Identification of acteoside as the active antioxidant principle of Premna serratifolia root wood tissues

Premna serratifolia Linn. (syn: Premna integrifolia) is one the most widely used plant in the Ayurvedic system of medicine. Several pharmacological activities including antioxidant effects and phytochemical investigations have been previously reported for the various parts of plant, except the root woody tissues. In the present study, the antioxidant activity and active principle of the root woody tissues were investigated. Antioxidant effect was routinely monitored using the DPPH radical scavenging assay while phytochemical investigation was based on analysis using HPLC and Teledyne Isco flash chromatography system. Through the use of comprehensive spectroscopy studies, the isolated active antioxidant principle was identified as acteoside (verbacoside). Aceoside, which was about four times more active (18.3 ± 3.7 μg/ml; 11.4 ± 2.3 μM) than the crude root wood extract (73.8 ± 2.4 μg/ml), could account for most of the reported pharmacological activity on P. serratifolia.