Antihypertensive effects of unripe persimmon (Diospyros kaki L. cv. Hiratanenashi) fruit and its component in spontaneously hypertensive rats

The feeding of unripe persimmon (PP) ('Hiratanenashi', pollination variant) and soluble tannin (PST), as its component, on blood pressure was examined in spontaneously hypertensive rats (SHR). Systolic blood pressure (SBP) was decreased by PP and PST administration for 2-3 days and increased after switching to the basal diet alone. Increases in serum nitric oxide level and liver NOS3 gene expression in SHR fed PP suggests that the induction of nitric oxide formation by PP administration might be involved in decreasing SBP. The decrease in ACE activity by PST administration suggests that, as a component of PP, PST mainly lowers SBP through its angiotensin I-converting enzyme (ACE) inhibitory effect. Scopoletin, contained as a minor component in PP and PST, decreased SBP by single oral administration, suggesting that it also might be involved in lowering SBP.