Research Article Bioactivity-Guided Fractionation Identifies Amygdalin as a Potent Neurotrophic Agent from Herbal Medicine Semen Persicae Extract Chuanbin Yang, 1 Jia Zhao, 1 Yuanyuan Cheng, 1 Xuechen Li, 2 and Jianhui Rong 1 1 School of Chinese Medicine, Li Ka Shing Faculty of Medicine, he University of Hong Kong, 10 Sassoon Road, Pokfulam, Hong Kong 2 Department of Chemistry, he University of Hong Kong, Pokfulam, Hong Kong Correspondence should be addressed to Jianhui Rong; jrong@hkucc.hku.hk Received 23 March 2014; Revised 3 June 2014; Accepted 3 June 2014; Published 24 June 2014 Academic Editor: Chung-Liang Chien Copyright © 2014 Chuanbin Yang et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Herbal medicine Semen Persicae is widely used to treat blood stasis in Chinese medicine and other oriental folk medicines. Although little is known about the efects of Semen Persicae and its active compounds on neuron diferentiation, our pilot study showed that Semen Persicae extract promoted neurite outgrowth in rat dopaminergic PC12 cells. In the present study, we developed a bioactivity- guided fractionation procedure for the characterization of the neurotrophic activity of Semen Persicae extract. he resultant fractions were assayed for neurite outgrowth in PC12 cells based on microscopic assessment. hrough liquid-liquid extraction and reverse phase HPLC separation, a botanical glycoside amygdalin was isolated as the active compound responsible for the neurotrophic activity of Semen Persicae extract. Moreover, we found that amygdalin rapidly induced the activation of extracellular- signal-regulated kinase 1/2 (ERK1/2). A speciic ERK1/2 inhibitor PD98059 attenuated the stimulatory efect of amygdalin on neurite outgrowth. Taken together, amygdalin was identiied as a potent neurotrophic agent from Semen Persicae extract through a bioactivity-guided fractional procedure. he neurotrophic activity of amygdalin may be mediated by the activation of ERK1/2 pathway. 1. Introduction Neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) regulate the survival, growth, and repair of neurons, thereby maintain- ing the integrity of neurons [1–3]. Recently, neurotrophic factors appear to hold great promise in treating not only acute neuronal injuries due to trauma and stroke, but also chronic neurodegenerative diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS) [1, 4, 5]. However, the therapeutic applications of neurotrophic factors are largely hindered by the lack of eicient delivery into the brains and the presence of undesirable side efects [5, 6]. hus, small molecules capable of mimicking the actions of these neurotrophic factors may serve as an alternative therapeutic strategy for neurological diseases [7]. Rat pheochromocytoma cell line PC12 is widely used as the cell model for in vitro studies of neuronal difer- entiation and the underlying mechanisms [8]. For example, NGF induced the diferentiation of PC12 cells into functional dopaminergic neurons [9]. Mechanistic studies revealed that NGF induced neurite outgrowth and neuronal diferentiation through sustained activation of extracellular signal-regulated kinase 1/2 (ERK1/2) by interacting with its speciic receptor tyrosine kinase (TrkA) in PC12 cells [10, 11]. Herbal medicines are used as an enormous source for drug discovery either as lead compounds or candidate drugs [12, 13]. Herbal medicine Semen Persicae, the fruit-kernel of peach, is commonly used to treat blood stagnant syndrome such as anticoagulant, antiphlogistic, and anodyne in tradi- tional Chinese medicine [14, 15]. Interestingly, Semen Persicae is also used in many herbal medicine formulations including Hindawi Publishing Corporation BioMed Research International Volume 2014, Article ID 306857, 10 pages http://dx.doi.org/10.1155/2014/306857