TLC image analysis for determination of the piperine content of the traditional medicinal preparations of Bhutan

Abstract

Piperine is the bioactive constituent of black pepper (Piper nigrum). For quality control of piperine content, expensive instruments are usually used. A simple and inexpensive TLC image-analysis method for quantification of the piperine content of the traditional medicinal preparations of Bhutan has been established in this study. An image of the TLC chromatogram, under UV light at 254 nm, was taken by use of a digital camera and was further transformed to a density profile plot, along the direction of development, by use of Scion Image software. The concentration of piperine was calculated by comparing its peak area with a calibration plot established by chromatography of piperine standards on the same TLC plate. Linear regression analysis of the calibration data revealed a good linear relationship (R 2 = 0.9962) between response and amount of piperine in the range 0.34-1.03 μg per spot. The specificity, precision, accuracy, and recovery of the method are satisfactory. The analytical results obtained by use of the method were not significantly different from those obtained by use of densitometric TLC. A disadvantage of the method is its low sensitivity -the limits of detection (LOD) and quantification (LOQ) were 15.36 and 46.54 ng per spot, respectively.