Separation and evaluation of free radical‐scavenging activity of phenol components of Emblica officinalis extract by using an HPTLC–DPPH• method

Abstract

A new procedure has been developed to separate and quantify the free radical‐scavenging activity of individual compounds from an Emblica officinalis extract based on the combination of HPTLC with a diode array detector (DAD) and postchromatographic DPPH^• radical derivatization. Free gallic and ellagic acids and emblicanins A and B in the E. officinalis extract were separated by TLC and identified. All the compounds of the extract were capable of scavenging of DPPH^• radicals. It was established that the DPPH^• scavenging activity of emblicanins A and B was 7.86 and 11.20 times more than that of ascorbic acid and 1.25 and 1.78 times more than gallic acid, respectively. From the estimated ID₅₀ values, it can be seen that the increasing order of activity was emblicanin B > emblicanin A > gallic acid > ellagic acid > ascorbic acid. Probably, the antioxidant activity of E. officinalis extract is associated with the presence of hydrolyzable tannins having ascorbic acid‐like action.