First report of substituted 2pyranoids from brown seaweed with antioxidant and anti-inflammatory activities.

The organic extract of , a brown seaweed harvested from the Gulf of Manner region of Indian peninsular was chromatographically fractionated to yield three substituted 2pyranoids, namely methyl-2-yl-[5', 6'- dihydro-5'-yl-{5-(4-hydroxybenzoyl)-oxy-(5-methylbutyl)}-3'-methyl-2-pyran]-2-methyl butanoate (), 11-[(3', 6'-dihydro-4'-methyl-2'-oxo-2-pyran-3'-yl)methyl]-10-methylhexyl benzoate (), and [6-ethyl-3,4-dimethyl-(tetrahydro-2', 2', 6'-trimethyl-2-pyran-3'-yl)-2,5-cycloheptadiene]-1-propanoate (). The compounds and bearing 2-pyranyl-4-hydroxybenzoyl and 2-pyranyl-10-methylhexylbenzoate moieties exhibited potential antioxidant activities (IC 0.54-0.69 mg mL) as commercial antioxidant (-tocopherol IC 0.63-0.73 mg mL). Likewise, potential bioactivity of the 2-pyran derivative, against 5-lipoxygenase (IC ∼ 1 mg mL) along with higher index of selectivity (COX-1 inhibitory/COX-2 inhibitory 1.88) indicated their selective anti-inflammatory properties against inducible inflammatory mediators than that displayed by commercially available non-steroidal anti-inflammatory drug (ibuprofen, 0.44). Structure activity relationship analysis of the studied compounds showed that the antioxidative and anti-inflammatory properties were directly proportional to their electronic properties. The previously undescribed pyranoids might constitute as potential antioxidative and anti-inflammatory pharmacophores for medicinal applications. [Formula: see text].