Chemical composition, in vitro larvicidal and antileishmanial activities of the essential oil from Citrus reticulata Blanco fruit peel / Composição química, atividades larvicida e leishmanicida in vitro do óleo essencial da casca do fruto de Citrus reticulata Blanco

Numerous studies have investigated the chemical composition and biological activities of essential oils from different Citrus species fruit peel, leaves and flowers. This paper aims to investigate the chemical composition, larvicidal and antileishmanial activities of essential oil from Citrus reticulata fruit peel (CR-EO). CR-EO was obtained by hydrodistillation in a Clevenger-type apparatus and its chemical composition was analyzed by GC-MS and GC-FID. Limonene (85.7%), ɣ-terpinene (6.7%) and myrcene (2.1%) were identified as its major components. CR-EO showed high activity against promastigote forms of Leishmania amazonensis (IC50 = 8.23 µg/mL). CR-EO also exhibited high larvicidal activity against third instar Aedes aegypti larvae at a lethal concentration (LC50 = 58.35 µg/mL) and 100% mortality at 150 µg/mL. This study suggests, for the first time, the potential use of CR-EO against this important mosquito-borne viral disease caused by the genus Aedes.

Numerosos estudos têm investigado a composição química e as atividades biológicas de óleos essenciais extraídos de cascas dos frutos, folhas e flores de diferentes espécies de Citrus. Este trabalho tem como objetivo investigar a composição química e as atividades larvicida e leishmanicida in vitro do óleo essencial das cascas dos frutos de Citrus reticulata (CR-EO). CR-EO foi obtido pela técnica de extração em aparelho Clevenger e sua composição química foi determinada por CG-EM e CG-DIC. Limoneno (85,7%), ɣ-terpineno (6,7%) and mirceno (2,1%) foram identificados como os constituintes majoritários. CR-EO mostrou alta atividade contra as formas promastigota de Leishmania amazonensis (CI50 = 8,23 µg/mL). CR-EO também exibiu alta atividade larvicida contra as larvas do terceiro estágio do Aedes aegypti com concentração letal (CL50 = 58,35 µg/mL) e mortalidade de 100% em 150 µg/mL. Este estudo sugere, pela primeira vez, o uso potencial de CR-EO contra esta importante doença viral transmitida por mosquitos do gênero Aedes.

Metformin promotes susceptibility to experimental Leishmania braziliensis infection

BACKGROUND Metformin (MET) is a hypoglycemic drug used for the treatment of diabetes, despite interference in host immunity against microorganisms. Cutaneous infection caused by pathogens such as Leishmania braziliensis (Lb), the agent responsible for cutaneous leishmaniasis (CL) in Brazil, represents an interesting model in which to evaluate the effects associated with MET. OBJECTIVE To evaluate the modulatory effect of MET in Lb infection. MATERIAL AND METHODS Experimental study of Lb infection and MET treatment in BALB/c mice and Raw 264.7 macrophages. FINDINGS MET treatment interfered with lesion kinetics, increased parasite load and reduced macrophage proliferation. Low concentrations of MET in Lb culture allow for the maintenance of stationary parasite growth phase. Lb-infected cells treated with MET exhibited increased parasite load. While both MET and Lb infection alone promoted the production of intracellular reactive oxygen species (ROS), reduced levels of ROS were seen in MET-treated Lb-infected macrophages. MAIN CONCLUSION Experimental treatment with MET interfered with the kinetics of cutaneous ulceration, increased Lb parasite load, altered ROS production and modulated cellular proliferation. Our experimental results indicate that MET interfere with the evolution of CL.

In vivo antileishmanial activity of Annona mucosa extracts

Abstract INTRODUCTION: Leishmaniasis, a disease caused by a parasite endemic to large areas of tropical and subtropical countries, is a growing public health problem. METHODS: Male BALB/c mice were infected with Leishmania amazonensis and treated with extracts isolated from Annona mucosa. RESULTS: Treated groups had significantly reduced footpad swelling. The group treated intraperitoneally with hexane extract showed footpad swelling similar to groups treated with Pentamidine® and Glucantime®. Groups treated with dichloromethane extract and hexane extract presented the recovering phenotype associated with reduced parasite levels. CONCLUSIONS: Extracts of A. mucosa are promising sources of novel antileishmanial compounds.

Anti-leishmanial activity and identification of chemical constituents of Scrophularia striata essential oil by head space solid phase micro extraction gas chromatography mass spectrometry (HS-SPME GC-MS) / Actividad anti-leishmanial e identificación de componentes químicos del aceite esencial de Scrophularia striata mediante microextracción en fase sólida en el espacio de cabeza seguido de cromatografía gaseosa acoplada a espectrometría de masas (HS-SPME GC-MS)

The aim of the present study was to determine the main constituents of Scrophularia striata essential oil and to evaluate in vitro effect of essential oil on Leishmania tropica and Leishmania major promastigotes and axenic amastigotes. Chemical constituents of the extracted essential oil were separated by headspace solid-phase microextraction (HS-SPME) equipped with a PDMS/DVB fiber. The fiber was injected to gas chromatogram- mass spectroscopy (GC-MS) to determine their identity. Finally, after exposure of parasites to different concentrations of water soluble fraction of essential oil, viability of promastigotes and axenic amastigotes were investigated. Based on the HS-SPME results, 47 compounds representing 95.6% of the total oil, were identified in essential oil. Essential oil analysis showed that nonane (19.7%), α-terpineol (17.4%) and linalool (10.2%) were the most abundant compounds. This study indicates that water soluble fraction of S. striata essential oil has promising anti-leishmanial activity.

El objetivo del presente estudio fue determinar los principales componentes del aceite esencial de Scrophularia striata y evaluar el efecto in vitro del aceite esencial en promastigotes y amastigotes axénicos de Leishmania tropica y Leishmania major. Los componentes químicos del aceite esencial extraído se separaron mediante microextracción de fase sólida en el espacio superior (HS-SPME) equipado con una fibra PDMS/DVB. Para determinar su identidad la fibra se inyectó en un cromatógrafo de gases acoplado un espectrómetro de masas (GC-MS). Finalmente, después de la exposición de los parásitos a diferentes concentraciones de fracción soluble del aceite esencial en agua, se investigó la viabilidad de los promastigotes y los amastigotes axénicos. En base a los resultados de HS-SPME, se identificaron 47 compuestos que representan el 95.6% del aceite total en el aceite esencial. El análisis de aceites esenciales mostró que el nonano (19.7%), el α-terpineol (17.4%) y el linalol (10.2%) fueron los compuestos más abundantes. Este estudio indica que la fracción soluble en agua del aceite esencial de S. striata tiene una actividad antileishmanial prometedora.

Antiprotozoal action of synthetic cinnamic acid analogs

Abstract INTRODUCTION Leishmaniasis, Chagas disease, and malaria cause morbidity globally. The drugs currently used for treatment have limitations. Activity of cinnamic acid analogs against Leishmania spp., Trypanosoma cruzi, and Plasmodium falciparum was evaluated in the interest of identifying new antiprotozoal compounds. METHODS In vitro effects of analogs against L. braziliensis, L. infantum chagasi, T. cruzi, and P. falciparum, and hemolytic and cytotoxic activities on NCTC 929 were determined. RESULTS Three analogs showed leishmanicidal and tripanocidal activity. No antiplasmodial, hemolytic, or cytotoxic activity was observed. CONCLUSIONS Antiprotozoal activity of analogs against L. infantum braziliensis, L. infantum chagasi, and T. cruzi was demonstrated.

Identificación y determinación estructural de un sesquiterpeno de las hojas de Tessaria integrifolia Ruiz & Pav. y evaluación de su actividad leishmanicida / Identification and structural determination of a sesquiterpene of Tessaria integrifolia Ruiz & Pav. leaves and evaluation of its leishmanicidal activity

RESUMEN Objetivos. Identificar y determinar la estructura del fitoconstituyente de hojas de Tessaria integrifolia Ruiz & Pav con efecto leishmanicida. Materiales y métodos. Se preparó un extracto fluido de hojas de Tessaria integrifolia Ruiz & Pav. que fue concentrado a extracto blando y se utilizó para evaluar la actividad leishmanicida en Mesocricetus auratus con leishmaniasis experimental, administrando vía intramuscular la dosis de 250 mg/kg del extracto blando por 15 días. El extracto fue fraccionado en columna cromatográfica de 45 cm, con un diámetro de 2,5 cm que contiene silicagel G-60, de 70-230 mesh (Sigma-Aldrich®), las nueve fracciones obtenidas fueron evaluadas sobre macrófagos infectados con Leishmania sp para determinar la fracción activa y aislar el compuesto activo, mediante separación, purificación y cristalización, siendo analizado por resonancia magnética nuclear (RMN) de 1H, 13C, y cromatografía líquida acoplada a espectroscopía de masas (LC/MS). Resultados. El extracto fluido de las hojas de Tessaria integrifolia Ruiz & Pav. presenta actividad leishmanicida en Mesocricetus auratus y la fracción F8 es activa sobre macrófagos infectados a dosis de 14 µg/mL. Se elucidó en esa fracción un sesquiterpeno tipo eudesmano ((4aS, 5R,6R,8aR)-6-hidroxi-5,8a-dimetil-3-(1-metiletiliden) octahidronaftalen-2(1H)-ona), según análisis de RMN 1H, 13C, y LC/MS. Conclusiones. El extracto fluido de hojas de Tessaria integrifolia Ruiz & Pav. presenta actividad leishmanicida sobre Mesocricetus auratus. La fracción F8 presenta actividad leishmanicida sobre macrófagos infectados a dosis de 14 µg/mL. Se elucidó en la fracción activa un sesquiterpeno tipo eudesmano según los análisis de RMN 1H, 13C, y LC/MS.

ABSTRACT Objective. To identify and determine the phytoconstituent structure of Tessaria integrifolia Ruiz & Pav. leaves with leishmanicidal activity. Materials and Methods. Fluid extract of leaves was prepared, concentrated to soft extract, and used to evaluate leishmanicidal activity in Mesocricetus auratus with experimental leishmaniasis, at the dose of 250 mg/kg of soft extract by intramuscular route for 15 days. Extract was fractionated in 45 cm column chromatography with a 2.5 cm diameter, containing G-60 silica gel, and 70-230 mesh (Sigma-Aldrich®). Nine fractions were obtained and assessed on macrophages infected with Leishmania sp to determine the active fraction and isolate the active compound, by separation, purification, and crystallization, analyzed by nuclear magnetic resonance (NMR) of 1H, 13C, and liquid chromatography coupled to mass spectroscopy (LC/ MS). Results. Fluid extract from the leaves of T. integrifolia presents leishmanicidal activity in M. auratus. Fraction F8 is active on infected macrophages at a dose of 14 μg/mL. An eudesman type sesquiterpene ((4aS, 5R, 6R, 8aR) -6-hydroxy-5, 8a-dimethyl-3- (1-methylethylidene) octahydronaphthalen-2 (1H) -one) was identified, by RMN 1 H, 13C, and LC / MS analysis. Conclusions. Fluid extract of leaves of Tessaria integrifolia Ruiz & Pav. presents leishmanicidal activity on Mesocricetus auratus with experimental leishmaniasis. Fraction F8 presents leishmanicidal activity on infected macrophages at a dose of 14 μg/mL. An eudesman type sesquiterpene was identified, according to 1 H, 13C, and LC / MS NMR analysis.

Toxicidad, genotoxicidad y actividad anti-Leishmania de aceites esenciales obtenidos de cuatro (4) quimiotipos del género Lippia / Toxicity, genotoxicity and anti-Leishmania activity of essential oils obtained of four chemotypes of Lippia genus

Los aceites esenciales (AEs), pertenecientes al género Lippia, son candidatos interesantes de formulaciones tópicas en el tratamiento de la leishmaniasis cutánea (LC). El objetivo de este trabajo fue determinar el perfil toxicológico y la actividad anti-Leishmania de AEs obtenidos de plantas colombianas del género Lippia. Ratones BALB/c fueron tratados tópica u oralmente con AEs obtenidos de L. alba quimiotipo citral (AE1) y de L. origanoides quimiotipos timol (AE2), carvacrol (AE3) y felandreno (AE4). El efecto del tratamiento en la irritación de la piel, la toxicidad aguda oral, la genotoxicidad (prueba cometa y micronúcleos), los cambios en la función hepática y renal, la inducción de reacción de hipersensibilidad de contacto y en la actividad contra L. (V) panamensis y L. (V.) braziliensis fueron determinados. Todos los AEs presentaron un perfil toxicológico similar a los parámetros normales, exceptuando los aceites AE2 y AE3 los cuales fueron irritantes y presentaron algunos signos de toxicidad aguda oral al ser utilizados en altas concentraciones (concentraciones bajas no fueron tóxicas). El AE2 mostró actividad antiparasitaria en las formas parasitarias evaluadas. Concentraciones bajas de los AEs podrían utilizarse de forma segura como componentes de formulaciones farmacológicas en LC.

Essential oils (EOs) belonging to the genus Lippia are interesting candidates in pharmaceutical systems for cutaneous leishmaniasis (CL). The aim of this work was to determine both toxicological and antileishmanial activities of EOs obtained from different species of Lippia, a widely distributed Colombian plants. BALB/c mice were treated topically or orally with EOs obtained from L. alba citral chemotype (EO1) and L. origanoides thymol (EO2), carvacrol (EO3) and phellandrene (EO4) chemotypes. The skin irritation, oral acute toxicity, genotoxicity (comet assay and micronucleus test), liver and renal adverse effects, All the EOs showed a toxicological profile similar to the normal parameters, except for oils EO2 and EO3 which were irritant and showed some signs of acute oral toxicity at high concentrations (low concentration were safe). The EO2 showed antiparasitic activity. Low concentrations of the EO could be used safely as components of pharmacological formulations in CL.

Effect of phospholipase A2 inhibitors during infection caused by Leishmania (Leishmania) amazonensis

Lipid metabolites play an important role in parasite differentiation and virulence. Studies have revealed that Leishmania sp. uses prostaglandins to evade innate barriers, thus enabling the parasites to survive inside immune cells. Despite the role of the enzyme Phospholipase A2 (PLA2) in prostaglandins production, few studies have investigated the role of parasite PLA2 during the interaction between L. (L.) amazonensis and the host (in vitro and in vivo) immune cells. Methods: In the present work, the leishmanicidal effect of PLA2 inhibitors, methyl arachidonyl fluorophosphonate (MAFP), bromoenol lactone (BEL) and aristolochic acid (AA) were investigated in vitro (promastigote and intracellular amastigote forms of L. (L.) amazonensis) and during in vivo infection using BALB/c mice. Results: The aforementioned inhibitors were deleterious to promastigote and amastigote forms of the L. (L.) amazonensis and were non-toxic to peritoneal macrophages from BALB/c mice. L. (L.) amazonensis-infected BALB/c mice treated with the inhibitor BEL presented decreased lesion size and skin parasitism; however, BEL treatment induced hepatotoxicity in BALB/c mice. Conclusions: Results presented herein suggested that PLA2 inhibitors altered L. (L.) amazonensis viability. In spite of liver toxicity, treatment with BEL was the most selective compound in vitro, as well in vivo, resulting in lower skin parasitism in the infected mice. These findings corroborate the role of PLA2 in parasite virulence and maintenance in vertebrate hosts, and suggest that molecules structurally related to BEL should be considered when planning compounds against Leishmania sp.(AU)

In vitro and in vivo antileishmanial activity of Artemisia annua L. leaf powder and its potential usefulness in the treatment of uncomplicated cutaneous leishmaniasis in humans

ABSTRACT INTRODUCTION: Cutaneous leishmaniasis (CL) is a tropical disease that affects millions of individuals worldwide. The current drugs for CL may be effective but have serious side effects; hence, alternatives are urgently needed. Although plant-derived materials are used for the treatment of various diseases in 80% of the global population, the validation of these products is essential. Gelatin capsules containing dried Artemisia annua leaf powder were recently developed as a new herbal formulation (totum) for the oral treatment of malaria and other parasitic diseases. Here, we aimed to determine the usefulness of A. annua gel capsules in CL. METHODS: The antileishmanial activity and cytotoxicity of A. annua L. capsules was determined via in vitro and in vivo studies. Moreover, a preliminary evaluation of its therapeutic potential as antileishmanial treatment in humans was conducted in 2 patients with uncomplicated CL. RESULTS: Artemisia annua capsules showed moderate in vitro activity in amastigotes of Leishmania (Viannia) panamensis; no cytotoxicity in U-937 macrophages or genotoxicity in human lymphocytes was observed. Five of 6 (83.3%) hamsters treated with A. annua capsules (500mg/kg/day) for 30 days were cured, and the 2 examined patients were cured 45 days after initiation of treatment with 30g of A. annua capsules, without any adverse reactions. Both patients remained disease-free 26 and 24 months after treatment completion. CONCLUSION: Capsules of A. annua L. represent an effective treatment for uncomplicated CL, although further randomized controlled trials are needed to validate its efficacy and safety.

Evaluation of the antiplasmodial and leishmanicidal potential of Myrciaria dubia (Myrtaceae) extract

Abstract INTRODUCTION: Malaria and leishmaniasis are prevalent in tropical regions, which have environmental characteristics that are highly favorable to protozoa and vectors of these diseases; the transmission of these infections in sub-tropical regions, although recognized, represents only a small fraction of cases. Plants are constantly being used in the search for and acquisition of new drugs, and many compounds derived from them have been used to combat various diseases. In this study, we evaluated the action of the dichloromethanolic extract of Myrciaria dubia leaves against the protozoa Plasmodium falciparum, Leishmania amazonensis, Leishmania braziliensis, and Leishmania chagasi through bioassays. METHODS The extract from M. dubia was tested for its anti-P. falciparum activity in an anti-histidine-rich protein II immunosorbent assay. The antileishmanial assays were performed using the resazurin method, while cytotoxicity against human hepatoma (HepG2) strain was determined using the colorimetric MTT [3-(4, 5-dimethyl-2- thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide] method. RESULTS The M. dubia extract presented a half-maximal inhibitory concentration equal to 2.35 (1.05)μg/mL for P. falciparum, 190.73 (6.41) μg/mL for L. amazonensis, and greater than equal to 200µg/mL for L. chagasi and L. braziliensis strains. The cytotoxic concentration for 50% of the cells was above 500μg/mL for HepG2, indicating no toxicity and greater selectivity against parasites. CONCLUSIONS The results obtained indicate the presence of antiplasmodial and leishmanicidal bioactive compounds in the dichloromethanolic extracts of M. dubia leaves, and point towards future studies to elucidate the mechanism of action for each physiological effect.

In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.

Antileishmanial activity of the essential oil from Tetradenia riparia obtained in different seasons

The herbaceous shrub Tetradenia riparia has been traditionally used to treat inflammatory and infectious diseases. Recently, a study showed that T. riparia essential oil (TrEO) obtained in summer has antileishmanial effects, although these results could be influenced by seasonal variation. This study evaluated the activity of the TrEO obtained in different seasons against Leishmania (Leishmania) amazonensis, in vitro and in vivo. The compounds in the TrEO were analysed by gas chromatography-mass spectrometry; terpenoids were present and oxygenated sesquiterpenes were the majority compounds (55.28%). The cytotoxicity and nitric oxide (NO) production were also tested after TrEO treatment. The TrEO from all seasons showed a 50% growth inhibitory concentration for promastigotes of about 15 ng/mL; at 30 ng/mL and 3 ng/mL, the TrEO reduced intracellular amastigote infection, independently of season. The TrEO from plants harvested in summer had the highest 50% cytotoxic concentration, 1,476 ng/mL for J774.A1 macrophages, and in spring (90.94 ng/mL) for murine macrophages. NO production did not change in samples of the TrEO from different seasons. The antileishmanial effect in vivo consisted of a reduction of the parasite load in the spleen. These results suggest that the TrEO has potential effects on L. (L.) amazonensis, consonant with its traditional use to treat parasitic diseases.

Detección de blancos moleculares en la ruta de señalización del fosfatidil-inositol en Leishmania spp. mediante herramientas bioinformáticas y de modelado matemático / Detection of molecular targets on the phosphatidylinositol signaling pathway of Leishmania spp. through bioinformatics tools and mathematical modeling

Introducción. La leishmaniasis es una enfermedad de gran impacto en la salud pública. La Organización Mundial de la Salud considera prioritaria la investigación orientada al desarrollo de medicamentos para su tratamiento. La exploración de la ruta del fosfatidil-inositol es interesante, ya que está implicada en la supervivencia del parásito mediante el control de la osmorregulación, el transporte a través de las membranas y la activación de diversos factores de transcripción. Objetivo. Proponer blancos para el desarrollo de medicamentos contra la leishmaniasis mediante el análisis bioinformático y el modelado matemático de esta ruta. Materiales y métodos. Se caracterizaron las proteínas pertenecientes a la ruta del fosfatidil-inositol en las bases de datos TriTrypDB y Pfam. Posteriormente, se hizo un análisis de similitud con las proteínas humanas mediante las herramientas InParanoid7 y OrthoMCL. Finalmente, se propuso un modelo booleano de la ruta, utilizando los programas PROMOT y CellNetAnalyzer. Resultados. Se reconstruyó y se describió la ruta de señalización del fosfatidil-inositol en Leishmania spp. El análisis de similitud con proteínas humanas determinó la viabilidad de las proteínas pertenecientes a la ruta del fosfatidil-inositol como potenciales blancos moleculares. Los modelos matemáticos permitieron integrar los elementos de la ruta y predecir un efecto inhibidor. Se propusieron los siguientes blancos para el desarrollo de medicamentos: inositol-3-fosfato-5-fosfatasa, fosfatidil-inositol-4-cinasa, fosfatidil-inositol-3,4,5-trisfosfato-3-fosfatasa, e inositol-polifosfato1P-fosfatasa. Conclusiones. La ruta de señalización del fosfatidil-inositol aparece como una alternativa sólida desde el punto de vista del modelo cualitativo y a partir de las proteínas encontradas. Se identificaron posibles blancos de medicamentos contra la leishmaniasis. Posteriormente, se buscarán medicamentos contra las proteínas detectadas y se hará la validación experimental.

Introduction: Leishmaniasis is a disease of high impact on public health. Research on drugs for its treatment is considered a priority by the World Health Organization. The phosphatidyl-inositol signaling pathway is interesting to explore because it is involved in the survival of the parasite, by controlling osmoregulation, transport through membranes, and activation of transcription factors. Objective: To propose drug targets against the disease through bioinformatic analysis and mathematical modeling of this signaling pathway. Materials and methods: The phosphatidyl-inositol pathway proteins were characterized through Pfam and TriTrypDB databases. Subsequently, a similarity analysis with human proteins was performed using the OrthoMCL and InParanoid7 tools. Finally, a boolean model of the pathway was proposed using PROMOT and CellNetAnalyzer softwares. Results: The phosphatidyl-inositol signaling pathway in Leishmania spp. was reconstructed and described. The similarity analysis determined the feasibility of the phosphatidyl-inositol pathway proteins as molecular targets. Mathematical models allowed integrating the elements of the path and predicted an inhibitor effect. The following were proposed as drug targets: inositol-3-phosphate-5-phosphatase, phosphatidylinositol-4-kinase, phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase and Inositol-1P-polyphosphate phosphatase. Conclusion: The phosphatidyl-inositol signaling pathway is robust from the point of view of the qualitative model and the proteins found. Thus, potential drug targets against leishmaniasis were identified. Subsequently we will seek to detect drugs against this set of proteins and validate them experimentally .

In vitro activity of the hydroethanolic extract and biflavonoids isolated from Selaginella sellowii on Leishmania (Leishmania) amazonensis

This study is the first phytochemical investigation of Selaginella sellowii and demonstrates the antileishmanial activity of the hydroethanolic extract from this plant (SSHE), as well as of the biflavonoids amentoflavone and robustaflavone, isolated from this species. The effects of these substances were evaluated on intracellular amastigotes of Leishmania (Leishmania) amazonensis, an aetiological agent of American cutaneous leishmaniasis. SSHE was highly active against intracellular amastigotes [the half maximum inhibitory concentration (IC50) = 20.2 µg/mL]. Fractionation of the extract led to the isolation of the two bioflavonoids with the highest activity: amentoflavone, which was about 200 times more active (IC50 = 0.1 μg/mL) and less cytotoxic than SSHE (IC50 = 2.2 and 3 μg/mL, respectively on NIH/3T3 and J774.A1 cells), with a high selectivity index (SI) (22 and 30), robustaflavone, which was also active against L. amazonensis (IC50 = 2.8 µg/mL), but more cytotoxic, with IC50 = 25.5 µg/mL (SI = 9.1) on NIH/3T3 cells and IC50 = 3.1 µg/mL (SI = 1.1) on J774.A1 cells. The production of nitric oxide (NO) was lower in cells treated with amentoflavone (suggesting that NO does not contribute to the leishmanicidal mechanism in this case), while NO release was higher after treatment with robustaflavone. S. sellowii may be a potential source of biflavonoids that could provide promising compounds for the treatment of cutaneous leishmaniasis.

Actividad contra Leishmania sp. (Kinetoplastida: Trypanosomatidae) de plantas en una Reserva Biológica de Costa Rica / Anti-leishmanial activity in plants from a Biological Reserve of Costa Rica

Leishmaniosis is an important human disease very difficult to treat. For this reason, many researchers in the world have been looking for anti-leishmanial chemical components present in several plant species. In Costa Rica, since no studies have been done in this field, this work aimed at the search of active chemical components in local plants that may have an activity against Leishmania sp. A total of 67 plants were selected from the Alberto Manuel Brenes Biological Reserve (REBAMB). For these collected plants, fresh or dried hidroalcoholic extracts of root, stem, mature or young leaves, flowers, and immature or mature fruits, were prepared under conventional methods. All extracts were tested for their effectagainst a strain of Leishmania (OCR with known characteristics). Firstly, by presumptive tests, we selected only those with some activity, and then, more specific studies were done to determine the IC50 in µg/mL; a promising plant was considered only if at least one of its parts presented an IC50<100µg/mL. Under this parameter, the following active plants were obtained and their lowest and highest IC50 obtained values presented (µg/mL): Bocconia frutescens (0.6 and 66.7), Clematis dioica (27.5 and 44.4), Cordia megalantha (80.0), Eugenia austin-smithi (90.6), Guarea bullata (98.8), Guateria tonduzii (44.4 and 66.3), Mikania holwayana (45.0 and 95.6), Nectandra membranacea (44.5 and 58.6), Neurolaena lobata (25.0 and 100.0), Persea povedae (76.9), Piper auritum (60.0), Rollinia pittieri (43.1), Solanum arboreum (25.8 and 72.5), Tetrorchidium euryphyllum (53.8 and 95.0), Witheringia solanacea (15.9 and 98.1) and Zanthoxylum juniperinum (23.4 and 97.5). Although the parasitic effect of fresh or dried extracts were almost similar, the fresh material slightly showed better results. That anti-parasitic effect occurred in one or more than four parts of the plant.Most of the active extracts did not produce lysis and aglutination which indicates a low toxicity. Since the species studied are different from those analyzed by other authors, we discuss the importance of these new findings, in relation to the new scientific knowledge, and the possible use of these plants as a leishmaniosis treatment. Rev. Biol. Trop. 62 (3): 1229-1240. Epub 2014 September 01.

La leishmaniosis es una enfermedad muy importante para el ser humano pero su tratamiento es bastante difícil. Por esta razón muchos investigadores han venido buscando plantas que contengan componentes químicos activos contra esta parasitosis. En Costa Rica no se tienen estudios al respecto y por eso el objetivo de este estudio fue la búsqueda de componentes activos contra Leishmania sp. en plantas de Costa Rica; 67 especies de la Reserva Biológica Alberto Manuel Brenes (REBAMB) fueron seleccionadas para realizar este trabajo. Para ello se prepararon extractos crudos hidro-alcohólicos de material fresco o desecado de raíz, tallo, hojas maduras o tiernas, flores y frutos inmaduros o maduros. Usando pruebas presuntivas y luego específicas, se analizó el efecto de tales extractos sobre una cepa de Leishmania (OCR). Se consideraron plantas promisorias solamente aquellas en que al menos una de sus partes presentara un CI50<100µg/mL. Las plantas seleccionadas fueron: Bocconia frutescens, Clematis dioica,Cordia megalantha, Eugenia austin-smithii, Guarea bullata, Guateria tonduzii, Mikania holwayana, Nectandra membranacea,Neurolaena lobata, Persea povedae, Piper auritum, Rollinia pittieri, Solanum arboreum, Tetrorchidium euryphyllum, Witheringia solanacea y Zanthoxylum juniperinum. Existió una ligera tendencia de positividad mayor para los extractos frescos y la actividad se presentó en una y hasta más de cuatro partes de la planta. La mayoría de los extractos activos no fueron tóxicos. Se discute la importancia de estos nuevos hallazgos, en relación con el nuevo conocimiento científico y su proyección en el tratamiento de la leishmaniosis.

Protease inhibitors in potential drug development for leishmaniasis.

Leishmaniasis is a deadly protozoan parasitic disease affecting millions of people worldwide. The treatment strategy of Leishmania infection depends exclusively on chemotherapy till date. But the treatment of the disease is greatly hampered due to high cost, toxicity of the available drugs and more importantly emergence of drug resistance. Hence the potential new drugs are highly needed to combat this disease. The first and foremost step of the drug discovery process is to search and select the putative target in a specific biological pathway in the parasite that should be either unambiguously absent in the host or considerably different from the host homolog. Importantly, Leishmania genome sequences enrich our knowledge about Leishmania and simultaneously reinforce us to identify the ideal drug targets that distinctly exist in the parasite as well as to develop the effective drugs for leishmaniasis. Though the leishmanial research has significantly progressed during the past two decades, the identification of suitable drug targets or development of effective drugs to combat leishmaniasis is far from satisfactory. Enzymatic systems of Leishmania metabolic and biochemical pathways are essential for their survival and infection. Concurrently, it is noteworthy that Leishmania proteases, especially the cysteine proteases, metalloproteases and serine proteases have been extensively investigated and found to be indispensable for the survival of the parasites and disease pathogenesis. Herein, we have discussed the importance of few enzymes, particularly the Leishmania proteases and their inhibitors as promising candidates for potential development of anti-leishmanial drugs.

In vitro antimicrobial assessment of Cuban propolis extracts

Propolis is a resinous mixture of different plant exudates collected by honeybees. Currently, propolis is widely used as a food supplement and in folk medicine. We have evaluated 20 Cuban propolis extracts of different chemical types, brown (BCP), red and yellow (YCP), with respect to their in vitro antibacterial, antifungal and antiprotozoal properties. The extracts inhibited the growth of Staphylococcus aureus and Trichophyton rubrum at low µg/mL concentrations, whereas they were not active against Escherichia coli and Candida albicans. The major activity of the extracts was found against the protozoa Leishmania, Trypanosoma and Plasmodium, although cytotoxicity against MRC-5 cells was also observed. The BCP-3, YCP-39 and YCP-60 extracts showed the highest activity against P. falciparum, with 50% of microbial growth (IC50) values of 0.2 µg/mL. A positive correlation between the biological activity and the chemical composition was observed for YCP extracts. The most promising antimicrobial activity corresponds to YCP subtype B, which contains acetyl triterpenes as the main constituents. The present in vitro study highlights the potential of propolis against protozoa, but further research is needed to increase selectivity towards the parasite. The observed chemical composition-activity relationship of propolis can contribute to the identification of the active principles and standardisation of this bee product.

In vitro efficacy of Coriandrum sativum, Lippia sidoides and Copaifera reticulata against Leishmania chagasi / Eficácia in vitro de Coriandrum sativum, Lippia sidoides e Copaifera reticulata sobre Leishmania chagasi

The increased incidence of visceral leishmaniasis (VL) in Brazil is due to a lack of effective disease control measures. In addition to that, no effective treatment exists for canine VL in response to synthetic drugs. Thus, the objective of this study was to evaluate the effect of the essential oils of Coriandrum sativum and Lippia sidoides, and oleoresin from Copaifera reticulata, on Leishmania chagasi promastigotes and amastigotes. We also examined the toxicity of these treatments on the murine monocyte cell line RAW 264.7. To determine the IC50 a MTT test (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed on promastigotes, and an in situ ELISA assay was conducted on amastigotes. Here, we demonstrate that oleoresin from C. reticulata was effective against both promastigotes (IC50 of 7.88 µg.mL-1) and amastigotes (IC50 of 0.52 µg.mL-1), and neither of the two treatments differed significantly (p > 0.05) from pentamidine (IC50 of 2.149 µg.mL-1) and amphotericin B (IC50 of 9.754 µg.mL-1). Of the three plant oils tested, only oleoresin showed no toxicity toward monocyte, with 78.45% viability after treatment. Inhibition of promastigote and amastigote growth and the lack of cytotoxicity by C. reticulata demonstrate that oleoresin may be a viable option for analyzing the in vivo therapeutic effects of leishmanicidal plants.

O aumento na incidência da Leishmaníase Visceral (LV) no Brasil deve-se à ineficácia das medidas de controle da doença. Além disso, não há tratamento efetivo para LV canina com drogas sintéticas. Assim, o objetivo deste trabalho foi avaliar o efeito dos óleos essenciais de Coriandrum sativum e de Lippia sidoides e do óleo-resina de Copaiferareticulata sobre promastigotas e amastigotas de Leishmania chagasi e analisar o grau de toxicidade sobre células monocíticas murinas RAW 264.7. Para determinar a CI50 sobre promastigotas foi usado teste MTT (brometo de 3-[4,5-dimetil-tiazol-2-il]-2,5-difeniltetrazólio) e sobre amastigotas foi realizado imunoensaio in situ pela técnica de ELISA. Os resultados obtidos comprovaram que o óleo-resina de C. reticulata foi o mais eficaz contra as formas promastigotas (CI50 de 7,88 µg.mL-1) e amastigotas (CI50 de 0,52 µg.mL-1) e em nenhum dos dois testes diferiu do controle pentamidina que obteve CI50 de 2,149 µg.mL-1, no teste sobre promastigotas, e anfotericina B que obteve CI50 de 9,754 µg.mL-1, nos testes com amastigotas (p > 0.05). Quanto à citotoxicidade apenas o óleo-resina não apresentou toxicidade com 78,45% de monócitos viáveis. Os resultados obtidos sobre promastigotas e amastigotas e a ausência de citotoxicidade do óleo-resina de C. reticulata evidenciam que este óleo-resina pode ser viável para a análise de seus efeitos terapêuticos em testes in vivo.

Actividad antileishmanial de seis extractos de organismos marinos / Antileishmanial activity of six extracts from marine organisms

Introducción: las infecciones causadas por protozoos del género Leishmania constituyen un problema de salud mundial con una alta prevalencia en países subdesarrollados. En la actualidad no existe una vacuna contra esta enfermedad y el tratamiento utilizado es deficiente, por lo que la búsqueda de medicamentos más efectivos y seguros constituye una urgente necesidad. Objetivo: evaluar la actividad antileishmanial in vitro de 6 extractos acuosos e hidroalcohólicos de organismos marinos. Métodos: se determinó la actividad frente a promastigotes y amastigotes de Leishmania amazonensis, así como su toxicidad frente a macrófagos peritoneales de ratones BALB/c. Resultados: en el ensayo de promastigotes los extractos de Bryothamnion triquetrum, Bunodosoma granulifera, Halimeda opuntia, y Physalia physalis mostraron una inhibición del crecimiento a concentraciones menores de 100 µg/mL; mientras que frente a amastigotes, estos 2 últimos extractos fueron los más activos y menos tóxicos con un índice de selectividad de 6 y 8, respectivamente. Conclusiones: teniendo en cuenta estos resultados se consideró que los extractos de H. opuntia y P. physalis mostraron una promisoria actividad, por lo que se sugiere continuar los estudios de su actividad in vivo.

Introduction: infections caused by protozoa of the genus Leishmania are a global health problem with a high prevalence in underdeveloped countries. There is no vaccine against this disease at present and the treatment used is poor, so the search for more effective and safe medicines is an urgent need. Objective: to assess the in vitro antileishmanial activity of six aqueous and hydroalcohol extracts from marine organisms. Methods: the activity of six extracts against Leishmania amazonensis promastigots and amastigots as well as their toxicity against peritoneal macrophages in BALB/c mice. Results: in the promastigot assay, the extracts from Bryothamnion triquetrum, Bunodosoma granulifera, Halimeda opuntia and Physalia physalis showed growth inhibition at concentrations lower than 100 µg/mL whereas in amastigots, these last two extracts were the most active and least toxic with a selectivity index of 6 and 8 respectively. Conclusions: taking these results into account, it was considered that the H. opuntia and P. physalis extracts showed a promising activity, so it is suggested that further studies on its in vivo activity be conducted.

Comparison of agar dilution, broth dilution, cylinder plate and disk diffusion methods for evaluation of anti-leishmanial drugs on Leishmania promastigotes

Leishmaniases are a group of diseases caused by Leishmania parasites. Growing of drug unresponsiveness in leishmaniasis patients necessitates the development of new drugs and accordingly a suitable assay is needed for evaluation of any modalities. The aim of this study was to compare four drug assays methods, agar dilution, broth dilution, cylinder plate and disk diffusion, for evaluation of anti-leishmanial drugs on Leishmania promastigotes, using glucantime as a currently available drug for treatment of leishmaniasis. For broth dilution method, different concentration of glucantime was added to the parasite culture [promastigotes of Leishmania], while in cylinder plate method wells were punched in agar gel and filled with different concentration of drug and zone of inhibition was measured in each well. In disk diffusion method, the parasites were cultivated on the surface of agar; filter paper disks were enriched with various concentration of glucantime and were placed on the surface of agar. In agar dilution method, various concentrations of drug were incorporated onto blood agar and the parasites were cultivated on the surface of the agar. A direct correlation was found between the drug concentration and size of inhibitory zones in cylinder plate and disk diffusion methods. These two drug assays methods provided much better performance in comparison with broth and agar dilution methods. Cylinder plate and disk diffusion methods seem to be acceptable methods for susceptibility testing of anti-leishmanial compounds on Leishmania promastigotes