PMID- 11518563 OWN - NLM STAT- MEDLINE DCOM- 20011204 LR - 20190826 IS - 0009-2797 (Print) IS - 0009-2797 (Linking) VI - 137 IP - 1 DP - 2001 Jul 31 TI - Effects of Ginkgo biloba extract (EGb 761) and quercetin on lipopolysaccharide-induced release of nitric oxide. PG - 43-58 AB - Administration of bacterial lipopolysaccharide (LPS) to laboratory animals and cultured macrophages is known to induce the production of nitric oxide (NO) from inducible nitric oxide synthase (iNOS). Here we show that pre-treatment with Ginkgo biloba extract (EGb 761) suppresses the in vivo production of NO (measured by the Griess reaction) after challenge with LPS. In order to begin to understand the mechanism of this inhibition, we evaluated in vitro effects of EGb 761 and its flavonoid component, quercetin, on LPS-treated RAW 264.7 macrophages. Pre-treatment with EGb 761 or quercetin dose-dependently inhibited NO release. Both substances scavenged NO generated from the decomposition of sodium nitroprusside. Western analysis showed that EGb 761 and quercetin inhibited LPS-induced levels of iNOS protein. Northern blotting demonstrated that EGb 761 and quercetin decreased LPS-induced iNOS mRNA levels without altering the half-life. Activation of mitogen activated protein kinases (MAPKs) and the redox-sensitive transcription factors, nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) are key events in the signal transduction pathways mediating iNOS induction. In our studies, both EGb 761 and quercetin inhibited p38 MAPK activity, which is necessary for iNOS expression in LPS-stimulated RAW 264.7 macrophages. However, differences in the response of NF-kappaB, AP-1, and Jun N-terminal kinase/stress activated protein kinase (JNK/SAPK) and its downstream substrates to EGb 761 and quercetin suggest that quercetin is not the sole component responsible for the in vivo inhibition of LPS-induced iNOS activation by EGb 761. FAU - Wadsworth, T L AU - Wadsworth TL AD - Department of Physiology and Pharmacology, Oregon Health Sciences University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97201-3098, USA. FAU - Koop, D R AU - Koop DR LA - eng GR - AA08608/AA/NIAAA NIH HHS/United States PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, P.H.S. PL - Ireland TA - Chem Biol Interact JT - Chemico-biological interactions JID - 0227276 RN - 0 (Enzyme Inhibitors) RN - 0 (Free Radical Scavengers) RN - 0 (Imidazoles) RN - 0 (Lipopolysaccharides) RN - 0 (Nitric Oxide Donors) RN - 0 (Plant Extracts) RN - 0 (Pyridines) RN - 0 (Tumor Necrosis Factor-alpha) RN - 169D1260KM (Nitroprusside) RN - 19FUJ2C58T (Ginkgo biloba extract) RN - 31C4KY9ESH (Nitric Oxide) RN - 9IKM0I5T1E (Quercetin) RN - EC 1.14.13.39 (Nitric Oxide Synthase) RN - EC 1.14.13.39 (Nitric Oxide Synthase Type II) RN - EC 1.14.13.39 (Nos2 protein, mouse) RN - OU13V1EYWQ (SB 203580) SB - IM MH - Animals MH - Cells, Cultured MH - Dose-Response Relationship, Drug MH - Enzyme Inhibitors/pharmacology MH - Free Radical Scavengers/pharmacology MH - *Ginkgo biloba MH - Imidazoles/pharmacology MH - Lipopolysaccharides/*pharmacology MH - Macrophages/*drug effects/metabolism MH - Male MH - Mice MH - Mice, Inbred C57BL MH - Nitric Oxide/*metabolism MH - Nitric Oxide Donors/pharmacology MH - Nitric Oxide Synthase/genetics/metabolism MH - Nitric Oxide Synthase Type II MH - Nitroprusside/pharmacology MH - Plant Extracts/*pharmacology MH - Pyridines/pharmacology MH - Quercetin/*pharmacology MH - Tumor Necrosis Factor-alpha/metabolism EDAT- 2001/08/24 10:00 MHDA- 2002/01/05 10:01 CRDT- 2001/08/24 10:00 PHST- 2001/08/24 10:00 [pubmed] PHST- 2002/01/05 10:01 [medline] PHST- 2001/08/24 10:00 [entrez] AID - S0009279701002083 [pii] AID - 10.1016/s0009-2797(01)00208-3 [doi] PST - ppublish SO - Chem Biol Interact. 2001 Jul 31;137(1):43-58. doi: 10.1016/s0009-2797(01)00208-3.