Determination of aloe emodin in Aloe vera extracts and commercial formulations by HPLC with tandem UV absorption and fluorescence detection

Aloe emodin is an anthraquinone compound found in Aloe vera and other species of the Asphodelaceae and the Polygonaceae families, which has recently attracted much attention as a prospective antineoplastic agent. A HPLC method with tandem UV absorption and fluorimetric detection, was developed and validated for the analysis of aloe emodin in products obtained from Aloe leaves, such as capsules, tablets, dried extracts and mother tinctures. The stationary phase was a C18 reversed-phase column and the mobile phase was composed of water and methanol (30/70, v/v). Satisfactory linearity was obtained over the 10.0-1000.0 ng/mL range for photodiode array detection (limit of detection: 3 ng/mL) and over the 2.5-1000.0 ng/mL range for fluorimetric detection (limit of detection: 0.8 ng/mL). Aloe emodin levels were determined in Aloe vera extracts and commercial formulations by both detection means, with good precision (R.S.D. < 9%) and accuracy (recovery > 85%) and consistent results. Thus, the method seems to be suitable for the analysis of aloe emodin in different herbal and commercial products; it could also be useful for the identity confirmation of formulations and extracts.