Atividade leishmanicida e citotoxicidade de constituintes químicos de duas espécies de Annonaceae cultivadas no nordeste do Brasil

INTRODUCTION: Visceral leishmaniasis is endemic in 88 countries, with a total of 12 million people infected and 350 million at risk. In the search for new leishmanicidal agents, alkaloids and acetogenins isolated from leaves of Annona squamosa and seeds of Annona muricata were tested against promastigote and amastigote forms of Leishmania chagasi. METHODS: Methanol-water (80:20) extracts of A. squamosa leaves and A. muricata seeds were extracted with 10% phosphoric acid and organic solvents to obtain the alkaloid and acetogenin-rich extracts. These extracts were chromatographed on a silica gel column and eluted with a mixture of several solvents in crescent order of polarity. The compounds were identified by spectroscopic analysis. The isolated compounds were tested against Leishmania chagasi, which is responsible for American visceral leishmaniasis, using the MTT test assay. The cytotoxicity assay was evaluated for all isolated compounds, and for this assay, RAW 264.7 cells were used. RESULTS: O-methylarmepavine, a benzylisoquinolinic alkaloid, and a C37 trihydroxy adjacent bistetrahydrofuran acetogenin were isolated from A. squamosa, while two acetogenins, annonacinone and corossolone, were isolated from A. muricata. Against promastigotes, the alkaloid showed an IC50 of 23.3 µg/mL, and the acetogenins showed an IC50 ranging from 25.9 to 37.6 µg/mL; in the amastigote assay, the IC50 values ranged from 13.5 to 28.7 µg/mL. The cytotoxicity assay showed results ranging from 43.5 to 79.9 µg/mL. CONCLUSIONS: These results characterize A. squamosa and A. muricata as potential sources of leishmanicidal agents. Plants from Annonaceae are rich sources of natural compounds and an important tool in the search for new leishmanicidal therapies.INTRODUÇÃO: A leishmaniose visceral é uma enfermidade endêmica em 88 países, com um total de 12 milhões de pessoas infectadas e 350 milhões em risco. Na procura de novos agentes com ação leishmanicida, alcalóides e acetogeninas isoladas de Annona squamosa e Annona muricata, foram testados contra as formas promastigotas e amastigotas de Leishmania chagasi. MÉTODOS: Foram preparados extratos com metanol: água (80: 20) das folhas de A. squamosa e sementes de A. muricata que foram extraídos com solução de ácido fosfórico 10% e solventes orgânicos, para obter extratos ricos em alcalóides e acetogeninas. Estes extratos foram cromatografados em coluna de sílica gel sendo eluídos com solventes de diferentes polaridades para o isolamento dos constituintes, e feita a determinação estrutural por análise espectroscópica. Os constituintes isolados foram testados contra Leishmania chagasi, responsável pela leishmaniose visceral, utilizando o teste MTT. Testes de toxicidade foram realizados em todos os compostos isolados, sendo utilizadas células RAW 264.7. RESULTADOS: Um alcalóide benzilisoquinolínico, O-metilarmepavina, e uma C37-triidróxi-acetogenina com anel bistetrahidrofurânico adjacente foram isolados de A. squamosa e duas acetogeninas annonacinona e corossolona da A. muricata. O alcalóide mostrou um índice de inibição médio (IC50) de 23,3µg/mL e as acetogeninas apresentaram IC50 variando entre 25,9 a 37,6µg/mL contra promastigotas, e no ensaio de amastigotas, o IC50 valores variaram entre 13,5 a 28,7 µg/mL. A toxicidade mostrou resultados que variaram entre 43,5 a 79,9µg/mL. CONCLUSÕES: Estes resultados caracterizam A. squamosa e A. muricata como fontes potenciais de agentes leishmanicidas.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FUNCAP Fundação Cearense de Apoio ao Desenvolvimento Científico e TecnológicoSistema Único de Saúd

Estudo fitoquímico e atividades leishmanicida, anticolinestarásica e antioxidante de extratos de Annona glabra L. (araticum panã)

<p>O objetivo deste estudo foi investigar as principais classes de compostos químicos presentes em Annona grabra L. (Araticum panã), e avaliar o seu potencial biológico analisando suas atividades antioxidante, antiacetilcolinesterase e leishmanicida. Para tanto, a entrecasca e sementes foram submetidas à extração em aparelho de soxhlet com os solventes orgânicos hexano, clorofórmio, acetato de etila e metanol, obtendo-se os respectivos extratos. Com os extratos foram realizados testes de prospecção fitoquímica, determinação da atividade antioxidante pelo método de inibição do radical livre DPPH e inibição da acetilcolinesterase em ensaio de cromatografia em camada delgada. Os testes de atividade leishmanicida in vitro em formas promastigotas de Leishmania infantum chagasi foram realizados em placa de 96 poços em aparelho ELISA. Os extratos foram testados a 100 μg/ mL. Os testes fitoquímicos revelaram a presença de esteroides, triterpenos, alcaloides, compostos fenólicos e saponinas. Todos os extratos apresentaram inibição da acetilcolinesterase e os extratos hexânicos de ambas partes mostraram maior percentual de inibição de L. infantum chagasi. Nestes extratos, compostos apolares como esteroides e triterpenos podem contribuir para a atividade leishmanicida. Os extratos de melhor atividade antioxidante foram o acetato de etila e metanólico da entrecasca e metanólico das sementes que correspondem aos que contem compostos fenólicos. Conclui-se que A. glabra constitui uma fonte potencial de agentes leishmanicida com possível mecanismo de ação pela inibição da enzima acetilcolinesterase das membranas da L. infantum chagasi, causador da leishmaniose visceral.</p><p>Phytochemical study and leishmanicidal, anticholinesterase and antioxidant activities of Annona glabra L. (araticum panã) extracts</p><p> </p><p>ABSTRACT</p><p> </p><p>The aim of this study was to investigate the main types of chemical constituents present in Annona grabra L. (araticum panã) and evaluate its biological potential by analyzing the antioxidant, antiacetylcholinesterase and antiLeishmanial activities. For this, the sapwood and seeds were subjected to extraction in soxhlet apparatus using the following organic solvents: hexane, chloroform, ethyl acetate and methanol for obtaining the respective extracts. These extracts were submitted to phytochemical prospection, antioxidant tests by scavenging the free radical DPPH, acetylcholinesterase inhibition assay on TLC plates. The in vitro antiLeishmanial assay in Leishmania infantum chagasi promastigotes were performed in a 96 well plate in an ELISA instrument. The extracts were tested at 100 μg/ mL. Phytochemical investigation revealed the presence of sterols, triterpenes, alkaloids, phenolic compounds and saponins. All extracts showed inhibition of acetylcholinesterase, and hexane extracts of both parts presented more action in L. infantum chagasi. The extracts with better antioxidant action were ethyl acetate and methanol extracts of the sapwood and methanol extract of seeds, which correspond to those, which contains phenolic compounds. In conclusion, A. glabra constitutes a potential source of antiLeishmanial agents with possible mechanism of action by inhibiting the acetylcholinesterase in the membranes of L. infantum chagasi responsible for visceral Leishmaniasis</p><p>Keywords: Leishmania infantum chagasi. Annona glabra L. Leishmanicidal activity.</p

Chemical Composition and Antifungal In Vitro and In Silico, Antioxidant, and Anticholinesterase Activities of Extracts and Constituents of Ouratea fieldingiana (DC.) Baill

Ouratea fieldingiana (Gardner) Engl is popularly used for wound healing. This study describes the main chemical compounds present in extracts of O. fieldingiana and evaluates their biological potential by investigating antifungal, antioxidant, and anticholinesterase activities. The action mechanism of main antifungal compound was investigated by molecular docking using the enzyme sterol 14-α demethylase, CYP51, required for ergosterol biosynthesis. The seeds and leaves were extracted with ethanol in a Soxhlet apparatus and by maceration, respectively. Both extracts were subjected to silica gel column chromatography for isolation of main constituents, followed by purification in sephadex. The structures of compounds were established by 1H and 13C-NMR spectroscopy and identified by comparison with literature data as amentoflavone and kaempferol 3-O-rutinoside, respectively. The antioxidant activities of the extracts were determined by the DPPH and ABTS free radical inhibition methods. In general, the extracts with the highest antioxidant activity corresponded to those with higher content of phenolic compounds and flavonoids. The ethanol extracts and two isolated compounds presented relevant antifungal activity against several Candida strains. The in silico findings revealed that the compound amentoflavone coupled with the CYP450 protein due to the low energy stabilization (-9.39 kcal/mol), indicating a possible mechanism of action by inhibition of the ergosterol biosynthesis of Candida fungi