Polysaccharides from pectinase digests of green tea enhances host immune defence through toll-like receptor 4

Abstract

To develop new immunostimulatory ingredients, green tea polysaccharides were obtained by pectinase-assisted extraction. The present study investigated the immune stimulating and protective ability of polysaccharides from pectinase digests of green tea (PPGT) against infectious disease and the mechanisms involved. Macrophages stimulated with PPGT exhibited dosedependent increases in nitric oxide, tumour necrosis factor-α (TNFα) production and phagocytosis. PPGT increased phosphorylation of mitogen-activated protein (MAP) kinase, nuclear factor-kappaB (NFκB) and signal transducers and activators of transcription (STATs) through toll-like receptor 4 (TLR4) activation. The survival of mice infected with a lethal dose (1 × 10 7 CFU) of S. typhimurium was significantly extended by PPGT administration. Furthermore, PPGT induced production of cytokines (interleukin-12, interferon-γ, and TNF-α) in mice infected with a sub-lethal dose (1 × 10 5 CFU) of S. typhimurium. Furthermore, PPGT was significantly promoted natural killer cell and cytotoxic T lymphocyte activity. The above results lead to conclude that PPGT have a potent immune stimulating effect on immune cells via TLR4 pathway.

Advances in the Utilization of Tea Polysaccharides: Preparation, Physicochemical Properties, and Health Benefits

“…Green, black, and oolong teas 1:20 solid/liquid ratio, 200-230 • C extraction temperature, and 2 min extraction time [28] Green tea flowers Extraction at controlled microwave power for 5 min followed by extraction with distilled water for 5 min at the same microwave power [21] Green tea Extraction in a 600 W microwave apparatus for 30 min, followed by stirring in a water bath for 90 min; repeated three times [29] Enzymolysis extraction Green tea Extraction at 100 • C for 3 h and aqueous extraction with pectinase and tannase at 35 • C for 2 h [30] Green tea Extraction with complex enzymes (cellulase:pectinase:glucanase = 1:1:2) at 50 • C for 30 min, boiling at 90 • C for 10 min, and then extraction in a water bath at 50 • C for 80 min [29] Green tea leaves and flowers 95% ethanol pretreatment at 40 • C for 2 h (repeated 3 times), treatment with 0.5% (m/v) pentosan complex enzyme solution (45 • C, pH 5.5) for 2 h, and extraction in 45 • C water bath for 2 h [14] Green tea Heating in a water bath at 90 • C for 2-4 h, repeated twice; incubating with 0.5% pectinase (260,001 PGU/mL, v/w) at 40 • C for 30 min; and heating at 90 • C for 1 h to inactivate the enzyme [31] Hydro/solvothermal extraction Chinese tea Zhongcha 108 Extraction at 120 • C for 1 h [1] Alkali-assisted extraction Fuzhuan brick tea Extraction with 0.…”