Studies On The Chemical Constituents Of Ethyl Acetate Fraction From Dendrobium Officinale

Dendrobium officinale Kimura et Migo is a rare and precious medicinal plant of the orchid family Dendrobium and was first listed as best tonic traditional Chinese medicine in Shennong’s Herbal Classic.It is still one of the orginal plants of Dendrobii caulis through several editions of revision of Chinese Pharmacopoeia since it was first recorded as " earring dendrobium " in 1963,and it is recorded as Dendrobii officinalis caulis in the 2010 edition of the Chinese Pharmacopoeia.Modern pharmacological studies have shown that Dendrobium officinale has a variety of pharmacological activities such as enhancing human immunity,anti-tumor,anti-oxidation,lowering blood glucose,lowering blood pressure and promoting digestion.In order to study the material basis of antitumor activity for Dendrobium officinale,a variety of column chromatography and thin layer chromatography and other modern chromatographic separation technology was used to isolate the chemical compouds from the ethyl acetate fraction of Dendrobium officinale stem with the antitumor activity,and the activity of some isolated bibenzyl compounds was evaluated in vitro.This study would provide evidence for further clarifying the material basis and find quality marker of Dendrobium officinale.1.Studies on the Chemical Composition of Dendrobium officinaleA total of 52 compounds were isolated from the ethyl acetate fraction of Dendrobium officinale by comprehensive application of normal and reverse phase silica gel,MCI,Sephadex LH-20 and preparative thin layer chromatography.Their structures were elucidated on the basis of spectroscopic analysis including IR,HR-ESI-MS,1D-NMR,2D-NMR,and DEPT.The isolated 52 compounds included 15 bibenzyls,containing(±)dendrocandin X(T1),3,4’-dihydroxy-4,5-dimethoxybibenzyl(T2),6’’-de-Omethyldendrofindlaphenol A(T3),3,4-dihydroxy-4’,5-dimethoxybibenzyl(T4),dendrosinen B(T5),3,4,4’-trihydroxy-5-methoxybibenzyl(T6),3,3’-dihydroxy-4,5-dimethoxybibenzyl(T7),3,4’-dihydroxy-5-methoxybibenzyl(T8),moscatilin(T9),gigantol(T10),4,4’-dihydroxy-3,5-dimethoxybibenzyl(T11),3,4’,5-trihydroxy-3’-methoxybibenzyl(T12),3-O-methylgigantol(T13),dendrocandin U(T14)and dendrocandin N(T15),one phenanthrene compound,moscatin(T16),one lactone compound,loliolide(T17),five flavonoids containing naringenin(T18),hesperetin(T19),liquiritigenin(T20),2-(4-hydroxy-3-methoxyphenyl)-3-(2-hydroxy-5-methoxyphenyl)-3-oxo-l-propanol(T21)and isoliquiritigenin(T22),five simple phenylpropanoids inculding(E)-4-hydroxycinnamic acid(T23),(Z)-4-hydroxycinnamic acid(T24),coniferyl ρ-coumarate(T25),sinapyl p-coumarate(T26)and tinosporaic acid A(T27),two amide compounds,N-trans-coumaroyl tyramine(T28)and N-trans-feruloyltyramine(T29),four lignan compounds,containing episyringaresinol(T30),pinoresinol(T31),medioresinol(T32)and lirioresionol(T33),and 19 other compounds,containing 2(5H)-furanone 5-hydroxy-3,4-dimethyl-5-pentyl(T34),syringic acid(T35),hexadecanoic acid(T36),p-hydroxybenzoic acid(T37),4-hydroxy-benzaldehyde(T38),ferulic-acid(T39),heptadecane(T40),3-guaiacylpropanol(T41),4-hydroxy-3,5-dimethoxycinnamaldehyde(T42),dihydrop-cinnamic acid(T43),(+)-(4S)-(2E)-4-hydroxy-2-nonenoic acid(T44),1,3-benzenediol(T45),hydroquinone(T46),salicylic acid(T47),4-hydroxyacetophenone(T48),vanillin(T49),3,4-dihydroxybenzoic acid(T50),syringaldehyde(T51)andβ-sitosterol(T52).Among these compounds,T1 was a new compound,T2 was isolated from Dendrobium genus for the first time,and T3-T7 and T34 were isolated from Dendrobium officinale stem for the first time.2.Studies on the anti-tumor activities of bibenzyl compounds from Dendrobium officinaleBased on the modern pharmacological activity of Dendrobium officinale against tumor,MTT assay was used to determine the inhibitory effect of nine isolated benzyl compounds on the proliferation of human triple negative breast cancer cell line MDA-MB-231,human liver cancer cell line Hep3 B,human liver cancer cell line MHCC97 H,mouse triple negative breast cancer cell line 4T1 and human liver cancer cell line Hep1-6.The results showed that compounds T3,T4,T5,T9 and T14 exhibited cytotoxic activity against tumor cell proliferation in different degrees.