Quantitative estimation of Gallic acid and Ascorbic acid in a marketed herbal medicine: Triphala Churna by High Performance Thin Layer Chromatography

Triphala is an age old commonly used Ayurvedic powdered preparation in Indian systems of medicine. This well known formulation is made by combining Terminalia chebula, Terminalia belerica and Embellica officinalis, in equal proportions. The formulation is prescribed in the first line treatment of many aliments and is used as laxative, detoxifying agent and rejuvenator. Terminalia chebula and Terminalia belerica consist of gallic acid and Embellica officinalis consist of ascorbic acid as marker constituent. A HPTLCdensitometric method of analysis for these markers i.e. gallic acid and ascorbic acid was developed. Water was selected as a solvent for preparing standard solutions. Quantitative estimation of gallic acid and ascorbic acid was performed separately on aluminum backed silica gel 60 F254 TLC plates (10 cm x 10 cm plate size, layer thickness 0.2 mm, E-Merck, Darmstadt, Germany). Ascorbic acid shows Rf value of 0.74 ± 0.1 using ethanol: glacial acetic acid: toluene (5.5:1:1.5) and gallic acid showed Rf value of 0.54 ±0.1, using ethyl acetate: toluene: acetone (4.5:4:1) as mobile phase. The polynomial regression data of ascorbic acid and gallic acid were interpreted separately for its linearity at 500-3500 μg/ml with R = 0.9986 and 0.9931 respectively. The literature survey reveals that, there is no such chromatographic method available for quantitative estimation of gallic acid and ascorbic acid.