Antioxidant activity of compounds isolated from the butanol fraction of Acalypha wilkesiana var. golden-yellow (Muell & Arg.)

Background : Free radicals (FR) and other reactive oxygen species (ROS) are major sources of concern in some health conditions such as wounds, ulcers, inflammations, heart troubles and cancers amongst many others. These chemical species have been implicated as the causative agents of these and many more similar disease conditions. The cost of treating / managing these medical conditions has continued to take a huge toll on the socio-economic status of sufferers/patients. Many bio-resources such as plants are now being used to mitigate this worrisome health challenge. Objective : To investigate the antioxidant activity of Acalypha wilkesiana var. golden-yellow ( Muell & Arg.) syn. A. wilkesiana var. tropical tempest . Methods : The leaf crude extract, butanol fraction and three isolates (W-1, W-2 and W-3 previously obtained from the silica-gel column chromatographic separation of the butanol fraction) were to be screened for antioxidant activities using the rapid free-radical scavenging activity test and absorption spectrophotometry, both employing DPPH reagent. Results: The initial free-radical scavenging activity of the plant was confirmed when the DPPH reagent-sprayed spots of the plant extract/fraction/isolates (W-1, W-2 and W-3) showed white color on purple background. W-1 (an ester) gave a marginal IC 50 of 0.77 μg mL -1 as vitamin A at 0.79 μg mL -1 while W-2 (a diol) and W-3 (phenol) both demonstrated moderate antioxidant activities of 0.58 and 0.53 μg mL -1 respectively. However, W-3 was more antioxidant in its action and its value compare favorably with IC 50 value obtained with vitamin C (a standard antioxidant drug) at 0.41μg mL -1 . Conclusion : The results of the antioxidant assays have showed that the compounds obtained from the plant (especially W-2 and W-3) could be considered as lead antioxidant drug templates in further in-vitro [especially structural activity relationship studies (SARS)] and in-vivo studies with the aim of improving on their activities. Keywords : Free- radicals; antioxidant activity; DPPH assay; isolates; Acalypha wilkesiana var.golden-yellow