Antioxidant responses of some common medicinal plants grown in copper mining areas

Abstract

The effect of bioaccumulated Cu on the antioxidant properties of medicinal plants grown in Cu rich soil is studied. The total phenolic and flavonoid content, 2,2′-Diphenyl-1-picrylhydrazyl (DPPH•) scavenging activity, reducing power, metal chelating activity and inhibition of lipid peroxidation were assayed in methanol (MeOH) extracts of eight medicinal plants grown in the vicinity of copper mining impact site and compared with control samples. Corresponding IC50 values of DPPH• scavenging ability and metal chelating ability were found to be significantly (P<0.05) higher in mining impact samples e.g., Withania somnifera, Azadirachta indica, Andrographics peniculata and Ocimum sanctum. The IC50 of inhibition of lipid peroxidation of all the mining impact samples were significantly (P<0.05) higher than the control samples, indicating lower inhibition capacity of lipid peroxidation by the mining impact samples. This was attributed to higher Cu contents in the MeOH extracts of mining impact samples measured by inductively coupled plasma mass spectrometry (ICP-MS).