Amoebiasis caused by Entamoeba histolytica is associated with high morbidity and mortality is becoming a major public health problem worldwide, especially in developing countries. Because of the side-effects and the resistance that pathogenic protozoa build against the standard antiparasitic drugs, e.g., metronidazole, much recent attention has been paid to plants used in traditional medicine around the world in order to find new antiprotozoal agents. We collected 32 plants used in Northeast Mexican traditional medicine and the methanolic extracts of these species were screened for antiprotozoal activity against E. histolytica trophozoites using in vitro tests. Only 18 extracts showed a significant inhibiting activity and among them six plant extracts showed more than 80% OPEN ACCESSMolecules 2014, 19 21045 growth inhibition against E. histolytica at a concentration of 150 µg/mL and the IC50 values of these extracts were determined. Lippia graveolens Kunth and Ruta chalepensis Pers. showed the more significant antiprotozoal activity (91.54% and 90.50% growth inhibition at a concentration of 150 µg/mL with IC50 values of 59.14 and 60.07 µg/mL, respectively). Bioassay-guided fractionation of the methanolic extracts from these two plants afforded carvacrol (1) and chalepensin (2), respectively, as bioactive compounds with antiprotozoal activity.

Entamoeba histolytica (protozoan; family Endomoebidae) is the cause of amoebiasis, a disease related to high morbidity and mortality. Nowadays, this illness is considered a significant public health issue in developing countries. In addition, parasite resistance to conventional medicinal treatment has increased in recent years. Traditional medicine around the world represents a valuable source of alternative treatment for many parasite diseases. In a previous paper, we communicated about the antiprotozoal activity in vitro of the methanolic (MeOH) extract of Ruta chalepensis (Rutaceae) against E. histolytica. The plant is extensively employed in Mexican traditional medicine. The following workup of the MeOH extract of R. chalepensis afforded the furocoumarins rutamarin (1) and chalepin (2), which showed high antiprotozoal activity on Entamoeba histolytica trophozoites employing in vitro tests (IC50 values of 6.52 and 28.95 µg/mL, respectively). Therefore, we offer a full scientific report about the bioguided isolation and the amebicide activity of chalepin and rutamarin.

Sexually transmitted diseases are a major cause of acute disease worldwide, and trichomoniasis is the most common and curable disease, generating more than 170 million cases annually worldwide. Trichomonas vaginalis is the causal agent of trichomoniasis and has the ability to destroy in vitro cell monolayers of the vaginal mucosa, where the phospholipases A 2 (PLA 2 ) have been reported as potential virulence factors. These enzymes have been partially characterized from the subcellular fraction S30 of pathogenic T. vaginalis strains. The main objective of this study was to purify a phospholipase A 2 from T. vaginalis, make a partial characterization, obtain a partial amino acid sequence, and determine its enzymatic participation as hemolytic factor causing lysis of erythrocytes. Trichomonas S30, RF30 and UFF30 sub-fractions from GT-15 strain have the capacity to hydrolyze [2-14 C-PA]-PC at pH 6.0. Proteins from the UFF30 sub-fraction were separated by affinity chromatography into two eluted fractions with detectable PLA A 2 activity. The EDTA-eluted fraction was analyzed by HPLC using on-line HPLC-tandem mass spectrometry and two protein peaks were observed at 8.2 and 13 kDa. Peptide sequences were identified from the proteins present in the eluted EDTA UFF30 fraction; bioinformatic analysis using Protein Link Global Server charged with T. vaginalis protein database suggests that eluted peptides correspond a putative ubiquitin protein in the 8.2 kDa fraction and a phospholipase preserved in the 13 kDa fraction. The EDTA-eluted fraction hydrolyzed [2-14 C-PA]-PC lyses erythrocytes from Sprague-Dawley in a time and dose-dependent manner. The acidic hemolytic activity decreased by 84% with the addition of 100 µM of Rosenthal's inhibitor.

The most common treatment to trichomoniasis is the use of metronidazole; however several studies have shown that at least 5% of clinical cases of trichomoniasis are caused by parasites resistant to the drug. Lipophilic bismuth nanoparticles (BisBAL NPs) have an important antimicrobial activity; however the influence of BisBAL NPs on human parasites has not been studied. The objective of this study was to determine the effect of bismuth lipophilic nanoparticles on Trichomonas vaginalis growth. The bismuth nanoparticles synthesized by colloidal method are composed of ≥ 100 nm crystallites and have a spherical structure, agglomerating into clusters of small nanoparticles. Based on cell viability assays and fluorescence microscopy, Trichomonas vaginalis growth was inhibited with the addition of 62.5–125 μg/mL of BisBAL NPs. Fluorescence micrographs showed live T. vaginalis in absence of any drug treatment and after exposed for 24 h. with 500 μg/mL of BisBAL NPs or 1.3 μg/mL metronidazole a dark background was observed with cellular debris stain. In summary, here we present evidence for first time of the antiparasitic activity of lipophilic bismuth nanoparticles being as effective as metronidazole to interfere with T. vaginalis growth. BisBAL nanoparticles could be an interesting alternative to treat and prevent parasitic infections.

Trichomoniasis is one of the most common acute sexually transmitted curable diseases, and it is disseminated worldwide generating more than 170 million cases annually. Trichomonas vaginalis is the parasite that causes trichomoniasis and has the ability to destroy cell monolayers of the vaginal mucosa in vitro. Sphingomyelinases (SMase) are enzymes that catalyze the hydrolysis of sphingomyelin into ceramide and phosphorylcholine. Ceramide appears to be a second messenger lipid in programmed apoptosis, cell differentiation, and cell proliferation. Sphingomyelinase is probably a major source of ceramide in cells. Signal transduction mediated by ceramide leads cells to produce cytokine induced apoptosis during several inflammatory responses. SMase are also relevant toxins in several microorganisms. The main objective of this research is to identify SMase activity of T. vaginalis in the total extract (TE), P30, and S30 subfractions from brooked trophozoites. It was found that these fractions of T. vaginalis have SMase activity, which comes principally from P30 subfraction and was mainly type C. Enzymatic activity of SMase increased linearly with time and is pH dependent with two peaks by pH 5.5 and pH 7.5. The addition of manganese to the reaction mixture increased the SMase activity by 1.97.