Two natural homogalacturonan (HG) pectins (MW ca. 20 kDa) were isolated from green tea based on their immunomodulatory activity. The crude tea polysaccharides (TPS1 and TPS2) were obtained from green tea leaves by hot water extraction and followed by 40% and 70% ethanol precipitation, respectively. Two homogenous water soluble polysaccharides (TPS1-2a and TPS1-2b) were obtained from TPS1 after purification with gel permeation, which gave a higher phagocytic effect than TPS2. A combination of composition, methylation and configuration analyses, as well as NMR (nuclear magnetic resonance) spectroscopy revealed that TPS1-2a and TPS1-2b were homogalacturonan (HG) pectins consisting of a backbone of 1,4-linked alpha-D-galacturonic acid (GalA) residues with 28.4% and 26.1% of carboxyl groups as methyl ester, respectively. The immunological assay results demonstrated that TPS1-2, which consisted mainly of HG pectins, showed phagocytosis-enhancing activity in HL-60 cells.
[1]Shanghai Univ Tradit Chinese Med, Inst Chinese Mat Med, MOE Key Lab Standardizat Chinese Med, Shanghai 201203, Peoples R China.
[2]Shanghai Univ Tradit Chinese Med, Inst Chinese Mat Med, SATCM Key Lab New Resources & Qual Evaluat Chines, Shanghai 201203, Peoples R China.
[3]Unilever R&D Shanghai, Shanghai 200335, Peoples R China.
[4]Unilever R&D Bangalore, Bangalore 560066, Karnataka, India.
[5]Univ Westminster, Fac Sci & Technol, Dept Complementary Med, London W1W 6UW, England.
(8.0+极速模式)