Development of HPTLC and Colorimetric Analysis Techniques for Aloe Gel Evaluation

Aloe gel is commonly used in herbal medicines. Many of the Aloe products available commercially, do not demonstrate beneficial effects, indicating the poor quality of the Aloe gel. Therefore, an efficient, reliable and accurate method is needed to evaluate the quality of Aloe products. The present research work discussed the development of a colorimetric and HPTLC method for the determination of Glucomannan (a marker compound for Aloe gel) in Aloe gels and its preparations. Shimadzu 1700 UV-Visible spectrophotometer was used for the colorimetric estimation. In the colorimetric method developed obeyed the Beer’s law in the concentration range of 50-90 μg-ml-1 with r2 of 0.999. CAMAG HPTLC instrument was used. The mobile phase comprised of n-butanol : ethanol : water : acetic acid (2 : 4 : 4 : 0.05 v/v) was used for the development of chromatogram. The densitometric scanning was done by TLC scanner III (CAMAG) in absorbance mode at the wavelength of 488 nm. After spraying with anisaldehyde sulfuric acid the system was found to give compact spots for glucomannan (Rf value of 0.69±0.02). The data obtained showed good linearity (r2 = 0.995) with respect to peak area in the concentration range of 400-1400 ng spot-1.