Journal de toxicologie clinique
Libre accès
ISSN: 2161-0495
ISSN: 2161-0495
Eleazu CO, Amadi CO, Iwo G, Nwosu P and Ironua CF
The polyphenolic composition, oleoresin contents and antioxidant activities of 10 elite accessions of ginger (Zingiber officinale Roscoe) were investigated using standard procedures. The accessions of ginger contained significant quantities of polyphenols and oleoresin which suggested their therapeutic potentials. The antioxidant activities of extracts of the ginger accessions as determined by reducing power tests and their scavenging activities on 2, 2 diphenyl-1-picylhydrazyl radical, indicated that most of them possessed very strong antioxidant activities with higher reductive capacity than standard quercetin at higher concentrations. There was a negative correlation between percentage oleoresin versus phenol (r2=-0.328) but a positive correlation between oleoresin versus percentage inhibition of DPPH radical (r2=0.251) and reducing power (r2=0.494). We obtained a positive correlation between the percentage inhibition of DPPH radical versus phenol (r2=0.827) and reducing power (r2=0.736) suggesting that any of the three assays could be used to determine the antioxidant activity of ginger, but a negative correlation between the percentage inhibition of DPPH radical versus flavonoids (r2=-0.754). Finally, we obtained a negative correlation between flavonoids versus reducing power (r2=-0.926). Results show these accessions of ginger will possess high economic potentials and could be utilized in the treatment of diseases that implicate free radicals. In addition, the oleoresins in ginger could contribute significantly to the reductive capacity of ginger. Finally, the negative correlation we obtained between the percentage inhibition of DPPH radical versus flavonoids and reducing power suggest to us that the flavonoids in ginger may have no contribution to their reductive capacity or hydrogen donating ability.