African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12278

Full Length Research Paper

Antioxidant activities in extracts of selected indigenous vegetables from Kenya and Malawi

Wakisa Lenard Kipandula*
  • Wakisa Lenard Kipandula*
  • Department of Biochemistry/Molecular Biology, Kamuzu Central Laboratory, Kamuzu Central Hospital, P.O. Box 149, Lilongwe, Malawi; Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197, 00100, Nairobi, Kenya.
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Benzon Mwanza
  • Benzon Mwanza
  • Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197, 00100, Nairobi, Kenya.
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Edward Nguu
  • Edward Nguu
  • Department of Biochemistry, School of Medicine, University of Nairobi, P.O. Box 30197, 00100, Nairobi, Kenya.
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Dorington Ogoyi
  • Dorington Ogoyi
  • Department of Biochemistry and Biotechnology, Technical University of Kenya, P.O. Box 52482, 00200, Nairobi, Kenya.
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  •  Received: 31 October 2013
  •  Accepted: 24 March 2014
  •  Published: 23 April 2014

Abstract

Antioxidant activities and phytochemical compounds of ethanol and hot water extracts of 7 selected indigenous vegetable species from Malawi and Kenya were Spectophotometrically determined and evaluated. Their effectiveness were also evaluated by their EC50 values through interpolation from linear regression analysis of their respective data. Generally, ethanolic extracts portrayed high quantities of total phenol, carotenoids and lycopene while hot water extracts showed high ascorbic acid. The highest total phenol (475.88±0.02 mg/g) and lycopene (0.13±0.02 mg/g) were detected in the ethanol extracts of I. batatas and C. gynandria, respectively. In the hot water extracts, the highest ascorbic acid (2.59±0.06 mg/g) and flavonoids (156.43±0.02 mg/g) were from M. esculenta. Dose-dependent antioxidant activities of the extracts were observed. Based on the EC50 values (mg/ml), the hot water extracts were significantly (p<0.05) more effective in all antioxidant activities assayed (DPPH, hydroxyl, superoxide anion radicals and reducing power) than ethanol extracts. It was observed that a single vegetable species did not posses all sorts of antioxidant phytochemical compounds in significant quantities and hence not effective in scavenging all different radicals. A combinatory intake of these vegetables species in sufficient concentrations should thus be recommended to enhance an optimal antioxidant capacity in the body.

 

Key words: Antioxidants, free radicals, health benefits, indigenous vegetables.