Journal of Ethnopharmacology 137 (2011) 1542–1546 Contents lists available at SciVerse ScienceDirect Journal of Ethnopharmacology jo ur nal homep age : www.elsevier.com/locate/jethpharm Ethnopharmacological communication Dual functions of ginsenosides in protecting human endothelial cells against influenza H9N2-induced inflammation and apoptosis Lok Yung Chan a,1 , Hoi Hin Kwok a,1 , Renee Wan Yi Chan b , Malik Joseph Sriyal Peiris b,c , Nai Ki Mak a , Ricky Ngok Shun Wong a , Michael Chi Wai Chan b , Patrick Ying Kit Yue a,∗ a Department of Biology, Faculty of Science, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China b Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China c HKU-Pasteur Research Centre, Pokfulam, Hong Kong SAR, China a r t i c l e i n f o Article history: Received 30 March 2011 Received in revised form 11 July 2011 Accepted 11 August 2011 Available online 22 August 2011 Keywords: Endothelial cell Ginsenoside Influenza IP-10 miR-15b a b s t r a c t Ethnopharmacological relevance: Panax ginseng is a precious traditional Chinese herbal medicine which has been utilized as herbal tonic for improving immunity. The active component, ginsenosides have been shown to possess various pharmacological functions including immunomodulation and cardiovascular protection. Aim of the study: To investigate the immunomodulatory effect and anti-apoptotic effect of ginsenosides on avian influenza-infected human endothelial cells, and to present evidence for the cardiovascular protection by ginseng during influenza infection. Materials and methods: Human umbilical vein endothelial cells (HUVECs) were infected with avian influenza H9N2/G1 to induce IP-10 production and cell death, cells were then incubated with ginsenosides PPT and Re. The level of IP-10 and microRNA was determined by ELISA and real-time PCR respectively. Cell death was determined by MTT, TUNEL and flow cytometry. Results: Ginsenoside metabolite protopanaxatriol showed significant suppression effect on IP-10 production upon H9N2/G1 infection through up-regulation of miR-15b expression. In addition, ginsenoside-induced cytoprotection was reflected in the increase of cell viability. Data from flow cytom- etry analysis and TUNEL assay also showed that ginsenoside Re could protect ECs from H9N2/G1-induced apoptosis and DNA damage. Conclusions: This report further supports the traditional belief for immunomodulatory effects of ginseng, also demonstrated the partial protective mechanism of ginsenosides on avian influenza infection and its related endothelial dysfunction. © 2011 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Infection by avian influenza virus such as H5N1 and H9N2 appears constantly in human population. The infection is usu- ally associated with significant morbidity and mortality (Peiris et al., 1999). Although primary targets of influenza viruses are Abbreviations: HUVECs, human umbilical vein endothelial cells; IP-10, interferon-inducible protein-10; FBS, fetal bovine serum; ECGS, endothe- lial cell growth supplement; PS, penicillin–streptomycin; ELISA, enzyme- linked immunosorbent assay; PCR, polymerase chain reaction; MTT, 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; TUNEL, TdT-mediated dUTP nick end labeling; MFI, mean fluorescent intensity; ROS, reactive oxygen species. ∗ Corresponding author. Tel.: +852 3411 5832; fax: +852 3411 5995. E-mail address: patrick@hkbu.edu.hk (P.Y.K. Yue). 1 These authors contributed equally to this work. alveolar and bronchial epithelial cells, several lines of evidences indicated the association between influenza infections and sys- temic dissemination in multiple organs (de Jong et al., 2006). Recent studies indicated that influenza virus infection is a strong risk factor of cardiovascular disorders (Lippi et al., 2010). In addition, the association between acute encephalopathy influenza infec- tion was reported in Hong Kong (Lee et al., 2010) and Japan (Morishima et al., 2002). Although the pathogenesis of influenza associated acute encephalopathy is unclear, abnormally high level of cytokines or chemokines including interferon-inducible protein- 10 (IP-10/CXCL10) was detected in patient’s cerebrospinal fluid (Lee et al., 2010). Furthermore, angiopathy in brain due to intravas- cular endothelial cell apoptosis was observed in the cases of influenza virus-induced encephalopathy (Togashi et al., 2004). These studies suggested that hypercytokinemia and endothelial cell apoptosis might play a central role in the pathogenesis of influenza-induced endothelial dysfunction (Yue et al., 2007). 0378-8741/$ – see front matter © 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.jep.2011.08.022