Send to

Choose Destination
J Agric Food Chem. 2011 Mar 23;59(6):2734-8. doi: 10.1021/jf103072z. Epub 2011 Feb 24.

Epigallocatechin-3-gallate inhibits lactase but is alleviated by salivary proline-rich proteins.

Author information

Department of Food Science and Technology, University of Karachi, Karachi 75270, Pakistan.


Lactase phlorizin hydrolase is a small intestinal brush border enzyme that catalyzes the hydrolysis of the milk sugar, lactose, and also many flavonoid glucosides. We demonstrate that epigallocatechin-3-gallate (EGCG), the principal flavonoid from green tea, inhibits in vitro hydrolysis of lactose by intestinal lactase. We then tested the hypothesis that salivary proline-rich proteins (PRPs) could modulate this inhibition and stabilize EGCG. Inhibition by EGCG of digestive enzymes (α-amylase>chymotrypsin>trypsin>lactase≫pepsin) was alleviated ∼2-6-fold by PRPs. Furthermore, PRPs appeared stable to proteolysis and also stabilized EGCG under digestive conditions in vitro. This is the first report on EGCG inhibition of lactase, and it quantifies the protective role of PRPs against EGCG inhibition of digestive enzymes.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for American Chemical Society
Loading ...
Support Center