o-Phenanthroline (1,10-Phenanthroline, phen), a hypoxia-mimicking agent, is a non-specific matrix metalloproteinase (MMP) inhibitor with IC50 of 110.5μM for Collagenase. O-phenanthroline reduces the expression of MMP3 and MMP13 mRNA levels during chondrogenic differentiation of human chondrocytes (hChs), as well as after TNFα/IL-1β exposure in an explant model. o-Phenanthroline is also a metal chelator which prevents the induction of chromosomal aberrations in streptozotocin-treated cells and forms a red chelate with Fe2+ that absorbs maximally at 510 nm.