title: Antihypertensive properties of spinach leaf protein digests.
abstract: 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.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Yang
authors.forename: Ewa D
authors.initials: ED
authors.lastname: Marczak
authors.forename: Hachiro
authors.initials: H
authors.lastname: Usui
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Masaaki
authors.initials: M
authors.lastname: Yoshikawa
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000302:isolation & purification / Q000627:therapeutic use; D000818:Animals; D000959:Antihypertensive Agents / Q000302:isolation & purification / Q000627:therapeutic use; D006863:Hydrogen-Ion Concentration; D006973:Hypertension / Q000188:drug therapy; D007700:Kinetics; D008297:Male; D010194:Pancreatin / Q000378:metabolism; D010434:Pepsin A / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry*; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism / Q000627:therapeutic use*; D051381:Rats; D011918:Rats, Inbred SHR; D012273:Ribulose-Bisphosphate Carboxylase / Q000032:analysis; D018724:Spinacia oleracea / Q000737:chemistry*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D010940:Plant Proteins; D010194:Pancreatin; D010434:Pepsin A; D012273:Ribulose-Bisphosphate Carboxylase