Quantification of Nobiletin and Tangeretin in Citrus by Micellar Electrokinetic Capillary Chromatography

Abstract

A micellar electrokinetic capillary chromatographic (MEKC) method was developed for the two major polymethoxylated flavones, nobiletin and tangeretin, using a fused-silica open-tubular capillary in a 70% methanol extract from citrus albedo tissue. A MEKC separation buffer (pH 7.0), consisting of 32mM sodium dodecyl sulphate (SDS), 20mM sodium dihydrogen phosopate, 12mM disodium tetraborate and 20% methanol, was selected in order to optimize separation conditions. The order of elution was nobiletin and tangeretin. Of the 46 species and cultivars in the Citrus genus, 17 were assayed for nobiletin and/or tangeretin in this study. The Acrumen and Pseudofortunella sections, classified by Tanaka, were found to contain the highest flavone concentrations.