Comparative study on the bioactive components and immune function of three species of sea cucumber
ZHAO Qin,WANG Jing-feng,XUE Yong,WANG Yi,GAO Sen,LEI Min,XUE Chang-hu (Food Science and Engineering College,Ocean University of China,Qingdao 266003,China)
Sea cucumber has been proved as a source of substance rich in nutritional components and biological activity. Sea cucumber saponins and triterpene glycosides,commonly known as holothurins,have drawn attention because of their wide spectrum of biological effects such as antifungal,cytotoxic,hemolytic,cytostatic and immunomodulatory activities. In this study,the bioactive components of Isostichopus badionotus,Isostichopus fuscus and Cucumaria frondosa and their function on immune regulation were determined by chemical analysis and immunological methods. The contents of polysaccharide,triterpene glycosides and amino acids in body wall were measured and compared,and their immune regulation were investigated with the model mice in normal and in immunodepression induced by hydrocortisone. The results showed that I. fuscus had the highest content of polysaccharide in the body wall among these three species of sea cucumber. The contents of triterpene glycosides,total amino acids,drug-effective amino acids and delicious amino acids are higher in C.frondosa than in the others. In normal mice,all three kinds of sea cucumber could increase thymus/body weight value,heighten delayed hypersensitivity level (P0.05 or P0.01) and the ability of macrophages for carbon particle clearance (P0.05 or P0.01). In hypoimmune mice,they all could antagonize the decline of thymus/body weight value induced by hydrocortisone (P0.05 or P0.01),increase hemolysin content (HC50) (P0.05 or P0.01),spleen lymphocyte transformation (P0.05 or P0.01) and the ability of macrophages for carbon particle clearance (P0.05 or P0.01). C.frondosa had the most remarkable effects in HC50 and phagocytic index (SNK,P0.05). Triterpene glycoside from another kind of sea cucumber C.japonica was found to stimulate phagocytosis and production of IL6 and TNF-?,and increase the number of antibody producing cells. At the same time,the preparation did not affect the delayed-type hypersensitivity and cytokine IL12 and IFN-γ release. This suggests triterpene glycoside in sea cucumber could promote humoral immunity and non-specific immunity. Sea cucumbers have high content of Gly,Glu and Arg in body wall. Gly can stimulate production and release of IL-2 and B cell antibody,and enhance phagocytosis. Gly and Glu are essential materials for cell to synthesize glutathione which can stimulate activation and proliferation of NK cell. Arg can enhance cell immunity by promoting activation and proliferation of T-cell. It is suggested that these three species of sea cucumbers all have remarkable function in immune regulation. They can both promote immune function by cell immunity and non-specific immunity in normal mice and promote immune function by cell immunity,humoral immunity and non-specific immunity in immunodepression mice. The significant effect on immune regulation of C.frondosa correlated to its higher contents of triterpene glycoside and active amino acids in all probability.