collagenase inhibition by water-pepper (polygonum hydropiper l.) sprout extract

Introduction: collagenase plays an important role in the degradation of dermal matrix proteins leading to wrinkle formation. the objectives of this study were to evaluate the inhibitory effect of water-pepper (polygonum hydropiper l.) sprout extract on the activity of collagenase and to identify the inhibitory compounds. methods: collagenase inhibitory activity was measured by spectrophotometric assay. activity-guided fractionation was performed using liquid-liquid extraction of water and n-butanol and diaion hp-20 column chromatography, followed by high-performance liquid chromatography (hplc) fraction collection. results: a methanolic extract of water-pepper sprout inhibited collagenase activity in a concentration-dependent manner with an ic50 value of 156.7 μg/ml. collagenase inhibitory activity (ic50 = 23.5 μg/ml) was found in 50% methanol eluate from the hp-20 column chromatography of the n-butanol soluble fraction. the active compound (ic50 = 1.9 μg/ml) in the eluate was isolated by hplc and identified as quercetin-3-o-galactoside (hyperoside) from comparing retention time, uv-vis absorption, and mass spectra with those of the standard. lineweaver-burk plots revealed that hyperoside was an uncompetitive inhibitor against collagenase. hyperoside was also the most abundant flavonoid present in the methanolic extract. conclusion: these results suggest that water-pepper sprouts could be beneficial as a natural source of collagenase inhibitor which might be used for the treatment of skin aging.