Brown Algae Polyphenolic Compounds Extraction, Purification And Biological Activity Study

Sargassum Kjellamanianum Yendo and Sargassum thunbeergii kuntze are two common kinds of brown algae along Qingdao coast. They are abundant in bioactive constituents, which make them potential resources for advanced pharmaceutical utilization.The present thesis is focused on the studies of the extraction, purification and bioactivities of the phlorotannins in the two brown algae.The results of the experiments are as follows:1.The conditions we choose for the extraction of the phlorotannins: Solvent is 90% alcohol; Temperature is 30 C; The duration is 12h and the liquid nitrogen is used before grounded.2.The bioactivities of the crude extract of brown algae phlorotannins include antioxidation, antibiosis, anticoagulation, and so on. (1) The crude extract has strong activity of scavenging free radicals. As marine natural products . they have significant advantage compared with synthestic antioxidant. (2) The crude extract has antibacterial activities on both positive and negative bacteria, especially on two kinds of marine bacteria. (3) The crude extract has evident anticoagulation activities. In vitro, they can sharply extend plasma calcium restoration and coagulation time. In vivo, they can change the time and the quantities of bleeding, the length of thrombi, the quantities and aggregation rate of blood plates, and so on.3.The purification of the extract crude can be divided into 11 bioactive fractions. The methods used in this process include TLC, column chromatography on silica, sephadex G and sephadex LH-20, superfiltration.4.The bioactivities of the 11 fractions are studied, and related to their molecular weights according to the experimental results. The bigger the molecule weight, the stronger the bioactivities.