Simultaneous quantification of anthrones and chromones in Aloe ferox (“Cape aloes”) using UHPLC–MS

Abstract

Aloe ferox is an important medicinal plant indigenous to South Africa where it has primarily been used as a purgative and also to treat skin disorders. Modern day uses include; health (tonic) drinks, flavourant in alcoholic beverages, treatment of digestive disorders and inclusion in cosmetic formulations. Due to increased commercialization of aloe products, a rapid, sensitive and reliable quality control method for the raw material has become a necessity. Ultra-high performance liquid chromatography coupled to mass spectrometry (UHPLC–MS) was investigated as an ultrafast, accurate, and sensitive method in the quantification of chromones (aloeresin A, aloesin) and anthrones (aloin A and B) in 101 A. ferox exudates. The method was validated for accuracy, precision and limits of detection and quantification. The calibration curves showed good linearity (R2>0.99) within the concentration range and the recoveries of the four analytes ranged from 100% to 114% with the relative standard deviation lower than 2%. The limits of detection and quantification for all compounds were within a range of 0.2–1.1μg/ml. Quantitative determination of the four biomarkers showed high levels of aloeresin A (129.0–371.6μg/mg) and aloesin (111.8–561.8μg/mg) while aloin A (21.3–133.4μg/mg) and aloin B (18.4–149.7μg/mg) were present in lower amounts. Hierarchical cluster analysis revealed two major groups within the dataset. However geographical locality was not a major factor in the clustering observed. This validated, ultra-fast method for simultaneous quantification of chromones and anthrones present in A. ferox is recommended for routine quality control analysis.