Application of radioligand-receptor binding assays in the search for the active principles of the traditional Chinese medicine ‘Gouteng’
✍ Scribed by M. Zhu; J. D. Phillipson; H. Yu; P. M. Greengrass; N. G. Norman
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 168 KB
- Volume
- 11
- Category
- Article
- ISSN
- 0951-418X
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✦ Synopsis
Uncaria rhynchophylla and related species (i.e. Gouteng of the Pharmacopoeia of the People's Republic of China) have antihypertensive, sedative and anticonvulsant activities. A methanol extract of 'Gouteng' (U. rhynchopylla) hooks and stems was assessed for its ability to inhibit the binding of radioligands to 13 different receptors in this study. The extract inhibited ligand-receptor binding by more than 60% to ␣ 2 -adrenoceptors, dopamine 1, 5-HT1A, opiate, GABA A and GABA B receptors. Bioassay-guided fractionation resulted in the isolation of ursolic acid (muscarinic and sulphonylureas activities), husutine (␣ 2 -and -adrenoceptor, 5-HT1A and 2, opiate and sulphonylureas activities) and epiallocorynanthine (-adrenoceptor, 5-HT1A and 2, and opiate receptor activities). These findings are discussed in relation to the reported pharmacological properties, clinical uses and differing alkaloid profiles of those Uncaria species which constitute 'Gouteng' of the Pharmacopoeia of the People's Republic of China.