Flavonoid-rich extracts of apple peel were associated with a dose-dependent inhibition of the activity of angiotensin converting enzyme (ACE), according to findings published in Food Chemistry.
ACE inhibitors work by inhibiting the conversion of angiotensin I to the potent vasoconstrictor, angiotensin II, thereby improving blood flow and blood pressure.
“Overall, the results suggest that flavonoid-rich apple peel extract has a potential to act as an effective ACE inhibitor in vivo; thus, animal and clinical studies are warranted to confirm the results,” wrote Nileeka Balasuriya, and Vasantha Rupasinghe.
BP and heart health
About one billion people worldwide reportedly suffer from high blood pressure, or hypertension, which is defined as having a systolic and diastolic blood pressure (BP) greater than 140 and 90 mmHg. It is a major risk factor for CVD.
Researchers around the world, both academic and industrial, are considering the potential of many dietary ingredients to inhibit ACE activity. To date, dairy peptides, green tea extracts, and cocoa extracts, to name but a few, reported to have blood pressure lowering effects.
The new in vitro cell study investigated the effects of a flavonoid-rich apple peel extract, and selected flavonoids and quercetin metabolites on ACE activity.
Results showed that the flavonoid-rich apple peel extract, and many of its constituents inhibited ACE activity in a dose-dependent manner, meaning the higher the dose tested, the greater the levels of inhibition.
“For better understating of the ACE inhibitory properties of flavonoids in general, compounds representing each sub-class of flavonoids were also investigated,” wrote the researchers. “Interestingly, most of the sub-classes of flavonoids including flavonols, anthocyanins, flavan-3-ols, flavones and flavanones showed concentration responsive ACE inhibition.”
The researchers stressed that their data is from cell studies and therefore needs to be further investigated in animal models and clinical trials before any strong conclusions can be drawn.
Source: Food Chemistry
Published online ahead of print, doi: 10.1016/j.foodchem.2012.07.023
“Antihypertensive Properties of Flavonoid-rich Apple Peel Extract”
Authors: N. Balasuriya, V. Rupasinghe