Dual inhibition of the renin and angiotensin converting enzyme activities of aqueous extracts of 22 edible flower petals.

In order to explore novel blood pressure-regulating substances and fulfill the high-value utilization of various edible flowers, the inhibitory activities of aqueous solutions of 22 edible flower petals extracts on renin and angiotensin converting enzyme (ACE) were investigated. The results showed that almost all the aqueous sample extracts demonstrated an inhibition of renin and/or ACE. The Rosa rugosa Thunb. (IC50 = 25.13 and 60.00 μg mL-1) and Paeonia suffruticosa Andr. (IC50 = 50.54 and 292.47 μg mL-1) extracts showed prominent dual inhibitory activity against renin and ACE. The antioxidant activities and content of total phenols and flavonoids of the aqueous sample extracts were tested, because the oxidative damage of blood vessels is closely related to the occurrence and development of hypertension. The correlation between the contents of total phenolic substances and flavonoids, and the functional activities was analyzed. Renin and ACE inhibitory activities, DPPH and ABTS free radical scavenging capacity, and iron reduction ability of different sample extracts were significantly positively correlated with the total phenolic content (p <0.01), whereby the correlation coefficients were 0.87, 0.83, 0.93, 0.95, and 0.93 respectively. It was indicated that the aqueous phenolic compounds in Rosa rugosa Thunb and Paeonia suffruticosa Andr extracts tended to show stronger renin and ACE inhibitory activities, and exhibited a potential prospect for auxiliary blood pressure control.