Anti-obesity effects of enzymatically-digested alginate oligomer in mice model fed a high-fat-diet

Abstract Alginate is an acidic linear polysaccharide isolated from brown seaweed, and is widely used in food, supplement, and medical industries. In this study, the anti-obesity effects of dietary acid-hydrolyzed (A-AO) and enzymatic-digested (E-AO) alginate oligomers were investigated in male mice fed a high-fat diet. E-AO showed stronger anti-obesity effects than A-AO, as judged by the reduction in body and adipose tissues weights. Further studies demonstrated that the anti-obesity effects of E-AO were superior to those of original alginate polymer (AP). E-AO also showed anti-obesity effects in female obese mice, in which E-AO suppressed the plasma leptin level. Dietary AP and E-AO suppressed the increase in serum triglyceride (TG) levels induced in mice by oral administration of corn oil. AP and E-AO inhibited pancreatic lipase. In vitro analysis showed that E-AO inhibited lipid accumulation in differentiated 3T3-L1 adipocytes, whereas AP had no effect, suggesting that a direct effect of E-AO on adipocytes, in addition to the suppression of gastrointestinal lipid absorption, is partly responsible for the superior anti-obesity effects of E-AO.