Geo-herbalism Study Of Magnoliae Officinalis Cortex Based On Analysis Of Secondary Metabolites

Daodi medicinal material is produced and assembled in specific geographic regions with designated natural conditions and ecological environment,with particular attention to cultivation technique,harvesting and processing.The quality and clinical effects surpass those of same botanical origin produced from other regions.It is thus widely recognized and has long enjoyed a good reputation.For centuries,Daodi medicinal material has played an important role in prevention and treatment of diseases and become a special comprehensive standard for quality control.Magnolia officinalis Rehd.et Wils.(MO)and its variety M officinalis Rehd.et Wils.var.biloba Rehd.et Wils.(MOB)are members of the Magnoliaceae family.Their stem barks,known as Houpo in Chinese and magnoliae officinalis cortex(MOC)in Latin,are traditional Chinese medicines for the treatment of abdominal distention and pain,dyspepsia,and asthmatic cough.MO and MOB are widely distributed in China,from Sichuan of the west to Zhejiang of the east and from Shaanxi in the north to Guangxi in the south.In the case of MOC,the samples of MOC produced in Hubei and Sichuan were traditionally regarded as Daodi medicinal material according to the textual research,which were called Chuan po.Other samples from other habitats have not been regarded as Daodi medicinal material.Currently,lignans(magnolol and honokiol)and essential oils were always regarded as the predominant chemical determinants for quality evaluation and most studies have shown that habitats and variety played a key role in quality of MOC.Besides lignans and essential oils,there were phenylethanoid glycosides(PhGs),phenolic glycosides and alkaloids distributed in MOC,it will be one-sided to compare the difference of MOC samples from different regions or varieties based only on lignans or essential oils.Thus,2LC-ECD,UPLC-QTOF/MS and GC-MS were employed to analyze the PhGs with allose as core sugar,non-volatile compounds and essential oils,and combined with the correlation analysis between the environmental factors and discriminant compounds,the reasons leading to the geoherbalism of MOC were explored.1)Water-soluble constituents of MOC and their bioactivitiesMOC was traditionally taken in water decoction,hydrophilic ingredients were thus regarded to have relation with its clinic effect.In the current study,ten PhGs and seven phenolic glycosides,totally eleven new compounds,were isolated from the water-soluble portion of the 70%aq.ethanol extract of the stem bark of M officinalis.Their structures were elucidated by a combination of 1D(1H,13C NMR and DEPT),2D(HSQC,HMBC,and NOESY)NMR spectroscopy,mass spectrometry(ESIMS,HRESIMS),GC and chemical hydrolysis methods and in comparison with literature data.Most evaluated phenylethanoid glycosides showed good a-glucosidase inhibitory effects and moderate cytotoxicity.2)Quantitative analysis of PhGs with allose as core sugar based on 2LC-ECDIn this study,a 2LC-ECD system with high sensitivity has been developed for the simultaneous determination of seven PhGs with allose as core sugar in MOC.Furthermore,multivariable analysis was provided to discriminate Daodi medicinal material and Others(including MO and MOB)based on the quantitative profiles of PhGs obtained by the 2LC-ECD.Based on the results of PCA and PLS-DA,it was found that Daodi medicinal material and Others were well grouped,which indicated that the habitat played a more important part than variety.Meanwhile,the content of PhGs with two sugars in Daodi medicinal material was obviously higher than that of Others,and the content of PhGs with three sugars in Daodi medicinal material was significantly lower than that of Others.Among the PhGs,magnolosides D and M were the important variables to help discriminate the MOC samples of Daodi medicinal material and Others.3)Profile of secondary metabolites from MOC based on UPLC-QTOF/MSIn the current study,one hundred one PhGs,sixty-nine lignans and phenolic compounds,and thirty alkaloids were identified or putatively characterized using UPLC-QTOF/MS.Meanwhile,a targeted scanning of diagnostic ion/neutral loss and untargeted fingerprint analysis of all fragment ions coupled with a home-made program and computational analysis was established to rapidly characterize PhGs from M.officinalis and to discriminate isomers with stereoisomerism and positional isomerism,and finally 14 isomers were rapidly recognized by isomer recognition models.What’s more,the study focused on geoherbalism of MOC was performed,and obvious distinction on metabolites was found between Daodi medicinal material and other MOC samples,as well as the flowers and leaves of MOC from Daodi districts and other regions.4)Analysis focused on essential oil from MOC using GC-MSMultivariable analysis was employed to analyze the GC-MS data of essential oils,the obvious difference in essential oils was found in MOC samples from Daodi districts and other regions.The relative content of a-agarofuran,y-eudesmol,β-eudesmol in other regions was obviously higher than that of MOC from Daodi districts.5)Effect of environmental factors on chemical compoundsThe correlation analysis between environmental factors and chemical compounds in MOC showed that the chemical differences were significantly related to temperature and precipitation.Meanwhile,combined with the previous study,the deduction was provided that the multi-factors conjointly lead to the geoherbalism of MOC.In conclusion,the methods of 2LC-ECD、UPLC-QTOF/MS and GC-MS were established to systematically study the PhGs with allose as core sugar,non-volatile compounds and essential oils.The results showed that there were significant difference in secondary metabolites between the Daodi medicinal material and other MOC samples.PhGs owning two sugars and three sugars with allose as core sugar,PhGs(magnoloside N isomer),lignans(magnolignan E),alkaloids(1,2-hydrazinedicarboxamide)and essential oils(a-agarofuran,y-eudesmol,β-eudesmol)were the important variables to help discriminate the Daodi medicinal materials and other MOC samples,meanwhile,the distinction among the chemical compounds were mainly related to temperature and precipitation.Combined with the previous research,the deduction was provided that the multi-factors,i.e.both variety and habitat,conjointly lead to the geoherbalism of MOC.