Studies On Chemical Constituents Of Sinacalia Tangutica

Sinacalia tangutica?Maxim.?B.Nord.belongs to the genus Sinacalia?Asteraceae family?.S.tangutica has been used as a folk medicine for expectorant,anti-cough,antihistamine,antiradical and cathartic purposes.There are few reports about the phytochemical constituents and pharmacological activities of S.tangutica.Some low-polarity components of S.tangutica have been reported,primarily isolated from P.ether extract,dichloromathane extract and ethyl acetate extract.Systematic phytochemical studies was conducted on the rhizomes of S.tangutica,which were collected in Mei county of Shaanxi province,and led to the isolation of 29compounds from the aqueous ethanol extract by solvent extraction,normal and reverse phase silica gel,polyamide and Sephadex LH-20 column chromatography,along with recrystallization.26 compounds of them were identified by ¹H NMR,¹³C NMR,IR,UV,DEPT,HMBC,HSQC,HR-ESI-MS and comparison with?-sitosterol and syringic acid authentic samples,including twenty phenolic compounds?hydrangetin?STP-6?,4-hydroxybenzaldehyde?STC-1?,p-hydroxycinnamic acid?STC-3?,ferulic acid?STC-4?,4-hydroxy-3,5-dimethoxybenzaldehyde?STC-5?,7-hydroxy-coumarin?STC-6?,syringic acid?STC-7?,caffeic acid?STE-3?,3,4-dihydroxybenzaldehyde?STE-5?,methyl 4,5-di-O-caffeoyl quinate?STE-6?,methyl 3,5-di-O-caffeoyl quinate?STE-7?,methyl 5-O-caffeoyl quinate?STE-8?,ethyl 5-O-caffeoyl quinate?STE-9?,methyl 4-O-caffeoyl quinate?STE-11?,daphnin methylether?STB 30-2?,7-hydroxycoumarin-8-O-?-D-glucopyranoside?STB 30-3?,trans-ferulicacid4-O-?-D-glucopyranoside?STB30-4?,3-?4-O-?-D-glucopyranosyloxy-3,5-dimethoxy?-phenyl-2E-propenol?STB 30-6?,5-hydroxyeugenol-4-O-?-D-xylopyranosyl-?1?6?-O-?-D-glucopyranoside?STB30-10?,n-butyl-caffeic acid?STB 70-2??;three terpenoids?bauerenol?STP-1?,petasin?STP-4?,isopetasin?STP-5??;two steroids??-sitosterol?STP-2?,the mixture of?-sitosterolandstigmasterol?STE-1??;andonefructoside?n-butyl-?-D-fructopyranoside?STB 30-1??.Among the 26 compounds,STB 30-10 was a new compound,and STP-1,STP-4,STC-3,STC-4,STC-5,STC-7,STE-3,STE-5,STE-6,STE-7,STE-8,STE-9,STE-11,STB 30-1,STB 30-2,STB 30-3,STB 30-4,STB 30-6,and STB 70-2 were found in this genus for the first time.It is worthy to be mentioned that five chlorogenic acids i.e.methyl 4,5-di-O-caffeoyl quinate?STE-6?,methyl 3,5-di-O-caffeoyl quinate?STE-7?,methyl 5-O-caffeoyl quinate?STE-8?,ethyl 5-O-caffeoyl quinate?STE-9?,and methyl 4-O-caffeoyl quinate?STE-11?had been isolated from S.tangutica.This is the first report of isolation of chlorogenic acids from the genus Sinacalia.The antioxidant activities of different fractions from the ethanol extracts of S.tanguticawereassessedbyDPPH?1,1-diphenyl-2-picrylhydrazyl?free radical-scavenging assay.All fractions showed antioxidant capacity.Especially,the ethyl acetate extract?STE?,30%ethanol eluate from n-butanol extract?STB 30?,70%ethanol eluate from n-butanol extract?STB 70?,and dichloromathene extract?STC?exhibited better antioxidant potential than others.Chemical investigation of these four fractions revealed a high content of phenolic compounds,accounting for their antioxidant activity.The ?-glucosidase inhibitory capacity of different fractions from the ethanol extract of the dried rhizomes of S.tangutica were assessed by PNPG?4-nitrophenyl-?-glucopyranoside?method.The ethyl acetate extract?STE?exhibited?-glucosidase inhibitory activity.From ethyl acetate extract,some chlorogenic acids were isolated.The?-glucosidase inhibitory activity of the isolated chlorogenic acids were also assessed by PNPG method,and the tested chlorogenic acids exhibited potent?-glucosidase inhibitory activity.This work provides scientific evidence not only for the medicinal application of S.tangutica,but also for its development as natural antioxidants and antioxidant functional food and for its development and utilization in the treatment of type 2diabetes.