Molecular characteristics and anti-inflammatory activity of the fucoidan extracted from Ecklonia cava

► We extracted the fucoidan from Ecklonia cava by enzymatic extraction technique. ► Their molecular characteristics and anti-inflammatory activities were investigated. ► The crude and fractionated fucoidan has various molecular characteristics ► E. cava fucoidan exhibited strong anti-inflammatory activities by NO inhibition ► E. cava fucoidan may be a useful therapeutic approach for the inflammatory diseases. Enzymatic extraction has been successfully used for extracting numerous biologically active compounds from a wide variety of seaweeds. In this study, we found that enzymatic extraction of the fucoidan from Ecklonia cava may be more advantageous than water extraction. Therefore, we studied the E. cava fucoidans extracted by the enzymatic extraction technique and used ion-exchange chromatography to determine their molecular characteristics and anti-inflammatory activities. The crude and fractionated fucoidans (F1, F2, and F3) consisted mostly of carbohydrates (47.1–57.1%), uronic acids (9.0–15.8%), and sulfates (16.5–39.1%), as well as varying levels of proteins (1.3–8.7%). The monosaccharide levels significantly differed, and the composition included fucose (53.1–77.9%) and galactose (10.1–32.8%), with a small amount of rhamnose (2.3–4.5%), xylose (4.0–8.2%), and glucose (0.8–2.2%). These fucoidans contained one or two subfractions with an average molecular weight (Mw) ranging from 18 to 359×103g/mol. These fucoidans significantly inhibited NO production in lipopolysaccharide (LPS)-induced Raw 264.7 macrophage cells by down-regulating the expression of iNOS, COX-2, and pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β. Thus, the present results suggest that E. cava fucoidan may be a potentially useful therapeutic approach for various inflammatory diseases.