Expression of cell adhesion molecules by endothelium and the attachment of monocytes to endothelium may play a major role in atherosclerosis. Ellagic acid (EA) is a phenolic compound found in fruits and nuts including raspberries, strawberries, grapes and walnuts. Previous studies have indicated that EA possesses antioxidant activity in vitro. In the present study, we investigated the effects of EA on the formation of intracellular reactive oxygen species, the translocation of NFkB and expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 and endothelial leucocyte adhesion molecule (E-selectin) induced by IL-1b in human umbilical vein endothelial cells (HUVEC). We found that EA significantly reduced the binding of human monocytic cell line, U937, to IL-1b-treated HUVEC. The production of reactive oxygen species by IL-1b was dose-dependently suppressed by EA. Supplementation with increasing doses of EA up to 50 mmol/l was most effective in inhibiting the expression of VCAM-1 and E-selectin. Furthermore, the inhibition of IL-1b-induced adhesion molecule expression by EA was manifested by the suppression of nuclear translocation of p65 and p50. In conclusion, EA inhibits IL-1b-induced nuclear translocation of p65 and p50, thereby suppressing the expression of VCAM-1 and E-selectin, resulting in decreased monocyte adhesion. Thus, EA has anti-inflammatory properties and may play an important role in the prevention of atherosclerosis.Ellagic acid: Cell adhesion molecule: NFkB: Reactive oxygen species: Atherosclerosis Activation of the vascular endothelium, increased adhesion of mononuclear cells to the injured endothelial layer, and their subsequent extravasations into the vessel wall are initial events in atherogenesis. Endothelial cells recruit leucocytes by expressing adhesion molecules, such as vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and endothelial leucocyte adhesion molecules (E-selectin; Cybulsky & Gimbrone, 1991). Several inflammatory cytokines including IL-1, TNF and interferon produced by activated monocytes and macrophages may stimulate the endothelium to up-regulate genes encoding chemokines, other cytokines and adhesion molecules (Ross, 1999).Previous studies have indicated that NF-kB/Rel transcription factors may play an important role in the development of atherosclerosis (Collins, 1993;Qwarnstrom et al. 1994). Activation of NF-kB by inflammatory stimuli has been demonstrated in cultures of endothelial cells using electrophoretic mobility shift assays (Collins, 1993). A variety of genes induced in the atherosclerotic lesion have been shown to be regulated by NF-kB proteins, including the genes encoding TNF-a (Baeuerle & Henkel, 1994), IL-1b (Hiscott et al. 1993), VCAM-1 (Neish et al. 1992) and ICAM-1 (Poston et al. 1992).It is well established that dietary polyphenolic compounds play significant roles in the prevention of atherosclerosis and CVD (Gaziano et al. 1992;Gey et al. 1993). Polyphenolic compounds affect the ...