Effect of Trichomonacide 6-Nitro-1H-benzimidazole Derivative Compounds on Expression Level of Metabolic Genes in Trichomonas vaginalis.

The parasite Trichomonas vaginalis is the etiologic agent of trichomoniasis, the most common non-viral sexually transmitted disease worldwide. This infection often remains asymptomatic and is related to several health complications. The traditional treatment for trichomoniasis is the use of drugs of the 5-nitroimidazole family, such as metronidazole; however, scientific reports indicate an increasing number of drug-resistant strains. Benzimidazole derivatives could offer an alternative in the search for new anti-trichomonas drugs. In this sense, two attractive candidates are the compounds O2N-BZM7 and O2N-BZM9 (1H-benzimidazole derivatives), since, through in vitro tests, they have shown a higher trichomonacide activity. In this study, we determined the effect on the expression level of metabolic genes in T. vaginalis. The results show that genes involved in redox balance (NADHOX, G6PD::6PGL) are overexpressed, as well as the gene that participates in the first reaction of glycolysis (CK); on the other hand, structural genes such as ACT and TUB are decreased in expression in trophozoites treated with the compound O2N-BZM9, which would probably affect its morphology, motility and virulence. These results align with the trichomonacidal activity of the compounds, with benzimidazole O2N-BZM9 being the most potent, with an IC50 value of 4.8 µM. These results are promising for potential future therapeutic applications.

In vitro anti-Trichomonas gallinae effects of Ziziphus vulgaris L. and Camellia sinensis (L.) Kuntze extracts.

BACKGROUND: Trichomonas gallinae is a parasite that causes canker and severe loss and death, especially in young pigeons. Metronidazole (MTZ) is the recommended drug for treating avian trichomoniasis. Due to drug resistance, non-chemical alternatives, such as medicinal plant extracts, are also considered possible therapies for this disease. OBJECTIVES: This study compares the antitrichomonal effects of MTZ with extracts of Camellia sinensis and Ziziphus vulgaris on T. gallinae in vitro. METHODS: Samples of T. gallinae were taken from infected pigeons. Multi-well plates with different concentrations (5, 10, 25, 50 and 100 µg/mL) of plant extracts were used for the in vitro study. RESULTS: The minimum inhibitory concentration (MIC) of C. sinensis extract was 25 µg/mL over 24 h, compared to 50 µg/mL for MTZ. The MIC value of the Z. vulgaris extracts was 50 µg/mL. CONCLUSIONS: The results suggest that the extracts of Z. vulgaris and C. sinensis, as potential natural agents, could have anti-avian trichomoniasis properties. This study also shows that MTZ, C. sinensis and Z. vulgaris are equally effective in preventing the growth of T. gallinae trophozoites in the culture.

Supplementation of exogenous bile acids improve antitrichomonal activity and enhance intestinal health in pigeon (Columba livia).

The study investigated the effects of supplementation of bile acids in drinking water on antitrichomonal activity, growth performance, immunity and microbial composition of pigeon. A total of 180 pairs of White King parent pigeons were randomly assigned to 5 treatments of 6 replications with 6 pairs of parent pigeons and 12 squabs in each replicate. The control (CON) group drank water without any additions. The metronidazole (MTZ) group drank water with 500 µg/mL metronidazole for 7 d and without any additions in other days. The else groups drank water with 500, 750, and 1,250 µg/mL bile acid (BAL, BAM, BAH) for 28 d. The results showed that Trichomonas gallinae (T. gallinae) in MTZ, BAL, BAM, and BAH groups were lower than that in CON group at 14, 21, and 28 d of parent pigeons (P < 0.05) and at 21 and 28 d of squabs (P < 0.05). Albumin and alanine transaminase in CON group were higher than those in MTZ, BAL, and BAH groups (P < 0.05). The levels of soluble CD8 were higher in MTZ and BAH groups compared with CON group (P < 0.05). The lesions in oral mucosa, thymus, liver, and spleen tissues of CON group could be observed. Abundance-based coverage estimator (ACE) index in BAH group was higher than that in CON and MTZ groups. Simpson index in CON and BAH groups was higher than MTZ group (P < 0.05). Lactobacillus was the highest colonized colonic bacteria in genera that were 77.21, 91.20, and 73.19% in CON, MTZ, and BAH, respectively. In conclusion, drinking water supplemented with 500, 750, and 1,250 µg/mL bile acid could inhibit growth of T. gallinae in both parent pigeons and squabs. Squabs infected with T. gallinae in control group had higher mortality rate and more serious tissue lesions. Squabs in bile acids treated group had more sCD8 in serum and abundant intestinal morphology. Bile acids could be an efficient drinking supplements to inhibit T. gallinae and improve pigeon adaptive immunity and intestinal health.

Antitrichomonal activity of nanoemulsion of carvacrol on Trichomonas galline: formulation development and in vitro characterization.

In recent years, increasing attention has been paid in veterinary medicine to find novel natural resources to reduce the use of synthetic drugs, avoid side effects, and for better compliance of the animals' owners. Metronidazole has been used for many years in the treatment of birds' trichomonosis. Carvacrol is a terpenoid and several biologic activities was attributed to it. The present study developed and characterized a carvacrol nanoemulsion (NanoCAV) and investigated its antitrichomonal activity on Trichomonas gallinae, the causative agent of pigeon trichomonosis, under in vitro condition and compared it with carvacrol (CAV) and the standard antitrichomonal dug, metronidazole (MTZ). Additionally, cytotoxicity of the developed formulation to the fibroblast cell line was evaluated. The NanoCAV mean size and surface charge were 80.5 nm and -31.2 mv, respectively. No significant cytotoxicity was observed for the NanoCAV. Incorporation efficiency of NanoCAV was measured as 75%. Results of antitrichomonal activity assay showed 12 h fifty percent lethal concentrations of 0.39 and 0.27 µg/ml for CAV and NanoCAV, respectively. The NanoCAV based on in vitro activity and low cytotoxicity, can be further studied for its efficacy and safety profile in the pigeons.

Antimicrobial properties of tomato leaves, stems, and fruit and their relationship to chemical composition.

BACKGROUND: We previously reported that the tomato glycoalkaloid tomatine inhibited the growth of Trichomonas vaginalis strain G3, Tritrichomonas foetus strain D1, and Tritrichomonas foetus-like strain C1 that cause disease in humans and farm and domesticated animals. The increasing prevalence of antibiotic resistance requires development of new tools to enhance or replace medicinal antibiotics. METHODS: Wild tomato plants were harvested and divided into leaves, stems, and fruit of different colors: green, yellow, and red. Samples were freeze dried and ground with a handheld mill. The resulting powders were evaluated for their potential anti-microbial effects on protozoan parasites, bacteria, and fungi. A concentration of 0.02% (w/v) was used for the inhibition of protozoan parasites. A high concentration of 10% (w/v) solution was tested for bacteria and fungi as an initial screen to evaluate potential anti-microbial activity and results using this high concentration limits its clinical relevance. RESULTS: Natural powders derived from various parts of tomato plants were all effective in inhibiting the growth of the three trichomonads to varying degrees. Test samples from leaves, stems, and immature 'green' tomato peels and fruit, all containing tomatine, were more effective as an inhibitor of the D1 strain than those prepared from yellow and red tomato peels which lack tomatine. Chlorogenic acid and quercetin glycosides were present in all parts of the plant and fruit, while caffeic acid was only found in the fruit peels. Any correlation between plant components and inhibition of the G3 and C1 strains was not apparent, although all the powders were variably effective. Tomato leaf was the most effective powder in all strains, and was also the highest in tomatine. S. enterica showed a minor susceptibility while B. cereus and C. albicans fungi both showed a significant growth inhibition with some of the test powders. The powders inhibited growth of the pathogens without affecting beneficial lactobacilli found in the normal flora of the vagina. CONCLUSIONS: The results suggest that powders prepared from tomato leaves, stems, and green tomato peels and to a lesser extent from peels from yellow and red tomatoes offer potential multiple health benefits against infections caused by pathogenic protozoa, bacteria, and fungi, without affecting beneficial lactobacilli that also reside in the normal flora of the vagina.

Distribution of genotypes in relation to metronidazole susceptibility patterns in Trichomonas vaginalis isolated from South African pregnant women.

Reports on metronidazole resistance of Trichomonas vaginalis strains have been on the increase. This study investigated the in vitro metronidazole resistance patterns in T. vaginalis isolates obtained from South African pregnant women and the genotypes of these isolates. This study included 362 pregnant women recruited from a hospital in Durban, South Africa. The women provided self-collected vaginal swabs for the detection of T. vaginalis by culture in Diamonds media. Cultured isolates were then subjected to anaerobic susceptibility assays to metronidazole. For the genotyping assays, the actin gene was digested by HindII, MseI, and RsaI. The banding patterns obtained after digestion was used to determine the genotypes. A total of 21/362 (5.8%) pregnant women tested positive for T. vaginalis infection. Of the 21 T. vaginalis isolates tested for metronidazole susceptibility, 9.5% (2/21) had a minimum inhibitory concentration (MIC) of 4 µg/ml (resistant), 38.1% (8/21) had a MIC of 2 µg/ml (intermediate), and 52.4% (11/21) had a MIC ≤ 1 µg/ml (susceptible). The dominant genotype that was identified across the isolates was genotype G. There was no correlation between genotype harboured and metronidazole susceptibility patterns. In this study, resistance to metronidazole was observed in clinical isolates of T. vaginalis. This study did not find a correlation between genotype harboured and metronidazole susceptibility patterns. Despite the lack of association, our study provides data on an area of research that is currently lacking in our setting.

Antitrichomonal activity and docking analysis of thiazole derivatives as TvMP50 protease inhibitors.

Trichomoniasis, caused by the protozoan Trichomonas vaginalis, is the most prevalent non-viral sexually transmitted infection that affects over 170 million people worldwide. The only type of drug recommended for the therapeutic control of trichomoniasis is the 5-nitroimidazoles, although there have been reports of some undesirable side effects and clinical resistance. Hence, the need for the search for new tricomonicidal agents is necessary. In a previous work, we demonstrated that two 2-amino-4-aryl thiazole derivatives (ATZ-1 and ATZ-2) possess a portent antigiardial effect. In the current paper, we investigated the in vitro antitrichomonal activity of these thiazole compounds. Both ATZ-1 and ATZ-2 reduced the viability and growth of parasites in a dose-dependent manner, with an IC50 value of 0.15 µg/mL and 0.18 µg/mL, respectively. Furthermore, both thiazole compounds were able to decrease the proteolytic activity in T. vaginalis trophozoites compared with untreated parasites. Interestingly, a full proteolytic inhibition profile was observed in the 50-kDa region which was associated with the decreased expression of the gene that codes for the trichomonad protease TvMP50. The docking simulations predicted strong interactions of the thiazole compounds in the TvMP50 protease's active site, suggesting a possible role as protease inhibitors. Our results demonstrate the potential of 2-amino-4-aryl thiazole derivatives as trichomonicidal compounds and could be, mechanistically, involved in the inhibition of key trichomonad proteases.

Successful treatment of trichomoniasis with tinidazole following desensitization in a patient allergic to metronidazole.

Metronidazole desensitization is recommended in patients with trichomoniasis and history of an allergic reaction to metronidazole due to presumed cross reactivity with tinidazole and lack of reliably safe and effective alternative therapies. We report our experiences in a patient with persistent trichomoniasis who failed to complete metronidazole desensitization due to a burning sensation over her whole body and pruritus but was later successfully desensitized to tinidazole without experiencing any adverse effects.

Biological activities of essential oil extracted from leaves of Atalantia sessiflora Guillauminin Vietnam.

INTRODUCTION: The present study aimed to determine the chemical compositions and bioactivities of the essential oil of Atalantia sessiflora Guillaumin (A. sessiflora), including antibacterial, antimycotic, antitrichomonas, anti-inflammatory and antiviral effects. METHODOLOGY: The essential oil from leaves of A. sessiflora was extracted by hydrodistillation using a Clevenger apparatus. Chemical compositions of oil were identified by GC/MS. Antimicrobial and antitrichomonas activity were determined by the microdilution method; anti-inflammatory and antiviral were determined by the MTT method. RESULTS: The average yield of oil was 0.46 ± 0.01% (v/w, dry leaves). A number of 45 constituents were identified by GC/MS. The essential oil comprised four main components. The oil showed antimicrobial activities against Gram-positive strains as Staphylococcus; Gram-negative bacteria such as Klebsiella pneumoniae and Escherichia coli; and finally four Candida species. Enterococcus faecalis and Pseudomonas aeruginosa were least susceptible to the oil of A. sessiflora, as seen in their MIC and MLC values over 16% (v/v). Activity against Trichomonas vaginalis was also undertaken, showing IC50, IC90 and MLC values of 0.016, 0.03 and 0.06% (v/v) respectively, after 48 hours of incubation. The oil of A. sessiflora displayed activity against the nitric oxide generation with the IC50 of 95.94 ± 6.18 µg/mL. The oil was completely ineffective against tested viruses, ssRNA+, ssRNA-, dsRNA, and dsDNA viruses. CONCLUSIONS: This is the first yet comprehensive scientific report about the chemical compositions and pharmacological properties of the essential oil of A. sessiflora. Further studies should be done to evaluate the safety and toxicity of A. sessiflora oil.

Repurposing the open access malaria box reveals compounds with activity against Tritrichomonas foetus trophozoites.

The protozoan parasite Tritrichomonas foetus causes early embryonic death in cattle which results in severe economic loss. In the United States, there are no drugs are approved for treatment of this pathogen. In this study, we evaluated in vitro anti-protozoal effects of compounds from an open access chemical library against T. foetus trophozoites. An initial high-throughput screen identified 16 compounds of interest. Further investigation revealed 12 compounds that inhibited parasite growth and 4 compounds with lethal effects. For lethal compounds, dose-response curves were constructed and the LD50 was calculated for laboratory and field strains of T. foetus. Our experiments revealed chemical scaffolds that were parasiticidal in the micromolar range, and these scaffolds provide a starting point for drug discovery efforts. Further investigation is still needed to investigate suitability of these scaffolds and related compounds in food animals. Importantly, open access chemical libraries can be useful for identifying compounds with activity against protozoan pathogens of veterinary importance.

20S Proteasome as a Drug Target in Trichomonas vaginalis.

Trichomoniasis is a sexually transmitted disease with hundreds of millions of annual cases worldwide. Approved treatment options are limited to two related nitro-heterocyclic compounds, yet resistance to these drugs is an increasing concern. New antimicrobials against the causative agent, Trichomonas vaginalis, are urgently needed. We show here that clinically approved anticancer drugs that inhibit the proteasome, a large protease complex with a critical role in degrading intracellular proteins in eukaryotes, have submicromolar activity against the parasite in vitro and on-target activity against the enriched T. vaginalis proteasome in cell-free assays. Proteomic analysis confirmed that the parasite has all seven α and seven ß subunits of the eukaryotic proteasome although they have only modest sequence identities, ranging from 28 to 52%, relative to the respective human proteasome subunits. A screen of proteasome inhibitors derived from a marine natural product, carmaphycin, revealed one derivative, carmaphycin-17, with greater activity against T. vaginalis than the reference drug metronidazole, the ability to overcome metronidazole resistance, and reduced human cytotoxicity compared to that of the anticancer proteasome inhibitors. The increased selectivity of carmaphycin-17 for T. vaginalis was related to its >5-fold greater potency against the ß1 and ß5 catalytic subunits of the T. vaginalis proteasome than against the human proteasome subunits. In a murine model of vaginal trichomonad infection, proteasome inhibitors eliminated or significantly reduced parasite burden upon topical treatment without any apparent adverse effects. Together, these findings validate the proteasome of T. vaginalis as a therapeutic target for development of a novel class of trichomonacidal agents.

Controlled delivery of the antiprotozoal agent (tinidazole) from intravaginal polymer matrices for treatment of the sexually transmitted infection, trichomoniasis.

Microporous polymeric matrices prepared from poly(ɛ-caprolactone) [PCL] were evaluated for controlled vaginal delivery of the antiprotozoal agent (tinidazole) in the treatment of the sexually transmitted infection, trichomoniasis. The matrices were produced by rapidly cooling co-solutions of PCL and tinidazole in acetone to -80 °C to induce crystallisation and hardening of the polymer. Tinidazole incorporation in the matrices increased from 1.4 to 3.9% (w/w), when the drug concentration in the starting PCL solution was raised from 10 to 20% (w/w), giving rise to drug loading efficiencies up to 20%. Rapid 'burst release' of 30% of the tinidazole content was recorded over 24 h when the PCL matrices were immersed in simulated vaginal fluid. Gradual drug release occurred over the next 6 days resulting in delivery of around 50% of the tinidazole load by day 7 with the released drug retaining antiprotozoal activity at levels almost 50% that of the 'non-formulated' drug in solution form. Basic modelling predicted that the concentration of tinidazole released into vaginal fluid in vivo from a PCL matrix in the form of an intravaginal ring would exceed the minimum inhibitory concentration against Trichomonas vaginalis. These findings recommend further investigation of PCL matrices as intravaginal devices for controlled delivery of antiprotozoal agents in the treatment and prevention of sexually transmitted infections.

Trichomonicidal activity of a new anthraquinone isolated from the roots of Morinda panamensis Seem.

Trichomoniasis, caused by the protozoan parasite Trichomonas vaginalis, is the most common nonviral sexually transmitted infection worldwide. Although drug treatment is available, unpleasant side effects and increased resistance to the nitroimidazole family have been documented. Hence, there is a need for the identification of new and safe therapeutic agents against T. vaginalis. Antimicrobial activity of anthraquinone compounds has been reported by a number of authors. The genus Morinda is well known for the diversity of anthraquinones with numerous biological activities. A new anthraquinone, lucidin-ω-isopropyl ether, was isolated from the roots of Morinda panamensis Seem. The structure of the compound was determined by 1 H and 13 C Nuclear Magnetic Resonance (NMR) analyses, in addition to comparison with literature reports. Using in vitro susceptibility assay, the half inhibitory concentration (IC50 ) of lucidin-ω-isopropyl ether for T. vaginalis (1.32 µg/mL) was found similar to that of metronidazole concentration tested (6 µM = 1.03 µg/mL). In addition, this anthraquinone was capable of inhibiting the parasite's ability to kill HeLa cells and decreased proteolytic activity of the proteinase TvMP50 from T. vaginalis. This was associated with the decreased expression of the mp50 gene. These results demonstrate the trichomonicidal potential by lucidin-ω-isopropyl ether. Further action-mode studies are necessary to elucidate the antiparasitic mechanism of this new anthraquinone to develop a more potent antitrichomonal agent.

Homopiperazine Derived Female Controlled Vaginal Trichomonacidal Contraceptive: An Addition to Structure-Activity Relationship.

BACKGROUND: In our previous work, several piperazine derived bis(dialkylaminethiocarbonyl) disulfides and disulfide esters of dithiocarbamic acid have been synthesized and evaluated for their spermicidal and microbicidal efficacy. These studies have provided some promising compounds for developing a dually active vaginal microbicidal contraceptive which is under pre-clinical stage. OBJECTIVE: The main objective of this study was the design synthesis and biological evaluation of bis(dialkylaminethiocarbonyl) disulfides (4-15) and 2,2'-disulfanediylbis (3-(substituted-1-yl) propane-2,1-diyl) disubstituted-1-carbodithioates (19-28) as non-surfactant molecules capable of eliminating Trichomonas vaginalis as well as irreversibly immobilizing 100% human sperm promptly. METHOD: Spermicidal, anti-trichomonas, cytotoxicity and biocompatibility study of the synthesized compounds was done as per the reported methodologies. RESULT: Among bis(dialkylaminethiocarbonyl) disulfides (4-15, Table 1), compound 4 (MEC 0.02 mM) was found to be the most desirable for spermicidal activity as it was 40 times more active than Nonoxynol-9 (N-9), and also active against Trichomonas vaginalis (MIC 0.02 &1.10 mM). 2, 2'-disulfanediylbis (3-(substituted- 1-yl) propane-2, 1-diyl) disubstituted-1-carbodithioates (19-28, Table 2), and compounds (19, 22, 23, and 24 MEC 0.05 mM) were sixteen times more active than N-9 with promising Trichomonacidal activity. CONCLUSION: This study suggested that the disulfide linkage alone and dithiocarbamate along with disulfide group within the same chemical entity impart the desired multiple activities of compounds.

Anti-Trichomonas vaginalis activity of ursolic acid derivative: a promising alternative.

Trichomonas vaginalis is an extracellular parasite that binds to the epithelium of the human urogenital tract and causes the sexually transmitted infection, trichomoniasis. In view of increased resistance to drugs belonging to the 5-nitroimidazole class, new treatment alternatives are urgently needed. In this study, eight semisynthetized triterpene derivatives were evaluated for in vitro anti-T. vaginalis activity. Ursolic acid and its derivative, 3-oxime-urs-12-en-28-oic-ursolic acid (9), presented the best anti-T. vaginalis activity when compared to other derivatives, with minimum inhibitory concentration (MIC) at 25 µM. Moreover, 9 was active against several T. vaginalis fresh clinical isolates. Hemolysis assay demonstrated that 9 presented a low hemolytic effect. Importantly, 25 µM 9 was not cytotoxic against the Vero cell lineage. Finally, we demonstrated that compound 9 acts synergistically with metronidazole against a T. vaginalis metronidazole-resistant isolate. This report reveals the high potential of the triterpenoid derivative 9 as trichomonicidal agent.

Antitrichomonal activity of δ opioid receptor antagonists, 7-benzylidenenaltrexone derivatives.

The 7-benzylidenenaltrexone (BNTX) derivatives 2a-v, 3a-c, 13a-c, and 14a were synthesized from naltrexone (1) and evaluated for their antitrichomonal activity. The structure-activity-relationship studies found that 4-iodo-BNTX (2g) showed the highest activity (IC50=10.5µM) and the affinity for the opioid receptor was less important for antitrichomonal activity against Trichomonas vaginalis. The morphinan skeleton bearing both the double bond for a Michael acceptor and the phenolic hydroxy group would be a specific template for development of antitrichomonal agents. In addition, the mechanism of the antitrichomonal activity of the BNTX derivatives may differ from that of the standard drug, metronidazole.

Antitrichomonal activity of Peganum harmala alkaloid extract against trichomoniasis in pigeon (Columba livia domestica).

1. This study was designed to evaluate the antitrichomonal effects of P. harmala alkaloid extract against T. gallinae, both in vitro and in vivo, as well as comparing it to that of metronidazole, conventional antitrichomonal medication and harmine and harmaline, the two alkaloids present in P. harmala. 2. T. gallinae were collected by the wet mount method from infected free-living pigeons. The in vitro assay was performed using multi-well plates containing test compounds in final concentrations of 5, 10, 15, 20, 30, 50 or 100 µg/ml. The in vivo assay was done on 60 experimentally infected pigeons dosed with metronidazole at 50 mg/kg body weight (BW) or alkaloids at 25 mg/kg BW. 3. The 24 h minimum inhibitory concentration (MIC) of alkaloid extract was 15 µg/ml while that of metronidazole was 50 µg/ml. Harmine and harmaline revealed 24 h MIC of 30 and 100 µg/ml, respectively. Treatment of infected pigeons with alkaloids led to a full recovery after 3 d but with metronidazole total eradication of trophozoites was not achieved. 4. In conclusion, data of the present study suggested P. harmala is a potent natural anti-trichomonal agent, effective against T. gallinae.

The Caatinga endemic Manilkara rufula possesses remarkable activity against Trichomonas vaginalis and Tritrichomonas foetus.

Tritrichomonas foetus infects the bovine urogenital tract, causing bovine trichomoniasis. Significant economic losses may occur due to infertility and abortion among cattle. Trichomonas vaginalis is the causative agent of trichomoniasis; the most common but overlooked non-viral sexually transmitted disease worldwide. Human and bovine trichomoniasis present treatment restrictions and efforts to identify new alternatives are essential. The present study evaluated the anti-trichomonads activities of seven fractions from northwest endemic plant Manilkara rufula. Flavonoids and condensed tannins were identified from these fractions by LC-DAD-MS/MS and MALDI-MS/MS. Altogether, the results demonstrated for the first time the structural description of tannins from leaves of M. rufula and the relation of these compounds with anti-T. vaginalis and anti-T. foetus activities. Overall, this report reveals the potential of M. rufula fractions against both parasites and shows new alternatives to treat the infection caused by trichomonads.

Bioisosteric ferrocenyl-containing quinolines with antiplasmodial and antitrichomonal properties.

Bioisosteric ferrocenyl-containing quinolines and ferrocenylamines containing organosilanes and their carbon analogues, were prepared and fully characterised. The molecular structures of two ferrocenyl-containing quinolines, determined using single-crystal X-ray diffraction, revealed that the compounds crystallise in a folded conformation. The compounds were screened for their antiplasmodial activity against the chloroquine-sensitive (NF54) and CQ-resistant (Dd2) strains of P. falciparum, as well as for their cytotoxicity against Chinese Hamster Ovarian (CHO) cells. The ferrocenyl-containing quinolines displayed activities in the low nanomolar range (6-36 nM), and showed selectivity towards parasites. ß-Haematin inhibition assays suggest that the compounds may in part act via the inhibition of haemozoin formation, while microsomal metabolic stability studies reveal that the ferrocenyl-containing quinolines are rapidly metabolised in liver microsomes. Further, antitrichomonal screening against the metronidazole-sensitive (G3) strain of the mucosal pathogen T. vaginalis revealed that the quinoline-based compounds displayed superior parasite growth inhibition when compared to the ferrocenylamines. The library was also tested E. coli and on Lactobacilli spp. found as part of the normal flora of the human microbiome and no effect on growth in vitro was observed, supporting the observation that these compounds are specific for eukaryotic pathogens.