title: Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves.
abstract: Bioactive polyphenolics are ubiquitously present in plants and may play an important role in the prevention and management of certain human diseases. Three known flavonoids viz Kaemperol-3-O-rutinoside (1), quercetin-3-O-glucoside (2) and kaemperol-3-O-glucoside (3) and inseparable mixture (1:1) of quercetin-3-O-glucose/galactose (4) were isolated, and identified for the first time from Holarrhena floribunda. The antioxidant capacity using the ORAC, FRAP and TEAC assays and inhibition of lipid peroxidation were measured for isolated flavonoids. The result showed that compounds 2 and 4 showed significantly increased ORAC, TEAC, and FRAP activities with low pro-oxidant potential as well as improved lipid peroxidation inhibition levels when compared to compounds 1 and 3. The most active compounds were found to be flavonoids with a quercetin basic structure. These results imply that the isolated flavonoid glycosides are responsible for the antioxidant activity of the plant leaves and it forms the scientific basis for its traditional usage.
authors.affiliation: Department of Medical Biosciences, University of the Western Cape, New Life Sciences Building, Private Bag X17 Bellville, Cape Town 7535, South Africa.
authors.forename: Jelili A
authors.initials: JA
authors.lastname: Badmus
authors.affiliation: Department of Medical Biosciences, University of the Western Cape, New Life Sciences Building, Private Bag X17 Bellville, Cape Town 7535, South Africa.
authors.forename: Okobi E
authors.initials: OE
authors.lastname: Ekpo
authors.affiliation: Oxidative Stress Research Centre, Institute of Biomedical and Microbial Biotechnology, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Cape Town South Africa.
authors.forename: Fanie
authors.initials: F
authors.lastname: Rautenbach
authors.affiliation: Oxidative Stress Research Centre, Institute of Biomedical and Microbial Biotechnology, Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Cape Town South Africa.
authors.forename: Jeanine L
authors.initials: JL
authors.lastname: Marnewick
authors.affiliation: Department of Chemistry, University of the Western Cape, Chemical Sciences Building, Private Bag X17 Bellville, Cape Town 7535, South Africa.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Hussein
authors.affiliation: Department of Medical Biosciences, University of the Western Cape, New Life Sciences Building, Private Bag X17 Bellville, Cape Town 7535, South Africa.
authors.forename: Donavon C
authors.initials: DC
authors.lastname: Hiss
mesh_terms: D000818:Animals; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D035462:Holarrhena / Q000737:chemistry; D015227:Lipid Peroxidation; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D018515:Plant Leaves / Q000737:chemistry; D011916:Rats, Inbred F344; D017382:Reactive Oxygen Species / Q000737:chemistry
chemical_list: D005419:Flavonoids; D016166:Free Radical Scavengers; D010936:Plant Extracts; D017382:Reactive Oxygen Species