title: Hydroxytyrosol is the major anti-inflammatory compound in aqueous olive extracts and impairs cytokine and chemokine production in macrophages.
abstract: Substances in olive products contribute to improved health as suggested by epidemiological data. In this study we assessed the effects of hydroxytyrosol (HT) on inflammatory mediators, cytokines and chemokines, and identified anti-inflammatory constituents of aqueous olive extracts, I.E., olive vegetation water (OVW). Murine macrophages (RAW264.7 cells) were stimulated with lipopolysaccharide (LPS) in the absence or presence of substances; inflammatory mediators [nitric oxide (NO), prostaglandin E₂ (PGE₂), cytokines, interleukins, chemokines] were determined by the Griess reaction, EIA, or multiplex ELISA (Luminex technology). Expression of inflammatory genes was determined by RT-PCR. Aqueous olive extracts were fractionated by preparative HPLC and the fractions investigated for their effects on NO and PGE₂ production. Results were further analyzed by principal component analysis. HT inhibited production of NO and PGE₂ with an IC₅₀ of 11.4 and 19.5 µM, respectively, reflecting strong anti-inflammatory activity. HT and OVW diminished secretion of cytokines (IL-1 α, IL-1 β, IL-6, IL-12, TNF- α), and chemokines (CXCL10/IP-10, CCL2/MCP-1). HT and OVW concentration-dependently reduced the expression of genes of inducible nitric oxide synthase (iNOS), IL-1 α, CXCL10/IP-10, MIP-1 β, matrix metalloproteinase-9, and prostaglandin E₂ synthase (PGES). The effects of HT were partly mediated VIA the NF- κB pathway, as shown by RT-PCR analysis. HT was identified as the main bioactive compound of OVW. The data provide a molecular basis for elucidating the effects of HT on inflammatory processes. The effects of HT on NO and chemokine production point to their impact on chronic inflammatory processes in endothelium or arthritis.
authors.affiliation: DSM Nutritional Products Ltd., Department of Human Nutrition & Health, Basel, Switzerland.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Richard
authors.forename: Sabine
authors.initials: S
authors.lastname: Arnold
authors.forename: Ulrich
authors.initials: U
authors.lastname: Hoeller
authors.forename: Claus
authors.initials: C
authors.lastname: Kilpert
authors.forename: Karin
authors.initials: K
authors.lastname: Wertz
authors.forename: Joseph
authors.initials: J
authors.lastname: Schwager
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D002460:Cell Line; D018925:Chemokines / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D015232:Dinoprostone / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D020128:Inhibitory Concentration 50; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D031658:Olea / Q000737:chemistry*; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D059808:Polyphenols / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D012313:RNA / Q000235:genetics
chemical_list: D000893:Anti-Inflammatory Agents; D018925:Chemokines; D016207:Cytokines; D008070:Lipopolysaccharides; D010936:Plant Extracts; D059808:Polyphenols; C005975:3,4-dihydroxyphenylethanol; D009569:Nitric Oxide; D012313:RNA; D015232:Dinoprostone; D010626:Phenylethyl Alcohol