Figure 7.

A proposed model describing the role of skullcapflavone II in collagenolysis inhibition. Growth factors in serum activate the transcription factor activator protein-1 (AP-1) through activation of the ERK and JNK pathways. TNF-α activates the transcription factor NF-κB as well as AP-1. Skullcapflavone II inhibits serum- and TNF-α-induced activation of AP-1 and NF-κB, which are required for MMP-1 expression. Skullcapflavone II thus maintains the integrity of extracellular matrix by suppressing MMP-1 expression.