Antioxidant Activity of Acalypha wilkesiana var. lace-acalypha (Muell &Arg.)

Abstract

Background: The incidence of free-radicals has become a major concern in health issues such as wounds, respiratory dysfunctions, heart troubles, cancers and inflammations amongst many others. The search for natural antioxidant drug templates led to the screening of Acalypha wilkesiana var. lace- acalypha for potential antioxidant activity.

Objectives of study. The crude extract, butanol fraction and four compounds previously obtained from the plant were to be screened for antioxidant activity.

Methodology: The extract, butanol fraction and four compounds designated as 5A-II (3), 5B (1), 5C (2) and 5D (H-2) obtained from silica-gel column chromatography of the butanol fraction were to be screened for antioxidant activity using DPPH reagent.

Results and Discussion: The extract and butanol fraction of A. wilkesiana var. lace-acalypha demonstrated marginal antioxidant activity (IC₅₀) of at 0.79 and 0.77 μg mL^-1 respectively. However, 5B (1) and 5C (2) (both polyphenols) gave moderate antioxidant activities of 0.47 and 0.56 μg mL-¹ respectively which compare favourably with the IC₅₀ values obtained with vitamins C and A at 0.46 and 0.58 μg mL-¹ respectively. However, 5D (H-2) demonstrated a relatively similar antioxidant activity as vitamin E at 0.66 and 0.60 μg mL-¹ respectively. The antioxidant activities demonstrated by the plant extract/ fraction/compounds were not surprising because the phytochemical investigations carried out on the plant revealed the presence of terpenes and tannins which have been reported in previous studies to exhibit antioxidant activities.

Conclusion: The results of the antioxidant assays have revealed that compounds isolated from the plant especially 5B (1) and 5C (2) could serve as potential antioxidant templates which could be further investigated in detailed in-vitro and in-vivo studies with the aim of improving on their activities for the fights against the destructive free-radical oxygenated species.

Keywords: Free-radicals; antioxidant activity; DPPH; assay; Acalypha wilkesiana