Onion extract and quercetin induce matrix metalloproteinase-1 in vitro and in vivo

Int J Mol Med. 2010 Mar;25(3):347-52.


A scar is usually developed by an imbalance of collagen synthesis and degradation. It is believed that the flavonoids (quercetin and kaempferol) in onion extract play a role in reducing scar formation through inhibition of fibroblast activities. Even though several commercial products are composed of onion extract, the precise molecular mechanisms of onion extract in reduction of scar formation in skin are still largely unknown. In this study we investigated the effect both of onion extract and quercetin on the proliferation of fibroblasts, expression of type I collagen and matrix metalloproteinase-1 (MMP-1). Our data show that proliferation rates of fibroblasts were decreased in a dose-dependent manner of the onion extract and quercetin. The expression of type I collagen was not markedly changed by the onion extract and quercetin. Interestingly, the expression of MMP-1 was markedly increased by both onion extract and quercetin in vitro and in vivo. Thus, our data indicate that onion extract and quercetin play a role in the anti-scar effect in skin through up-regulation of MMP-1 expression, implying this agent is a promising material for reducing scar formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • Cicatrix / prevention & control*
  • Collagen Type I / metabolism
  • Dose-Response Relationship, Drug
  • Enzyme Activation
  • Extracellular Signal-Regulated MAP Kinases / genetics
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fibroblasts / cytology
  • Fibroblasts / drug effects
  • Fibroblasts / metabolism
  • Humans
  • JNK Mitogen-Activated Protein Kinases / genetics
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Kaempferols / metabolism
  • Kaempferols / pharmacology
  • Matrix Metalloproteinase 1 / genetics
  • Matrix Metalloproteinase 1 / metabolism*
  • Mice
  • Mice, Nude
  • Onions / chemistry*
  • Plant Extracts / metabolism
  • Plant Extracts / pharmacology*
  • Quercetin / metabolism
  • Quercetin / pharmacology*
  • Skin* / drug effects
  • Skin* / pathology
  • Tissue Inhibitor of Metalloproteinase-1 / metabolism


  • Collagen Type I
  • Kaempferols
  • Plant Extracts
  • Tissue Inhibitor of Metalloproteinase-1
  • kaempferol
  • Quercetin
  • Extracellular Signal-Regulated MAP Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Matrix Metalloproteinase 1