Planta Med 2007; 73 - P_479
DOI: 10.1055/s-2007-987259

Acetylcholinesterase inhibitor from Clitoria ternatea

V Kumar 1, K Mukherjee 1, BC Pal 2, PJ Houghton 3, PK Mukherjee 1
  • 1School of Natural Product Studies, Department of Pharmaceutical Technology, Jadavpur University, Kolkata 700032, India
  • 2Division of Medicinal Chemistry, Indian Institute of Chemical Biology, Kolkata 700032, India
  • 3Pharmacognosy Research, Pharmaceutical Sciences Research Division, King's College London, 150 Stamford St, SE1 9NH London, UK

Clitoria ternatea L. (Fabaceae) is commonly known as 'Butterfly pea'. Extracts of C. ternatea have been used as an ingredient in 'Medhya Rasayana' as a rejuvenating recipe used for treatment of neurological disorders and considered as wholesome for intellect. C. ternatea has been shown to improve learning, memory and also increase the acetylcholine content of the hippocampus in rats. The aim of study was to isolate triterpenoids from C. ternatea and to determine their ability to inhibit acetylcholinesterase (AChE). The alcohol extract C. ternatea was fractionated and triterpenoid compounds were purified using column chromatography, IR and ESI-MS were used for the chemical characterization. The structure was elucidated by means of 1H, 13C, Cosy NMR and mass spectrometry. Taraxerol, a pentacyclic compound was tested for in vitro and ex vivo AChE inhibitory activity. The in vitro AChE inhibitory activity of taraxerol was determined by TLC and micro plate AChE assay based on Ellman's method [1]. Taraxerol and physostigmine was found to inhibit AChE activity in TLC assay. Taraxerol showed significant AChE inhibition and found to have IC50 values of 69.01±4.26µM/ml. Physostigmine was used as standard and showed inhibition of AChE with an IC50 value of 0.28±0.015µM/ml. Taraxerol and physostigmine were administered to male Wistar rats and ex vivo AChE activity was determined using rat brain homogenate preparations. The results of this in vivo treatment indicate that taraxerol and physostigmine caused a dose-dependent inhibition of brain AChE activity, and that physostigmine appeared to be a more potent inhibitor than taraxerol. Since improved learning and memory performance are related to acetylcholine levels, the AChE inhibitory effect of taraxerol from C. ternatea may account for its traditional use.

Acknowledgements: The authors wish to express their gratitude to the Department of Biotechnology, Govt. of India, New Delhi, India.

References: [1] Mukherjee, P. K., Kumar, V., Mal, M., Houghton, P. J., (2007) Planta Med.73: 283–285.