Studies On The Chemical Constituents From Cultivated “Qi-Nan” Agarwood And Their Biological Activities

Topic basis:Due to its high resin concentration and refined smell,“Qi-Nan”is the best quality agarwood available and contains high levels of 2-（2-phenylethyl）chromones.Recently,there are more than 100 sprouts produced“Qi-Nan”agarwood in the market.Our team bred a fine variety named Aquilaria sinensis“Reke2”by selecting high-grade and stable strains.A.sinensis“Reke2”produced characteristic“Qi-Nan”agarwood with rich 2-（2-phenylethyl）chromone and 2-[2-（4-methoxyphenyl）ethyl]chromone.To explore the possibility of replacing wild“Qi-Nan”agarwood with cultivated“Qi-Nan”agarwood,and utilize cultivated“Qi-Nan”agarwood efficiently,it was urgent to investigate the chemical components and bioactivities of cultivated“Qi-Nan”agarwood systematically.Objective:To provide the theoretical basis for establishing the quality standards system of cultivated“Qi-Nan”agarwood and utilizing cultivated“Qi-Nan”agarwood scientifically and efficiently by studying the chemical components in cultivated“Qi-Nan”agarwood and testing their bioactivities systematically.Methods:1.Compounds were isolated from Et OH extract of cultivated“Qi-Nan”agarwood of A.sinensis“Reke 2”by chromatographic methods such as silica gel and Sephadex LH-20 columns.Their structures were identified by spectral methods.2.The inhibitory activities of compounds against tyrosinase andα-glucosidase were tested by absorptiometry and the p NPG method.The anti-inflammatory activity was determined by the Griess assay.The cytotoxic and neuroprotective activities were evaluated by the MTT method.Results:Twenty-two compounds were isolated from cultivated“Qi-Nan”agarwood of Aquilaria sinensis“Reke 2”.Their structures were identified as 2-[（4-methoxybenzoyloxy）methyl]chromone（1）,2-（2-phenylethyl）chromone（2）,2-[2-（3-hydroxy-4-methoxyphenyl）ethyl]chromone（3）,2-[2-（3-methoxy-4-hydroxyphenyl）ethyl]chromone（4）,2-[2-（4-methoxyphenyl）ethyl]chromone（5）,2-[2-（2-hydroxyphenyl）ethyl]chromone（6）,2-[2-（4-hydroxyphenyl）ethyl]chromone（7）,6-hydroxy-2-[2-（3-hydroxy-4-methoxyphenyl）ethyl]chromone（8）,6-methoxy-2-[2-（4-methoxyphenyl）ethyl]chromone（9）,（R）-2-[2-hydroxy-2-（4-hydroxyphenyl）ethyl]chromone（10）,（S）-2-[2-hydroxy-2-（4-hydroxyphenyl）ethyl]chromone（11）,（R）-2-[2-hydroxy-2-（3-hydroxy-4-methoxyphenyl）ethyl]chromone（12）,7β-H-9（10）-ene-11,12-epoxy-8-oxoeremophilane（13）,（5S,7S,9S,10S）-（-）-9-hydroxy-selina-3,11-dien-14-al（14）,β-elemen-9β-ol（15）,（+）-（1S,4S,5R）-hydroxyeremophila-7（11）,9-dien-8-one（16）,（+）-（4R,5R,7S）-guaia-1（10）,11-dien-4-ol-9-one（17）,（-）-sinenofuranal（18）,methyl 4-hydroxybenzoate（19）,（E）-anethole（20）,1-hydroxy-5-（4-hydroxyphenyl）-1-phenylpentane-3-one（21）,squalene（22）,including twelve 2-（2-phenylethyl）chromone derivatives（1-12）,six sesquiterpenes（13-18）,one 2-（2-phenylethyl）chromone precursor（21）,one triterpene（22）and two aromatic compounds.Eight compounds had a fragrant odor at room temperature.Compounds 1,12,17,18,21 were new.Elemane-type sesquiterpene（15）was identified from agarwood for the first time.Compounds 1-7,and 10-12 were 2-（2-phenylethyl）chromones without substitution of the chromone moiety,which were the major components in wild“Qi-Nan”agarwood.In vitro activity assay results showed that compounds 3,5,and 8 had weak inhibitory activities at a concentration of 100μM against tyrosinase.Compounds 2,3,5,and 8had weak inhibitory activities at a concentration of 125μM againstα-glucosidase,while compound 8 had slender betterα-glucosidase inhibition with IC₅₀ value of（36.10±4.02）than other compounds.None of the compounds had cytotoxicity against RAW264.7 macrophage.Compound 8 had significant anti-inflammatory activity with IC₅₀ value of（27.81±2.34）μM.Compounds 3,5,and 12 had notable neuroprotective activity.Conclusion:Compounds in cultivated“Qi-Nan”agarwood were similar to those in wild“Qi-Nan”agarwood.Compounds 2,3,5,and 8 accounted for 0.95%,4.26%,11.90%,and7.49%of ethanol extract respectively and these compounds were characteristic in cultivated“Qi-Nan”agarwood.Compounds 2,3,5,and 8 provided material support to produce high-quality agarwood standards,modify the structure of 2-（2-phenylethyl）chromone derivatives,and determine their bioactivities.And made it easier to study the pharmacology of agarwood.2-（2-phenylethyl）chromones in cultivated“Qi-Nan”agarwood showed many bioactivities,anti-inflammatory activity of compound 8,and neuroprotective activity of compound 3 were significant,which had high values to be lucubrated as new medicines.