Antioxidant and anti-inflammatory potential of the aqueous extract and polysaccharide fraction from brown marine macroalgae Padina sp.from Gulf of Mannar of Peninsular India

Objective:To evaluate the antioxidant and anti-inflammatory potential of the aqueous extract and polysaccharide fraction from two brown marine macroalga,Padina gymnospora(P.gymnospora)and Padina tetrastomatica(P.tetrastomatica)harvested from Gulf of Mannar of peninsular India.Methods:The antioxidant activity was evaluated using different in vitro systems,viz.,1,1-diphenyl-2-picrylhydrazyl(DPPH),2,2′-azino-bis-3ethylbenzothiozoline-6-sulfonic acid diammonium salt(ABTS),H_(2)O_(2)/HO.radical scavenging,Fe^(2+)ion chelating ability,and reducing potential.Folin–Ciocalteu method was used to determine the total phenolic content,and the results were expressed as mg of gallic acid equivalents(GE).Thiobarbituric acid-reactive substance formation inhibition assay was employed to assess the ability of the samples to inhibit lipid oxidation in a model system.COX_(II)and LOX_(V)inhibition assays were employed to assess the anti-inflammatory potential of aqueous extract and polysaccharide fraction.Results:The aqueous extract fraction of P.tetrastomatica realized high total phenolic content(288 mg GE/g),and its activity towards scavenging short-lived radicals(OH.and H_(2)O_(2))(27.8%and 68.3%,respectively;0.6 mg/mL)are higher than those registered for Padina gymnospora.Aqueous extract and polysaccharide fractions of P.gymnospora showed higher anti-inflammatory activities against LOX_(V)(56%and 53%,respectively)and COX_(II)(30%and 35%,respectively;1 mg/mL)enzymes.The correlation studies confirmed that polysaccharides present with the Padina sp.are responsible for their anti-inflammatory potential.IR spectral data of polysaccharide fraction revealed the presence of polysaccharide in alginate form and also confirmed the presence of sulphated polysaccharides as principle bioactive constituents.Conclusions:The study revealed that these seaweeds possess beneficial value as human food or health additives and can be used as a natural green remedy against oxidative stress induced inflammatory diseases.