Extraoral Functions of Salivary Proteins

Two groups of salivary proteins, basic Proline-rich Proteins(PRPs) and Histatins(Hsts) effectively interact with food tannins and form insoluble complexes that are stable under conditions similar to those in vivo. The proteins diminish transport of tannin across intestinal cells probably due to the formation of insoluble tannin-protein complexes. In contrast the transport of flavonoids is not affected by PRPs or Hsts. The proteins may act as scavenger molecules preventing intestinal uptake of tannins with their associated harmful effect but allowing absorption of flavonoids and exploitation of their beneficial properties.