One-step Separation and Purification of Two Chromones and One Pyrone from Aloe barbadensis Miller: a Comparison Between Reversed-phase Flash Chromatography and High-speed Counter Current Chromatography

Abstract

Chromones and pyrones are the major secondary metabolites of Aloe barbadensis Miller. As they are minor components of the plant, an efficient purification procedure for them is of great importance for promoting their pharmacological studies. To develop efficient methods for one-step separation and purification of two chromones (5-((S)-2'-oxo-4'-hydroxypentyl)-2-hydroxymethylchromone (1) and 5-((4E)-2'-oxo-pentenyl)-2-hydroxymethylchromone (3)) and one pyrone (aloenin aglycone (2)) from A. barbadensis via reversed-phase flash chromatography (RP-FC) and high-speed counter current chromatography (HSCCC). The RP-FC separation was performed using methanol:water (26:74, v/v) as the mobile phase at a flow rate of 20 mL/min. A solvent system composed of dichloromethane:methanol:water (3:1.5:1, v/v/v) was used for the HSCCC separation, at a flow rate of 2.0 mL/min. A one-step RP-FC operation within 110 min was successfully used for the purification of compounds 1 (27.9 mg, 96.5%), 2 (32.4 mg, 98.2%) and 3 (4.1 mg, 99.0%) from 129 mg of crude sample, and a one-step HSCCC separation within 95 min was successfully implemented for the purification of compounds 1 (31.1 mg, 97.6%), 2 (35.8 mg, 96.7%) and 3 (2.7 mg, 98.1%) from 134 mg of crude sample. The developed procedures were efficient, with low cost and high yield, which would afford sufficient amounts of high-purity compounds for chromatographic purposes and pharmacological activity screening.