A Tricholoma matsutake Peptide with Angiotensin Converting Enzyme Inhibitory and Antioxidative Activities and Antihypertensive Effects in Spontaneously Hypertensive Rats

Hypertension is a major risk factor for cardiovascular disease. A crude water extract of the fruiting bodies of a highly prized mushroom Tricholoma matsutakei exerted an antihypertensive action on spontaneously hypertensive rats (SHRs) at a dosage of 400 mg/kg. An angiotensin converting enzyme (ACE) inhibitory peptide with an IC50 of 0.40 mu M was purified from the extract and designated as TMP. Its amino acid sequence was elucidated to be WALKGYK through LC-MS/MS analysis. The Lineweaver-Burk plot suggested that TMP was a non-competitive inhibitor of ACE. A short-term assay of antihypertensive activity demonstrated that TMP at the dosage of 25 mg/kg could significantly lower the systolic blood pressure (SBP) of SHRs. TMP exhibited remarkable stability over a wide range of temperatures and pH values. It also demonstrated 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. The aforementioned activities of TMP were corroborated by utilizing the synthetic peptide. Hence T. matsutake can be used as a functional food to help prevent hypertension-associated diseases.