Anti-diarrheal constituents of Alpinia oxyphylla ☆ Junqing Zhang a, b, c, 1 , Sheng Wang a, b, 1 , Yonghui Li a, b , Peng Xu a, b , Feng Chen a, b , Yinfeng Tan a, b , Jinao Duan c, ⁎ a School of Pharmacy, Hainan Medical University, Haikou 571199, China b Hainan Provincial Key Laboratory of Research and Development of Tropical Medicinal Plants, Hainan Medical University, Haikou 571199, China c Jiangsu Key Laboratory for TCM Formulae Research, Nanjing University of Chinese Medicine, Nanjing 210046, China article info abstract Article history: Received 6 December 2012 Accepted in revised form 3 April 2013 Available online 12 April 2013 Isolation, screening and in vivo assays have been used for evaluating anti-diarrhea bioactive of Alpinia oxyphylla. Preliminary experimental results showed that 95% ethanol extract and 90% ethanol elution significantly extended the onset time of diarrhea and reduced the wet feces proportion, however 50% ethanol election had no effect on diarrhea. Chemical analysis results displayed that Nootkatone, Tectochrysin and yakuchinone A may be bioactive ingredients for curing diarrhea. Duodenum in vitro experiment showed that Tectochrysin 50, 100 μM reduces carbachol-induced contraction, while yakuchinone A and Nootkatone had no effect. Bioinfor- matic computational method as molecular docking has been complementary to experimentally work to explore the potential mechanism. The study of pathogenesis of diarrhea in humans and animal models suggested that Na + /H + exchanger3 (NHE3) and aquaporin4 (AQP4) are causative agents of diarrhea. The analysis was done on the basis of scoring and binding ability and the docking analysis showed that Tectochrysin has maximum potential against NHE3 (PDB ID: 2OCS) and AQP4 (PDB ID: 3GD8). Tectochrysin indicated minimum energy score and the highest number of interactions with active site residues. These results suggested that A. oxyphylla might exhibit its anti-diarrhea effect partially by affecting the proteins of NHE3 and AQP4 with its active ingredient Tectochrysin. © 2013 Published by Elsevier B.V. Keywords: Anti-diarrhea Alpinia oxyphylla Autodock Tectochrysin 1. Introduction Diarrhea disease, a common gastrointestinal problem with potentially fatal implications, is a serious public health challenge [1]. The study of diarrhea disease in humans and animal models suggested that many different factors may trigger diarrhea, including infections, food intolerances, intes- tinal disorders and medications [2–5]. According to the National Institutes of Health, the average adult can expect about four bouts of acute diarrhea per year. Children in the United States average seven to 15 episodes of diarrhea by age 5 [6]. Overview of pathogenesis found that diarrhea exists in serious energy metabolism disorders, the Na + /H + exchanger3 (NHE3) and aquaporin4 (AQP4) had played a critical role in the life cycle of diarrhea and they were, consequently, interesting targets for anti-diarrhea drug therapy. It has been reported that NHE3 and AQP4 activity and expression are significantly down-regulated in most diarrhea [7]. In NHE3-knockout mice, the basal fluid absorption was severely decreased and the mice suffered from diarrhea [8]. In AQP4-deficient mice, a high water content in feces and a reduced water osmotic permeability Fitoterapia 89 (2013) 149–156 ☆ Financial support: We are grateful for the financial support from the National 12th Five-Year Plan Regional Base Project (2011BA101B07), Hainan Special Plan for the Modernization of Chinese Medicines (2010ZY012 and 2011ZY004), the Foundation of Shanghai Municipal Health Bureau (20114060), Natural Science Foundation of Hainan Province (812189) and research development fund supported by Hainan Medical University (HY2012-006 and HY2012-013). ⁎ Corresponding author at: Jiangsu Key Laboratory for TCM Formulae Research, School of Pharmacy, Nanjing University of Chinese Medicine, 282 Hanzhong Road, Nanjing, Jiangsu, 210029, China. Tel./fax: +86 25 86581116. E-mail addresses: jqzhang2011@163.com (J. Zhang), wang1986sheng@163.com (S. Wang), lyhssl@126.com (Y. Li), 1181254886@qq.com (P. Xu), cy.chen508@gmail.com (F. Chen), 112552819@qq.com (Y. Tan), dja@njutcm.edu.cn (J. Duan). 1 These authors contributed equally to this study and share first authorship. 0367-326X/$ – see front matter © 2013 Published by Elsevier B.V. http://dx.doi.org/10.1016/j.fitote.2013.04.001 Contents lists available at ScienceDirect Fitoterapia journal homepage: www.elsevier.com/locate/fitote