2015AbstractThis study sought to investigate the possible mechanisms for the use of phenolic extracts from grapefruit peels in the management/prevention ofcardiovascular complications. The effects of the phenolic extracts on key enzymes relevant to cardiovascular diseases [3-hydroxy-methyl-3-glutarylcoenzyme A reductase (HMG-CoA reductase) and angiotensin-I converting enzyme (ACE)], cellular antioxidant activity in human endothelial cells(EA.Hy 926) and radicals [1,1-diphenyl-2 picrylhydrazyl (DPPH) and 2,2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)] scavengingabilities were investigated. The phenolic contents of the extracts were investigated using HPLC–DAD. There was no significant (P > 0.05) differencein the HMG-CoA reductase inhibitory ability of the two extracts, while the bound phenolic extracts had a stronger ACE inhibitory ability thanthe soluble free phenolics. The extracts also showed intracellular antioxidant activity in human endothelial (EA.Hy 926) cells. Furthermore, thebound phenolics had significantly higher radicals (DPPH* and ABTS*) scavenging abilities than the free phenolics. The HPLC analysis revealedthe presence of flavonoids (quercetin and kaempferol), phenolics acids (resveratrol, gallic acid, ellagic acid and caffeic acid) and tannin (catechin).The cellular antioxidative properties and inhibition of enzymes relevant to the management of cardiovascular complications showed that grapefruitpeels could be used as nutraceuticals for the management of such conditions.© 2015 Beijing Academy of Food Sciences. Production and hosting by Elsevier B.V. All rights reserved.