Avaliação das Atividades Antioxidante in Vitro e Citotóxica dos Extratos da Esponja Marinha Ircinia sp.

Abstract

Sponges are filter-feeding benthic invertebrates, capable of synthesizing different secondary metabolites with high intraspecific chemical variability. There is a growing scientific interest in these animals, especially because of their pharmacological properties and application potentiality. Specimens of the marine sponge Ircinia sp. were collected at Praia do Pacheco, Caucaia-CE in February 2015. The washed, lyophilized and comminuted biomass was extracted in dichloromethane (DCM) and 70% ethanol (70% EtOH), in order to determine the antioxidant activity in vitro and cytotoxic activity using nauplii of Artemia sp. Separately, the extracts were rotary evaporated under vacuum. The DCM and 70% EtOH extracts were solubilized in 5% dimethylsulfoxide (5% DMSO) and 50% methanol (50% MeOH) to prepare the concentration 1000 μg mL-1, from which successive dilutions were carried out. They were used in the determination of in vitro antioxidant activity by DPPH (2,2-diphenyl-1-picryl-hydrazyl) radical scavenging activity, ferrous ion chelating (FIC) assay, ferric reducing antioxidant power (FRAP), and β-carotene bleaching inhibiting activity (BCB). The cytotoxic activity was tested in the two extracts against nauplii of Artemia sp. at the same dilutions as above. The results of DPPH (%) ranged from 27.98 ± 1.75 to 40.31 ± 1.66 (DCM) and from 23.40 ± 2.94 to 31.60 ± 0.56 (70% EtOH). The FIC of the DCM extract was between 10.13% and 40.15%, while that of the 70% EtOH ranged from 17.73% to 28.30%. The highest FRAP values, 0.164 ± 0.010 (DCM) and 0.287 ± 0.002 (EtOH 70%), were observed at the highest concentration tested. The BCB inhibitory activity of the DCM extract reached 67.88%, and approximately 66% for the 70% EtOH. In the cytotoxic activity the LC50 of the DCM extract after 24 hour-exposure was 232.74 μg mL-1, and after 48 h it was 21.56 μg mL-1. LC50 of the 70% EtOH extract after 24 hour-exposure was 406.98 μg mL-1. Mortality was greater than 50% at the lowest concentration tested after 48 hour-exposure. The antioxidant activity found in both DCM and 70% EtOH extracts of Ircinia sp. was compatible with the information available in the literature. Artemia sp. nauplii lethality assay showed that highest toxicity was observed at the highest concentrations and the longest exposure time. Based on the results, compounds with pharmacological potential can be isolated from the marine sponge Ircinia sp., and further studies are needed to evaluate the potential of the bioactive compounds of the species as well as their applicability.