Simultaneous equation method for the estimation of gallic acid and apigenin by UV–visible spectrophotometry

Apigenin and gallic acid are advantageous for people's health since they aid in the treatment of liver illness. The study mainly illustrated that a simple, rapid, accurate, economic, and precise UV–visible spectrophotometry method has been developed and validated. Methods are validated according to the ICH guidelines and can be adopted for the routine analysis of gallic acid and apigenin in hepatoprotective polyherbal formulation. Choices of a common solvent were essential so various solvent ranges including methanol, ethanol, and acetonitrile were analyzed. Hence, methanol was selected as a solvent for the proposed method. Gallic acid and apigenin showed maximum absorbance at 217 and 268 nm, respectively. Both drugs obey Beer–Lambert’s law in the concentration range of 0.5 µg mL⁻¹–3 µg mL⁻¹ for gallic acid and apigenin, respectively. The limit of detection and limit of quantification were found to be 0.00379 µg mL⁻¹ and 0.011 µg mL⁻¹ for gallic acid, respectively. For apigenin, the limit of detection and limit of quantification values were found to be 0.00801 µg mL⁻¹ and 0.024 µg mL⁻¹, respectively. The method was validated statistically and by recovery studies for linearity, precision, repeatability, and reproducibility. The obtained results proved that the method can be employed for the routine analysis of gallic acid and apigenin in bulks as well as in the commercial herbal formulations.