Fluorophotometry of Barbaloin in Aloe

Abstract

We have developed a new method for the determination of barbaloin, the main laxative component in Aloe. Our method utilizes fluorophotometry based on Schoutelen's reaction which takes place between barbaloin and borax. Barbaloin was heated in 0.2 M borax solution at 60°C for 5 min, then the reaction mixture was immediately diluted with an equal volume of water and the mixture was cooled. The yellow-green fluorescence intensity of the solution was measured at excitation and emission wavelengths of 383 and 510 nm. Barbaloin contents in Aloe pulv. and pulv. of aloe leaf were determined by using this method. The data were compared with those obtained by the methods of the European pharmacopeia (EP) and the German pharmacopeia (DAB 7). It was concluded that our method is superior to the EP and DAB 7 methods in sensitivity, accuracy and simplicity.