title: Luteolin and luteolin-7-O-glucoside from dandelion flower suppress iNOS and COX-2 in RAW264.7 cells.
abstract: Both reactive oxygen- and nitrogen-derived reactive species play important roles in physiological and pathophysiological conditions. Flavones, luteolin and luteolin-7-O-glucoside along with a rich plant source of both flavones, namely dandelion (Taraxacum officinale) flower extract were studied for antioxidant activity in different in vitro model systems. In this current study, luteolin and luteolin-7-O-glucoside at concentrations lower than 20 microM, significantly (p < 0.05) suppressed the productions of nitric oxide and prostaglandin E2 (PGE2) in bacterial lipopolysaccharide activated-mouse macrophage RAW264.7 cells without introducing cytotoxicity. The inhibitory effects were further attributed to the suppression of both inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression, and not reduced enzymatic activity. Similar suppression for both inducible enzymes was also found with the presence of dandelion flower extract, specifically, the ethyl acetate fraction of dandelion flower extract which contained 10% luteolin and luteolin-7-O-glucoside.
authors.affiliation: Food, Nutrition and Health, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Chun
authors.initials: C
authors.lastname: Hu
authors.forename: David D
authors.initials: DD
authors.lastname: Kitts
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D015232:Dinoprostone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D047309:Flavones; D005960:Glucosides / Q000378:metabolism / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000378:metabolism; D047311:Luteolin / Q000494:pharmacology*; D051379:Mice; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D010936:Plant Extracts; D010944:Plants / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D031205:Taraxacum / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004365:Drugs, Chinese Herbal; D047309:Flavones; D005960:Glucosides; D008070:Lipopolysaccharides; D009573:Nitrites; D010936:Plant Extracts; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; C066408:luteolin-7-glucoside; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone; D047311:Luteolin; D010100:Oxygen