Differential effect of Rhizoma coptidis and its main alkaloid compound berberine on TNF-α induced NFκB translocation in human keratinocytes

The Chinese medicine Rhizoma coptidis (RC) is well established in the treatment of common dermatological disorders although the mechanism of its' anti-inflammatory effects have previously remained elusive. We stimulated an inflammatory state in human keratinocyte cultures using TNF-alpha in the presence of RC extract (RCE) and berberine, to identify the dose-dependent anti-inflammatory role of these compounds. Control data demonstrates significant translocation of NF kappa B into the nucleus after stimulation with TNF-a. This translocation can be inhibited, and hence anti-inflammatory effects inferred, by RCE but not by berberine. We conclude that in dermatological disorders berberine exerts its anti-inflammatory effects by inhibiting signal transduction pathways other than the NF kappa B dependent pathway, while the RCE complex acts partially by blocking the NF kappa B dependent pathway. Rhizoma coptidis extract therefore appears to be a potent inhibitor of TNF-a induced inflammation in dermatological conditions. (c) 2006 Elsevier Ireland Ltd. All rights reserved.