The Study On Extraction Of Polyphenols From Sargassum Kjellmaniamum And Its Biological Activities

The Sargassum kjellmaniamum belongs to Phaeophyta Sargasso family, which is widely distributed in the Atlantic coast,China’s southeast coast,the Bohai Bay and other sea areas. The S. kjellmaniamum are rich in a variety of bioactive substances, including the polyphenols, which showed activities in antioxidant, antibacterial, antiviral and antitumor studies. In this paper, the extracting methods and antioxidative/antibacterial activities of polyphenols from S. kjellmaniamum were studied. The results will provide useful information for the development and utilization of S. kjellmaniamum resources.The polyphenols from S. kjellmaniamum were extracted with ethanol. The extracting parameters were optimized using single-factor trials combined with orthogonal experiment. NKA-9 macroporous resin and SephadexLH-20 were used for separation and purification of polyphenols. In order to assess the antioxidant capacity of polyphenols from S. kjellmaniamum, the scavenging activities of DPPH·, OH·, superoxide anion radicals, reducing power and ORAC value of polyphenols were determined using in vitro antioxidant methods. Through the filter paper method and kinetic experiments, antibacterial activity of polyphenols from S. kjellmaniamum was measured.The results were as follows:1.The results showed that the optimum technological conditions were 50% ethanol concentration with solid-liquid ratio of 1:25 at 70 ℃for 8 hours. The polyphenol yield was 5.96mgGA/g under this condition. The polyphenol content was 2.17mgGA/g. After anhydrous ether and chloroform extract, the polyphenol content was increased to 3.62mgGA/g. After NKA-9 macroporous resin, the polyphenol was separated into two components F1 and F2, which polyphenol contents were 4.40mgGA/g and 6.52mgGA/g, respectively. Then after isolation and purification of Sephadex LH- 20, the first component F1 had the only component F1-1, which polyphenol content was 4.57mgGA/g. The second component F2 was separated into two components F2-1 and F2-2, which polyphenol contents were 6.28 mgGA/g and 8.61 mgGA/g, respectively.2.The polyphenols from S. kjellmaniamum showed remarkable antioxidative capacities in vitro,with scavenging of DPPH·,OH·and superoxide anion radicals, have reducing power and oxidation radical absorbance capacity. With the concentration increased, the antioxidant activity of all components were increased. F1 had the best DPPH and superoxide anion radical scavenging activity and oxidative radical absorbance capacity. Extracts had the best hydroxyl radical scavenging capacity. F2-1 had the best reduction of Fe ions. The polyphenols have the better antioxidative activities than Vc.3.The polyphenols from S. kjellmaniamum had effective antibacterial activity on four kinds of bacterias such as Bacillus subtilis,anthraci,proteusbacillus vulgaris and Staphylococcus aureus.The best antibacterial activity was on proteusbacillus vulgaris. But there hadn’t effective antibacterial activity on Escherichia coli and Shewanella. The polyphenols have the better antibacterial activities on Gram-positive bacterias than Gram-negative bacterias. The best antibacterial activity on Bacillus subtilis were F1 and F2, and both of their MIC were 6.25μg/mL. The best antibacterial activity on anthraci were F1,F2 and F2-1,and all of their MIC were 3.125μg/mL. The best antibacterial activity on proteusbacillus vulgaris were F2,F2-1 and F2-2,and all of their MIC were 3.125μg/mL. The best antibacterial activity on Staphylococcus aureus was F2, which MIC was 3.125μg/mL.