Immunostimulating Activity of a Crude Polysaccharide Derived from Green Tea (Camellia sinensis) Extract

Manami Monobe*, Kaori Ema, Fumiko Kato and Mari Maeda-Yamamoto
National Institute of Vegetable and Tea Science, NARO, 2769 Kanaya, Shimada, Shizuoka 428-8501, Japan
J. Agric. Food Chem., 2008, 56 (4), pp 1423–1427
DOI: 10.1021/jf073127h
Publication Date (Web): January 31, 2008
Copyright © 2008 American Chemical Society
* To whom correspondence should be addressed. Phone: +81-547-45-4101 . Fax: +81-547-46-2169. E-mail: monobe@affrc.go.jp.

Abstract

Green tea extract is well-known to reduce the risk of a variety of diseases. Here, we investigated the immunostimulating activity of tea polysaccharide (TPS), one of the main components in green tea extract. The water extracts from mature or immature tea leaves were precipitated by using ethanol at room temperature. The sediment was washed with ethanol and acetone alternately and then dried. We used the phagocytic activity of macrophage-like cells as an indicator of immune function activation. Chemical components were analyzed by HPLC. The immunostimulating activity of TPS from immature leaves extract was higher than that of TPS from mature leaves, and its activities were dependent on the content of strictinin in the leaf extract. Futhermore, a mixture of catechin and TPS that removed polyphenols did not increase the immunostimulating activity. These results suggest that the catechin−polysaccharide complex is a very important molecule in the immunomodulating activity of tea extracts.

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History

  • Published In Issue February 27, 2008
  • Article ASAPJanuary 31, 2008
  • Received: October 24, 2007
    Accepted: January 03, 2008
    Revised: December 18, 2007

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