Analysis of aloenin in foods containing Aloe arborescens MILL.

Abstract

A simple and rapid analysis for identification of aloenin in foods containing Aloe arborescens MILL. by thin layer chromatography (TLC) has been developed. The extract with water was cleaned-up on C18 disposable cartridge. After evaporation to dryness and dissolving the residue in methanol, the solution was spotted on a silica gel TLC plate, and the plate was developed with ethyl acetate-methanol-water (100 : 16.5 : 13.5). Aloenin was visualyzed by spraying the plate with the p-anisaldehyde or the Vaughn's reagent as pink or bluish violet spot, respectively. The detection limit of aloenin by using these reagents was ca. 0.5 μg. The quantitative determination of aloenin in foods by high performance liquid chromatography (HPLC) has also been developed. Aloenin was separated on a Inertsil ODS-2 column with methanol-water (30 : 70) as a mobile phase, and detected at 293 nm using ethenzamide as the internal standard. The calibration curve was linear in a range of 2.0-50.0 μg. The minimum detectable concentration of aloenin in foods was ca. 0.03 mg/g. The contents of aloenin in aloe materials and foods such as candy and jelly were 5.3-13.9 and 0.013-12.5 mg/g, respectively. The proposed methods using TLC and HPLC are easily and reliably applicable for the characterization and estimation of Aloe arborescens M. in foods containing aloe.