Total antioxidant capacity in the black mussel (Mytilus galloprovincialis) from Black Sea coasts

The aim of this investigation was to evaluate the total antioxidant radical scavenging capacity (TARSC) in tissue extracts for understanding biochemical adaptations involving the antioxidant defense system of a bivalve mussel, Mytilus galloprovincialis, sampled in polluted (Pol) and non-polluted (Npol) sites from Black Sea coasts. Antioxidant-rich polyphenol fractions were extracted from whole dry mussel tissue with methanol and water in different proportions. The extracts were screened for polyphenol content and their potential as antioxidants using various in vitro models, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH^•), β-carotene- linoleate (β-carotene) and nitric oxide (NO^•). The total polyphenol extract of the whole mussel tissue from polluted site (TPMEPoI) showed the highest antioxidant capacity among all of the extracts with the tested methods and was comparable with the antioxidant capacity of butylated hydroxyanisole (BHA). The antioxidant capacities of this extract determined by DPPH^•, β-carotene and NO^• methods and polyphenol content showed the highest correlation coefficients (R²) such as 0.9985, 0.9915 and 0.9895, respectively. The free polyphenol extracts (FPMEPol and FPMENPol) had lower antioxidant capacity than the two others of total polyphenols (TPMEPol and TPMENPol) with three scavenging methods. Responses were linear in all tested methods and the antioxidant capacity values of soluble antioxidants showed the following relative order: Trolox > BHA > TPMEPol > TPMENPol > FPMEPol > FPMENPol. Nutritional antioxidants, such as polyphenols, were probably the main antioxidant contribution to mussel antioxidants. The mussel extracts from the polluted site exhibited higher antioxidant capacity than from the non-polluted one. The results presented in this report indicate that the antioxidant capacity of the whole tissue of the mussel extract could possibly be a useful biomarker for aquatic environments.