title: Olive leaf extracts are a natural source of advanced glycation end product inhibitors.
abstract: Advanced glycation end products (AGEs), which are readily formed and accumulated with sustained hyperglycemia, contribute to the development of diabetic complications. As a consequence, inhibition of AGE formation constitutes an attractive therapeutic/preventive target. In the current study, we explored the phytochemical composition and the in vitro effect of two different olive leaf extracts (an aqueous and a methanolic) on AGE formation. The methanolic olive leaf extract inhibited fluorescent AGE formation in a bovine serum albumin (BSA)-ribose system, whereas the aqueous extract had no effect in both BSA-fructose and BSA-ribose systems. The phytochemical profile was investigated with liquid chromatography-ultraviolet-visible (UV-Vis) diode array coupled to electrospray ionization multistage mass spectrometry (LC/DAD/ESI-MS(n)). Quantification of the major phenolic compounds was performed with high performance liquid chromatography with UV-Vis diode array detection and nuclear magnetic resonance spectroscopy. Among the major phenolic components (luteolin, hydroxytyrosol, luteolin-4'-O-β-D-glucopyranoside, luteolin-7-O-β-D-glucopyranoside, and oleuropein), luteolin and luteolin-4'-O-β-D-glucopyranoside were assigned as potent inhibitors of AGE formation. The extraction procedure greatly affects the composition and therefore the anti-glycation potential of olive leaves.
authors.affiliation: 1 Department of Chemistry, University of Ioannina , Ioannina, Greece .
authors.forename: Vassiliki G
authors.initials: VG
authors.lastname: Kontogianni
authors.forename: Pantelis
authors.initials: P
authors.lastname: Charisiadis
authors.forename: Evangelia
authors.initials: E
authors.lastname: Margianni
authors.forename: Fotini N
authors.initials: FN
authors.lastname: Lamari
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Gerothanassis
authors.forename: Andreas G
authors.initials: AG
authors.lastname: Tzakos
mesh_terms: D017127:Glycation End Products, Advanced / Q000037:antagonists & inhibitors* / Q000737:chemistry; D015394:Molecular Structure; D031658:Olea / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry; D010936:Plant Extracts / Q000737:chemistry*; D018515:Plant Leaves / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D017127:Glycation End Products, Advanced; D010636:Phenols; D010936:Plant Extracts
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