5-Lipoxygenase inhibition of polyphenolic antioxidants from
undomesticated plants of South Africa
Akula and Bharti Odhav*
Durban University of Technology, Faculty of Engineering,
Science and the Built Environment, Department of
Biotechnology, ML Sultan Campus, P.O. Box 1334, Durban,
4000, South Africa.
*Corresponding author. E-mail: Odhavb@dut.ac.za. Tel: +27 31
373 5330. Fax: +27 31 373 5351.
Accepted 10 July 2008
and methanolic extracts of 18 leafy vegetables from South Africa were
investigated for their free radical scavenging activity, total phenolic
dubius, Amaranthus hybridus, Amaranthus spinosus, Asystasia gangetica,
Bidens pilosa, Centella asiatica, Ceratotheca triloba, Chenopodium
album, Cleome monophylla, Emex australis, Galinsoga parviflora, Justicia
flava, Momordica balsamina, Oxygonum sinuatum, Physalis viscosa,
Portulaca oleracea, Senna occidentalis and Solanum nigrum
were used in this study.
radical scavenging studies
2,2-diphenyl-2-picrylhydrazyl hydrate(DPPH), methanolic
extracts from six plants almost completely inhibited DPPH absorption (J.
flava-96.6%, P. oleracea-96.5%, M. balsamina-94.7%,
O. sinuatum-92.1%, S. nigrum-92.0% and A. hybridus-90.5%),
whereas methanolic extracts from E. australis-78.6% and G.
parviflora-76.5% showed lowest activities among the plants studied.
Aqueous extracts were considerably less effective radical scavengers
compared to methanolic extracts showing highest activity with J.
flava-48.0% and lowest with A. gangetica-36.2%. A correlation
between radical scavenging activity of extracts with total phenolic
content was observed.
18 plants studied for anti-inflammatory activity, methanolic extracts
from eight plants showed significant inhibition of 5-lipoxygenase
(5-Lox) activity. Among the plants studied Bidens pilosa (IC50
21.8 µg/ml) showed maximum anti-inflammatory activity while Emex
australis (IC50 81.4 µg/ml) showed minimum inhibition of
5-Lox activity. Large amounts of phenolic compounds may contribute
towards the antioxidant and anti-inflammatory properties among the
Leafy vegetables, radical scavenging, DPPH, total phenolics,