Journal of Ethnopharmacology 130 (2010) 614–620 Contents lists available at ScienceDirect Journal of Ethnopharmacology journal homepage: www.elsevier.com/locate/jethpharm Inhibitory effects of Bulnesia sarmienti aqueous extract on agonist-induced platelet activation and thrombus formation involves mitogen-activated protein kinases S.M. Kamruzzaman a , Mehari Endale a , Won Jun Oh a , Seung-Chun Park a , Kil-Soo Kim a , Joo Heon Hong b , Yi-Seong Kwak c , Bong-Sik Yun d , Man Hee Rhee a,∗ a College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea b College of Hospitality and Tourism Administration, Catholic University of Daegu, Kyungbuk 712-702, Republic of Korea c Central Research Institute of Korea Ginseng Corporation, Daejeon 305-805, Republic of Korea d College of Environmental & Bioresource Sciences, Chonbuk National University, Jeonbuk 570-752, Republic of Korea article info Article history: Received 17 February 2010 Received in revised form 10 May 2010 Accepted 25 May 2010 Available online 15 June 2010 Keywords: Platelet B. sarmienti extract Catechins Thrombus MAP kinases abstract Ethnopharmacological relevance: B. sarmienti has long been recognized in folk medicine as a medicinal plant with various medicinal uses. Traditionally, it has been appreciated for the skin-healing properties of its essence. The bark has also been employed to treat stomach and cardiovascular disorders and reported to have antitumor, antioxidant and anti-inflammatory activities. However, information on its antiplatelet activity is limited. Aim of the study: To examined the effects of B. sarmienti aqueous extract (BSAE) in platelet physiology. Materials and methods: The anti-platelet activity of BSAE was studied using rat platelets for in vitro deter- mination of the extract effect on agonist-induced platelet aggregation, ATP secretion, [Ca 2+ ] i mobilization and MAP kinase phosphorylation. The extract in vivo effects was also examined in arterio-venous shunt thrombus formation in rats, and tail bleeding time in mice. Result: HPLC chromatographic analysis revealed that B. sarmienti extract contained (+)-catechin (C), (-)- epigallocatechin (EGC), (-)-epicatechin (EC), and (-)-epicatechin gallate (ECG). BSAE, significantly and dose dependently, inhibited collagen, thrombin, or ADP-induced platelet aggregation. The 50 percent inhibitory concentrations (IC 50 ) of the extract for collagen, thrombin and ADP-induced platelet aggre- gation were 45.3 ± 2.6, 100 ± 5.6 and 110 ± 4.6 g/ml, respectively. Collagen activated ATP release and thrombin-induced intracellular Ca 2+ concentration were reduced in BSAE-treated platelets. In addition, the extract in vivo activity showed that BSAE at 100 mg/kg significantly attenuated thrombus forma- tion in rat extracorporeal shunt model while mice tail bleeding time was not affected. Moreover, BSAE attenuated p38 mitogen-activated protein kinase (p38 MAPK), c-Jun N-terminal kinase 1 (JNK1) and extracellular-signal-regulated protein kinase 2 (ERK2) phosphorylations. Conclusion: BSAE inhibits platelet activation, granule secretion, aggregation, and thrombus formation without affecting bleeding time, and that this effect is mediated by inhibition of P38, JNK1 and ERK2 phosphorylations. The ability of BSAE to inhibit platelet function might be relevant in cases involving aberrant platelet activation where the plant extract could be considered as a candidate to anti-platelet and antithrombotic agent. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Platelets play a key role in hemostasis but also involved in pathophysiological conditions associated with cardiovascular dis- ∗ Corresponding author at: Laboratory of Physiology & Signaling, College of Veteri- nary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea. Tel.: +82 53 950 5967; fax: +82 53 950 5955. E-mail address: rheemh@knu.ac.kr (M.H. Rhee). orders. Several lines of evidences revealed that platelet dysfunction contributes in the development and progression of many cardio- vascular diseases like arterial hypertension (Perros et al., 2008; El Haouari and Rosado, 2009), atherosclerosis (Huo and Ley, 2001; Huo and Ley, 2004), thrombosis (Huo and Ley, 2004; Furie and Furie, 2005; Davi and Patrono, 2007; Mackman, 2008) and inflam- mation (Zarbock et al., 2007; Malaver et al., 2009; Lee et al., 2010). Platelet aggregation is known to be a result of complex sig- nal transduction cascade reactions brought about by stimulants. 0378-8741/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2010.05.049