Studies On The Chemical Constituents Of Lignum Aquilariae Resinatum

Lignum Aquilariae Resinatum(agarwood)is the resin lingum of Aquilaria sinensis(Lour).Gilg,possessing the actions of promoting qi to relieve pain,arrestting vomiting by warming the stomach,and promoting inspiration to relieve asthma.It is used for the treatment of distension and pain in the chest and abdomen,vomiting or hiccupping due to cold in the stomach,qi and kidney-deficiency syndrome.Previous studies on Lignum Aquilariae Resinatum mainly focused on the chemical constituents,while their pharmacological activities are seldom concerned,especially the biological activities of the characteristic constituents of 2-(2-phenylethyl)chromone.Our previous study has demonstrated that the petroleum ether and EtOAc extract of Lignum Aquilariae Resinatum,could significantly inhibit the nitric oxide(NO)production in(lipopolysaccharide)LPS-stimulated BV-2 microglial cells.In order to clarify the efficacy material basis and action mechanism of Lignum Aquilariae Resinatum,a bioassay together with LC-MS/MS-guided fractionation was performed on the chemical constituents of this plant.In addition,the NO inhibitory activities of the isolated compounds on NO production in LPS-stimulated BV-2 microglial cells were evaluated in vitro.The results are listed as below.1.The research progress of chemical constituents and pharmacologic al activities of the resin lingum of Aquilaria sinensis(Lour).Gilg have been reviewed.Among the isolated components,the main chemical constituents of the plants from this species are sesquiterpenes,2-(2-phenylethyl)chromone,aromatic compounds,flavonoids,among others.Pharmacological studies suggested that the crude extracts and pure compounds from this species have antispasmodic,antimicrobial,anti-inflammatory,neuroprotective,and cytotoxic activities.2.A bioassay together with LC-MS/MS-guided fractionation was adopted to investigate the in vitro anti-inflammatory constituents of Lignum Aquilariae Resinatum,the separation and purification were performed by solvent extraction and repeated column chromatography on silica gel,Sephadex LH-20,ODS,and semipreparative HPLC.Their structures were elucidated on the basis of spectroscopic analysis and physiochemical properties.As a result,fifty-nine compounds were isolated from the 95%EtOH extract of Lignum Aquilariae Resinatum including twenty-six sesquiterpenes:(+)-9?-hydroxy-selina-4,11-dien-12-al(1),(+)-8a-hydroxy-selina-3,11-dien-14-al(2),(+)-8a-hydroxyeudesma-3,11(13)-dien-14-al(3),(+)-eudesma-3,11(13)-dien-8?,9?-diol(4),(+)-eudesma-4(14),11(13)-dien-8?,9?-diol(5),(4R,5R,7S,9S,10S)-(-)-eudesma-11(13)-en-4,9-diol(6),(+)-9?,10?-epoxyeremophila-11(13)-en(7),(+)-11-hydroxyvalenc-1(10),8-dien-2-one(8),(-)-eremophila-9-en-8?,11-diol(9),12,15-dioxo-selina-4,11-dine(26),12-hydroxy-4(5),11(13)-eudesmadien-15-al(27),(7S,9S,10S)-(+)-9-hydroxyselina-4,11-dien-14-al(28),(5S,7S,9S,10S)-(+)-9-hydroxyeudesma-3,11(13)-dien-12-methylester(29),(5S,7S,9S,10S)-(+)-9-hydroxyselina-3,11-dien-12-al(30),(4??,7?,8??)-3,4,4?,5,6,7,8,8?-octahydro-7-[1-(hydroxymethyl)ethenyl]-4?-methylnaphthalene-1-carboxaldehyde(31),selin-11-en-4a-ol(32),5-desoxylongilobol(33),eudesma-4-en-11,15-diol(34),baimuxifuranic acid(35),(1?,4??,7?,8??)-octahydro-7-[1-(hydroxymethyl)ethenyl]-1,8?-dimethylnaphthalen-4?(2H)-ol(36),2-[(2?,4??,8?,8??)-decahydro-4?-hydroxy-8,8a-dimethylnaphthalen-2-yl]prop-2-enal(37),11-hydroxyvalenc-1(10)-en-2-one(38),15-hydroxyacorenone(39),14-hydroxy-a-humulene(40),baimuxinal(41),(4R,5R,7R)-1(10)-spirovetiven-11-ol-2-one(42);Eleven simple 2-(2-phenylethyl)chromones:2-(2-phenylethyl)chromone(43),8-chloro-6-hydroxy-2-(2-phenylethyl)chromone(44),6,3'-dimethoxy-2-(2-phenylethyl)chromone(45),7-hydroxy-2-(2-phenylethyl)chromone(46),5-hydroxy-6-methoxy-2-(2-phenylethyl)chromone(47),6-methoxy-2-(2-phenylethyl)chromone(48),7-methoxy-2-(2-phenylethyl)chromone(49),4'-methoxy-2-(2-phenylethyl)chromone(50),6,7-dimethoxy-2-(2-phenylethyl)chromone(51),6,7-dimethoxy-2-(2-phenylethyl)chromone(52),6-hydroxy-7-methoxy-2-[2-(3'-hydroxy-4'-methoxyphenyl)ethyl]chromone(53);Four tetrahydro-2-(2-phenylethyl)chromones:oxidoagarochromone C(54),rel-(1?R,2R,3R,7?S)-1?,2,3,7?-tetrahydro-2,3-dihydroxy-5-[2-(4-methoxyphenyl)ethyl]-7H-oxireno[f][1]benzopyran-7-one(55),aquilarone C(56),(5S,6R,7R,8S)-4'-methoxy-2-(2-phenylethyl)-5e',6e',7e',8e'-tetrahydroxy-5,6,7,8-tetrahydrochromone(57);Sixteen 2-(2-phenylethyl)chromone dimers:Aquisinenones A-P(10-25),and two other compounds:1-hydroxy-1,5-diphenylpentan-3-one(58),?-sitosterol(59).Among them,compounds 1-25 are new ones;compounds 27,32-33,and 38-40 were isolated from the family Thymelaeaceae for the first time,while compounds 26,31,34,36-37,42,and 58 were first reported from A.sinensis.3.The NO inhibitory effects of the isolated compounds on LPS-stimulated BV-2 microglial cells were evaluated in vitro.(+)-9?,10?-epoxyeremophila-11(13)-en(7),12,15-dioxo-selina-4,11-dine(26),(5S,7S,9S,10S)-(+)-9-hydroxyselina-3,11-dien-12-al(30),(4??,7?,8??)-3,4,4?,5,6,7,8,8a-octahydro-7-[1-(hydroxymethyl)ethenyl]-4cx-methylnaphthalene-1-carboxaldehyde(31),and 2-[(2??,4??,8?,8??)-decahydro-4?-hydroxy-8,8a-dimethyl naphthalene-2-yl]prop-2-enal(37)exhibited significant inhibition of nitric oxide production in LPS-stimulated BV-2 microglial cells.