Study On Chemical Constituents And Allelopathic Activity Of E.Urophylla×E.grandis

E.urophylla×E.grandis belongs to Myrtaceae family.In recent years,it is popularized cultivation vigorously in our Country.And it is considered to have wide application prospect.But at present,the research about the chemical constituents of E.urophylla×E.grandis and the allelopathy activity of eucalyptus effect on economic plant for medicine is few.In this study,a series of chemical constituents were isolated from E.urophylla×E.grandis.Some constituents with allelopathy activity were selected by the tests of seed germination of medicinal herbs.Some medicinal herbs can grow under the eucalyptus forests were selected by the tests of seedling growth.The results were as follows.1.The chemical constituents of E.urophylla×E.grandis were isolated and purified by various column chromatographies,and their structures were identified by spectral analysis.Thses chemical constituents included two flavonoids,four tannins and six phenolic.Their structures were identified as:trans-p-cournaric acid(EL-1),cis-p-coumaric acid 4-O-?-D-glucopyranoside(EL-2),apigenin-7-O-?-D-glucuronopyranoside(EL-3),gallic acid(EL-4),1-O-galloyl-?-D-glu-cose(EL-5),quercetin-3-O-?-D-glucuronopyranoside(EL-6),caffeic acid(EL-7),ellagic acid(ER-1),3-O-methylellagic acid(ER-2),3,3'-di-O-methylellagic acid(ER-3),3-O-methyl ellagic acid 4'-O-?-L-rhamnopyranoside(ER-4),cis-p-coumaric acid(ER-5).The higher content of them was ellagic acid(ER-1).Ten compounds were isolated from E.urophylla×E.grandis for the first time,they were EL-1,EL-2,EL-3,EL-5,EL-6,EL-7,ER-2,ER-3,ER-4 and ER-5.2.Thirty-nine constituents were identified by the use of GC-MS,they account for 98.88%of total volatile constituents.The higher content of them were Eucalyptol(40.47%),a-Pinene(32.44%),?-Terpinyl propionate(6.63%),?-Terpineol(5.73%),Bormeol(2.26%),they account for 87.53%of the total volatile constituents.3.Water extract of E.urophylla×E.grandis had strong inhibition effect on seed germination of Carthamus tinctorius,Astragalus membranaceus and Isatis indigotica.It showed that the extent of inhibition was stengthened according to concentration rising.Isatis indigotica was inhibited mostly,fellowed by Carthamus tinctorius and Astragalus membranaceus.4.Essential oil of E.urophylla×E.grandis had strong inhibition effect on Carthamus tinctorius and Isatis indigotica,and the higher concentration,the stronger inhibition.The germination of Astragalus membranaceus was promoted by the essential oil in low concentration,while being inhibited in high;oncentration.The order of inhibition extent from high to low was Isatis indigotica,Carthamus tinctorius,Astragalus membranaceus.5.Five main chemical components of E.urophylla×E.grandis essential oil,Eucalyptol,a-Pinene,a-Terpinyl propionate,a-Terpineol,Borneol,and one water-soluble chemical components ellagic acid were proved to be allelochemicals.They have different inhibition effect on three kinds of medicinal herbs.a-Terpineol,Eucalyptol and a-Terpinyl propionate showed stronger inhibition on Carthamus tinctorius than other components.Borneol,?-Terpineol and ?-Pinene have stronger inhibition on Astragalus membranaceus than other components.Borneol,a-Terpinyl propionate and a-Terpineol have stronger inhibition on Isatis indigotica than other components.a-Terpineol have strong inhibition effect on three kinds of medicinal herbs.6.The growth of Astragalus membranaceus seedlings was promoted by water extract of E.urophylla×E.grandis when it was in low concentration.but being inhibited obviously when it was in high concentration.Water extract of E.urophylla×E.grandis had stroner inhibition effect on Isatis indigotica than Astragalus membranaceus,and the extent of inhibition was stengthened according to concentration rising.However the inhibition would be relieved when the seedlings of Isatis indigotica grew up.7.By the effect of water extract of E.urophylla×E.grandis,with the growth of seedlings,the SOD and CAT activity of Astragalus membranaceus increased,it showed that the inhibition of water extract of E.urophylla×E.grandis to Astragalus memmbranaceus had a rising trend.The SOD and CAT activity of Isatis indigotica reduced,it showed that the inhibition of water extract of E.urophylla×E.grandis to Isatis indigotica had a weakening trend.8.Compared of these two kinds of herbs,Isatis indigotica is more suitable for planting under the woods of E.urophylla×E.grandis It was better to transplante seedlings to the woods of E.urophylla×E.grandis instead of sowing directly.The detail cultivation method needs further research.