P40 Alchornea cordifolia Leaf-Extracts Confer Protection from DNA Damage and Reactive Oxygen Species (ROS)

Abstract

Excess production of reactive oxygen species (ROS) can lead to tissue injury but this itself initiates the generation of ROS, thereby completing a vicious cycle. Deoxyribonucleic acid (DNA) appears to be the most vulnerable target in ROS induced cellular injury. In this work we demonstrate DNA protection by methanolic leaf extract of Alchornea cordifolia against oxidative damage. The extracts were investigated for antioxidant activity and the ability to confer protection from DNA damage in vitro through DPPH radical scavenging, inhibition of lipid peroxidation (ILP), and DNA protection assays. Total phenolic and flavonoid contents of these plant extracts were determined as gallic acid equivalent (GAE) and rutin equivalent (RE), respectively. The total phenolic content was highest in methanolic extract at 239.66 mg GAE/g of extract (at a concentration of 1 mg/ml) followed by the aqueous extracts at 195.17 mg GAE/g and flavonoids content in the methanolic extract was 776.00 mg of rutin equivalent per gram of sample and 686.0 mg RE/g in the aqueous extracts. The methanol and aqueous extracts exhibited a high 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, which was concentration dependent. In the DNA protection assay, supercoiled plasmid (pBluescript SK-) freshly extracted from Escherichia coli was pre-incubated with various extracts of Alchornea cordifolia leaves prior to hydrogen peroxide stress. Only the methanol extract was able to preserve DNA integrity. The results suggests that bioactive components of Alchornea cordifolia can be tapped as new source of natural antioxidants agents as it preserves DNA integrity and confer a coping mechanism for oxidative stress.