title: Prevention of arterial thrombosis by nobiletin: in vitro and in vivo studies.
abstract: Nobiletin, a bioactive polymethoxylated flavone isolated from citrus fruits, has been proven to prevent cancer and inflammation. Dietary flavonoids have been shown to reduce the risk of cardiovascular diseases (CVDs), and platelet activation plays a crucial role in CVDs. This study investigated the effect of nobiletin on platelet activation in vitro and in vivo. Nobiletin (10-30μM) inhibited collagen- and arachidonic acid-induced platelet aggregation in washed human platelets, but it did not inhibit platelet aggregation induced by other agonists such as thrombin and 9,11-dideoxy-11α,9α-epoxymethanoprostaglandin. Nobiletin inhibited the phosphorylation of phospholipase PLCγ2, protein kinase PKC, Akt and mitogen-activated protein kinase MAPKs in collagen-activated human platelets and markedly reduced intracellular calcium mobilization and hydroxyl radical (OH(·)) formation. Nobiletin did not affect either phorbol-12,13-dibutyrate-stimulated PKC activation or platelet aggregation. In addition, neither SQ22536, an adenylate cyclase inhibitor nor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a guanylate cyclase inhibitor, significantly reversed the nobiletin-mediated inhibition of platelet aggregation. Moreover, nobiletin substantially prolonged the closure time in whole blood according to platelet function analysis and increased the occlusion time of thrombotic platelet plug formation in mice. In conclusion, this study demonstrates for the first time that, in addition to being a potential agent for preventing tumor growth and inflammation, nobiletin exhibits potent antiplatelet activity, which initially inhibits the PLCγ2/PKC cascade and hydroxyl radical formation, subsequently suppresses the activation of Akt and MAPKs and ultimately inhibits platelet activation. Our study suggests that nobiletin represents a potential therapeutic agent for preventing or treating thromboembolic disorders.
authors.affiliation: Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei 110, Taiwan; Translational Laboratory, Research Department, Taipei Medical University Hospital, Taipei 110, Taiwan; School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan.
authors.forename: Wan-Jung
authors.initials: WJ
authors.lastname: Lu
authors.affiliation: Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei 110, Taiwan; Department of Neurology, Chi Mei Medical Center, Tainan 710, Taiwan.
authors.forename: Kao-Chang
authors.initials: KC
authors.lastname: Lin
authors.affiliation: Department of Cardiology, Yuan's General Hospital, Kaohsiung 80249, Taiwan.
authors.forename: Chun-Ping
authors.initials: CP
authors.lastname: Liu
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan 110.
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Lin
authors.affiliation: Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan 110.
authors.forename: Hsh-Chu
authors.initials: HC
authors.lastname: Wu
authors.affiliation: Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
authors.forename: Duen-Suey
authors.initials: DS
authors.lastname: Chou
authors.affiliation: Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620024, India.
authors.forename: Pitchairaj
authors.initials: P
authors.lastname: Geraldine
authors.affiliation: School of Nutrition and Health Sciences, Taipei Medical University, Taipei 110, Taiwan.
authors.forename: Shih-Yi
authors.initials: SY
authors.lastname: Huang
authors.affiliation: Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei 110, Taiwan.
authors.forename: Cheng-Ying
authors.initials: CY
authors.lastname: Hsieh
authors.affiliation: Department of Pharmacology, College of Medicine, Taipei Medical University, Taipei 110, Taiwan; Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan 110. Electronic address: sheujr@tmu.edu.tw.
authors.forename: Joen-Rong
authors.initials: JR
authors.lastname: Sheu
mesh_terms: D000328:Adult; D001158:Arteries / Q000473:pathology*; D004789:Enzyme Activation; D047309:Flavones / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D051966:Phospholipase C gamma / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D013927:Thrombosis / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D047309:Flavones; C008661:nobiletin; D011493:Protein Kinase C; D051966:Phospholipase C gamma
keywords: Akt; Arterial thrombosis; Citrus fruits; Hydroxyl radical; Nobiletin