An effective and simple procedure to isolate abundant quantities of biologically active chemopreventive Lunasin Protease Inhibitor Concentrate (LPIC) from soybean

Food Chem. 2015 Jun 15;177:120-6. doi: 10.1016/j.foodchem.2015.01.006. Epub 2015 Jan 9.


Lunasin is a 5-kDa soybean bioactive peptide with demonstrated anti-cancer and anti-inflammatory properties. Recently, purification methods have been developed to obtain gram quantities of lunasin. However, these methods are cumbersome, time consuming and cost-prohibitive. To overcome these constrains we have developed a novel method which involves extraction of soybean flour with 30% ethanol followed by preferential precipitation of lunasin and protease inhibitors by calcium. The calcium precipitated protein fraction, which we termed as Lunasin Protease Inhibitor Concentrate (LPIC), contains three abundant proteins with molecular weights of 21, 14 and 5 kDa. This simple procedure yields 3.2g of LPIC from 100g of soybean flour and the entire isolation procedure can be completed in less than 2h. Treatment of THP-1 human monocyte cell lines with LPIC resulted in suppression of lipopolysaccharide-stimulated cytokine expression, demonstrating that the LPIC isolated by our simple procedure is biologically active.

Keywords: Bowman-Birk inhibitor; Calcium chloride anhydrous (PubChem CID: 5284359); Chemopreventive agent; Ethyl alcohol (PubChem CID: 702); LPIC (Lunasin Protease Inhibitor Concentrate); Lunasin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Humans
  • Monocytes / drug effects
  • Protease Inhibitors / chemistry
  • Protease Inhibitors / isolation & purification*
  • Protease Inhibitors / pharmacology
  • Soybean Proteins / chemistry
  • Soybean Proteins / isolation & purification*
  • Soybean Proteins / pharmacology
  • Soybeans / chemistry*


  • GM2S-1 protein, soybean
  • Protease Inhibitors
  • Soybean Proteins