Novel Broccoli-Derived Peptides Hydrolyzed by Trypsin with Dual-Angiotensin I-Converting Enzymes and Dipeptidyl Peptidase-IV-Inhibitory Activities

Broccoli-derived peptides show beneficial metabolic effects, and it is necessary to examine their exact functional sequences. First, peptides from the trypsin hydrolysate of broccoli proteins were isolated and identified using column chromatography and quadrupole time-of-flight mass spectrometry. After that, their functions were verified by oral administration. The results identified two novel peptides as Leu-Pro-Gly-Val-Leu-Pro-Val-Ala (LPGVLPVA) and Tyr-Leu-Tyr-Ser-Pro-Ala-Tyr (YLYSPAY). LPGVLPVA exhibited an ACE IC50 value of 0.776 ± 0.03 μM and a DPP-IV IC50 value of 392 ± 24 μM; YLYSPAY showed an ACE IC50 value of 8.52 ± 0.63 μM and a DPP-IV IC50 value of 181 ± 4 μM. Administration of the peptides reduced the blood pressure of spontaneously hypertensive rats and reduced blood glucose levels in the oral glucose tolerance test in mice. The results indicated that LPGVLPVA and YLYSPAY could be potential nutritional candidates for hypertensive and diabetic people, especially for those with diabetes associated with hypertension.