Antioxidant Capacities of Phlorotannins Extracted from the Brown Algae Fucus vesiculosus

Abstract

A process for the effective extraction and fractionation of phlorotannins from Fucus vesiculosus with high antioxidant potentials was investigated. The antioxidant activity of F. vesiculosus extract/fractions was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, reducing power, and ferrous ion-chelating assays. Among the crude extract and different polarity fractions, the phlorotannin-enriched ethyl acetate fraction possessed the highest DPPH scavenging activity and reducing power. This fraction was further fractionated by Sephadex LH-20 column chromatography or ultrafiltration. The antioxidant properties were evaluated by both the above chemical antioxidant tests and a mononuclear cell-based bioassay. Sephadex subfractions LH-2 and LH-3 with high total phlorotannin content exhibited strong DPPH quenching activity, comparable to those of ascorbic acid and butylated hydroxytoluene and significantly higher than that of α-tocopherol. Polyphenols in F. vesiculosus were found to consist mainly of high molecular weight phlorotannin polymers. There were no clear relationships between the degree of polymerization, molecular size, and antioxidant activity. All the subfractions separated by Sephadex LH-20 column chromatography and ultrafiltration showed a high ability to scavenge reactive oxygen species generated by mononuclear cells. Further characterization of the phlorotannin compounds was performed on six Sephadex subfractions. Several phlorotannin oligomers were tentatively identified on the basis of HPLC-ESI-MS(n) analyses.

<b><i>In vitro</i> evaluation of antioxidant activity of methanolic extracts obtained from seaweeds endemic to the coast of Ceará, Brazil

“…The extracts of D. dichotoma, A. multifida, C. cupressoides, and S. vulgare were found to have the highest TPC values (p < 0.05), while the seaweeds C. crenulata and U. fasciata had the lowest ones. High levels of TPC in brown marine algae are expected, considering reports indicating they are rich sources in fucoxanthin (D'Orazio et al, 2012) and phlorotannins (Wang et al, 2012). Similar results were also described by Wang et al (2009) (Vinayak, Sabu, & Chatterji, 2011), whose values were very similar to the methanolic extracts from the brown seaweeds D. dichotoma and S. vulgare analyzed in this study.…”

Evaluation of phenolic contents and antioxidant activities of brown seaweeds belonging to Turbinaria spp. (Phaeophyta, Sargassaceae) collected from Gulf of Mannar

“…The reduced form of iron (Fe 2+ ) can stimulate and accelerate lipid peroxidation by decomposing lipid hydroperoxides into peroxyl and alkoxyl radicals that can themselves abstract hydrogen and perpetuate the chain reaction of lipid peroxidation [27][28][29][30] . As a result chelators of Fe 2+ ion can be considered as potential inhibitors of lipid peroxidation.…”

“…It was reported that low-molecular compounds in the dried brown seaweed Scytosiphon lomentaria with Fe 2+ iron chelating activity [17] . There are other reports that the phlorotanins which are usually present in the polar solvent fractions of brown seaweeds are strong chelators of heavy metals [4,28] . The Fe 2+ chelating abilities of the seaweed fractions were also reported to be due to the presence of non phenolic compounds like different types of polysaccharides present in the seaweed extracts [32] .…”

Effect of tuna skin gelatin-based coating enriched with seaweed extracts on the quality of tuna fillets during storage at 4 °C

“…These results were consistent with the literature, where Fucus sp. is known to be a source of natural antioxidants and polyphenols (Pinteus et al, 2017;Wang et al, 2012), while Codium spp. is known to be poor in antioxidant activity and polyphenol content (Augusto, Simoes, et al, 2016;Pinteus et al, 2017).…”