Glycinyl-histidinyl-serine (GHS), a novel rapeseed protein-derived peptide has blood pressure-lowering effect in spontaneously hypertensive rats.

A novel antihypertensive peptide (Gly-His-Ser or GHS) with dual inhibition of angiotensin I-converting enzyme (ACE) and renin activities was isolated from the 3 kDa membrane ultrafiltration permeate of a pepsin+pancreatin rapeseed protein digest. The IC50 values of GHS were 0.52 ± 0.01 mg/mL and 0.32 ± 0.01 mg/mL for ACE and renin inhibitions, respectively, which are 1.5 times the ACE inhibition and 3.5 times the renin inhibition of the 3 kDa permeate. Oral administration (30 mg/kg body weight) to spontaneously hypertensive rats showed GHS to be an effective hypotensive agent with maximum blood pressure reduction of -17.29 ± 2.47 mmHg after 6 h. In contrast, the 3 kDa permeate exhibited a maximum of -21.29 ± 9.29 mmHg after 4 h, although at a relatively higher dose of 100 mg/kg body weight). GHS inhibited ACE and renin activities noncompetitively, but the renin inhibition became uncompetitive at a higher peptide concentration.