Antimicrobial potential of selected brown seaweeds from Vedalai coastal waters,Gulf of Mannar

Objective:To evaluate the antimicrobial activity of Turbinaria conoides(T.conoides).Padina gymnospora(P.gymnospora) and Sargassum tenerrimum against human bacterial and fungal pathogens.Methods:The antimicrobial activities of the extracts against various organisms were tested by using disc diffusion method.Results:The methanol extract showed the better result than the other extracts.Whereas,the strong antibacterial inhibition was noted in methanol extracts of P.gymnospora against Bacillus subtilus(26.33±1.86) and the mild inhibition of ethanol extracts from T.conoides against Klebsiella pneumoniae(2.33±0.51).Acetone extraction of P. gymnospora had strong antifungal inhibition against Cryptococcus neoformans(23.00±1.78), and acetone extract of T.conoides had mild inhibition against Aspergillus niger(3.00±0.89). Conclusions:The seven different solvent extracts of seaweeds used in the present study have shown significant bacterial action.Further,a detailed study on the principle compound in the seaweeds which is responsible for antimicrobial activity is still needed and it can be achieved by using advanced separation techniques.

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.