Characterisation of a new antihypertensive angiotensin I-converting enzyme inhibitory peptide from Pleurotus cornucopiae.

This study describes the characterisation of a new angiotensin I-converting enzyme (ACE) inhibitory peptide from the fruiting body of Pleurotus cornucopiae which could be used as a functional food or nutraceutical compounds. After purification of the ACE inhibitor in an ultrafiltration, Sephadex G-25 column chromatography, successively C(18) and SCX solid-phase extraction and reverse-phase HPLC, two types of the purified ACE inhibitors with IC(50) values of 0.46 and 1.14mg/ml were obtained. The two purified ACE inhibitors were analysed, showing two types of oligopeptides. The amino acid sequences of the two purified oligopeptides were found to be RLPSEFDLSAFLRA and RLSGQTIEVTSEYLFRH. The molecular mass of the purified ACE inhibitors was estimated to be 1622.85 and 2037.26Da, respectively. Water extracts of P. cornucopiae fruiting body showed a clear antihypertensive effect on spontaneously hypertensive rats at a dosage of 600mg/kg.