Anti-protozoal activity of diamine derivatives

Recent Advances in the Development of Broad-Spectrum Antiprotozoal Agents

Infections caused by Trypanosoma brucei, Trypanosoma cruzi, Leishmania spp., Entamoeba histolytica, Giardia lamblia, Plasmodium spp., and Trichomonas vaginalis, are part of a large list of human parasitic diseases. Together, they cause more than 500 million infections per year. These protozoa parasites affect both low- and high-income countries and their pharmacological treatments are limited. Therefore, new and more effective drugs in preclinical development could improve overall therapy for parasitic infections even when their mechanisms of action are unknown. In this review, a number of heterocyclic compounds (diamidine, guanidine, quinoline, benzimidazole, thiazole, diazanaphthalene, and their derivatives) reported as antiprotozoal agents are discussed as options for developing new pharmacological treatments for parasitic diseases.

Recent developments in anti-Trichomonas research: An update review

Trichomonas vaginalis is a major non-viral sexually-transmitted infection resulted into serious obstetrical and gynecological troubles. The increasing resistance to nitroimidazole therapy and recurrence makes it crucial to develop new drugs against trichomoniasis. Over the past few years, a large number of research articles highlighting the synthetic and natural product research to combat Trichomonas vaginalis have been published. Electronic databases were searched to collect all data from the year 2006 through June 2017 for anti-Trichomonas activity potential of synthetic and natural products. This review article put together the synthetic and natural product research to find out an effective metronidazole alternative to cure trichomoniasis.

In vitro and in vivo evaluation of 2-aminoalkanol and 1,2-alkanediamine derivatives against Strongyloides venezuelensis

Background

Strongyloidiasis is a parasitic disease widely present in tropical and subtropical areas. Strongyloides stercoralis represents the main species that infects human beings. Ivermectin is the current drug of choice; however, issues related with treatment failure in patients with diabetes or infected with T-lymphotropic virus-1 make the identification of new molecules for alternative treatment a priority. In the present study, the activity of sphingosine-related aminoalcohol and diamine were evaluated against Strongyloides venezuelensis third-stage larva (L3) cultures and experimental infections in mice.

Methods

The efficacy of each compound against L3 was assessed using both XTT (2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide) assay and microscopic observation with concentrations ranging from 1 to 350 μM. Cytotoxicity was evaluated using J774.2 macrophage cell line and XTT assay. Lethal concentration 50 (LC₅₀), selectivity index (SI) and structure-activity relationships were established. The activity compounds 4 (2-(ethylamino) hexadecan-1-ol), 6 (2-(butylamino) hexadecan-1-ol), 17 (tert-butyl N-(1-aminododecan-2-yl) carbamate) and 18 (tert-butyl N-(1-aminohexadecan-2-yl) carbamate) were further assessed against experimental S. venezuelensis infections in CD1 mice measuring reductions in the numbers of parthenogenetic females and egg passed in faeces. Mice were infected with 3,000 L3 and treated with 20 mg/kg/day for five days.

Results

In the screening study of 15 aminoalcohols [lauryl (n = 9); palmityl (n = 13); stearyl (n = 15) and alcohol derivatives], the presence of a palmitol chain was associated with the highest efficacy against L3 (LC₅₀ 31.9–39.1 μM). Alkylation of the 2-amino group with medium size fragments as ethyl or n-butyl showed the best larvicidal activity. The dialkylation did not improve efficacy. Aminoalcohols 4 and 6 showed the highest SI (1.5 and 1.6, respectively). With respect to diamine derivative compounds, a chain size of sixteen carbon atoms (palmitoyl chain, n = 13), and the alkylation of the 2-amino group with medium-sized fragments, were associated with the highest lethal activities. The presence of carbamoyl group in diamines 17 and 18 yielded high SI (1.7 and 1.4, respectively). Infected mice treated with aminoalcohol 6 showed reduction in parthenogenetic females (59 %) and eggs in faeces (51 %).

Conclusions

These results support the potentiality of aminoalcohol and diamine sphingosine-related compounds as suitable prototypes for developing new promising drugs against strongyloidiasis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1648-5) contains supplementary material, which is available to authorized users.

Natural and synthetic compound anti-Trichomonas vaginalis: an update review

Trichomonas vaginalis is a flagellate protozoan that causes trichomonosis, a sexually transmitted disease of worldwide importance. However, the infection has long received much less attention than other parasitic and sexually transmitted diseases. This negligence leads to poor diagnosis and underestimated prevalence values, and consequently, it has been associated to increasing acquisition and transmission of HIV, pregnancy outcomes, infertility, pelvic inflammatory disease, and cervical and prostate cancer. In view of increased resistance to drugs belonging to the nitroimidazole class, new treatment alternatives are urgently needed. Natural products provide an immeasurable wealth of active molecules, and a great number of new drugs have been originated from these compounds. In addition, new synthetic products or derivatives from old drugs also provide an alternative to treat trichomonosis. Albeit many studies have been performed with natural products against T. vaginalis, none of them progressed to clinical trials. Overall, inadequate financial investments are made, and no alternative treatment for trichomonosis has been discovered; meanwhile, hundreds of thousands of people will remain infected and suffering the serious consequences of this nonviral STD. Thus, it is highlighted that clinical trials for better understanding the potential in vitro are necessary and urgent in order to furnish a new therapeutic alternative for trichomonosis treatment. The current review attempts to give an overview on the potential of natural and synthetic products as antitrichomonal.

Anthelmintic effects of alkylated diamines and amino alcohols against Schistosoma mansoni

Polyamines are substances involved in many aspects of cell growth, division, and differentiation. Because of the metabolic differences between host cells and parasite cells, polyamine metabolism has been considered as a potential target for the chemotherapy of parasitic diseases. The aim of this work was to evaluate the schistosomicidal activity of different N-alkylated diamines (3a-3h), amino alcohols (4a-4d), and glycosylated amino alcohols (10a-10d). Compounds were prepared by synthetic methods and submitted to in vitro evaluation against adult worms of Schistosoma mansoni. At 100 μM, 3b, 3e, and 3h as well as 4a, 4b, 4d, 10a, 10b, and 10d resulted in 100% mortality of adult schistosomes. Compound 3d (12.5 to 100 μM) caused the death of 100% of both male and female adult schistosomes, while 3f (12.5 to 100 μM) resulted in 100% mortality of only male adult worms, whereas no mortality in female worms was observed. Compounds 3d and 3f were also able to reduce viability and decrease production of developed eggs in comparison with the negative control group. Diamines 3d and 3f may represent useful lead compounds for further optimization in order to develop new schistosomicidal agents.

In vitro leishmanicidal activity of N-dodecyl-1,2-ethanediamine

Polyamine biosynthesis and inhibition in parasites have been an attractive chemotherapeutic approach in the design of novel antiparasitic drugs. We study in this work the effect of N-dodecyl-1,2-ethylenediamine (NDDE) on the morphology and replication of Leishmania using macrophages cultured from the peritoneal exudate of mice infected in vitro with three species of Leishmania: Leishmania (Leishmania) amazonensis, Leishmania (Viannia) brasiliensis and Leishmania (Leishmania) chagasi. The results showed that NDDE inhibited Leishmania amastigotes multiplication into inflammatory peritoneal cells in concentrations which were not toxic to mammalian cells (0.5-1μg/mL). An intracellular disorganization of the promastigote forms was observed by transmission electron microscopy after 3 to 24h of treatment with 1μg/mL NDDE, suggesting that this compound affects the viability of the parasite by an autophagy pathway.