Nicotianamine-rich foods for improving the learning and memory functions and as an effective preventing agent of hypertension

Abstract

Hypertension is considered one of the most serious long-term medical conditions. Angiotensin I-converting enzyme (ACE), as one of the most important targets for hypertension drugs. It converts angiotensin I to vasopressor angiotensin II through a catalytic hydrolysis process. ACE has been found in higher amounts in the brain cells of Alzheimer disease patients. Brain-penetrating ACE inhibitors (ACEI) decreased the impact of Alzheimer disease in elderly hypertensive patients. It is expected that the inclusion of ACEI-rich foods has a potential to eliminate these health issues. Therefore, this study explored the occurrence of ACEI in food extracts combining an ACE inhibition assay with LC/ESIMS quantification analysis, showing that naturally occurring nicotianamine (NA), ubiquitously present in higher plants, is an important constituent in ACEI active foods. Furthermore, oral administration of NA and NA-rich food extracts improved spatial learning and memory functions in rats, in addition to hypertensive relief. Thus, NA is suggested to be a brain-penetrating ACEI, while the inclusion of NA-rich foods will contribute to the “quality of life” of patients with Alzheimer disease by relieving hypertension and dementia.