Matrix metalloproteinases (MMPs) are essential for the degradation and turnover of components of the extracellular matrix
(ECM) and, when pathologically elevated, mediate connective tissue loss (including bone destruction) in various inflammatory and other
diseases. Tetracyclines (TCs) are known inhibitors of mammalian-derived MMPs, and non-antibiotic formulations of Doxycycline are
FDA-approved to treat periodontitis and the chronic inflammatory skin disease, rosacea. Because the C-11/ C-12 diketonic moiety of the
tetracyclines is primarily responsible, through zinc-binding, for MMP inhibition, we have uniquely modified curcumin as a “core” molecule,
since it contains a similar enolic system and is known to have beneficial effects in diseases where connective-tissue loss occurs.
Specifically we have developed new congeners which exhibit improved zinc-binding and solubility, and potent reduction of excessive
MMP levels and activity. We now describe a series of curcuminoid bi- and tri-carbonylmethanes in which all of these properties are substantially
improved. An N-phenylaminocarbonyl derivative of bis-demethoxycurcumin (CMC2.24) was selected as the “lead” substance
because it showed superior potency in vitro (i.e., the lowest IC50) against a series of neutral proteases (MMPs) associated with tissue erosion.
Moreover, CMC2.24 administered to diabetic rats orally (30mg/kg), reduced the secretion of pathologically-excessive levels of
MMP-9 to normal in cultured peritoneal macrophages with no evidence of toxicity. Thus, this (and other similar novel) compound(s) may
be useful in various diseases of connective-tissue loss.