Abstract

Fucoidans are sulphated fucose rich heteropolysaccharides found in marine source seaweed. Fucoidan has gained interest due to its diverse biological activities. Dual inhibition of cyclooxygenase and lipoxygenase prevents shunting of the arachidonic acid metabolism sparing gastric toxicity observed with selective cyclooxygenase-2 inhibitors. The present study investigated dual inhibition potential of fucoidan extracted from Sargassum wightii on cyclooxygenase, lipoxygenase and its anti-inflammatory effect on carrageenan induced paw oedema. Fucoidan and diclofenac demonstrated dual inhibition towards cyclooxygenase and lipoxygenase with half-maximal inhibitory concentration of 44.03±3.74 μg/ml, 34.92±5.14 μg/ml (cyclooxygenase) and 28.26±2.06 μg/ml and 26.54±1.37 μg/ml (lipoxygenase) in lipopolysaccharide stimulated RAW 264.7 macrophage cells respectively. Fucoidan is showing concentration dependant reduction in nitric oxide level of lipopolysaccharide stimulated RAW 264.7 cells with a half-maximal inhibitory concentration of 17.88±2.43 μg/ml and 17.99±3.15 μg/ml for diclofenac. Fucoidan showed suppression of lipopolysaccharide stimulated gene expression of cyclooxygenase-2 and 5-lipoxygenase in RAW 264.7 macrophage cells. Fucoidan showed 99.62±1.69 % cell viability in RAW 264.7 macrophage cells. The acute oral toxicity study of fucoidan showed no abnormal clinical signs. The fucoidan attenuated carrageenan induced increase in paw volume in Wistar rats at the tested doses of 100 mg/kg and 200 mg/kg at 60, 120 and 240 min (p<0.05). Results suggest that the anti-inflammatory activities of fucoidan involve attenuation of eicosanoid production.