Differential effect of Rhizoma coptidis and its main alkaloid compound berberine on TNF-alpha induced NFkappaB 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 NFkappaB into the nucleus after stimulation with TNF-alpha. 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 NFkappaB dependent pathway, while the RCE complex acts partially by blocking the NFkappaB dependent pathway. Rhizoma coptidis extract therefore appears to be a potent inhibitor of TNF-alpha induced inflammation in dermatological conditions.