Banca de DEFESA: MARIELE RONDON SANTOS GONÇALVES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : MARIELE RONDON SANTOS GONÇALVES
DATE: 28/08/2025
TIME: 09:00
LOCAL: PPGQ-Online
TITLE:

Phytochemical study and evaluation of biological activities of Galianthe matogrossiana E.L. Cabral (Rubiaceae) and Crateva tapia L. (Capparaceae); contribution to the structural elucidation of a new alkaloid isolated from Justicia wasshauseniana Profice (Acanthaceae)

KEY WORDS:

Galianthe matogrossiana, Crateva tapia, Justicia wasshauseniana Phytochemistry, Bioactivity.

PAGES: 209
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

This thesis integrates a phytochemical study and evaluation of some biological activities of two Neotropical species: Galianthe matogrossiana E.L. Cabral (Rubiaceae) and Crateva tapia L. (Capparaceae). It details the definition of the molecular structure of a new alkaloid isolated from Justicia wasshauseniana Profice (Acanthaceae). In addition to describing the experimental procedures of isolation, the identification of molecular structures of special metabolites are described. Chromatographic techniques and detailed NMR and MS spectral analyses were used in this work. Biological activities such as anti-nociceptive, anti-inflammatory, and antioxidant activities were evaluated. Twenty-one compounds were identified in the nonpolar fractions of roots and aerial parts of G. matogrossiana, including fatty acid, anthraquinone, chalcone and coumarin derivatives, benzoic acid derivatives, steroids, and some pentacyclic triterpenes. In vivo assays (abdominal writhing, formalin, and open field in Swiss mice), with the exception of the hexane root fraction, the other fractions showed strong antinociceptive and anti-inflammatory activity, even superior to morphine. Antioxidant activity, performed in vitro (wild-type and Δyap1 strains of Saccharomyces cerevisiae), revealed that the hexane and dichloromethane fractions are potent radical scavengers. 3O-acetyl oleanolic acid inhibited Trypanosoma cruzi amastigotes (IC50 = 11.06 µM; selectivity = 3.11). Preliminary molecular docking studies suggested promising affinity of triterpenes against Aurora B kinase for anticancer applications. The in vitro antiglycation activity of the crude bark extract of C. tapia was evaluated, but was not very significant. Until now, glycosylated sitosterol and lupeol have been isolated from the dichloromethane fraction. Detailed discussion of the spectrometric data of the alkaloid, previously isolated from J. wasshauseniana, including TD DFT calculations, has defined its molecular structure, including absolute stereochemistry, which was named as "Brazoid E". These results provide insight into the phytochemical composition and biological activities of species with no record study in the literature.

COMMITTEE MEMBERS:
Externa à Instituição - ALAÍDE DE SÁ BARRETO - UERJ
Externo ao Programa - 1674073 - BRUNO GUIMARAES MARINHO - UFRRJExterno à Instituição - JULIO CESAR ESCALONA ARRANZ
Presidente - 6386421 - MARIO GERALDO DE CARVALHO
Externo ao Programa - 3446481 - THIAGO WOLFF - UFRRJ