J Neurosci Res. 2002 Nov; 70(3): 484-92.

Novel cognitive improving and neuroprotective activities of Polygala tenuifolia Willdenow extract, BT-11.

Park CH, Choi SH, Koo JW, Seo JH, Kim HS, Jeong SJ, Suh YH.

Department of Pharmacology, College of Medicine, National Creative Research Initiative Center for Alzheimer's Dementia and Neuroscience Research Institute, MRC, Seoul National University, Seoul, South Korea.

We carried out this study to search a new active constituent that had cognitive enhancing activity and low side effects from natural source. We found that the extract of dried root of Polygala tenuifolia Willdenow (BT-11, 10 mg/kg, i.p.) could significantly reverse scopolamine-induced cognitive impairments in rat, using a passive avoidance and a water maze test. We also investigated the effects of BT-11 on neurotoxicity induced by glutamate (Glu) and toxic metabolites of amyloid precursor protein (APP) such as amyloid beta protein (A beta) and C-terminal fragment of APP (CT) in primary cultured neurons of rat. The pretreatment of BT-11 (0.5, 3, and 5 micro g/ml) significantly reduced cell death induced by Glu (1 mM), A beta (10 micro M) and CT105 (10 micro M) in a dose-dependent manner. In addition, BT-11 inhibited acetylcholinesterase (AChE) activity in a dose-dependent and non-competitive manner (IC(50) value; 263.7 micro g/ml). Our novel findings suggest the possibility that this extract may have some protective effects against neuronal death and cognitive impairments in Alzheimer's disease (AD), or other neurodegenerative diseases related to excitotoxicity and central cholinergic dysfunction.Copyright 2002 Wiley-Liss, Inc.