In Northeastern Brazil visceral leishmaniasis is endemic with lethal cases among humans and dogs. Treatment is toxic and 5–10% of humans die despite treatment. The aim of this work was to survey natural active compounds to find new molecules with high activity and low toxicity against Leishmania infantum chagasi. The compounds thymol and eugenol were chosen to be starting compounds to synthesize acetyl and benzoyl derivatives and to test their antileishmanial activity in vitro and in vivo against L. i. chagasi. A screening assay using luciferase-expressing promastigotes was used to measure the growth inhibition of promastigotes, and an ELISA in situ was performed to evaluate the growth inhibition of amastigote. For the in vivo assay, thymol and eugenol derivatives were given IP to BALB/c mice at 100 mg/kg/day for 30 days. The thymol derivatives demonstrated the greater activity than the eugenol derivatives, and benzoyl- thymol was the best inhibitor (8.67 ± 0.28 μg/mL). All compounds demonstrated similar activity against amastigotes, and acetyl-thymol was more active than thymol and the positive control drug amphotericin B. Immunohistochemistry demonstrated the presence of Leishmania amastigote only in the spleen but not the liver of mice treated with acetyl-thymol. Thus, these synthesized derivatives demonstrated anti-leishmanial activity both in vitro and in vivo. These may constitute useful compounds to generate new agents for treatment of leishmaniasis.

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RESUMO.-O objetivo do trabalho foi analisar os dados relacionados à transmissão da leishmaniose visceral (LV), no município de Fortaleza, e discutir a respeito da distribuição do vetor, reservatório doméstico e casos humanos ocorridos no The objective was to analyze the data relating to the transmission of visceral leishmaniasis (LV) in Fortaleza municipality, and discuss about the vector distribution, domestic reservoir and human cases from 2009 to 2013.This study is descriptive conducted through a survey of secondary data. The correlation between human and canine cases and sandflies number was taken by Spearman correlation test, with 5% significance level. In the period 2009 to 2013, 941 cases and 55 deaths were confirmed. The mortality rate for the period was 5.84%. There was a higher proportion of cases among men in all the years analyzed. The age group 1-4 years old had the highest percentage of cases, highlighting the year 2010 with 31.5% of the cases. The average distribution of cases by SER demonstrated a predominance in SER I, V and VI. With regard to the vector species found in greater abundance was Lutzomyia (Lutzomyia) longipalpis, followed by Lutzomyia (Lutzomyia) migonei and Lutzomyia (Lutzomyia) lenti. According to the records, 39,626 dogs were serum reagents for LV in the years 2009-2013, these 14,313 were killed. The year 2013 stood out with 17,808 dogs serum reagents, and 1,273 of SER III, 2572 of SER V and 1909 of SER VI. There was no significant correlation between the number of sand flies and the number of canine VL cases (p>0.05). There was a negative correlation between human and canine cases (r = -0.0388) and correlation was observed between human cases and number of sand flies (r= 0.7469). Our findings create prospects for the identification of other factors that may influence the incidence of human and canine cases, such as the participation of other possible reservoirs and vectors in the transmission of the visceral leishmaniasis in Fortaleza.

In recent years, the Brazilian Health Ministry and the World Health Organization have supported research into new technologies that may contribute to the surveillance, new treatments, and control of visceral leishmaniasis within the country. In light of this, the aim of this study was to isolate compounds from plants of the Caatinga biome, and to investigate their toxicity against promastigote and amastigote forms of Leishmania infantum chagasi, the main responsible parasite for South American visceral leishmaniasis, and evaluate their ability to inhibit acetylcholinesterase enzyme (AChE). A screen assay using luciferase-expressing promastigote form and an in situ ELISA assay were used to measure the viability of promastigote and amastigote forms, respectively, after exposure to these substances. The MTT colorimetric assay was performed to determine the toxicity of these compounds in murine monocytic RAW 264.7 cell line. All compounds were tested in vitro for their anti-cholinesterase properties. A coumarin, scoparone, was isolated from Platymiscium floribundum stems, and the flavonoids rutin and quercetin were isolated from Dimorphandra gardneriana beans. These compounds were purified using silica gel column chromatography, eluted with organic solvents in mixtures of increasing polarity, and identified by spectral analysis. In the leishmanicidal assays, the compounds showed dose-dependent efficacy against the extracellular promastigote forms, with an EC50 for scoporone of 21.4µg/mL, quercetin and rutin 26 and 30.3µg/mL, respectively. The flavonoids presented comparable results to the positive control drug, amphotericin B, against the amastigote forms with EC50 for quercetin and rutin of 10.6 and 43.3µg/mL, respectively. All compounds inhibited AChE with inhibition zones varying from 0.8 to 0.6, indicating a possible mechanism of action for leishmacicidal activity.