Abstract: Nattokinase (NK), a serine protease, can be used as a thrombolytic agent. Compared with clinical thrombolytic drugs (urokinase and streptokinase), NK has the advantages of low price, high thrombolytic efficiency, oral administration, and no toxic side effect, making it an ideal natural thrombolytic agent. At present, commercial thrombolytic NK products have the problems of low activity and bioavailability, which enter the bloodstream to exert thrombolytic effects through the oral and gastrointestinal digestion and absorption system. The gastrointestinal tract (GIT) environment (strong acidity, pepsin and trypsin) can destroy the spatial structure of NK, leading to a decrease or loss of its thrombolytic activity. The construction of functional vectors for NK delivery using natural biomaterials such as lipids, polysaccharides, and proteins can effectively avoid these adverse factors in the digestive system, enhancing the stability of NK, and improving its biological activity and bioavailability in the body. Beginning with an overview of the structural and functional properties of NK, this paper summarizes recent progress in research on functional vectors for NK delivery in order to provide a theoretical basis and technical support for efficient and stable thrombolytic NK products.

Key words: nattokinase; encapsulation; functional delivery vector; antithrombotic