Structural identification and comprehensive comparison of saponin-related impurities present in the three different compound glycyrrhizin tablets.

Compound Glycyrrhizin Tablet (CGT) is a glycyrrhizin-containing (monoammonium glycyrrhizate, MAG) preparation, which has been widely used in clinical treatment of chronic liver diseases, eczema, atopic dermatitis and other conditions. However, the impurity profile of CGT has not yet been completely elucidated. In this study, eight main saponin-related impurity compounds were initially isolated and identified. Thereafter, based on the characteristic MS/MS fragmentation pathways analysis of the isolated compounds, a novel strategy for characterization and identification of saponin-related impurities was proposed. Then, a total of 41 saponin-related impurities were identified or tentatively characterized in CGTs. Furthermore, principal component analysis (PCA), Wayne diagram and heatmap analysis revealed that the process-related impurity profile in CGTs from three different manufacturers was significantly different. Overall, our findings provided additional technological support for evaluating saponin-related impurities, thereby laying a solid foundation to develop strategies for future product quality improvement.

Two pairs of enantiomeric neolignans from Lobelia chinensis.

A pair of new enantiomeric neolignans, ethyl 3-[(2R,3S)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (+) (1) and ethyl 3-[(2S,3R)-2-(4-hydroxy-3-methoxyphenyl)-3-(hydroxymethyl)-7-methoxy-2,3-dihydro-1-benzofuran-5-yl] propanoate (-) (1), together with a pair of known enantiomeric neolignans (+) (2) and (-) (2), as well as five known lignans (3-7) were isolated from the ethanol extract of Lobelia chinensis. Their structures were elucidated on the basis of extensive spectroscopic analyses, including 1D and 2D NMR, HR-ESI-MS and CD spectra.

[Studies on the chemical constituents from Lobelia chinensis].

OBJECTIVE: To study the chemical constituents of the full plant of Lobelia chinensis. METHODS: The compounds were isolated and purified using several column chromatographic methods. Their structures were elucidated based on their physicochemical properties and spectral data. RESULTS: Twelve compounds were isolated from L. chinensis. Their structures were elucidated as 6,7-dimethoxycoumarin (1), fraxinol (2), 5-hydroxy-7-methoxycoumarin (3), tomentin (4), 3'-hydroxygenkwanin (5), apigenin (6), quercetin (7), luteolin (8), linarin (9), luteolin 3',4'-dimethylether-7-O-beta-D-glucoside (10), isoferulic acid (11), and ethyl ros-marinate (12), respectively. CONCLUSION: Compounds 1 -5 and 10 -12 are isolated from this plant for the first time.