Abstract: Globally, obesity has become the fifth leading risk factor for death, and discoverying prebiotics with preventive and therapeutic effects on obesity is a hot topic in current research. Marine polysaccharides, a special class of bioactive substances from marine organisms, have novel structural features and unique bioactivities due to the unique environment of the ocean. Marine polysaccharides have an excellent potential to treat obesity by regulating glucose and lipid metabolism, inflammatory factor levels, and the gut microbiota. This article reviews the types of marine polysaccharides, the effects of their structures and compositions on their antiobesity activity, and the underlying mechanisms of action. With the aim of providing a basis for the development of antiobesity drugs using marine polysaccharides, the article focuses on discussing the signaling pathways by which marine polysaccharides inhibit obesity through the gut microbiota, and gives an outlook on the application of marine polysaccharides for obesity inhibition.

Key words: marine polysaccharides; structure; composition; antiobesity; action mechanism