Perilla frutescens Seeds as a Source of Antihypertensive Peptides: Discovery of Novel Tetrapeptides with ACE...

Hypertension, a major risk factor for cardiovascular diseases, remains a leading global health concern and has prompted growing interest in angiotensin-converting enzyme (ACE) inhibitory peptides from plant seeds as promising nutraceutical ingredients. To our knowledge, this is the first study to identify antihypertensive peptides from Perilla frutescens seed protein, with thermolysin hydrolysate demonstrated the favorable ACE-inhibitory (ACEI) activity (IC₅₀ = 141 µg/mL). Two parallel bioassay-guided fractionations (SCX and RP-HPLC) were used to screen the fractions with the best ACEI activity, from which two novel tetrapeptides, TLVY (TY4) and LLVY (LY4), were identically found. Both peptides exhibited notable ACEI activities with IC₅₀ values of 31 µM and 44 µM, respectively. Enzyme kinetics showed that TY4 and LY4 antagonized ACE via a competitive inhibition mechanism, while molecular docking revealed specific interactions with canonical catalytic residues of ACE through hydrogen bonding. The structural characteristics and bioactivity profiles of TY4 and LY4 support their potential as naturally derived antihypertensive agents. This study highlights the discovery of novel tetrapeptides from Perilla frutescens seeds with ACE inhibitory activity, providing a foundation for the development of functional foods targeting hypertension.