Evaluation of antioxidant potentials and total phenolic contents of selected Indian herbs powder extracts

The aim of the study was to compare 19 commonly used antidiabetic plants for their antioxidant potential by seven assays and identify the plants that are good sources of natural antioxidants. The antioxidant potential was evaluated by estimating reducing power (using potassium ferricyanide), lipid peroxidation inhibitory activity (thiobarbituric acid assay) and scavenging activities of DPPH^•, ABTS^•, NO^• and H2O2^• radicals; whereas total phenolic contents were also estimated. T. chebula extract demonstrated high phenolic content with significant antioxidant activity. Total phenolic content were positively correlated with reducing power and ABTS scavenging activity. However, three plant extracts (C. mukul, P. crispum and W. somnifera) having less phenolic contents exhibited excellent antioxidant potential and some plants (T. arjuna, S. reticulata and G. glabra) with high phenolics where devoid of comparable antioxidant property. Results indicate that the plants extracts offer promising sources of natural antioxidants and in addition to phenolics, there could be other non phenolic antioxidants which contribute to antioxidant potential.