Study on Extraction Conditions and Bioactivities of Polysaccharide from Gynostemma pentaphyllum Makino

Autor: Shu-Chen Tseng, 曾淑真
Rok vydání: 2009
Druh dokumentu: 學位論文 ; thesis
Popis: 97
Gynostemma pentaphyllum (Thunb.) Makino has been shown to possess many biological functions. Active substances have been focused on saponins, however, polysaccharides may also play a vital role. The objectives of this study were to develop optimal methods to extract polysaccharides and to produce microparticles by using a planetary ball mill and to evaluate the antioxidant activities and anti-/pro-bacterial growth effects of microparticles of polysaccharides form G. pentaphyllum. G. pentaphyllum powder was extracted twice with a liquid: solid ratio of 16: 1 (deionized water: G. pentaphyllum powder) at 80℃ for 1 h, followed by vacuum concentration and precipitation by a two-fold volume of 95% ethanol at 4℃ for 8 h. Maximum yield of 5.30±0.02% crude polysaccharides (CP) was obtained by this process. The polysaccharide was then dissolved in sodium phosphate buffer (pH 8.0) and deproteinated by trypsin (2.5 U/mL) at 37℃for 5 h, and a total of 85.50±0.31% protein was removed. The CP and deproteinated polysaccharide (DP) were further purified by DEAE Sepharose CL-6B chromatography column (2.6 × 40 cm). The fractions of each neutral and acidic polysaccharide were effectively separated when the column was eluted with deionized water (180 mL) and followed by 1 M NaCl (180 mL) at a flow rate of 2 mL/min. The neutral and acidic polysaccharide fractions were successfully eluted at 20 min and 130 min, respectively. The molecular weights of CP were 84000 and 7800 Da estimated by high performance size exclusion chromatography (HPSEC) and its neutral (CPN) and acidic (CPA) fractions of polysaccharide were 61000 and 8500 Da, respectively. Furthermore, the molecular weights of DP were 23000 Da and its neutral (DPN) and acidic fractions (DPA) of deproteinated polysaccharide were 11000 and 12000 Da, respectively. The results indicated that CP, CPA, DP, and DPA had significant (p
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