The Anticoagulation Activities And Their Mechanism Of Phlorotannins Extracted From Sargassum Thunbeergii Kuntze

In this thesis, phlorotannins which have peculiar bioactivities were extracted and purified from Sargassum thunbeergii Kuntze. Then the emphasis was focused on the studies of the anticoagulation activities and their mechanism of phlorotannins, and the conclusions are as follows:1. The extracting procedure of phlorotannins was optimized. In order to purify the extract once more, phlorotannins were classified into six groups according to their molecular weights.2. Items showing anticoagulation activity (including BT, CT, APTT, PT, TT) were examined by animal experiments. The results showed that every group of the phlorotannins has excellent anticoagulate effects. Moreover, the anticoagulate effect is affected by its molecular weights. In other words, the higher its molecular weight, the stronger its anticoagulate effect. The results also showed that the group that its molecular weight is bigger than 1.0×10⁵ has the best anticoagulate effect compared with other groups.3. Effects of phlorotannins on APTT, PT, TT, MDA, TXB₂, 6-Keto-PGF₁.. the rate of platelet aggregation and the concentration of Ca²⁺ in the platelet activated by ADP were examined by animal experiments. According to the experimental results, phlorotannins can effectively inhibit the platelet aggregation. Moreover, it can lower the content of TXB₂ while increase the content of 6-Keto-PGF₁. in plasma; Besides, it also can significantly inhibit the rise of the concentration of free calcium in platelet. From the experimental results above, it can be concluded that phlorotannins can significantly prolong the coagulation time and platelet aggregation time through affecting normal inside and outside coagulate process and platelet's physiological function by decreasing the concentration of Ca²⁺ in plasma. Therefore, phlorotannins probably could be applied in the prevention and cure of thrombosis in the future.