonas effects. In addition, the aqueous leaf extract had a good effect with the least toxicity. Considering that this research was performed for the first time, to generalize the results, extensive research is needed in in vivo conditions.