Study On The Alkaloids And Phenols Of Dendrobium Pendulum

Dendrobium Sw.is a perennial epiphytic herb of the Orchidaceae,with high medicinal value.In this study,the composition and contents of alkaloids and phenols in the flower,stem and leaf of Dendrobium pendulum Roxb.were systematically studied by UPLC-Q-TOF-MS.At the same time,we studied the volatile components in flower of D.pendulum by using GC-MS technology.Meanwhile,the contents of total alkaloids and total polysaccharides in different organs and parts of D.pendulum,Dendrobium findlayanum Par.et Rchb.f.,Dendrobium crepidatum Lindl.ex Paxt.,Dendrobium parishii Rchb.f.and Dendrobium nobile Lindl.were determined,and the differences of total alkaloids and total polysaccharides in different parts of Dendrobium and D.nobile were explored to provide scientific basis for the development of Dendrobium resources.The conclusions of this study are as follows:（1）The alkaloids of D.pendulum are abundant,and the main alkaloids are octahydroindolizine alkaloids.Fifteen components were identified from flower,stem and leaf of D.pendulum in which seven components were octahydroindolizine alkaloids:dendrocrepine（I）,dendrocrepine C（II）,credidamine（III）,crepidine（V）,dendrocrepidine B（VIII）,dendrocrepidine D（IX）,homocrepidine B（X）.Seven components were sesquiterpenoid alkaloids:dendrobine（IV）,dendramine（VI）,nobiline（VII）,mubironine A（XI）,N-isopentenyl-dendroxine（XII）,N-isopentenyl-dendrobine（XIII）,findlayine D（XIV）.One component was amides alkaloids:N-p-cinnamoyl-tyramine（XV）.The above 15 components were obtained from D.pendulum for the first time.（2）There are 13 phenol compounds from D.pendulum,among which seven components were bibenzyl compounds:dendrocandin L（Ⅰ）,densiflorol A（Ⅳ）,tristin（Ⅴ）,cannabistilbene II（Ⅷ）,longicornuol A（Ⅸ）,aloifol I（Ⅹ）,isomoniliformine A（Ⅻ）.Four components were flavone compounds:rutin（Ⅱ）,hyperoside（Ⅲ）,apigenin（Ⅵ）,naringenin（Ⅶ）.Tow components were phenanthrenes compounds:coelonin（Ⅺ）,denchryside A（ⅩⅢ）.In addition to the compoundⅤ（tristin）,the above 12 components were obtained from D.pendulum for the first time.（3）The contents of total alkaloids and total polysaccharides were relatively high in D.pendulum,D.findlayanum,D.crepidatum,D.parishii and D.nobile.The distribution of total alkaloids has a certain rule:the content of total alkaloids of flower is higher than that of leaf.The total alkaloid content of annual stem was higher than that of biennial stem.The content of total alkaloid in the upper part of annual stem was higher than that in the lower part of annual stem.The content of total alkaloid in the upper part of biennial stem was higher than that in the lower part of biennial stem.According to the above research,the best collecting position of Dendrobium alkaloid was the upper part of annual stem.（4）The content of alkaloid was the highest in flower of D.pendulum,dendrocrepine,dendrocrepidine B,N-isopentenyl-dendroxine,crepidine,dendrocrepine C,credidamine,dendrocrepidine D,homocrepidine B,N-isopentenyl-dendrobine and N-p-cinnamoyl-tyramine components were higher than stem and leaf.Therefore,it is proved that flower of D.pendulum has high research value.（5）Among the 13 phenol compounds obtained from D.pendulum,the flower,stem and leaf organs were evenly distributed.The flower organs were mainly bibenzyl compounds,containing a total of 28.633μg·g^-1 include 8 compounds,the stem organs contained a total of28.265μg·g^-1 include 5 compounds,and the leaf organs were mainly flavone,containing a total of 36.129μg·g^-1 include 5 compounds.（6）The volatile components in flower of D.pendulum were analyzed qualitatively and quantitatively by GC-MS.The characteristic aroma components of D.pendulum were linalool,（Z）-β-ocimene andβ-caryophyllene.（7）This experiment to optimize the extraction methods of phenolic compounds,designed scheme by the existing literature,found that using ethanol extraction,petroleum ether extraction,methanol constant volume better than contrast ultrasound extraction and solvents extraction.Get to the solution of the type and content of phenolic compounds in the best performance.Finally,a new method for extracting D.pendulum was established by further optimizing the extraction conditions through orthogonal test,which provided a basis for the further research of Dendrobium compounds.The optimal alkaloid harvesting site of Dendrobium was the upper part of the annual stem,and identified the volatile components of D.pendulum.The alkaloids and phenol compounds of D.pendulum were determined.