Development and validation of UV-visible method to determine gallic acid in hydroalcoholic extract of Erythrina fusca leaves

Gallic acid (GA) inhibitory potential against oxidative stress and associated diseases, creates the importance for GA standardization in plant medicines. The present investigation was intended to quantify the amount of GA in Erythrina fusca leaves hydro-alcoholic extract (EFLHE) by the development of UV/Visible-spectrophotometric method and its validation. The study involved of EFLHE preparation via ethanolic maceration, followed by estimation of total phenolic content (TPC) or GA through the development of Folin-Ciocalteu reagent-based UV/Visible-spectrometric method and standard GA calibration curve. Developed method to estimate GA was validated using linearity, accuracy, precision, repeatability and ruggedness studies. The TPC analysis of EFLHE in concentration of 0.5, 1.0, 2.5, 3.0, 5.0, 10.0 μg/ml exhibited amount of GA as 98.0±8.71, 117.0±1.73, 217.1±3.45, 276.0±0.80, 289.1±1.11 and 295.2±1.19 GA equivalent (mg/g, dry weight) respectively. The linearity study revealed the range of GA from 0.5-10 μg/ml. The correlation coefficient for GA was found as 0.997 at 212 nm. Recovery analysis (accuracy) showed that little change in drug concentration could be accurately estimated. The precision study revealed low %RSD with the highest value of 0.43%, indicating substantial precision. The present study concludes that advanced method to estimate GA in EFLHE is rapid, simple, accurate, precise, and economic; and validated for linearity, accuracy, precision, repeatability and ruggedness. The study recommends that this method can be used for GA estimation in Erythrina fusca leaves extract.