Study On 2-(2-Phenylethyl) Chromones Of Agarwood Originating From Aquilaria Crassna In Cambodia And The Chinese Agarwood Induced By Artificial Holing

Agarwood is fragrant resinous heartwood from wounded tree of the Aquilaria and Gyrinops species.It is a precious medicinal material and natural flavor of China and Southeast Asian countries,which has a very high market value,historical and wide range of uses.Agarwood is facing resource depletion due to large market demand,slow formation of itself,and low output.In this study,the chemical constituents of Aquilaria crassna in Cambodia and Chinese agarwood induced by artificial holing was studied in order to obtian monomer compounds with novel structures,and enriched the structural types of compounds in agarwood.It provides a reference for the quality evaluation and authenticity identification of agarwood from different origins and sources,which also provides a scientific basis for the development and utilization of artificial agarwood and wild Aquilaria crassna in the market.In this study,different polar extracts were obtained from agarwood of Aquilaria crassna in Cambodia through ethanol extraction and petroleum ether extraction.Sixteen monomer compounds were isolated from agarwood of Aquilaria crassna by ODS,Sephadex LH-20,silica gel column chromatography,semi-preparative HPLC column chromatography and other methods.The sixteen compounds included eleven2-(2-phenethyl)chromone(1～11),three sesquiterpenoids(12～14),and two phenylpropanoids(15～16).Three of them are new compounds,including two2-(2-phenethyl)chromone compounds(2 and 4)and one sesquiterpene compound(12).According to the spectral data of the compounds,their structures were identified as :(5S,6R,7S,8S)-2-[2-(4′-methoxyphenyl)ethyl]-6,7-epoxy-5,8-dihydroxy-5,6,7,8-tetrahydrochromone(1)、5,6-epoxy-7β-hydroxy-8β-methoxy-2-[2-4-methoxyphenyl)ethyl]chromone(2)、Aquilarone I(3)、8-chloro-6-hydroxy-2-[2-(4-hydroxy-3-methoxyphenyl)ethyl] chromone(4)、Tetrahydrochromone F(5)、(5R,6S,7S,8R)-2-[2-(3′-Hydroxy-4′-methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone(6)、Tetrahydrochromone I(7)、Isoagarotetrol(8)、5,6,7,8-tetrahydroxy-2-hydroxy-4-methoxyphenethyl)-5,6,7,8-tetrahydro-4H-chromen-4-one(9)、(5R,6S,7S,8R)-2-[2-(4′-Methoxyphenyl)ethyl]-5,6,7,8-tetrahydroxy-5,6,7,8-tetrahydrochromone(10)、8-chloro-5,6,7-thihydroxy-2-(3-hydroxy-4-methoxyphenethyl)-5,6,7,8-tetrahydro-4H-chro men-4-one(11)、Baimuxinal A(12)、(rel)-4β,5β,7β-eremophil-9-en-12,8α-olide(13)、15-hydroxyl-12-oxo-α-selinen(14)、 Dihydroferulic acid methyl ester(15)、3-hydroxy-4-methoxy-phenylpropanoic acid methyl ester(16).The biological activity test was performed on the isolated and identified compounds,and the results showed that compounds 3 and 9 have a certain acetylcholinesterase inhibitory activity.At the same time,Chinese agarwood induced by artificial holing was extracted with ethanol,ethyl acetate and n-butanol to obtain different polar extracts.Two new2-(2-phenylethyl)chromone polymers were isolated from Chinese agarwood by ODS,Sephadex LH-20,silica gel column chromatography,semi-preparative HPLC column chromatography and other methods.According to tspectral data of the compounds,their structures were identified as :(+)-3′,3′′′-dihydroxy-4′,4′′′-dimethoxyaquisinenone G(1)、(5α,6β,7α,8β)-2-[2-(3-hydroxy-4-methoxyphenyl)ethyl]-5,6,7-trihydroxy-5,6,7,8-tetrahydr o-8-{6-methoxy-2-[2-(4-methoxyphenyl)ethyl]chromone-7-oxy}chromone(2).Biological activity was performed on the isolated and identified compounds,the test results showed that compound 1 had a certain DPPH free radical scavenging rate.