Among plant lignans, pinoresinol has the strongest antiinammatory properties in human intestinal Caco-2 cells

Abstract

Dietary lignans show some promising health benets, but little is known about their fate and activities in the small intestine. The purpose of this study was thus to investigate whether plant lignans are taken up by intestinal cells and modulate the intestinal inammatory response using the Caco-2 cell model. Six lignan standards [secoisolariciresinol diglucoside (SDG), secoisolariciresinol (SECO), pinoresinol (PINO), lariciresinol, matairesinol (MAT), and hydroxymatair-esinol] and their colonic metabolites [enterolactone (ENL) and enterodiol] were studied. First, differentiated cells were exposed to SDG, SECO, PINO, or ENL at increasing concentrations for 4 h, and their cellular contents (before and after deconjugation)were determined by HPLC. Second, in IL-1β-stimulated conuent and/or differentiated cells, lignan effects were tested on different soluble proinammatory mediators quantied by enzyme immunoassays and on the NF-κB activation pathway by using cells transiently transfected. SECO, PINO, and ENL, but not SDG, were taken up and partly conjugated by cells, which is a saturable conjugation process. PINO was the most efciently conjugated (75% of total in cells). In inamed cells, PINO signicantly reduced IL-6 by 65% and 30% in conuent and differentiated cells, respec-tively, and cyclooxygenase (COX)-2-derived prostaglandin E2 by 62% in conuent cells. In contrast, MAT increased signicantly COX-2-derived prostaglandin E2 in conuent cells. Moreover, PINO dose-dependently decreased IL-6 and macrophage chemoattractant protein-1 secretions and NF-κB activity. Our ndings suggest that plant lignans can be absorbed and metabolized in the small intestine and, among the plant lignans tested, PINO exhibited the strongest antiinammatory properties by acting on the NF-κB signaling pathway, possibly in relation to its furofuran structure and/or its intestinal metabolism. © 2012 American Society for Nutrition.