Phytomedicine 17 (2010) 963–973 Contents lists available at ScienceDirect Phytomedicine journal homepage: www.elsevier.de/phymed Preventive effect of silymarin in cerebral ischemia–reperfusion-induced brain injury in rats possibly through impairing NF-B and STAT-1 activation Yu-Chang Hou b,c,1 , Kuo-Tong Liou e,1 , Chang-Ming Chern f,1 , Yea-Hwey Wang h,1 , Jyh-Fei Liao i , Shiou Chang g , Yuan-Hwa Chou h , Yuh-Chiang Shen a,d,∗ a National Research Institute of Chinese Medicine, Taipei, Taiwan b Department of Chinese Medicine, Taoyuan General Hospital, Department of Health; Department of Nursing, Yuanpei University, Hsinchu, Taiwan c Department of Bioscience Technology, Chuan-Yuan Christian University, Taoyuan, Taiwan d Institute of Biomedical Sciences, National Chung-Hsing University, Taichung, Taiwan e Department of Chinese Martial Arts, Chinese Culture University, Taipei, Taiwan f Neurovascular Disease, Neurological Institute, Taipei Veterans General Hospital & School of Medicine, National Yang-Ming University, Taipei, Taiwan g Department of Surgery, Taoyuan General Hospital, Department of Health, Taiwan h Department of Psychiatry, Taipei Veterans General Hospital & National Yang-Ming University, Taipei, Taiwan i Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan article info Keywords: Silymarin Cerebral ischemia–reperfusional (CI/R) injury Cytokine Signal transducer and activator of transcription-1 (STAT-1) Inducible nitric oxide synthase (iNOS) Nuclear factor-kappa B (NF-B) abstract Silymarin and silibinin are bioactive components isolated from Silybum marianum. They have been reported to exhibit anti-oxidative and anti-inflammatory effects. Many studies revealed that drugs with potent anti-inflammatory potential can protect animals against inflammation-associated neurodegener- ative disease, e.g., stroke. In this current work we established an animal model of acute ischemic stroke injury by inducing cerebral ischemic/reperfusion (CI/R) in rats to elucidate whether silymarin or silibinin can protect animals from CI/R injury. Pretreatment with silymarin, but not silibinin, dose-dependently (1–10 g/kg, i.v.) reduced CI/R-induced brain infarction by 16–40% and improved neurological deficits in rats with a stroke. Elevated pathophysiological biomarkers for CI/R-induced brain injury, including lipid peroxidation, protein nitrosylation, and oxidative stress, were all reduced by silymarin. In addition, expression of inflammation-associated proteins (e.g., inducible nitric oxide synthase, cyclooxygenase-2 and myeloperoxidase), and transcriptional factors (e.g., nuclear factor (NF)-kappa B and signal trans- ducer and activator of transcription (STAT)-1), as well as production of proinflammatory cytokine (e.g., interleukin-1 and tumor necrosis factor-) was all significantly prevented by silymarin. Furthermore, an in vitro study on microglial BV2 cells showed that silymarin could inhibit nitric oxide and super- oxide anion production, possibly by interfering with NF-B nuclear translocation/activation. Likewise, silymarin pretreatment also inhibited IB- degradation and NF-B nuclear translocation in brain tis- sues of ischemic rats. Our results reveal that silymarin, but not its active component silibinin, protected rats against CI/R-induced stroke injury by amelioration of the oxidative and nitrosative stresses and inflammation-mediated tissue injury through impeding the activation of proinflammatory transcrip- tion factors (e.g., NF-B and STAT-1) in the upregulation of proinflammatory proteins and cytokines in stroke-damaged sites. In conclusion, silymarin displays beneficial effects of preventing inflammation- related neurodegenerative disease, e.g., stroke, which needs further investigation and clinical evidences. © 2010 Elsevier GmbH. All rights reserved. ∗ Corresponding author at: National Research Institute of Chinese Medicine, 155- 1 Li-Nung Street, Sec. 2, Shih-Pai, Taipei 112, Taiwan. Tel.: +886 2 28201999x9101; fax: +886 2 28264266. E-mail address: yuhcs@nricm.edu.tw (Y.-C. Shen). 1 These authors contributed equally to this work. Introduction Ischemic stroke is one of the important causes of death in indus- trialized countries with a high incidence affecting up to 0.2% of the population each year (Klijn and Hankey 2003). The major patho- logical mechanism leading to ischemic/reperfusion brain injury during ischemic stroke is the so-called “excitotoxicity”, an inap- propriate activation of ionotropic N-methyl-d-aspartate (NMDA) receptors in the brain by excessive released glutamate which accumulates in the extracellular space after stroke onset. Exci- 0944-7113/$ – see front matter © 2010 Elsevier GmbH. All rights reserved. doi:10.1016/j.phymed.2010.03.012