title: Assessment of phenolics-enriched extract and fractions of olive leaves and their antioxidant activities.
abstract: Recent studies suggest that olive leaf is a significant source of bioactive phenolic compounds comparable to olive oil and fruits. Identifying appropriate extraction methods is thus an important step to increase the yield of such bioactive components from olive leaf, which is otherwise agricultural waste. The present study evaluates phenolic contents and compositions of olive leaf extracted by several solvent methods and to further establish their antioxidant activities using various radical scavenging systems. Total flavonoid and phenolic contents were significantly higher in the 80% ethanol extract, butanol, and ethylacetate fractions than hexane, chloroform and water fractions (p<0.05). Oleuropein was identified as a major phenolic compound with considerable contents in these major three fractions and the extract that correlated with their higher antioxidant and radical scavenging. These results indicate that olive leaf contains significant amounts of oleuropein and phenolics, important factors for antioxidant capacity, which can be substantially modified by different extraction methods.
authors.affiliation: Department of Nutrition, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Ok-Hwan
authors.initials: OH
authors.lastname: Lee
authors.forename: Boo-Yong
authors.initials: BY
authors.lastname: Lee
authors.forename: Junsoo
authors.initials: J
authors.lastname: Lee
authors.forename: Hee-Bong
authors.initials: HB
authors.lastname: Lee
authors.forename: Jong-Youn
authors.initials: JY
authors.lastname: Son
authors.forename: Cheon-Seok
authors.initials: CS
authors.lastname: Park
authors.forename: Kalidas
authors.initials: K
authors.lastname: Shetty
authors.forename: Young-Cheul
authors.initials: YC
authors.lastname: Kim
mesh_terms: D000383:Agriculture / Q000379:methods; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism*; D002725:Chloroform / Q000737:chemistry; D016166:Free Radical Scavengers; D006586:Hexanes / Q000737:chemistry; D007220:Industrial Waste; D057888:Iridoid Glucosides; D039823:Iridoids; D019787:Linoleic Acid / Q000737:chemistry; D031658:Olea / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry; D010545:Peroxides / Q000737:chemistry; D019800:Phenol; D010636:Phenols / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D011714:Pyrans / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D000975:Antioxidants; D016166:Free Radical Scavengers; D006586:Hexanes; D007220:Industrial Waste; D057888:Iridoid Glucosides; D039823:Iridoids; D010545:Peroxides; D010636:Phenols; D010936:Plant Extracts; D011714:Pyrans; D014867:Water; C002769:oleuropein; D019800:Phenol; D002725:Chloroform; D019787:Linoleic Acid; D010100:Oxygen