| Glycyrrhiza uralensis Fisch(Leguminosae)which is one of the plant resources for licorice,is a perennial herb in genus Glycyrrhiza.In the Chinese Pharmacopoeia,G.uralensis,G.inflata and G.glabra are all recorded as medicinal plants for licorice.Traditionally,G.uralensis is used for its root and rhizome,and most of the aerial parts are wasted.In order to separate more undiscovered chemical constituents from the leaves of G.uralensis,to find more highly active compounds and to make better use the aerial part,this research was carried out to investigate the 80% ethanol eluted part from a macroporous resin chromatography of an ethanol extract of G.uralensis leaves.The contents of the bioactive constituents in different parts of G.uralensis and in the leaves collected at different months were studied.The chemical constituents were isolated and purified,and their bioactivities were assessed as regard to DPPH radical scavenging,?-glucosidase inhibitory,and maltase inhibitory activities.The chemical constituents of G.uralensis leaves were separated and purified using repeated chromatography on silica gel,ODS,Sephadex LH-20 and preparative high performance liquid chromatography,and the structures were determined by analysis of their spectroscopic data.As the result,15 compounds were isolated and identified as 3 new dihydrostilbenes,glycypytilbene A(1),glycydipytilbene(2),andglycypytilbene B(3),and 12 known compounds,?,?'-dihydro-3,5,4'-trihydroxy-4,5'-diisopentenylstilbene(4),?,??-dihydro-3,5,3?,4?-tetrahydroxy-2,5?-diisopentenylstilbene(5),6-prenyleriodictyol(6),5?-prenyleriodictyol(7),6-prenylquercetin-3-Me ether(8),5?-prenylquercetin(9),6-prenylquercetin(10),6-prenylnaringenin(11),3?-prenylnaringenin(12),sigmoidin C(13),8-[(Z)-3-hydroxymethyl-2-butenyl]-eriodictyol(14),and quercetin-3-Me ether(15).The isolated compounds include 5 dihydrostilbenes(1-5),6 flavanones(6,7,11-14),and 4 flavonols(8-10,15).Quantification analysis was carried out using ultra-high performance liquid chromatography tandem mass spectrometry quantification analysis was carried out by HPLC-MS for the root,rhizome,stem,leaf,seed and seed pods of G.uralensis and for the leaves collected at different months during the high yield period of G.uralensis leaves in Ordos(June to October).The result revealed that the contents of the 15 constituents of G.uralensis leaves and 8 other related compounds distributed specifically in G.uralensis leaves and seed pods.In the leaves,the contents of compounds 1,3,5,7,8,13,15,16(luteolin),17(quercetin)and 18(eriodictyol)in the G.uralensis leaves decreased from June to October,with the contents being the highest in June;the contents of compounds 4,6,9,11,and 21(3,3',4',5,7-pentahydroxyflavanone)increased from June to October;the highest contents of compounds 10 and 14 were detected in July;the highest contents of compounds 2 and 12 were in August,and the highest content of compounds 19(rutin)and 20(isoquercitrin)were found in September.The 15 compounds obtained from the leaves of G.uralensis and 8 other related compounds were tested for their antioxidant,and inhibition on ?-glucosidase and small intestinal disaccharidase activities.The results showed that compounds 1,5-11,14-15 had strong antioxidant activity,compounds 2-11,15,17,21 inhibited the activity of ?-glucosidase,and the compounds 5,7,9-10,14,15 inhibited the activity of maltase.The above findings provided scientific data for collecting G.uralensis leaves at the best time,and for making better use of the above ground parts. |
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