ZHAO Yanyan1,2, LIU Liyan1, HAN Yuanyuan1, WANG Yan2, SHI Minjian2
2014, 45(7): 663-670.
According to the information of HPLC, MS and NMR, the chromatographic and spectral characteristics of principal component isomers and the related substances in bulk drug of ammonium glycyrrhizate were studied. Firstly, according to the information of retention time, the validity of the substance's structure assignments of relative retention time of 1.2 in the European pharmacopoeia 7.0 version and British pharmacopoeia 2012 version was questioned. A high resolution electrospray ionization mass spectrometry (HR-ESI-MS) was used to confirm the molecular weight and formula, and the molecular unsaturation was calculated. Moreover, the 1H NMR and 13C NMR signals were completely assigned by 2D-NMR techniques including correlation spectroscopy (COSY), heteronuclear singlequantum coherence (HSQC), nuclear overhauser enhanced spectroscopy (NOESY), and heteronuclear multiple-bonds correlation (HMBC). As a result, we concluded that the principal components of ammonium glycyrrhizate were 18α,20β-glycyrrhizic acid and 18β,20β-glycyrrhizic acid, the related substance A and the compound of relative retention time of 1.2 were (18β,20β)-24-hydroxyglycyrrhizinic acid and 18β,20α-glycyrrhizic acid, respectively.