Chemical Constituents of Eucommiae Cortex by LC-Triple TOF MS/MS

Eucommia ulmoides Oliv. is the sole species of the genus Eucommia, which is an important traditional Chinese herbal medicine with vast clinical consumption because of its positive effects. The leaf, stem, and bark as well as staminate flower of Eucommia ulmoides have been traditionally used to cure many diseases. Many studies indicated that monomer compounds and extracts from Eucommiae Cortex possess wide-ranging pharmacological actions, especially in treating hypertension, hyperlipemia, diabetes and obesity. In this study, LC-Triple TOF MS/MS was used to analyze the chemical constituents in Eucommiae Cortex. The separation and analysis were carried out on a reversed phase C18 column with gradient elution of 0.1% formic acid (A)-acetonitrile (B). The gradient elution program was set as follow: 5%-10%B at 0-10 min, 10%-15%B at 10-12 min, 15%-20%B at 12-22 min, 20%-30%B at 22-35 min, 30%-60%B at 35-42 min, 60%85%B at 42-55 min, 85%-5%B at 55-57 min, 5%-5%B at 57-60 min. The Triple TOF MS/MS system was equipped with an ESI source operating under both positive and negative ionization modes and the spectra were acquired in the range of m/z 50-1 500. According to the accurate mass of molecular and product ions provided by Triple TOF MS/MS, a total of thirty-five compounds in Eucommiae Cortex were identified or tentative presumed by comparised with reference standards and literature reports, which included thirteen lignans (Olivil-4′,4″-di-O-β-D-glucopyranoside, 1-Hydroxypinoresinol-4′,4″-di-O-β-D-glucopyranoside, Olivil-O-β-D-glucopyranoside, Pinoresinol-di-O-β-D-glucopyranoside, Eucommin A, Medioresinol-di-O-β-D-glucopyranoside, Syringaresionl-di-O-β-D-glucopyranoside, Syringaresionl, 1-Hydroxypinoresinol-O-β-D-glucopyranoside, Olivil, Pinoresinol, Pinoresinol-4′-O-β-D-glucopyranoside, and Syringaresionl-O-β-D-glucopyranoside), eleven iridoids (Eucommioside, Aucubin, Deacetyl asperulosidic acid, Geniposidic acid, Harpagide, Asperulosidic acid, Catalpol, Geniposide, Genipin, Eucomoside B, and Eucommiol), nine penylpropanoids (Protocatechuic acid 4-glucoside, Vanillic acid, Neochlorogenic acid, Chlorogenic acid, Cryptochlorogenic acid, Caffeic acid, Methyl chlorogenate, Isochlorogenic acid A, and Isochlorogenic acid C), and two flavonoids (Rutin and Isoquercitrin). Twelve of the compounds were identified by comparing their retention times and ESI-MS/MS data with those of reference standards, while other twenty-three compounds were tentatively identified or deduced according to their Triple TOF MS/MS data which afforded sufficient structural information. This study may provide the foundation and support for study on material foundation of efficacy and the overall assessment on quality of Eucommiae Cortex.