The effects of Tabernaemontana divaricata root extract on amyloid β-peptide 25-35 peptides induced cognitive deficits in mice

Ethnophamacological relevance: Tabernaemontana divaricata (TD), a Thai medicinal herb, has been widely used as an analgesic, sedative, or a cough syrup. Moreover, it has been used in traditional rejuvenation remedies as for preventing forgetfulness and improving the memory. Aim of study: The present study aimed to determine the effect of TD on A beta 25-35 peptides induced cognitive deficits and acetylcholinesterase activity in mice. Materials and methods: Mice were pretreated with TDE (250,500 and 1000 mg/kg body weight) for 28 days and then received i.c.v, injection of A beta 25-35 peptides. Cognitive performance was evaluated using the Morris water maze (MWM) and step-down avoidance test. The Ellman's colorimetric method was used to investigate the levels of cortical and hippocampal AChE activity. Results: A beta 25-35 peptides induced the memory impairment and the increased levels of cortical and hippocampal AChE activity. The consumption of TDE significantly improved the memory impairment and attenuated the brain levels of AChE activity induced by A beta 25-35 peptides. Conclusions: These findings suggest that subchronic administration of TOE might prevent the A beta 25-35 peptides induced memory deficits by decreasing the AChE activity level. Therefore TDE could potentially be one of nootropic supplements for those elderly people suffering from dementia such as the AD patients. (C) 2010 Elsevier Ireland Ltd. All rights reserved.