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Antioxidant activity and
quantitative estimation of azadirachtin and nimbin in
Azadirachta Indica A. Juss grown in foothills of Nepal
Amal Kumar Ghimeray1,
Cheng-Wu Jin1, Bimal Kumar Ghimire2
and Dong Ha Cho1
1School
of Bioscience and Biotechnology, Kangwon National
University, Chuncheon 200-701, South Korea.
2Bioherb
Research Institute, Kangwon National University, Chuncheon,
South Korea.
*Corresponding author.
E-mail:
chodh@kangwon.ac.kr. Tel: 82-33-250-6475.
Fax: 82-33-250-6470
Accepted 17 June, 2009 |
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The leaf and bark fraction extracts of Azadirachta indica
A. Juss. (neem) grown in the foothills (sub-tropical region)
of Nepal were evaluated for their antioxidant activity,
total phenolic (TP) and total flavonid (TF) contents.
HPLC method was employed to quantify the amount of
azadirachtin and nimbin present in the seed, leaf and the
bark extracts of neem. The result showed that the highest
azadirachtin content was found in the methanolic extract of
the seed (3300 µg/g dw).
Similarly, the hexane fraction of bark showed the highest
nimbin content (271 µg/g dw)
followed by the methanolic extract (260 µg/g
dw).
Antioxidant activity was determined by measuring
1,1-diphenyl-2-picrylhydrazyl
free radical scavenging activity, hydroxyl radical
scavenging activity, DNA protection assay, metal chelating
and the inhibition of peroxidation using linoleic acid
system and their results were found at different magnitudes
of potency. The results of TP content expressed in tannic
acid equivalents ranged from 66.63 to 629.04
µg/mg in the bark extracts and 23.85 to 237.00
µg/mg in the leaf extracts. Likewise, the content
of TF expressed in quercetine equivalents ranged from 12.87
to 17.07
µg/mg in the bark and 13.72 to 93.17
µg/mg in the leaf extracts.
Key
words:
Azadirachta indica A. Juss (neem), antioxidant,
azadirachtin, flavonoid, foothills (subtropical region),
HPLC, nimbin, polyphenol. |
