RO314724 is a HDAC inhibitor. RO314724 is also a a reversible, tightly binding, MMP inhibitor with a Ki of 26 nm. Matrix metalloproteinases (MMPs) belong to the key enzymes of the proteolytic destruction of cartilage matrix during chronic rheumatic diseases. Ro314724 displayed MMP-proteoglycanase inhibitory activity both in vitro and ex vivo and proved to be not harmful to the morphology, viability and proteoglycan biosynthesis of bovine articular cartilage explants.