Investigation On Preparation Of Acemannan Analogy By Molecular Modification Of KGM And Its Bioactivity

This paper is mainly focused on the modification of konjac glucomannan polysaccharide (KGM) and the improvement of its bioactivity. In this paper, the preparation of water-soluble high molecular weight acetylated KGM (AKGM) with high acetylating degree and degradation of KGM by ultrasonic were studied. Through biological technique, the relationship between bioactivity and degree of acetylating substitution and the relationship between bioactivity and molecular weight were also studied.In the AKGM preparation section, improved spectrophotometric method was used to inspect acetylating content, with both the acetylating degree and molecular weight used as the criteria, and the optimal laboratory preparation Parameters were determined: mass ratio of Acetic anhydride to KGM 15, reaction temperature 60-80℃, reaction time 0.5-1.5h, Sodium Acetate 0.4-0.8g. Based on the above results a significant regression equation about acetylating degree was obtained. In this way, AKGM have high molecular and its acetylating degree can be controlled within 0.3-1.1.In the ultrasonic degradation section, effects of single factor (such as power of ultrasonic, ultrasonic processing time, concentration of KGM and so on) on ultrasonic production were studied. Results showed that: under different ultrasonic power degradation productions had different molecular weight limits; Bandwidth of molecular weight distribution depended on degradation time; and the degradation speed depended on ultrasonic power and KGM concentration. It was also confirmed that the broken location of KGM main chain by ultrasonic degradation was non-random, and side chain was not destroyed. According to the data of HPGFC and [η], Mark-Honwind equation was established, [η]=4.5×10-2Mw0.7.Based on biology technique, cell proliferation activity and immune-activity of AKGMs with different molecular weight and acetylating degree were studied. These two factors have significant effects on bioactivity, but they were different. The orders of significance of different factors to bioactivities were investigated. The result were as follows: acetylating degree to cell proliferation activity: 0.48>0.76>0.22; acetylating degree to immunocompetence: 0.76>0.48>0.22; molecular weight to cell proliferation activity 55,000>150,000>300,000; and molecular weight to immunocompetence 300,000>150,000>55,000. Orthogonal tests analysis showed that acetylating degree had more important roles in cell proliferation activity and proliferation of lymphocytes, and molecular weight had more important roles in phagocytosis of peritoneal macrophage. Further study of the interaction between molecular weight and acetylating degree showed that the interaction was significant in cell proliferation activity and proliferation of lymphocytes, but not in phagocytosis of peritoneal macrophage.