Abstract: Oligosaccharides are linear or branched carbohydrate compounds composed of two to ten monosaccharide residues connected by glycosidic bonds. They have many health benefits, and can function as sweeteners. Oligosaccharides are a combination of nutritiousness, health care, and dietetic therapy. Compared with polysaccharides, oligosaccharides have several advantages, such as stronger biological activity and easier absorption by the body. In recent years, marine-derived oligosaccharides have been proven to have a variety of biological activities, such as antioxidant, anti-tumor, anti-inflammatory, antibacterial, anticoagulant, and immunity-enhancing activities. They can be widely used in food, medicine, cosmetics, agriculture, aquatic products, and other fields. This paper introduces four major marine-derived oligosaccharides, including N-acetyl chitooligosaccharide/chitooligosaccharide, alginate oligosaccharides, agarooligosaccharides, and carrageenan oligosaccharides, and presents a brief description of their sources, structural characteristics, various biological activities and applications. It is expected to provide a reference for the high-value utilization of marine polysaccharide resources and the in-depth development of marine oligosaccharides.

Key words: marine-derived oligosaccharide; N-acetyl chitooligosaccharides/chitosan oligosaccharide; alginate oligosaccharides; carrageenan oligosaccharides; agarooligosaccharides