Banca de QUALIFICAÇÃO: NATHÁLIA CRISTINA LOPES DE JORGE

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : NATHÁLIA CRISTINA LOPES DE JORGE
DATE: 16/10/2023
TIME: 14:00
LOCAL: remota
TITLE:

Chemical, antioxidant and toxicological prospecting of marine sponge extracts from Rio Grande do Norte - Brazil

KEY WORDS:

Antioxidant activity. Bioprospecting. Metabolites from marine sponges

PAGES: 70
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUBÁREA: Química de Macromoléculas
SPECIALTY: Proteínas
SUMMARY:

Marine sponges represent one of the most promising organisms in the search for bioactive molecules, with a range of biological activities already reported in the scientific literature. In this context, considering that oxidative stress is associated with various health conditions such as cancer, Parkinson's, Alzheimer's, among others, the pursuit of compounds that regulate oxidative stress becomes a critical element in the quest for new treatments. The Potiguar Basin in RN boasts a vast coastline with a rich diversity of marine sponge species. However, it remains largely unexplored in terms of its biotechnological potential. In light of this, chemical and biological prospecting was conducted on three sponge species collected along the coast of the Potiguar Basin: Halichondrida, Suberites aurantiacus, and Mycale angulosa. Sequential extractions were carried out using n-hexane (HE) and chloroform/methanol (CM). The samples extracted with HE were named HEMYC, HEHALI, HESUB, while those re-extracted with CM were named CMMYC, CMHALI, and CMSUB. The yield of the extracts played a crucial role in chemical characterization via GC/MS. Additionally, the antioxidant activity was evaluated using various methods including Total Antioxidant Capacity (CAT), Reducing power, ion sequestration (superoxide, DPPH, Hydroxyl Radical (OH-)), and Ion chelator activity (Ferrous (Fe²⁺) and Cuprous (Cu²⁺)). CM extracts from the three sponges were subjected to in vitro toxicological tests with human erythrocytes and in vivo tests using Tenebrio molitor larvae. Chemical characterization via GC/MS revealed the presence of compounds from the groups alcohols, alkaloids, phenolic compounds, and lipids, with a notable abundance of lipids, particularly in the sterol class. In in vitro antioxidant tests, the extracts exhibited the ability to chelate copper ions (EBHA 113.5% ± 1.93; EBSA 112.1% ± 5.81 and EBMY with 110.6% ± 3.19 activity with 25 µg/mL of sample), scavenge DPPH radicals (EBHA 60.91% ± 3.05; EBSA 59.32% ± 3.71 and EBMY 53.78% ± 6.96 with 1000 µg/mL), and hydroxyl radicals (EBSA 96% ± 0.04 at a concentration of 2000 µg/mL; EBMY 37% ± 0.17 and EBHA 54% ± 0.086 with 1000 µg/mL of extract), with a noteworthy emphasis on copper chelation activity for all three extracts. In vitro toxicological tests were conducted using human red blood cells, and in vivo tests using Tenebrio molitor as a model organism. In both sets of tests, at various concentrations, the samples did not exhibit toxic effects. The results presented here suggest that marine sponges from this coast possess pharmacological properties that warrant further investigation for the isolation of metabolites responsible for the observed antioxidant activities. Furthermore, there is potential for exploring these metabolites' efficacy in relation to other biological activities.

COMMITTEE MEMBERS:
Externa à Instituição - LUCIANA MARIA ARAÚJO RABÊLO - IFRN
Externo à Instituição - MARCELO VICTOR DOS SANTOS ALVES - IFRN
Interno - 1544647 - MATHEUS DE FREITAS FERNANDES PEDROSA