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2 Acta Biochimica Polonica

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Isolation and antioxidant activity of flavonoids from Holarrhena floribunda (G.don) leaves

100%

Badmus J. , Ekpo O. , Rautenbach F. , Marnewick J. , Hussein A. , Hiss D.

Acta Biochimica Polonica

2016

tom 63

nr 2

353-358

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.

Evaluation of antioxidant, antimutagenic, and lipid peroxidation inhibitory activities of selected fractions of Holarrhena floribunda (G. Don) leaves

84%

Badmus J. , Odunola O. , Yekeen T. , Gbadegesin A. , Fatoki J. , Godo M. , Oyebanjo K. , Hiss D.

Acta Biochimica Polonica

2013

tom 60

nr 3

435-442

Exposure to environmental pollutants often leads to an upsurge in the production of reactive oxygen species (ROS). ROS oxidize cellular fatty acids to produce lipid peroxyl radicals, subsequently transformed into lipid peroxides, which decrease membrane fluidity and increase the activity of various enzymes implicated in degenerative diseases and cancer formation. Edible plants that contain exogenous compounds like curcumeroid, β-carotene, turmeric, and so on, protect the aerobic cells from oxidation of free radicals. This study thus evaluates antioxidant and antimutagenic activities of ethyl acetate, aqueous and methanolic fractions of Holarrhena floribunda leaves. Inhibitory activities of the ethyl acetate fraction on Fe2+-induced lipid peroxidation in hen egg yolk; rat liver and brain tissues were also evaluated. The Allium cepa root assay was used to evaluate antimutagenic activity. Results showed that the ethyl acetate scavenged DPPH, OH•, and •O2- much stronger than other fractions, as evidenced by its lowest respective IC50 values. All the fractions displayed antimutagenic activities against cyclophosphamide-induced chromosomal aberrations. Likewise, all the fractions induced a reduction in mitotic index, a hallmark of cytotoxicity in the root meristem of Allium cepa. The decrease in mitotic index was most profound for the ethyl acetate fraction, which also demonstrated a significant lipid peroxidation inhibitory activity in the liver and brain homogenates, but not in egg yolk, compared with the ascorbic acid standard. In general, the results suggest that the ethyl acetate fraction might contain beneficial phytochemicals that should be explored as novel candidates for preclinical drug development.