title: Apple peel bioactive rich extracts effectively inhibit in vitro human LDL cholesterol oxidation.
abstract: Apple peels are rich in antioxidant bioactives and hence can possess the ability to inhibit human low density lipoprotein cholesterol (LDL-C) oxidation. LDL-C oxidation is known to initiate atherosclerotic plaque formation. Unique quercetin-rich (QAE) and triterpene-rich (TAE) apple peel extracts, their constituent compounds and three in vivo quercetin metabolites were investigated for in vitro LDL-C oxidation inhibition. Both extracts effectively inhibited Cu(2+)-induced LDL-C oxidation. IC(50) of QAE and TAE for LDL-C oxidation products were 0.06-8.29 mg/L and 29.58-95.49 mg/L, respectively. Quercetin compounds, chlorogenic acid and phloridzin could contribute more to the effectiveness of QAE at physiological concentrations. The three in vivo quercetin metabolites; quercetin-3'-sulfate, quercetin-3-glucuronic acid and isorhamnetin-3-glucuronic acid were effective at physiological concentrations and therefore, QAE can be effective in LDL-C oxidation inhibition under physiological conditions. Constituent TAE compounds did not perform well under Cu(2+)-induction. Overall, both extracts effectively inhibited LDL-C oxidation in vitro.
authors.affiliation: Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, Nova Scotia, Canada B2N 5E3.
authors.forename: Surangi H
authors.initials: SH
authors.lastname: Thilakarathna
authors.forename: H P Vasantha
authors.initials: HP
authors.lastname: Rupasinghe
authors.forename: Paul W
authors.initials: PW
authors.lastname: Needs
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D008078:Cholesterol, LDL / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry*; D006801:Humans; D027845:Malus / Q000737:chemistry*; D010084:Oxidation-Reduction; D010936:Plant Extracts / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D008078:Cholesterol, LDL; D010936:Plant Extracts