USA Africa Dialogue Series - Ten Immune Boosters based on their Extremely High Content of Vitamin C/more info

Annals. Food Science and Technology
2012
Available on-line at www.afst.valahia.ro Volume 37 13, Issue 1, 2012

PHYTOCHEMICAL AND ANTIOXIDANT ANALYSIS OF METHANOLIC EXTRACTS
OF FOUR AFRICAN INDIGENOUS LEAFY VEGETABLES

Elias K. Mibei1*, Nelson K. O. Ojijo2, Simon M. Karanja1, Johnson K. Kinyua1.

1Biochemistry Department, Faculty of Science, Jomo Kenyatta University of Agriculture and Technology, Kenya
P.O. Box 62000-00200, Nairobi.
2 Department of Food Science, Faculty of Agriculture, JKUAT, Kenya.
*E-mail: elimibei@yahoo.com<mailto:elimibei@yahoo.com>

Abstract

The present study investigated the phytochemical composition and relative antioxidant activity of selected African
indigenous leafy vegetables (ILVs): Corchorus olitorius (Jute mallow), Crotalaria ochroleuca (Slender leaf), Solanum
scabrum (Black nightshade) and Cleome gynandra (Spider plant). The crude extracts were prepared by methanol
extraction. The study revealed the presence of a wide array of phytochemicals including alkaloids, flavonoids, tannins,
saponins, steroids and phenols whereas terpenoids, steroids and anthraquinones were absent in most ILVs. The
antioxidant activity was achieved by screening the leaf extracts for their free radical scavenging properties using
diphenyl picryl hydrazyl (DPPH) and ascorbic acid as standard antioxidant.The ability of the extracts to scavenge
DPPH radicals was determined spectrophotometrically at 517nm. The four ILV extracts had significant radical
scavenging effects and almost all reported a significantly higher percentage of DPPH inhibition than ascorbic acid (P
< 0.05). The extracts of C. olitorius and C. gynandra were most effective since they had higher percentages of radical
scavenging activity and lower IC50 values (concentration which scavenged 50% of the DPPH radicals). The results
therefore indicated that these vegetables are phytochemical rich and natural antioxidants with potent antioxidative
activities. This is of health or nutraceutical significance and thus authenticates their usefulness for medicinal purposes.
Key words: African leafy vegetables, 1, 1 diphenyl-2-picrylhydrazyl, radical scavenging activity, antioxidants.
…………………………………………………………………………………………………………………..

http://www.ajol.info/index.php/ajb/article/viewFile/58988/47301

African Journal of Biotechnology Vol. 7 (14), pp. 2304-2309, 18 July, 2008
Available online at http://www.academicjournals.org/AJB
ISSN 1684–5315 © 2008 Academic Journals
Full length Research Paper

Phytochemical, nutritional and medical properties of
some leafy vegetables consumed by Edo people of
Nigeria

J.K. Mensah1*, R.I. Okoli2, J.O. Ohaju-Obodo2 and K. Eifediyi3
1Department. of Botany, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
2Department of Pharmacology and Therapeutics, Ambrose Alli University, Ekpoma, Edo State, Nigeria.
3Department of Agronomy, Ambrose Alli University, Ekpoma, Edo State, Nigeria.


...........................................................................................................

http://www.sciencedirect.com/science/article/pii/S030881461400692X Food Chemistry<http://www.sciencedirect.com/science/journal/03088146>
Volume 165<http://www.sciencedirect.com/science/journal/03088146/165/supp/C>, 15 December 2014, Pages 424–443 (forthcoming)
Hibiscus sabdariffa L. – A phytochemical and pharmacological review
Inês Da-Costa-Rocha<http://www.sciencedirect.com/science/article/pii/S030881461400692X>a<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af005>,
Bernd Bonnlaender<http://www.sciencedirect.com/science/article/pii/S030881461400692X>b<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af010>,
Hartwig Sievers<http://www.sciencedirect.com/science/article/pii/S030881461400692X>c<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af015>,
Ivo Pischel<http://www.sciencedirect.com/science/article/pii/S030881461400692X>a<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af005>, c<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af015>,
Michael Heinrich<http://www.sciencedirect.com/science/article/pii/S030881461400692X>a<http://www.sciencedirect.com/science/article/pii/S030881461400692X#af005>, ,
•
Abstract
……….. Extracts showed antibacterial, anti-oxidant, nephro- and hepato-protective, renal/diuretic effect, effects on lipid metabolism
(anti-cholesterol), anti-diabetic and anti-hypertensive effects among others. This might be linked to strong antioxidant activities,
inhibition of α-glucosidase and α-amylase, inhibition of angiotensin-converting enzymes (ACE), and direct vaso-relaxant effect
or calcium channel modulation. Phenolic acids (esp. protocatechuic acid), organic acid (hydroxycitric acid and hibiscus acid)
and anthocyanins (delphinidin-3-sambubioside and cyanidin-3-sambubioside) are likely to contribute to the reported effects.





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