A Novel Dimeric Melampolide and Further Terpenoids from Smallanthus sonchifolius (Asteraceae) and the Inhibition of the Transcription Factor NF-κB

Abstract

A novel dimeric melampolide was isolated from the leaf rinse extract of Smallanthus sonchifolius (Poepp. & Endl.) H. Robinson (Asteraceae), an Andean medicinal plant popularly known as yacón. Dimeric sesquiterpene lactones are rare in Asteraceae, especially melampolides. In addition, eight known melampolides and a new ester derivative were also isolated. All compounds were detected in glandular trichomes collected from the leaves and were analysed by HPLC. The anti-inflammatory properties of uvedalin, a known melampolide isolated in this study, were assessed in vitro by analyzing its effect on the DNA binding of the transcription factor NF-κB. These results were compared to those previously reported for the closely related melampolide enhydrin. Our data demonstrated that NF-κB DNA binding was inhibited in leukaemia and macrophage cells at an uvedalin concentration of 2.5 and 5 μM, respectively.