Regulation of osteoclastogenesis by Simon extracts composed of caffeic acid and related compounds: successful suppression of bone destruction accompanied with adjuvant-induced arthritis in rats

Histochem Cell Biol. 2006 Mar;125(3):215-25. doi: 10.1007/s00418-005-0062-4. Epub 2005 Oct 5.


Simon extracts are vitamin K(1)-rich food materials extracted from the leaves of the Simon sweet potato. Although vitamin K is known to stimulate bone formation, we postulated that Simon extracts also contain unknown biological compounds having the ability to regulate bone resorption. Here we prepared the vitamin K-free fraction from the Simon extracts and investigated the ability of this fraction on the differentiation of osteoclasts. A remarkable inhibitory effect of osteoclastogenesis was observed when osteoclast precursors were treated with this fraction in rat bone marrow culture systems as well as in a pure differentiation system using murine osteoclast precursor cell line. The vitamin K-free Simon extracts markedly suppressed severe bone destruction mediated by abundant osteoclasts associated with adjuvant-induced arthritis in rats. High performance liquid chromatography (HPLC) analysis revealed that the vitamin K-free Simon extracts contained three types of low molecular weight inhibitors for osteoclastogenesis; caffeic acid, chlorogenic acids and isochlorogenic acids. Among these substances, caffeic acid showed the most powerful inhibitory effects on osteoclastogenesis. Caffeic acid significantly suppressed expression of NFATc1, a key transcription factor for the induction of osteoclastogenesis. Our current study enlightened a high utility of the Simon extracts and their chemical components as effective regulators for bone resorption accompanied with inflammation and metabolic bone diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arthritis, Experimental / drug therapy*
  • Arthritis, Experimental / genetics
  • Arthritis, Experimental / pathology
  • Base Sequence
  • Bone Resorption / drug therapy
  • Bone Resorption / genetics
  • Bone Resorption / pathology
  • Caffeic Acids / pharmacology*
  • Cathepsin K
  • Cathepsins / genetics
  • Cells, Cultured
  • DNA Primers / genetics
  • Glyceraldehyde-3-Phosphate Dehydrogenases / genetics
  • In Vitro Techniques
  • Ipomoea batatas / chemistry
  • Male
  • Osteoclasts / drug effects*
  • Osteoclasts / pathology
  • Phytotherapy
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology
  • Rats
  • Rats, Inbred Lew
  • Rats, Sprague-Dawley
  • Receptor Activator of Nuclear Factor-kappa B / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Vitamin K / isolation & purification


  • Caffeic Acids
  • DNA Primers
  • Plant Extracts
  • Receptor Activator of Nuclear Factor-kappa B
  • Vitamin K
  • Glyceraldehyde-3-Phosphate Dehydrogenases
  • Cathepsins
  • Cathepsin K
  • Ctsk protein, rat
  • caffeic acid