Comparative Analysis of Rhein Content in Cassia fistula Pod Extract by Thin-Layer Chromatographic-Densitometric and TLC Image Methods

A simple, rapid, and cost-effective thin-layer chromatography (TLC) image analysis was developed and validated to quantify rhein content in Cassia fistula pod pulp extract. ImageJ software was used in the proposed method, and its data were compared to TLC-densitometric data. The TLC image analysis method promoted acceptable validation parameters, showing linear relationship with r2 = 0.9988 in the concentration range of 400–1200 ng spot−1. The limit of detection (LOD) and limit of quantification (LOQ) were 84.60 and 256.36 ng spot−1, respectively. The paired t-test showed no statistically significant difference (P > 0.05) between the mean content of rhein performed by these two methods. TLC image analysis is reliable and can be used as an alternative analytical method for rhein content in C. fistula pod pulp extract and its finished products.