The in vitro activity of fatty diamines and amino alcohols against mixed amastigote and trypomastigote Trypanosoma cruzi forms

Novel diamides inspired by protein kinase inhibitors as anti-Trypanosoma cruzi agents: in vitro and in vivo evaluations

Background: Chagas disease is a life-threatening illness caused by Trypanosoma cruzi. The involvement of serine-/arginine-rich protein kinase in the T. cruzi life cycle is significant. Aims: To synthesize, characterize and evaluate the trypanocidal activity of diamides inspired by kinase inhibitor, SRPIN340. Material & Methods: Synthesis using a three-step process and characterization by infrared, nuclear magnetic resonance and high-resolution mass spectrometry were conducted. The selectivity index was obtained by the ratio of CC50/IC50 in two in vitro models. The most active compound, 3j, was evaluated using in vitro cytokine assays and assessing in vivo trypanocidal activity. Results: 3j activity in the macrophage J774 lineage showed an anti-inflammatory profile, and mice showed significantly reduced parasitemia and morbidity at low compound dosages. Conclusion: Novel diamide is active against T. cruzi in vitro and in vivo.

Evaluation of the anti-Trypanosoma cruzi activity in vitro and in vivo of silibinin and silibinin in association to benznidazole

Chagas disease (CD) is endemic in Latin America. Drugs available for its treatment are benznidazole (BZ)/nifurtimox (NF), both with low efficacy in the late infection and responsible for several side effects. Studies of new drugs for CD among natural products, and using drug combinations with BZ/NF are recommended. Silibinin (SLB) is a natural compound that inhibits the efflux pump (Pgp) of drugs in host cell membranes, causes death of trypanosomatids, has anti-inflammatory activity, and was never assayed against T. cruzi. Here, in vitro and in vivo activities of SLB, SLB+BZ, and BZ against T. cruzi Y strain were evaluated. Cytotoxicity of SLB in VERO cells by the MTT method revealed IC50 of 250.22 μM. The trypanocidal activity evaluated by resazurin method in epimastigotes showed that SLB 25 μM inhibited parasite growth. SLB IC50 and selectivity index (SI) for amastigote were 79.81 μM and 3.13, respectively. SLB100+BZ10 showed higher parasite inhibition (91.44%) than SLB or BZ. Swiss mice infected with Y strain were treated with SLB, SLB+BZ, and BZ. Parasitemia was evaluated daily and 90, 180, and 240 days after treatment in surviving animals by hemoculture, blood qPCR, and after euthanasia, by qPCR in heart tissue. SLB monotherapy was not able to control the parasitemia/mortality of the animals. Parasitological negativation of 85.7-100% was observed in the experimental groups treated with SLB+BZ. Although SLB had shown activity against T. cruzi in vitro, it was not active in mice. Thus, the results of the therapeutic effect observed with SLB+BZ may be interpreted as a result from BZ action.

The terpenic diamine GIB24 inhibits the growth of Trypanosoma cruzi epimastigotes and intracellular amastigotes, with proteomic analysis of drug-resistant epimastigotes

The effect of N-geranyl-ethane-1,2-diamine dihydochloride (GIB24), a synthetic diamine, was assayed against different developmental forms of the parasitic protozoan Trypanosoma cruzi (strain Dm28c). The compound was effective against culture epimastigote forms (IC₅₀/24h = 5.64 μM; SI = 16.4) and intracellular amastigotes (IC₅₀/24h = 12.89 μM; SI = 7.18), as detected by the MTT methodology and by cell counting, respectively. Incubation of epimastigotes for 6h with 6 μM GIB24 (IC₅₀/24h value) resulted in significant dissipation of the mitochondrial membrane potential, prior to permeabilization of the plasma membrane. Rounded epimastigotes with cell size reduction were observed by scanning electron microscopy. These morpho-physiological changes induced by GIB24 suggest an incidental death process. Treatment of infected Vero cells did not prevent the intracellular amastigotes from completing the intracellular cycle. However, there was a decrease in the number of released parasites, increasing the ratio amastigotes/trypomastigotes. Proteomic analysis of 15 μM GIB24 resistant epimastigotes indicated that the compound acts mainly on mitochondrial components involved in the Krebs cycle and in maintaining the oxidative homeostasis of the parasites. Our data suggest that GIB24 is active against the main morphological forms of T. cruzi.

In vitro antifungal activity of organic compounds derived from amino alcohols against onychomycosis

Onychomycosis is a fungal infection of the nail caused by high densities of filamentous fungi and yeasts. Treatment for this illness is long-term, and recurrences are frequently detected. This study evaluated in vitro antifungal activities of 12 organic compounds derived from amino alcohols against standard fungal strains, such as Trichophyton rubrum CCT 5507 URM 1666, Trichophyton mentagrophytes ATCC 11481, and Candida albicans ATCC 10231. The antifungal compounds were synthesized from p-hydroxybenzaldehyde (4a–4f) and p-hydroxybenzoic acid (9a–9f). Minimum inhibitory concentrations and minimum fungicidal concentrations were determined according to Clinical and Laboratory Standards Institute protocols M38-A2, M27-A3, and M27-S4. The amine series 4b–4e, mainly 4c and 4e compounds, were effective against filamentous fungi and yeast (MIC from 7.8 to 312 μg/mL). On the other hand, the amide series (9a–9f) did not present inhibitory effect against fungi, except amide 9c, which demonstrated activity only against C. albicans. This allowed us to infer that the presence of amine group and intermediate carbon number (8C–11C) in its aliphatic side chain seems to be important for antifungal activity. Although these compounds present cytotoxic activity on macrophages J774, our results suggest that these aromatic compounds might constitute potential as leader molecules in the development of more effective and less toxic analogs that could have considerable implications for future therapies of onychomycosis.

In vitro drug susceptibility of two strains of the wildlife trypanosome, Trypanosoma copemani: A comparison with Trypanosoma cruzi

Trypanosomes are blood protozoan parasites that are capable of producing illness in the vertebrate host. Within Australia, several native Trypanosoma species have been described infecting wildlife. However, only Trypanosoma copemani has been associated with pathological lesions in wildlife hosts and more recently has been associated with the drastic decline of the critically endangered woylie (Bettongia penicillata). The impact that some trypanosomes have on the health of the vertebrate host has led to the development of numerous drug compounds that could inhibit the growth or kill the parasite. This study investigated and compared the in vitro susceptibility of two strains of T. copemani (G1 and G2) and one strain of Trypanosoma cruzi (10R26) against drugs that are known to show trypanocidal activity (benznidazole, posaconazole, miltefosine and melarsoprol) and against four lead compounds, two fenarimols and two pyridine derivatives (EPL-BS1937, EPL-BS2391, EPL-BS0967, and EPL-BS1246), that have been developed primarily against T.cruzi. The in vitro cytotoxicity of all drugs against L6 rat myoblast cells was also assessed. Results showed that both strains of T. copemani were more susceptible to all drugs and lead compounds than T. cruzi, with all IC50 values in the low and sub-μM range for both species. Melarsoprol and miltefosine exhibited the highest drug activity against both T. copemani and T. cruzi, but they also showed the highest toxicity in L6 cells. Interestingly, both fenarimol and pyridine derivative compounds were more active against T. copemani and T. cruzi than the reference drugs benznidazole and posaconazole. T. copemani strains exhibited differences in susceptibility to all drugs demonstrating once again considerable differences in their biological behaviour.