Diacerein is a diacetyl precursor of rhein, an anthraquinone found in plants. Rhein, at 10 μM, inhibits IL-1β signaling, suppressing signaling through NF-κB and AP-1, and reduces the expression of the matrix metalloproteases MMP-1 and MMP-13. Diacerein, presumably after conversion to rhein, down-regulates the expression of the IL-1β receptor on articular chondrocytes, enhances the expression of TGF-β, and increases collagen and aggrecan. It does not alter COX activity. It is mildly effective in ameliorating osteoarthritis.
