Inhibition by Dietary Tea Polyphenols of Chemical Mediator Release from Rat Peritoneal Exudate Cells

Abstract

Male Wistar rats were given purified diets containing safflower (SAF), perilla (PER), or palm (PAL) oils with or without 1% tea polyphenols (TP) for 3 weeks, and chemical mediator releasing activity from rat peritoneal exudate cells (PEC) was measured. Histamine releasing activity was not influenced by TP, while histamine release and intracellular histamine content were significantly increased in the PAL-fed group. On the contrary, leukotriene B₄ (LTB₄) release was significantly lower in rats fed PER than in those fed SAF and PAL, and TP significantly decreased the release in all fat groups. TP also significantly inhibited the release of LTB₅, which was generated only in rats fed PER. TP significantly decreased the proportion of arachidonic acid (AA) in PEC in the SAF-fed group and that of eicosapentaenoic acid (EPA), the precursor of LTB₅ in the PER-fed group, but did not influence that of AA in the PAL- and PER-fed group. These results suggest that ingestion of TP improves type I allergic symptom through the inhibition of LT release though the inhibition by TP could not be totally explained by the reduction of substrate fatty acid.

• dietary fats
• tea polyphenols
• histamine
• leukotriene
• peritoneal exudate cells