Prospecção química, antioxidante e toxicológica das Esponjas Marinhas Suberites aurantiacus, Mycale angulosa e Halichondrida da Bacia Potiguar - RN

Abstract

Marine sponges are very promising organisms in the search for bioactive molecules, with a range of biological activities already reported in the scientific literature, particularly focusing on antioxidant agents. Given that oxidative stress is associated with several health conditions, such as cancer, Parkinson's, Alzheimer's, among others, the search for compounds that act in oxidative control becomes a key element in the quest for new treatments. The Potiguar Basin in RN has a vast coastline with a rich diversity of marine sponge species; however, its biotechnological potential is underexplored. In this study, we conducted chemical, antioxidant, and toxicological prospecting of three sponge species collected from the coast of the Potiguar Basin: Suberites aurantiacus, Mycale (Zygomycale) angulosa, and Halichondrida. Sequential extractions were performed with n-hexane (HE) to prepare the extracts, followed by extraction with chloroform/methanol (CM). The extracts obtained with HE were named HESUB, HEMYC, and HEHALI, and those obtained with CM were named CMSUB, CMMYC, and CMHALI for S. aurantiacus, M. angulosa, and Halichondrida, respectively. The CM extracts were chemically characterized by Gas Chromatography coupled with Mass Spectrometry (GC/MS) and evaluated for their antioxidant activity using the following methods: Total Antioxidant Capacity (TAC), Reducing Power, Ion Scavenging (superoxide, DPPH, Hydroxyl Radical (OH•)), and Ion Chelating Activity (Ferrous (Fe²⁺) and Cuprous (Cu²⁺)). The CM extracts of the three sponges were also subjected to in vitro toxicological tests with human erythrocytes and in vivo tests with Tenebrio molitor larvae. The chemical characterization by GC/MS revealed specific chemical patterns for the genera of the sponges studied. The extracts contained alcohols, alkaloids, phenolic compounds, and lipids (mainly sterols, stanols, acids, and fatty alcohols). In the in vitro antioxidant tests, the extracts demonstrated the ability to scavenge DPPH radicals (CMHALI 60.91% ± 3.05; CMSUB 59.32% ± 3.71; CMMYC 53.78% ± 6.96 at 1000 µg/mL) and hydroxyl radicals (CMSUB 96% ± 0.04 at a concentration of 2000 µg/mL; CMMYC 37% ± 0.17; CMHALI 54% ± 0.086 at 1000 µg/mL) and copper ion chelation (CMHALI 113.5% ± 1.93; CMSUB 112.1% ± 5.81; CMMYC 110.6% ± 3.19 at 25 µg/mL). The copper chelation activity was especially notable in all three extracts. The in vitro and in vivo toxicological tests showed that the samples did not exhibit toxic effects at different concentrations. Additionally, antibacterial tests were performed using the Minimum Inhibitory Concentration (MIC) method against the pathogenic bacteria Staphylococcus aureus and Escherichia coli, but no antibacterial activity was observed. The results presented here suggest that marine sponges from this coastline possess pharmacological properties that can be further investigated for the isolation of metabolites responsible for the observed antioxidant activities. Moreover, there is potential for exploring these metabolites in relation to other biological activities.