Fig. 4. Effect of I. obliquus on hydrogen peroxide-induced MMP activity and collagen degradation in human dermal fibroblasts. (A) The cells were treated with 1 mM hydrogen peroxide for 2 h in the presence or absence of I. obliquus extract and collected supernatant after recovered with serum-free DMEM for 48 h. The caseinolytic activity MMP-1 and the gelatinolytic activities of MMP-2 and MMP-9 were determined by casein- and gelatin-zymography, respectively. (B) The cells were treated with 1mM hydrogen peroxide for 2 h in the presence or absence of I. obliquus extract and then harvested further incubation with serum-free DMEM for 48 h. Total cell lysates were measured for their total collagen contents using a Sircol assay kit. Data represents the mean ± SE of three independent experiments. Significant differences were compared with the control at *p < 0.05 by Student’s t-test.