Inhibition of NF-kB and metalloproteinase-9 expression and secretion by parthenolide derivatives.

Semisynthetic derivatives of parthenolide (1) were tested on NF-kB driven transcription and metalloproteinase-9 (MMP-9) expression and secretion. The four membered ring compounds 5 and 6, obtained by acidic treatment of 1, exhibited a higher activity with respect to 1 in all the biological assays. Then an increased ability of the 5 and 6 to inhibit NF-kB driven transcription may lead to a down-regulation of MMP-9 expression and secretion. This work provides new details about the structural requisites for NF-kB inhibition.