Studies on Interaction between Soy Constituents and Central Nervous System

Effect of a pentapeptide Leu-Pro-Tyr-Pro-Arg (LPYPR), which corresponds to residues No. 63-67 of soy bean glycinin A5A4B3 subunit, on central nervous system was investigated in mice. LPYPR showed analgesic activity after intracerebroventricular (icv) administration at a dose of 30 nmol/mouse. The analgesic activity was nonopiodic since it was not blocked by naloxone. In passive avoidance test, LPYPR improved memory retention at a dose of 20 nmol/mouse (icv) or 100 mg/kg (per os). Soy Protein Research, Japan 7, 75-78, 2004.