Banca de QUALIFICAÇÃO: WAGNER JOSÉ ODILON DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : WAGNER JOSÉ ODILON DOS SANTOS
DATA : 07/04/2021
HORA: 13:00
LOCAL: remoto
TÍTULO:

Study of the cytotoxic activity of cauranic diterpenes isolated from Baccharis lateralis Baker and Baccharis retusa

PÁGINAS: 42
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Química dos Produtos Naturais
RESUMO:

Cancer is a disease that affects the lives of millions of people around the world annually. When diagnosed late, cancer can present an aggressive and often deadly condition. The search for new, more specific drugs with more subtle side effects has aroused the interest of scientists. Natural products are great sources of a range of substances with structural diversity that can be exploited for the development of new drugs. The Baccharis genus comprises about 500 species originally distributed across America; however, only 30% of the species of this genus have been studied chemically. The present work sought to evaluate the cytotoxic activity of diterpenes from the hexanic extracts of Baccharis retusa and Baccharis lateralis against the MCF-7 strain. Chromatographic fractionation of hexane extracts resulted in the isolation of ent-kaurenoic acid (I), and its derivatives, grandifloric acid (II), ent-15β senecioloxicaurenoic acid (III), present in the hexanic extract of Baccharis retusa, while ent acid -caurenoic (I) and ent-15β tiglinoxicaurenoic acid (IV) were found in the hexanic extract of Baccharis lateralis, which were identified by 1H and 13C NMR spectra. The cytotoxic study of the four diterpenes against the MCF-7 strain revealed that greater activity for the compounds ent-15β senecioloxicaurenoic acid and ent-15β tiglinoxicaurenoic acid in relation to ent-kaurenoic acid and grandifloric acid. This result suggested that the isoprene units, present in the tiglinoxyl and senecioloxyl groups, are responsible for the increase in cytotoxic activity, while the hydroxyl group, present in the compound, grandifloric acid, decreases the cytotoxic activity, in relation to ent-kaurenoic acid. One possible explanation may be related to the ability to inhibit the activity of ubiquitin isopeptidase by carbon-β sterically available in the tiglinoxyl and senecioloxyl groups, which would lead to cell death, due to the change in the polyubiquitin chain length balance. However, more detailed research is needed to substantiate such a proposition. Finally, the compounds ent-15β senecioloxicaurenoic acid and ent-15β tiglinoxicaurenoic acid have potential for antitumor studies.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1544365 - GISELLE CERCHIARO
Membro Titular - Examinador(a) Interno ao Programa - 1544344 - VANI XAVIER DE OLIVEIRA JUNIOR
Membro Titular - Examinador(a) Externo à Instituição - MARISI GOMES SOARES - UNIFAL-MG
Membro Suplente - Examinador(a) Interno ao Programa - 1844792 - AMEDEA BAROZZI SEABRA