Blood Pressure-Lowering Effects of Alacalase-Hydrolyzed Camellia Seed Hull In Vitro and in Spontaneous Hypertensive Rats.

High blood pressure is one of the major risk factors for various diseases and angiotensin-converting enzyme (ACE) plays a critical role in blood pressure regulation. In our study, the responsive surface methodology was adopted to establish optimal Alcalase-hydrolysis conditions of camellia seed hull against ACE activity. The optimum conditions are hydrolysis temperature of 50.98°C, enzyme/substrate ratio of 2.85%, and hydrolysis pH of 7.12. In an animal feeding study, spontaneously hypertensive rats were treated with either a low or high dose of hydrolyzed Camellia japonica seed cake over 5 weeks. Even though systolic blood pressure was not statistically different, the high dose of C. japonica hydrolysate lowered diastolic blood pressure (106 ± 4.4 mmHg vs. 145 ± 5.9 mmHg) at the 5th week. A similar trend was also observed in serum ACE activity. Considering that this camellia seed hull is a major resource of this plant, our study provides important data to utilize this plant for both academic and industrial applications.