iridoids and erythrocentaurin

The metabolism of gentiopicroside in vivo was studied by LC/MS following 2,4-dinitrophenylhydrazine derivatization for the first time. The ionization efficiency of the major metabolites erythrocentaurin and gentiopicral were greatly enhanced by the new analytical method developed, and they were successfully detected in rat plasma after oral administration of gentiopicroside. Methyl 4-formylbenzoate was used as the internal standard to quantify erythrocentaurin and gentiopicral in rat plasma in negative mode by UPLC-TOF-MS. It was found that erythrocentaurin reached the maximum plasma concentration of 625.2±246.3 ng/mL at about 2 h and gentiopicral reached the maximum plasma concentration of 157.6±86.6 ng/mL at about 4 h after oral administration of gentiopicroside at a dose of 200 mg/kg. The metabolic pathway of gentiopicroside to erythrocentaurin and gentiopicral was proposed. The monoterpene compound gentiopicroside was found to be metabolized to dihydroisocoumarin in vivo which may be responsible for the pharmacological effect of gentiopicroside. The results may shed light on clinical efficacy of gentiopicroside and the new analytical method developed may assist in studies for the metabolism of other natural iridoids and secoiridoids in vivo.

Topics: Animals; Chromatography, High Pressure Liquid; Iridoid Glucosides; Iridoids; Isocoumarins; Mass Spectrometry; Phenylhydrazines; Plasma; Rats; Rats, Wistar

When cultivated with Aspergillus niger, swertiamarin, an important drug, is rapidly transformed into erythrocentaurin and (5Z)-5-ethylidene-8-hydroxy-3,4,5,6,7,8-hexahydro-1H-pyrano[3,4-c]pyridin-1-one (M(1)), a new compound with high anti-inflammatory activity. A simple and rapid HPLC method for simultaneous determination of swertiamarin and its two metabolites in broth of A. niger is described. The chromatographic separation was achieved on a C(18) ODS column (250 x 4.6 mm i.d.) by gradient elution with 0.04% formic acid in water and 0.04% formic acid in acetonitrile as the gradient mixtures. The flow rate was 1 mL/min, the detection wavelength was 237 nm and the column temperature was kept at 30 degrees C. The retention times of swertiamarin, erythrocentaurin and M(1) were 14.6, 16.8 and 24.8 min, respectively. The mean absolute recoveries of three analysts were over 96%. Quantification limits were 0.02 microg/mL for swertiamarin and 0.05 microg/mL for both of the two metabolites. The method was applied for the quantification of swertiamarin and its two metabolites during the fermentation process and the evaluation of the bioavailabilities in the Caco-2 monolayer.

Topics: Aspergillus niger; Cell Line; Chromatography, High Pressure Liquid; Glucosides; Humans; Iridoid Glucosides; Iridoids; Isocoumarins; Pyrones; Reproducibility of Results

To in vestigate the constituents in root of Gentiana macrophylla.. Various column chromatographic techniques were used for isolation and purification of the principles. The structures were elucidated on the basis of spectral data (UV, IR, MS, 1H-, 13C-NMR etc.) and identified by comparing with standard substance.. Eight compounds were identified. Four compounds isolated from the chloroform fraction are: 5-carboxyl-3,4-dihydrogen-1H-2-benzopyran-1-one (1), erythrocentauric acid (2), roburic acid (3), oleanolic acid (4). Water fraction gave four known secoiridoid glucosides. They were: gentiopicroside (5), swertiamarine (6), sweroside (7), 6'-O-beta-D-glucosylgentiopicroside (8).. 1 is a novel compound. It was named as erythrocentauric acid. 2 was isolated from genus Gentiana and 8 was isolated from G. macrophylla for the first time.

Topics: Gentiana; Glucosides; Iridoid Glucosides; Iridoids; Isocoumarins; Molecular Structure; Plant Roots; Plants, Medicinal