Studies On Chemical Constituents And Extraction Of Lignans From Hemistepta Lyrata Bunge

Hemistepta lyrata Bunge, an herbaceous plant of Hemistepta genus in Compositea family. The decoction of H. lyrata is used in local folk medicine against cyclomastopathy in area of Changbai maintain and against cataractogensis in Sichuan province. Hemistepta lyrata is aboundant in natural resources as weeds from,which has been discarded for limited in development and utilization, In order to provide scientific basics for reasonablely using the medicine and search the bioactive constituents,we have separated and identified chemical constituents of H. lyrata a systematic study on chemical constituents of H. lyrata and determined content of three lignans from H. lyrata by HPLC-DAD method.In this paper, a systematic study on chemical composition was carried out deeply used by various chromatographers. Simultaneously,we studied the optimum extraction technique of lignans in H. lyrata by ultrasonic wave.Compounds are isolated from the chloroform and ethyl acetate soluble fractions of ethanolic extract of H. lyrata by Silica gel column chromatography,ODS column chromatography,Sephadex LH-20 chromatopraphy and HPLC separation techniqueand and their structures of 20 compounds including nine sesquiterpen lactones,four lignans, four flavonoids, two phenolic compounds and one lactone compound. By the data of EI-MS、ESI-MS、1H-NMR、13C-NMR、HSQC、HMBC、1H-1H COSYand NOESY,the structures were identified as p-hydroxybeIlzaJdehyde (N1),loliolide (N2),11β,13-dihydriaguerin B (N3), aguerin B (N4),acacetin (N5),3-hydroxy-1-(4-hydroxyl-3,5-dimethoxyphenyl)-1-propanone(N6),scrophulein(N7),vladinol D(N8),wikstrone(N9),alycone (N10),8α-O-(2-hydroxy-propionate)-13-nor-desacylcynaropicrin(N11),8a-O-(2-methyl-3-hydroxy-propionate) deacylcynaropicrin(N12),8α-O-(2-meth-yl-3-hydroxy-propionate)-13-nor-desacylcynaropicrin(N13),13-nor-desacyl-cynaropicrin (N14),lip,13-dihydrodeacylcynaropicrin (N15),desacylcynar-opicrin(N16),tracheloside(N17),cynaropecrin(N18),kaempferol(N19),apig-enin (N20).Among them,three new compounds N11,N13 and N14 were isolated from H. lyrata together with nine known compounds, N1,N2,N3,N6,N8,N9,N10, N12and N15 were isolated for the first time from H. lyrata.In this research, we optimize the extraction process for the lignans(Tracheloside、Hemislienoside and Arceiin) from H. lyrata. The conditions for the extraction by ultrasonic wave were studied by the contents of three lignans in the extract. The effects of main ultrasound-assisted extraction conditions were evaluated, including types of extraction solvent (water、methanol、ethanol、n-butanol), concentrations of extraction solvent (10% ethanol、30% ethanol、50% ethanol、70% ethanol、90% ethanol), the ratio of solvent to material (10:1、20:1、30:1、.40:1) and extraction time (5min、10min、15min、20min、25min、30min). And then,the effects of ultrasound-assisted extraction and conventional refux extraction were compared. Results showed the optimal parameters to extract lignans from H. lyrata. This study shows that an ultrasound-assisted extraction can be easily carried out within a short time period and possesses advantages such as low heating and higher yield efficiency.In this paper,a systematic study on chemical composition of Hemistepta lyrata Bunge, optimize the extraction process for the lignans(Tracheloside、Hemislienoside and Arceiin) from Hemiste Ptaly,for the development of H. lyrata lay the foundation.