Optimization of Extraction and Purification of Polysaccharides from Veronicastrum axillare,and Evaluation of Their Biological Activities |
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Authors: | Yijia Qi Weiming Ren Haixia Zhang Gang Chen Weiyi Huang Xuexia Li Jie He Weichun Zhao |
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Institution: | 1. College of Life Sciences, Zhejiang Chinese Medical University, Hangzhou, 310053 P. R. China;2. Department of Chemistry, Simon Fraser University, Burnaby, BC, V5 A 1S6 Canada |
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Abstract: | Veronicastrum axillare polysaccharides (VAP) were isolated by cellulase-assisted digestion. The optimum conditions (2 % cellulase, 47 °C for 2.5 h, then, 95 °C for 2.5 h, pH 4.1, solid/liquid ratio 1 : 7.6) were identified by a combination of single factor optimization and response surface DOE (design of experiment) methods, and achieved a yield of 4.7 %. Treatment with 1 % TCA for 10 min, then, 2 % DEAE-cellulose removed protein and colored impurities. Purified VAP retained most of the radical-scavenging activities and GES-1 cell protection capability in vitro, indicating VAP were the key active components of V. axillare. Some molecular features were identified by FT-IR and NMR analyses. The molecular weight was estimated from DOSY NMR experiments to be around 21 kDa. There were 6.3 % uronic acid residues in the VAP. The constituent sugars after TFA hydrolysis were identified by HPLC to include glucose, arabinose, rhamnose, galactose, and xylose in a molar ratio of 405 : 259 : 82 : 42 : 1. |
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Keywords: | Veronicastrum axillare polysaccharides (VAP) response surface method structure analysis antioxidant activity anti-gastric ulcer activity |
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