RESUMEN
Excessive free radicals in the body system are known to cause oxidative stress, resulting in some pathological conditions which are fast becoming a challenge that needs urgent attention. Plants are known to be good sources of antioxidants that have the potential of scavenging for free radicals in the body system. In a bid to find solution to the challenge of oxidative stress, three species of kolanut were analysed in this study for their antioxidant properties. The husk and testa of three species of kolanut (Cola acuminata, Cola nitida and Cola verticillata) were subjected to liquid and solid state fermentation for 10 days, after which it was dried, grounded and analysed. The effect of fermentation was checked quantitatively, comparing the antioxidant properties of the fermented and unfermented (control) samples. Radical scavenging ability (DPPH), Ferric Reducing Antioxidant Property (FRAP), Iron chelation, vitamin C, phenol and flavonoid were determined. The values obtained for the husk and testa of fermented and unfermented (control) samples were within the range of 0.210 to 1.17 mg/g for FRAP, 1.120 to 4.700 mg/g for phenol, 55.740 to 70.230% for DPPH, 0.263 to 1.577 mg/g for flavonoid, 88.410 to 97.733% for iron chelation, while that of vitamin C ranged between 1.913 to 4.633 mg/g respectively. The fermented samples had higher antioxidant properties for DPPH, phenol, Iron chelation and vitamin C than unfermented samples. This study has established the fact that the husk and testa of the kolanut species has antioxidant properties and thus can exert several beneficial effects by virtue of these properties.