Study On The Separation, Purification And Elementary Structure Of The Polysaccharide From Tea Flower

This thesis main focused on the extraction, separation, purification, characterization and bioactivity of polysaccharides from tea flowers. These studies have the extremely vital significance to exploit the tea flower polysaccharides (TFPS) and also can make full use of tea resource, then to create good economic and social benefits. This thesis is outlined as follows:1) Physicochemical properties of tea flowers were determined, including fat, total polysaccharides, flavonoids, polyphenols, proteins, and so on. The contents of total polysaccharides (31.82 %), uronic acid (7.42 %), polyphenols (11.67 %) and flavonoids (10.66 %) in tea flowers were similar to that in tea leaves.2) The effect of ethanol precipitant by grade and sub-step on the yield and purity of TFPS was investigated. The results showed that TFPS accounted for 85 % (m/m) of total polysaccharides, when the concentration of ethanol approached to 30 % (v/v). It showed that most of TFPS can be precipitate with 30 % ethanol.Compared with the industrial application (70 % ethanol), this method is used less alcohol.3) This thesis discussed the effect of extraction processes on composition and bioactivity of TFPS, including hot water, boiling water and enzyme extraction. The yield of TFPS by boiling water which was similar to enzyme extraction was about 5 times higher than that by hot water, but the contents of acidic and neutral polysaccharides were almost same. Theα- glucosidase inhibitory percentage of TFPS obtained by boiling water, hot water and enzyme extraction were determined as 79.15 %>64.62 % >16.25 %. Antioxidant activity of TFPS was studied here by DPPH and Linoleic acid system.The results showed that TFPS had a strong antioxidant activity. TFPS (3.0μg/ml, P< 0.01) by boiling water extraction played an important role in promoting lymphocyte growth.4) TFPS was separated and purified by macroporous resin adsorption, anion-exchange and gel chromatography. Two homogeneous polysaccharides TFPS1 and TFPS2-2 were obtained.5) TFPS1 and TFPS2-2 were characterized by gas chromatography, high performance gel permeation chromatography, ion chromatography, infrared spectroscopy, 1H NMR, 13C NMR spectroscopy and the atomic force microscopy. TFPS1 was a glycoprotein with a molecular weight 500kDa. The alanine, threonine, glycine, valine, serine, histidine, glutamic acid, histidine and tyrosine were found in TFPS1 and the totall content was 2.03 %. TFPS1 consisted of rhamnose, arabinose, mannose, glucose and galactose, with mole ratio of 1.0:2.9:0.5:1.3:3.3. Monosaccharide residues linked each other withа-,β-glycosidic bond. Sugar backbone of TFPS1 may consist of glucose and galactose, but branched chain may consist of arabinose, galactose and rhamnose. TFPS2-2 was an acidic polysaccharides with a molecular weight 200kDa. TFPS2-2 consisted of rhamnose, arabinose, galactose, glucose and galacturonic acid, with mole ratio of 1.60:4.40:6.94:1.00:13.83. Sugar backbone of TFPS2-2 may consist of galacturonic acid and galactose, but branched chain may consist of rhamnose, arabinose, glucose and galactose Infrared spectra revealed that TFPS2-2 contained D-glucopyranosyl ring andβ-D-arabinopyranosyl. TFPS1 and TFPS2-2 were uniform spherical particles observing under atomic force microscopy. Diameters of TFPS1 and TFPS2-2 were 50 ~ 70 nm and 80 ~ 100 nm, respectively.