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

Objective:To evaluate the antioxidant activities and total phenolic contents of brown seaweeds belonging to Turbinaria spp.[Turbinaria conoides(T.conoides)and Turbinaria ornata(T.ornata)collected from Gulf of Mannar of southeastern coast of India in various in vitro systems.Methods:The antioxidant activity was evaluated using different in vitro systems,viz.,I,I-diphenyl-2-picrylhydrazyl(DPPH),2,2'-azino-bis-3 ethylbenzothiozoline-6-sulfonic acid diammonium salt(ABTS),H_20_2/H0 radical scavenging,Fe^(2+)ion chelating ability,and reducing potential.Folin-Ciocalteu method was used to determine the total phenolic content of the extracts,and the results were expressed as mg of gallic acid equivalents(GE)/g of the seaweed extracts.Thiobarbituric acid-reactive substances assay was employed to assess the ability of the seaweed extracts to inhibit lipid oxidation.Results:Ethyl acetate(EtOAc)fraction of T.conoides registered significantly higher phenolic content(105.97 mg GE/g)than that of T.ornata(69.63 mg GE/g).Significantly higher antioxidant potential as determined by DPPH(64.14%)radical scavenging activity was registered in EtOAc fraction of T.ornata.A higher ABTS(?)radical scavenging(IC_(50)3.16μg/mL),Fe^(2+)chelating(IC_(50)0.46 mg/mL),H_2O_2 scavenging(IC_(50)4.25 mg/mL),lipid peroxidation inhibitory(TBARS,IC_(50)0.21 mg/mL),and reducing abilities(IC_(50)52.67 mg/mL)(P<0.05)were realized in EtOAc fraction of T.ornata than other fractions.Conclusions:This study indicated the potential use of T.conoides and T.ornata as candidate species to be used as food supplements/functional foods to increase shelf-life of food items for human consumption,and nutraceuticals to deter deleterious free radical-induced life-threatening diseases.

Objective:To evaluate the antioxidant activities and total phenolic contents of brown seaweeds belonging to Turbinaria spp.[Turbinaria conoides（T.conoides）and Turbinaria ornata（T.ornata）collected from Gulf of Mannar of southeastern coast of India in various in vitro systems.Methods:The antioxidant activity was evaluated using different in vitro systems,viz.,I,I-diphenyl-2-picrylhydrazyl（DPPH）,2,2’-azino-bis-3 ethylbenzothiozoline-6-sulfonic acid diammonium salt（ABTS）,H202/H0 radical scavenging,Fe2+ion chelating ability,and reducing potential.Folin-Ciocalteu method was used to determine the total phenolic content of the extracts,and the results were expressed as mg of gallic acid equivalents（GE）/g of the seaweed extracts.Thiobarbituric acid-reactive substances assay was employed to assess the ability of the seaweed extracts to inhibit lipid oxidation.Results:Ethyl acetate（EtOAc）fraction of T.conoides registered significantly higher phenolic content（105.97 mg GE/g）than that of T.ornata（69.63 mg GE/g）.Significantly higher antioxidant potential as determined by DPPH（64.14%）radical scavenging activity was registered in EtOAc fraction of T.ornata.A higher ABTS（?）radical scavenging(IC503.16μg/mL),Fe2+chelating(IC500.46 mg/mL),H2O2 scavenging(IC504.25 mg/mL),lipid peroxidation inhibitory(TBARS,IC500.21 mg/mL),and reducing abilities(IC5052.67 mg/mL)（P&lt;0.05）were realized in EtOAc fraction of T.ornata than other fractions.Conclusions:This study indicated the potential use of T.conoides and T.ornata as candidate species to be used as food supplements/functional foods to increase shelf-life of food items for human consumption,and nutraceuticals to deter deleterious free radical-induced life-threatening diseases.