American Journal of Animal and Veterinary Sciences

Analysis of Phenolic Content and Antioxidant Properties of Selected Cowpea Varieties Tested in Bovine Peripheral Blood

Sarah Adjei-Fremah, Louis EN Jackai and Mulumebet Worku

DOI : 10.3844/ajavsp.2015.235.245

American Journal of Animal and Veterinary Sciences

Volume 10, Issue 4

Pages 235-245


Cowpea is an important grain legumewith a dual purpose function as a food and feed resource. Cowpea containsphenolic compounds that are beneficial to human and animal health. We evaluatedthe phenolic content, condensed tannin content and antioxidant capacities ofmethanol extracts of seed and leaf of seven varieties commonly used in food andanimal feed. The total phenolic content and condensed tannins were quantifiedusing the Folin-Ciocalteu and Vanillin-HCL method respectively. The effects of cowpeaphenolic extract on total antioxidant capacity, glutathione peroxidase andsuperoxide dismutase activity was evaluated in vitro in bovine blood.Overall, the methanol extracts of the leaves contained high concentrations(p<0.0001) of total phenolic content (290.51±38.02 mg GAE/g) compared toseed extracts (118.10±71.96 mg GAE/g), although high antioxidant capacity wasobserved in both extracts. In addition, a positive correlation was foundbetween total phenol and tannins content and antioxidant capacity of theextracts. Treatment with cowpea phenolic extract increased (p<0.0001) thetotal antioxidant capacity in cow blood (5.33±0.27 mM UAE) relative to controls(1.62±0.10 mM UAE). The enzymatic activities of GSH-Px and SOD were alsoincreased. Our findings, suggest the potential of cowpea polyphenols to reduceoxidative stress in livestock production. Results of the present study showedthat leaf and seeds of cowpea possess rich amounts of natural antioxidants andcan be further explored for their possible use as a natural additive in food oruse in pharmaceutical industries and in animal feed.


© 2015 Sarah Adjei-Fremah, Louis EN Jackai and Mulumebet Worku. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.