Cancer-preventive peptide lunasin from Solanum nigrum L. inhibits acetylation of core histones H3 and H4 and phosphorylation of retinoblastoma protein (Rb)

J Agric Food Chem. 2007 Dec 26;55(26):10707-13. doi: 10.1021/jf072363p. Epub 2007 Nov 27.


Lunasin, a unique 43 amino acid, 4.8 kDa cancer-chemopreventive peptide initially reported in soybean and now found in barley and wheat, has been shown to be cancer-chemopreventive in mammalian cells and in a skin cancer mouse model against oncogenes and chemical carcinogens. To identify bioactive components in traditional herbal medicines and in search for new sources of lunasin, we report here the properties of lunasin from Solanum nigrum L. (SNL), a plant indigenous to northeast Asia. Lunasin was screened in the crude extracts of five varieties of the medicinal plants of Solanaceae origin and seven other major herbal plants. An in vitro digestion stability assay for measuring bioavailability was carried out on SNL crude protein and autoclaved SNL using pepsin and pancreatin. A nonradioactive histone acetyltransferase (HAT) assay and HAT activity colorimetric assay were used to measure the inhibition of core histone acetylation. The inhibitory effect of lunasin on the phosphorylation of retinoblastoma protein (Rb) was determined by immunoblotting against phospho-Rb. Lunasin isolated from autoclaved SNL inhibited core histone H3 and H4 acetylation, the activities of the HATs, and the phosphorylation of the Rb protein. Lunasin in the crude protein and in the autoclaved crude protein was very stable to pepsin and pancreatin in vitro digestion, while the synthetic pure lunasin was digested at 2 min after the reaction. We conclude that lunasin is a bioactive and bioavailable component in SNL and that consumption of SNL may play an important role in cancer prevention.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation / drug effects
  • Animals
  • Anticarcinogenic Agents / pharmacology*
  • Drug Stability
  • Histones / metabolism*
  • Mice
  • NIH 3T3 Cells
  • Pancreatin / metabolism
  • Pepsin A / metabolism
  • Phosphorylation / drug effects
  • Plant Proteins / analysis
  • Plant Proteins / metabolism
  • Plant Proteins / pharmacology*
  • Retinoblastoma Protein / metabolism*
  • Solanum nigrum / chemistry*


  • Anticarcinogenic Agents
  • Histones
  • Plant Proteins
  • Retinoblastoma Protein
  • Pancreatin
  • Pepsin A