High-performance liquid chromatographic determination of phenolic compounds in Aloe species

A procedure has been developed for determination of aloesin, 2'-O-feruloylaloesin, aloeresin A, barbaloin, isobarbaloin, aloenin, aloe-emodin, 8-C-glucosyl-7-O-methyl-(S)-aloesol, isoaloeresin D and aloeresin E which are phenolic constituents of aloe. Aloe or commercial aloin was extracted with methanol multiple times, centrifuged and then filtered. Filtrates were analyzed by a reversed-phase high-performance liquid chromatography employing UV-Vis detection (290 nm). The samples were separated with a Wakosil-II 5C18 HG column by linear gradient elution using water-acetonitrile (88:12 to 54:46) as the mobile phase at a flow-rate of 1.0 ml/min. The detection limits of these compounds were 0.04-0.35 ng per injection (5 mu l) and linearity of response existed. Very satisfactory and reproducible results were obtained within 38 min for simultaneous determination of these compounds. This method was applied to determine these compounds in Aloe barbadensis Miller, A. arborescens Miller var. natalensis Berger, A. vera var. chinensis Berger, A. marlothii Berger and A. striata Haw. Two commercial aloins were also analyzed.