Angiotensin-I converting enzyme inhibitory activity of mushroom Lentinus polychrous Lév. and its development of healthy drink recipes

Hypertension is a major health problem affecting all populations around the world. Angiotensin I-converting enzyme (ACE-I), an important enzyme in renin angiotensin system (RAS) catalysis, yields a product that increases blood pressure in our bodies. Many mushrooms have been reported to have blood pressure lowering properties. However, such activities have not been investigated in Lentinus polychrous Lév., one of the most consumed mushrooms in Thailand. In this study, an ACE-I inhibitory activity of crude protein extract of L. polychrous was examined. The crude protein was separated by a dialysis membrane of 10 kDa MWCO and an anion exchange chromatography on Q-Sepharose XL column, consecutively. The fraction with MW <10 kDa with better ACE-I inhibitory activity was further purified by Q-sepharose XL. The active unbound (UQ) fraction contained the highest ACE-I inhibitory activity of 60.93±9.94% (1.066 µg protein/ml) which is equivalent to 15.46±0.71 nmol Captopril per µg protein extract. The bound protein fractions (BQ1-BQ5) resulted in no protein bands appearing in 15% SDS-PAGE. However, thin layer chromatography (TLC) indicated that these active fractions might contain peptides or very small proteins. Additionally, this mushroom extract had been developed as healthy drink recipes for helping lower blood pressure.