Prospecção química e avaliação leishmanicida das flores de Pterodon pubescens
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Data
2020-10-23
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Universidade Federal de Goiás
Resumo
The species Pterodon pubescens (Fabaceae) is a plant known as “sucupira-branca” and its leaves and fruits are used in folk medicine to treat respiratory diseases. In previous works, chemical investigations of the leaves of this species allowed the identification of sesquiterpenes, flavonoids, steroids and diterpenes and also revealed potential leishmanicidal activity. Leishmaniasis is an infectious disease that affects millions of people worldwide and the drugs that are used in the treatment have several side effects, high toxicity and parasitic resistance. Bearing in mind that there are no studies of P. pubescens flowers and the importance of identifying new leishmanicidal agents, this work aimed to contribute to the chemical and biological knowledge of this species. The chemical profile of P. pubescens flowers was determined using hyphenated analytical techniques of UPLC-ESI-QqTOF-EM / EM and GC-MS, and 1H NMR spectroscopy, confirming the presence of secondary metabolites from the flavonoid and terpene classes. The study of the ethyl acetate fraction led to the isolation of the phenolic compound ethyl gallate (I), which originated from the acetylation of gallic acid. From the ethanolic extract and the ethyl acetate (EPpEA), hexane (EPpEH) and hydroalcoholic (EPpEHi) fractions of P. pubescens flowers it was possible to identify six flavonoids, a sesquiterpene and a diterpene by UPLC-ESI QqTOF-MS/MS and by GC-MS it was possible to identify thirteen sequiterpenes. In particular, in vitro screenings were carried out on the parasite and Leishmania amazonensis arginase (ARG), an enzyme involved in the parasite's life cycle using the ethanolic extract and the EPpEA, EPpEH and EPpEHi fractions. The evaluation of the ethanolic extract and fractions against the L. amazonensis ARG enzyme showed an inhibition rate between 67% and 82%. In the active fractions EPpEA and EPpEHi several flavonoids (gallic acid, quercetin-O-dihexoside, quercetin-O-hexoside, flavan-3-ol, quercetin, luteolin and kaempferol) and were identified that may be related to the inhibitory activities found, as they are described in the literature as inhibitors of ARG. In the evaluation against the Leishmania infantum protozoan, the extracts and fractions did not significantly inhibit the parasite. The results obtained are relevant for the knowledge of the studied species, which until now, within our knowledge, there has been no study of white sucupira flowers.
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Leishmaniose, Arginase, Galato de etila, Pterodon pubescens, Leishmaniasis, Arginase, Ethyl gallate, Pterodon pubescens
Citação
RIBEIRO, A. M. Prospecção química e avaliação leishmanicida das flores de Pterodon pubescens. 2020. 106 f. Dissertação (Mestrado em Química) - Universidade Federal de Goiás, Catalão, 2020.