Assessment of phenolics-enriched extract and fractions of olive leaves and their antioxidant activities.
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.
Lee
Ok-Hwan
OH
Department of Nutrition, University of Massachusetts, Amherst, MA 01003, USA.
Lee
Boo-Yong
BY
Lee
Junsoo
J
Lee
Hee-Bong
HB
Son
Jong-Youn
JY
Park
Cheon-Seok
CS
Shetty
Kalidas
K
Kim
Young-Cheul
YC
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
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