Isolation of aucubin and catalpol from Melitaea cinxia larvae and quantification by micellar electrokinetic capillary chromatography

Abstract

Two iridoid glycosides, aucubin and catalpol, were extracted from Melitaea cinxia larvae with hot, dilute aqueous SDS solution and then separated and quantified by micellar electrokinetic capillary chromatography. Solutions of pure aucubin and catalpol were used to optimise the separation. The extraction method was developed for a mixture of 80 larvae and single larvae were then analysed with the optimised procedure. The repeatabilities of both the pretreatment step and the determination were satisfactory. The study presents the first time that iridoid glycosides in Melitaea cinxia have been determined. Determinations were successfully made in butterfly larvae weighing only 1 mg. The total concentration of aucubin and catalpol in Melitaea cinxia varied between 0.1 and 3% of the dry mass of the larva.