chinese postpartum care ( zuoyuezi ) has been regarded as a crucial rite - to - passage for the woman 's recovery and the transition to motherhood after childbirth . the use of sheng - hua - tang , a well - known traditional chinese medicine ( tcm ) compound prescription , during the postpartum has been popular in chinese communities over a long period . previous study has shown that sheng - hua - tang use during the first month of the postpartum period may have a positive effect on women 's health - related quality of life , especially in terms of role limitations due to physical health and emotional problems . wu - jia sheng - hua capsule ( comprising radix et caulis acanthopanacis senticosi , radix angelicae sinensis , rhizoma chuanxiong , semen persicae , radix glycyrrhizae , and rhizoma zingiberis preparata ) , derived from sheng - hua - tang , has been used widely in chinese women to promote blood flow , resolve blood stasis , ease postchildbirth pain , reduce bleeding volume and shorten bleeding duration after induced abortion in chinese women [ 3 , 4 ] . the material base , namely the bioactive components , of wu - jia sheng - hua ( wjsh ) capsule is still unclear , though the prostaglandin f2alpha ( pgf2 ) , prostaglandin e2 ( pge2 ) , endothelin ( et ) , and nitrogen monoxide ( no ) levels were found to be partially responsible for the curative effects and recovery benefits of wjsh capsule on induced abortion with vaginal haemorrhage . tcm serum pharmacochemistry , based on hypothesis that active compounds should appear in blood after administration of tcm , was proposed by homma et al . , it was proved to be helpful in recognizing the real active components in tcm and in gaining a better understanding of the mechanisms under the therapeutic effects of tcm [ 79 ] . in the present study , an ultraperformance liquid chromatography coupled with electrospray ionization mass spectrometry ( uplc / esi - ms ) method was developed and applied for investigating the serum pharmacochemistry of wjsh capsule . the identification of wjsh 's multiple absorbed bioactive components and metabolites might be helpful for better understanding the mechanisms under its therapeutic effects . syringin , protocatechuic acid , liguiritin , ferulic acid , isofraxidine , chlorogenic acid , and liqustilide ( standards ) were purchased from national institute of control of pharmaceutical and biological products ( beijing , china ) . acetonitrile , methanol , formic acid , and ammonium formate ( hplc grade ) were obtained from merck ( darmstadt , germany ) and sigma - aldrich ( st . louis , mo , usa ) , respectively . wu - jia - sheng - hua capsule and each single herb in the prescription of wu jia sheng hua capsule were gifts from duo duo pharmaceutical co. ltd . the chromatographic separation of the absorbed components and metabolites were performed on a waters acquity uplc system ( waters corp . , milford , ma , usa ) equipped with an uv detector , an autosampler , an acquity uplc beh c18 column ( 2.1  50  mm , 1.7  m ) , and an automatic thermostatic column oven . the mobile phase consisted of ( a ) water buffered with ammonium acetate ( 10  mm ) and formic acid ( 0.1% , v / v ) and ( b ) acetonitrile . the elution of the target compounds was conducted in a gradient mode with the volume percentage of b changed from 5% to 50% in the initial 10 minutes and from 50% to 80% in the next 6 minutes . the flow rate was 0.4  ml / min , and the injection volume was 8  l .    to obtain the ms and ms / ms data of the investigated compounds , a waters quattro premiere xe triple - quadrupole mass spectrometer ( micromass ms technologies ) was coupled to the abovementioned uplc system . the mass range was set at m / z 1001000  da with the scan time being 0.5  s. the ionization parameters were as follows : interval time , 0.2  s ; capillary voltage , 3.5  kv ; cone voltage , 35  kv ; ionization resource temperature , 120c ; desolvation temperature , 380c , desolvation gas flow rate , 500  l / h ( n2 ) ; and cone gas flow rate , 50  l / h ( n2 ) . masslynx software ( version 4.1 ) and quanlynx software were used for system control and data processing , respectively .   5  ml methanol was added to 1  ml blank rat serum sample or wjsh capsule serum sample . the mixture was vortexed for 3  min . and centrifuged for 15  min . each residue was reconstituted in 1  ml methanol and centrifuged for 15  min . the extracts of wjsh capsule and raw medicinal materials of wjsh capsule were prepared separately . 10  ml methanol was added to 0.4  g wjsh or each raw medicinal material . centrifuged ( 3000  rpm ) for 15  min . , and filtered through 0.45  m micropore film ( millipore , usa ) . male sprague - dawley rats ( 230  g  10  g , experimental animal center of heilongjiang university of traditional chinese medicine ) were randomly divided into eight groups ( six for each ) : group a to group h. all care and handling of animals were performed with the approval of institutional authority for laboratory animal care of heilongjiang university of traditional chinese medicine . after 12 hours of fasting , normal saline ( blank control ) and extract of wjsh capsule were given intragastrically to rats in group a and group b , separately . extracts of raw medicinal materials were given intragastrically to rats of the other 6 groups ( one extract per group ) . the dosage was 1.5  ml/100  g body weight , and the administration frequency was once daily in three consecutive days in each group . at forty minutes after the last administration , 5  ml blood the blood samples were centrifugated for 10  min . at 5000  rpm at 4c to separate serum samples . to purify the serum sample , the protein precipitation , liquid - liquid extraction , and solid - phase extraction methods were tried . finally , the simple protein precipitation method with methanol was chosen , since most investigated compounds were found in the purified samples . as compared to methanol - water system , higher resolution , better peak shape , and faster elution of compounds were achieved using acetonitrile - water system buffered with ammonium acetate and formic acid . the chromatographic separation of the absorbed components and metabolites was conducted in gradient elution mode to overall reduce the retention time of these compounds characterized by different polarities . the timetable of gradient elution was listed in table 1 . for the esi - ms conditions , the stronger responses of all compounds were obtained in positive ionization mode than in negative mode . thus , positive mode was employed in the total ion current ( tic ) chromatograms of wjsh capsule serum samples in the m / z range of 100 to 1000  da . the multiple bioactive components in tcm could be simultaneously identified using the uplc - esi - ms technique . it is generally helpful in better understanding the mechanisms underlying tcm 's therapeutic effects . the serum pharmacochemistry study of wjsh capsule was conducted in rats orally administered with wjsh capsule . then , the absorbed bioactive components including their metabolites were identified by the established uplc - esi / ms method . the typical tic chromatograms of wjsh capsule extract , wjsh capsule serum sample , and blank serum sample were shown in figure 1 . twelve chemicals of which chromatographic peaks appeared in the tic chromatograms of wjsh capsule serum sample and wjsh capsule extract , but not in that of the blank serum sample , were presumed to be the absorbed components . similarly , four chemicals whose chromatographic peaks presented only in the tic chromatograms of wjsh capsule serum sample , but not in that of the wjsh capsule extract or the blank serum sample , were supposed to be metabolites .   by comparing the ms / ms spectra , the chromatographic peaks in tic chromatogram of wjsh capsule serum sample versus the standards , respectively , seven absorbed components were identified unequivocally . for instance , the ms / ms spectrum of peak 5 was compared with that of the isofraxidine standard . these ms / ms spectra were shown in figure 2 . since the quasi - molecular ion at m / z 223 [ m + h ] , fragmentation ions at m / z 192 [ m + h - och3 ] , and at m / z 161 [ m + h - och3-och3 ] were found simultaneously in the ms / ms spectra of peak 5 and the standard of isofraxidine ; this absorbed component was confirmed to be isofraxidine . the other five absorbed components and the four metabolites were not identified and need further investigation . by comparing the tic chromatograms of serum samples , wjsh capsule , wjsh capsule without radix et caulis acanthopanacis senticosi , and radix et caulis acanthopanacis senticosi alone , similarly , the original plant(s ) of the other absorbed components and metabolites were confirmed . the retention times , ms / ms data , and original plants of the absorbed components and metabolites were listed in tables 2 and 3 , respectively .   by revealing the bioactive components of tcm compound prescriptions , serum pharmacochemistry studies might be significantly helpful in better understanding the mechanisms under the therapeutic effects of these prescriptions . for instance , wjsh capsule and danggui - shaoyao - san have been used extensively in chinese women to enhance uterine involution after giving birth and alleviate dysmenorrhea , respectively [ 11 , 12 ] . in pharmacological experiments , the prostaglandins ( pg ) levels regulation was proved to be partially responsible for the myometrium contraction stimulation and inhibition effects of wjsh capsule and danggui - shaoyao - san , separately [ 4 , 12 ] . in previous and present serum pharmacochemistry investigations , identical ( ferulic acid and liqustilide ) and different ( syringin , protocatechuic acid , liguiritin , isofraxidine , and chlorogenic acid for wjsh capsule ; paeoniflorin sulfonate , albiflorin , paeoniflorin , butylidenephthalide , and senkyunolide i for danggui - shaoyao - san ) bioactive components in wjsh capsule and danggui - shaoyao - san were identified . by conducting comparative pharmacokinetic and pharmacological experiments , the major bioactive components in wjsh capsule and danggui - shaoyao - san related to the up- and downregulation effect on myometrium contraction might be confirmed , and the influence of other coexisting components on these effected might be revealed . thus , the mechanisms under wjsh capsule and danggui - shaoyao - san 's therapeutic effects might be elucidated . in this study , an uplc - esi - ms method was established for investigating the serum pharmacochemistry of wjsh capsule . in this way these results might be helpful for better understanding the mechanisms underlying the therapeutic effects of wjsh capsule .