Banca de DEFESA: CRISTIANE CARDOSO DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : CRISTIANE CARDOSO DOS SANTOS
DATE: 10/02/2025
TIME: 10:00
LOCAL: Programa de Pós-graduação em Química
TITLE:

Isolation and biological evaluation of special metabolites from green propolis by countercurrent chromatography

KEY WORDS:

COVID-19, anti-cancer activity, artepillin C, baccharin, anacardic acid and betuletol

PAGES: 195
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

Green propolis, a widely recognised Brazilian apicultural product, has been the focus of scientific research for its promising medicinal properties and benefits, particularly in the fight against SARS-CoV-2 and cancer. The importance of characterising the bioactive chemical constituents present in this resin produced by honeybees cannot be underestimated, as its chemical composition is remarkably complex, requiring several steps to effectively isolate the main substances. In this context, the choice of an isolation method that reduces costs, long execution times and significant sample losses is crucial. Countercurrent chromatography (CCC), a liquid-liquid partition technique characterised by full recovery of the analyte without the need for solid supports, is emerging as a suitable alternative. Thus, in the present study, both the hexane (HEGP) and ethanol (EEGP) extracts of green propolis were evaluated with the aim of isolating, with a higher degree of purity, prenylated substances, especially artepillin C, baccharin and chromene. The fractionation of HEGP involved two different isocratic chromatographic procedures, one with normal elution mode and the other with reverse elution, using hexane-ethanol-water 4:3:1 (v/v) as a biphasic solvent system. The results obtained for the isolation of the compounds in the hexane extract were different, with the normal elution mode promoting greater selectivity for baccharin (89% purity) and artepillin C (93% purity), whereas in the reverse mode chromene stood out with 96% purity. In addition, the isolated substances were tested for inhibition of the interaction between the receptor binding domain (RBD) of the spike protein and the ACE2 protein receptor, which was evaluated by the Lumitᵀᴹ immunoassay, showing that bacharin and artepillin C exhibited significant inhibitory activities, with 51% and 67% inhibition, respectively, at concentrations of 10 μM. With regard to the fractionation of EEGP, particular attention was paid to the methodology for the isolation of artepillin C. For this purpose, the solvent system of hexane-ethyl acetate (8:2) and 4% aqueous sodium bicarbonate (1:1) was used in the reverse elution mode, resulting in artepillin C with 82% purity.These fractionations were monitored by LCQTOF fingerprinting, providing an effective parameter for monitoring the separation. As part of the phytochemical study, the ethanol extract of green propolis (EEGP), substances such as anacardic acid, capillartemisin, p-coumaric acid, aromadendrin, betuletol and kaempferide were also isolated using multidimensional countercurrent chromatography (MDCCC), alternating aqueous and non-aqueous solvent systems and tested in vitro in breast cancer (MCF-7 e MDA-MD-231). Baccharin showed promising preliminary results on aggressive breast cancer (MDA) strains. Thus, the results obtained for the isolation of specific metabolites from green propolis demonstrate the potential of the CCC technique and offer new perspectives in the field of natural products for the isolation of bioactive substances with high purity in order to evaluate their biological potential.

COMMITTEE MEMBERS:
Externo à Instituição - REGINA OLIVEIRA - UFSCAR
Interna - ***.742.388-** - AUREA ECHEVARRIA AZNAR NEVES LIMA - UFRRJ
Externo à Instituição - DAVYSON DE LIMA MOREIRA - JBRJ
Externo à Instituição - LUCAS SILVA ABREU - UFF
Externa à Instituição - MARIA RAQUEL FIGUEIRO - FIOCRUZ
Presidente - 1177598 - ROSANE NORA CASTRO
Externo à Instituição - Rodrigo Rodrigues de Oliveira - UENF