Validated high-performance thin-layer chromatographic densitometric method for quantification of gallic acid, quercetin, and ursolic acid in the combined formulation of Emblica officinalis, Punica granatum Linn, and Ocimum sanctum Linn extracts

A quantitative high-performance thin-layer chromatography method has been developed for the estimation of three markers gallic acid, quercetin, and ursolic acid in the extracts and combined formulation of Emblica officinalis, Punica granatum Linn, and Ocimum sanctum Linn extracts. Chromatographic development was performed using precoated silica gel 60 F-254 TLC plate and final optimized mobile phase as toluene:ethyl acetate:formic acid (4.5:3:0.2 v/v/v), resulting in optimum resolution with R-f of 0.29, 0.51, and 0.78 for gallic acid, quercetin, and ursolic acid, respectively. Gallic acid and quercetin were detected at 258 nm and ursolic acid at 529 nm after derivatization. All markers showed a good correlation coefficient of 0.9950 for gallic acid, 0.9953 for quercetin, and 0.9945 for ursolic acid. The accuracy and precision measured were less than 2% relative standard deviation for all markers. The mean percent recovery found for gallic acid, quercetin, and ursolic acid were within acceptable limits in formulation indicating that the excipients present have no interference. The proposed method was found to be specific, accurate, linear, precise, and robust, and can be applicable for the simultaneous estimation of gallic acid, quercetin, and ursolic acid for the analysis of individual plant extracts and herbal formulation.