Extraction and Biological Activity Analysis of Polysaccharides from Low Grade Tobacco

In order to optimize the technology for extracting polysaccharides from low grade tobacco and study their bioactivity, four factors, including ultrasonic power, extraction time, extraction temperature and solid/liquid ratio, were optimized with single factor test and L₉(3⁴) orthogonal test. The obtained crude polysaccharides were purified with a Sepharose CL-6B carboxymethyl agarose gel column, the scavenging activity of polysaccharides to free-radicals·OH and DPPH·was investigated, and the general antioxidant activity of polysaccharides was determined in vitro with ABTS method. The results showed that:1) The optimal conditions were:ultrasonic power 600 W, solid/liquid ratio 1:25, and extracting for 4 minutes at 60℃. Under such conditions, the yield of polysaccharides was 2.56%. 2) The obtained polysaccharides contained two fractions of different molecular weights. 3) The polysaccharides possessed strong in vitro antioxidant activity, obvious free-radical scavenging activity and potential nourishing and health care function. The results provided certain theoretical references for the utilization of low grade tobacco.