Research Of Sesquiterpenoids And Screening Of Some Biological Activities From Agarwood Of Aquilaria Crassna In Cambodia

Agarwood is the resinous heartwood originating from the wounded tree of Aquilaria and Gyrinops species of Thymelaeaceae family.As one of the four major agarwoods traded on the international market,agarwood of Aquilaria crassna is mainly distributed in Cambodia,Laos,Thailand,Vietnam and other countries.So far,there have been few reports on the research about agarwood in Cambodian.We made research the chemical constituents of sesquiterpenoids and the bioactivities of isolated compounds in the wild agarwood of A.crassna in Cambodia.In order to discover new compounds with good biological activity.It provide a certain research basis for the further comprehensive development and utilization of agarwood.In this study,sesquiterpenes and other compounds were isolated by silica gel column chromatography technology and(HPLC)technology,combined with the target compound sesquiterpene polarity and literature review.The structures of the compounds were identified by various spectral methods(1D NMR,2D NMR,IR,UV,HR-ESI-MS,optical rotation,and CD calculation)and combination with physicochemical properties of compounds,and comparison with published data.Twenty-six compounds were isolated from the ethanol extract of wild agarwood originating from agarwood of A.crassna in Cambodia,and the structures were identified as 7?-H-9(10)-ene-11,12-epoxy-8-oxo-eremophilane(1),7?-H-9(10)-ene-11,12-epoxy-8-oxoeremophilane(2),neopetasane(eremophila-9,11-dien-8-one)(3),jinkoh-er-emol(4),11-hydroxy-valenc-1(10)-en-2-one(5),nootkatone(6),(rel)-4?,5?,7?-eremophil-9-en-12(7),7(11)-epoxyeremophil-9(10)-en-8-one(8),11-hydroxyeremophil-6(7),9(10)-dien-8-one(9),eremophila-9-en-1?,8?,11-triol(10~*),methyl 2-(8S~*,8a R~*)-4a-hydroxy-8,8a-dimethyldecahydronaphthalen-2-yl)acrylate(11~*),(4R~*,5a S~*,6S~*)-5a,6-dimethyl-(prop-1-en-2-yl)-5,5a,6,7,8,9-hexahydrobenzo[d]oxepin-2(4H)-one(12~*),(1R~*,4R~*,5R~*,7R~*,10S~*)-agarospir-1,10,11-triol(13~*),baimuxifuranic acid(14),(7S,9S,10S)-(+)-9-hydroxy-selina-4,11-dien-14-al(15),(7S,9S,10S)-(+)-9-hydroxy-selina-4,11-dien-14-al(16),2-(2-phenylethyl)chromone(17),5-hydroxy-6-methoxy-2-(2-phenylethyl)chromone(18),6-methoxy-2-(2-phenylethyl)chromone(19),5-hydroxy-6-methoxy-2-[2-(4-methoxyphenyl)ethyl)]chromone(20),4-(3,4-dimethoxyphenyl)butan-2-one(21),dihydroferulic acid ethylester(22),ethyl 5-(4-methoxyphenyl)-3-oxopentanoat(23),(+)-3-hydroxy-1,5-diphenyl-l-pentanone(24),1-hydroxy-1,5-diphenylpentan-3-one(25),1,5-bis(4-methoxyphenyl)pentan-3-one(26),including 4new compounds(10~*-13~*),the remaining are known compounds.Among them,compounds 1-15 are sesquiterpenoids,compound 16 is 2-(2-phenylethenyl)chromone,compounds 17-20 are 2-(2-phenylethyl)chromone compounds,and compounds 21-26 are metabolic precursor compounds of chromones.Compounds 2-16 and 18-26 were isolated from agarwood of A.crassna for the first time.The acetylcholinesterase inhibitory activities of compounds were evaluated by Ellman colorimetric method.The experimental results of acetylcholinesterase inhibitory activity showed that compounds 1-3,7,11~*-13~*,20 exhibited certain acetylcholinesterase inhibitory activity,among which compound 3 activity was relatively good,which was comparable to the positive drug tacrine.Screening for cytotoxic activity of all the isolated compounds by MTT method,the results showed that only compound 18 had weak cytotoxic activity on human gastric cancer cells(SGC-7901).Using the model of LPS-induced release of NO in RAW264 7 cells to screen some representative monomer compounds for anti-inflammatory activity,The results showed that compounds 3,10~*,12~*,14,15,20 showed certain anti-inflammatory activity.In this study,four new sesquiterpenes were isolated and purified from the ethanol extract of agarwood originating from Aquilaria crassna in Cambodia,it shows that the chemical constituents of sesquiterpenes in agarwood have great research potential;and a series of metabolic precursors of chromones were isolated for the first time,It provides a certain basis for the biosynthetic pathway of 2-(2-phenylethyl)chromone compounds in agarwood.The main chemical compositions of agarwood originating from A.crassna in Cambodia is the same as those of other agarwood,both are sesquiterpene and 2-(2-phenethyl)chromone compounds.The cytotoxic activity results show that all compounds identified in this separation have basically no cytotoxic activity,which provides a certain scientific basis for the safety of agarwood used in incense and cosmetics industries.At the same time,this study conducted partial biological activity screening on the isolated and identified compounds,The results of biological activity screening show that most sesquiterpenes have certain anti-acetylcholinesterase activity(1-3,7,11~*-13~*)or anti-inflammatory activity(3,10~*,12~*,14,15),Which provides a certain reference for the research on the pharmacological activity of agarwood,and also shows that sesquiterpenes are potential active ingredients with good biological activity in agarwood,and have the value of continuing in-depth research.To some extent,this study enriched the research on the chemical compositions and biological activities of agarwood in Cambodia,and provided a certain research basis for the quality identification of agarwood in Cambodia.