Development and validation of an HPTLC method for extraction optimization and simultaneous quantification of gallic acid and quercetin, with comparative FTIR analysis of Nymphaea nouchali var. nouchali flowers from different geographical location

A simple, precise and efficient HPTLC technique has been developed for simultaneous quantification of Gallic acid (GA) and Quercetin (Q) in methanolic extract of flower of Nymphaea nouchali var. nouchali, collected from four different location of West Bengal. The HPTLC results showed that ultrasonication extraction yielded the highest mean contents of both markers, gallic acid and quercetin, compared with hot and cold extraction methods. The FTIR analysis of flowers indicated a common phytochemical profiling across all geographical locations and minor variation in peak intensity and peak wave number which may be associated with geographical factors. The optimised mobile phase was toluene: ethyl acetate: chloroform: methanol: formic Acid (2:4:4:1:1, V/V). A good linearity of the method was found over the concentration range of 200–700 ng/band of both the marker with the determination coefficients (r2) of 0.9975 and 0.9978 for GA and Q respectively. The LOD andLOQ of GA and Q were 46.95 and 142.27 ng per band and 45.33 and 137.35 ng per band respectively. The results showed that gallic acid (GA) content was highest in the extract of Bankura sample, whereas quercetin (Q) content was highest in the extract of Kolkata sample.