Antihypertensive properties of spinach leaf protein digests

J Agric Food Chem. 2004 Apr 21;52(8):2223-5. doi: 10.1021/jf034551v.


Leaf protein containing approximately 50% rubisco (ribulose bisphosphate carboxylase/oxygenase) was obtained from fresh spinach leaf with the use of a simple extraction method. Pepsin and pepsin-pancreatin digests of spinach leaf protein have potent angiotensin-I converting enzyme inhibitory properties with IC(50) values of 56 and 120 microg/mL, respectively. Both digests of leaf protein have antihypertensive effects after oral administration to spontaneously hypertensive rats (SHR) with minimum effective doses of 0.25 and 0.5 g/kg, respectively. The maximum antihypertensive effect for the pepsin digest was observed 4 h after oral administration, while for the pepsin-pancreatin digest, the maximum effect was observed 2 h after oral administration. Undigested spinach leaf protein did not exert any significant antihypertensive effect after oral administration to SHR at doses of 0.5 and 1 g/kg. Obtained results show that the pepsin digest of leaf protein may be useful in treatment of hypertension.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin-Converting Enzyme Inhibitors / isolation & purification
  • Angiotensin-Converting Enzyme Inhibitors / therapeutic use
  • Animals
  • Antihypertensive Agents / isolation & purification
  • Antihypertensive Agents / therapeutic use
  • Hydrogen-Ion Concentration
  • Hypertension / drug therapy
  • Kinetics
  • Male
  • Pancreatin / metabolism
  • Pepsin A / metabolism
  • Plant Leaves / chemistry*
  • Plant Proteins / isolation & purification
  • Plant Proteins / metabolism
  • Plant Proteins / therapeutic use*
  • Rats
  • Rats, Inbred SHR
  • Ribulose-Bisphosphate Carboxylase / analysis
  • Spinacia oleracea / chemistry*


  • Angiotensin-Converting Enzyme Inhibitors
  • Antihypertensive Agents
  • Plant Proteins
  • Pancreatin
  • Pepsin A
  • Ribulose-Bisphosphate Carboxylase