MMP9 and breast cancer: Quercetin-3-O-glucuronide was also reported as an active compound which could inhibit intracellular reactive oxygen species in mouse fibroblast 3T3 cells induced by H2O2 attack and suppress invasion of MDA-MB-231 breast cancer cells and matrix metalloproteinase 9 (MMP-9) induction (Shirai et al., 2002; Yamazaki et al., 2014).