Planta Med 2008; 74 - PG34
DOI: 10.1055/s-0028-1084787

Cinnamamides from Piper capense with affinity to the benzodiazepine site on the GABAA receptor

ME Pedersen 1, 2, HB Rasmussen 1, B Metzler 1, GI Stafford 2, J van Staden 2, AK Jäger 1
  • 1University of Copenhagen, Faculty of Pharmaceutical Sciences, 2 Universitetsparken, DK-2100 Copenhagen Ø, Denmark
  • 2Research Centre for Plant Growth and Development, University of KwaZulu-Natal, Pietermaritzburg, Private Bag X01, Scottsville 3209, South Africa

Epilepsy is among the most prevalent of the serious neurological disorders, affecting from 0.5–1.0% of the world's population and the prevalence of epilepsy in developing countries is generally higher than in developed countries [1]. Recently, plants used in South African traditional medicine for treatment of epilepsy and convulsion were examined for their pharmacological properties in the search for new and better anti-epileptic drugs [2, 3, 4].

The root of Piper capense L.f. (Piperaceae) is used in traditional South African medicine. A bioassay guided fractionation of an ethanolic extract using VLC, HPLC-UV, GC-MS and 1H-NMR led to the isolation and identification of cinnamamides with affinity to the benzodiazepine site on the GABAA receptor in the [3H]flumazenil receptor binding assay. The isolated cinnamides piperine and 4,5 dihydropiperine binded to the receptor with IC50 values of 0.9 and 1.7±mM respectively.

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References: 1. Sander and Shorvon (1996)J Neurol Neurosurg Psych 65:433–443. 2. Svenningsen et al. (2006)J Ethnopharmacol. 103: 276–280. 3. Stafford, et al. (2005)J Ethnopharmacol 100: 210–215. 4. Risa, et al. (2004)J Ethnopharmacol 93:177–182