| Traditional Tibetan medicine,Lignum Caraganae(LIC),which is also known as Zuomoxing,belongs to genus Caragana,family Leguminosae and mainly distributes in Qinghai-Tibet plateau.The literature textual investigation has exhibited that the original plants of Lignum Caraganae are C.jubata(Pall.)Poir.,C.changduensis Liou f.and C.tibetica Kom.,and the other five plants,C.erinacea Kom.,C.tangutica Maxim.,C.sajaensis Liou f.,C.franchetiana Kom.,and C.bicolor Kom.,which are also members of genus caragana,are used as the common substituents.The red heartwoods of the stems and roots of these plants,which have the efficacy of promoting blood circulation,inhibiting blood stasis and lowering blood pressure,are their medicinal parts and used for the treatment of blood congestion,hypertension and menstrual disorders.Previous researches have exhibited that flavonoids are the main components of Lignum Caraganae,and stilbenes,phenylpropanoids,terpenoids,sterols and amino acids have been reported as well.Up to now,the study on chemical constituents of Lignum Caraganae all use traditional phytochemical methods,and there is no efficient approach for systematic,comprehensive and rapid qualitative analysis of the target compounds of it.The quantitative analysis methods are mainly focused on the analysis of total flavonoids or several compounds like quercetin,kaempferol and rutin which are not characteristic components in it.The insufficient of the qualitative and quantitative analysis methods for the chemical constituents of LIC not only is detrimental to the quality evaluation of LIC and its preparations,but also limits the extensive application and implementation of further research work of LIC.In present research,chemical compounds isolated from genus caragana have been summarized to facilitate the subsequent qualitative analysis.Phytochemical study was carried out on the red heartwoods of the stems and roots of Caragana jubata based on the preliminary qualitative results,and this research aimed to separate and identify compounds that haven't been obtained in this lab to be used as standards.As a result,the structures of 11 obtained compounds were assigned mainly by NMR and mass spectrometry,among them,ethyl-4-hydroxy-2-methoxybenzoate and 7,3 ?-dihydroxy-4 ?-methoxyisoflavanone were isolated from genus caragana for the first time,4,7,2 ?-trihydroxy-4?-methoxyisoflavanol was firstly obtained from Lignum Caraganae.The UV features and MS fragmentation patterns of six subtypes of flavonoids were investigated by UPLC-DAD/ESI-QTOF-MS,and some typical fragmentation patterns of isoflavones and pterocarpans under four different collision-induced dissociation energy conditions have been firstly discovered.The proposed fragmentation patterns could facilitate the structural elucidation of these six subtypes of flavonoids in complex mixtures and lay foundation for subsequent qualitative analysis.An efficient approach for rapid characterization of the target compounds in LIC was developed by UPLC-DAD/ESI-QTOF-MS.As a result,a total of 38 compounds were identified or tentatively characterized,including 19 isoflavones,7 pterocarpans,3 flavanones,2 isoflavanones,2 isoflavans,1 chalcone,1 isodihydrochalcone,1isoflavanol and 2 others.The results could not only benefit the comprehensive quality evaluation of this medicinal herb,but also provide a solid foundation for subsequent studies of pharmacological material basis and mechanism of action.The absorbed and metabolic constituents of LIC were preliminarily investigated.A total of 50 components were detected in plasma and urine samples,of which 8 were prototypes,24 were glucuronidation products,1 was hydroxylation and glucuronidation product,1 was dehydrogenation and glucuronidation product and the other were nitrogenous products.The results of this study would benefit the interpretation of its pharmacological material basis and mechanism of action.In summary,this study has initially profiled the chemical constituents of LIC and the results lay a solid foundation for quality control and subsequent pharmacological studies of LIC and its preparations.Besides,the method developed herein is highly generic and efficient,and would be widely applied to complicated mixtures that are derived from LIC preparations.In addition,the database constructed from 292 compounds isolated from this genus can contribute to chemical constituent analysis of plants which belong to this genus and the proposed fragmentation patterns discovered there can facilitate the structural elucidation of these six subtypes of flavonoids in complex mixtures. |
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