Investigating the effect of whole extract and different fractions of Henna plant (Lawsonia inermis) on Trichomonas vaginalis parasite in laboratory environment

Background: Trichomoniasis is the most common nonviral disease that is transmitted through sexual contact and is caused by Trichomonas vaginalis. The most common treatment is metronidazole or tinidazole, to which drug resistance is relatively common. Henna, with the scientific name Lawsonia inermis, is a tall shrub found in tropical and subtropical regions. The main active component of henna is Lawson, which causes its antimicrobial activity. Considering the observation of anti-trichomonas effects of henna hydroalcoholic extract in previous studies, we decided to investigate the effect of hydroalcoholic extract and different fractions of henna on Trichomonas vaginalis in this research project. Methods: henna was extracted by maceration method and then hexane, chloroform, ethyl acetate and butanol fractions were prepared from it. The amount of total phenol in the extract was measured. Thin layer chromatography (TLC) was performed for Lawson and Luteolin standards compared to the total extract and fractions. To investigate and compare the effect of henna extract and different fractions on Trichomonas vaginalis, different concentrations of the plant were exposed to the parasite, and then the percentage of cell growth inhibition at different concentrations was calculated using the hemocytometer method. Results: The amount of total phenol at a concentration of 1 mg/ml from henna extract was 95.333 μg/ml. According to TLC results, lawsone and luteolin were observed in the total extract and all fractions. The growth inhibition percentage of Trichomonas vaginalis in the presence of the total extract and all henna fractions increased with increasing concentration. Parasite growth inhibition percentage increased significantly with time in the presence of total extract and ethyl acetate and butanol fractions. After 24 hours, the lowest IC50 was related to n-hexane fraction, followed by chloroform and total extract. After 48 hours, the lowest IC50 was related to ethyl acetate fraction, then n-hexane, total extract and chloroform. After 72 hours, the lowest IC50 was related to total extract, ethyl acetate fraction, butanol, n-hexane and chloroform, respectively. Conclusion: Among the fractions of whole henna extract after 24 hours, the growth inhibition percentage of Trichomonas vaginalis parasite increased in order of polarity; That is, the highest percentage of parasite growth inhibition was related to n-hexane fraction, followed by chloroform, ethyl acetate and butanol fractions. After 48 and 72 hours, the order of polarity was changed for the percentage of parasite growth inhibition. According to previous studies, Luteolin is probably found in polar fractions and Lawson in non-polar fractions in larger amounts, and the reason that in our study all fractions had a good effect over time is the presence of these compounds with different percentages in each of the fractions. According to the results of this study, the antitrichomonas effects of the total hydroalcoholic extract and its different fractions, especially the n-hexane and ethyl acetate fractions, can be used in the treatment of trichomoniasis and the development of new drugs.