Metabolite profiling of polyphenols in peels of Citrus limetta Risso by combination of preparative high-speed countercurrent chromatography and LC-ESI-MS/MS

The polar constituents of peels from Citrus limetta variety Risso (Rutaceae) were investigated by a combination of two complementary chromatographic techniques consisting of preparative high-speed countercurrent chromatography (HSCCC), and off-line LC-ESI-MS/MS analysis to design a two-dimensional metabolite profile. Countercurrent chromatography (CCC) using solely immiscible solvent systems allowed the fractionation of principal components and an enrichment of minor concentrated metabolites from a crude polar solvent partition of C limetta peels for subsequent structural identification by LC-ESI-MS/MS analysis. The combination of two very different chromatographic techniques resulted in lower detection limits for electrospray mass-spectrometry and revealed eighty-five compounds, including three abscisic acid derivatives, five limonoid glycosides, twenty-six dihydro-cinnamic and cinnamic acid glycosides, eleven flavanone glycosides, seven flavone glycosides, seventeen flavonol glycosides, including limocitrol and limocitrin derivatives. As a chemocharacteristic for C limetta metabolites, many of the detected structures were linked to single and multiple 3-hydroxy-3-methyl-glutaryl (HMG) substitutions. C limetta peels are a by-product of juice production, and not only the antioxidant fractions but also some of the fortified compounds could be used for food and pharmaceutical purposes. (C) 2014 Elsevier Ltd. All rights reserved.