simultaneous determination of phenols in radix polygalae by high performance liquid chromatography:...

J. Sep. Sci. 2007, 30, 2583 –2589 J. Li et al. 2583

Jun Li1

Xiaobing Dong1

Yong Jiang2

Qiutao Gao1

Zhiyong Jiang1

Anna W. H. Cheung1

Ran Duan1

Tina T. X. Dong1

Pengfei Tu2

Karl W. K. Tsim1

1Department of Biology andCenter for Chinese Medicine,The Hong Kong University ofScience and Technology, HongKong

2Department of NaturalMedicines, School ofPharmaceutical Sciences, PekingUniversity Health ScienceCenter, China

Original Paper

Simultaneous determination of phenols in RadixPolygalae by high performance liquidchromatography: Quality assurance of herbs fromdifferent regions and seasons

Radix Polygalae, roots of Polygala tenuifolia or of Polygala sibirica, is a Chinese herbalmedicine commonly used to prevent dementia. Reliable chemical markers for qual-ity assurance of this herb are missing. Here, a high performance liquid chromatog-raphy method coupled with diode array detection was developed to simultaneouslydetermine nine different phenols in Radix Polygalae, including sibiricose A5, sibiri-cose A6, glomeratose A, tenuifoliside A, glomeratose D, 39,6-di-O-sinapoyl sucroseester, mangiferin, polygalaxanthone III, and polygalaxanthone XI. By using twodifferent detection wavelengths in the HPLC analysis, the developed method wasable to determine the phenols with excellent resolution, precision, and recovery.This established method was therefore applied to determine the amounts of phe-nols in thirty-two samples from different cultivation regions and harvest seasons inChina, and significant variations were revealed. The amounts of phenols in theroots of P. tenuifolia collected in Shanxi and Shannxi Provinces were markedly higherthan in roots collected from other Provinces. Moreover, the samples harvested inthe spring contained higher contents of phenols than those collected in other sea-sons.

Keywords: HPLC – DAD / Phenols / Quality control / Radix Polygalae /

Received: March 22, 2007; revised: June 6, 2007; accepted: June 10, 2007

DOI 10.1002/jssc.200700118

1 Introduction

Traditional Chinese medicine (TCM) plays an importantrole in public health because of the limited side effects.Multiple constituents are responsible for the pharmaco-logical and biological effects of TCM. The major obstaclepreventing development of TCM to provide drugs orhealth food supplements is the standardization of crudeherbs. In order to ensure the stability and efficacy of TCMin clinical usage, effective methods are needed to permittheir quality assurance; in particular, we are dealingwith multi-bioactive compounds in these herbs. In recentyears, high performance liquid chromatography coupledwith diode array detection (HPLC–DAD) has become anefficient tool in determining various bioactive com-

pounds of TCM [1]. It is well known that some of theingredients, especially those of different structural types,have rather distinct UV absorption properties; it is oftendifficult to quantify them simultaneously with UV detec-tion at a single fixed wavelength [2, 3]. The developmentof DAD, however, can provide comprehensive qualitativeand quantitative information due to its multi-wave-length monitoring capability.

Radix Polygalae, the roots of Polygala tenuifolia or of Poly-gala sibirica, is a well-known TCM, called ,Yuanzhi‘, whichis used as an expectorant, tonic, and sedative, and to pre-vent dementia [4]. Chemical investigations have shownthat phenols, such as oligosaccharide esters and xan-thones, and saponins, are the major constituents withinthis crude herb [5–15]. In addition, pharmacologicalstudies have revealed that both phenols and saponins arethe bioactive constituents of Radix Polygalae, which arebelieved to be responsible for a diversity of effects includ-ing cognitive improvement and cerebral protection [16–19], anti-depression [20], anti-psychotic behavior [21, 22],and anti-stress [23]. Although Polygala saponins areknown to have biological functions, they are not recom-mended as chemical markers for quality assurance of

Correspondence: Dr. Karl W. K. Tsim, Department of Biologyand Center for Chinese Medicine, The Hong Kong University ofScience and Technology, Clear Water Bay Road, Hong Kong SAR,China.E-mail: [email protected]: +852-2358-1559

Abbreviations: DAD, diode array detector; TCM, traditional Chi-nese medicine

i 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.jss-journal.com

2584 J. Li et al. J. Sep. Sci. 2007, 30, 2583 – 2589

Radix Polygalae due to their chemical instability [24, 25].In view of this difficulty, several methods have beendeveloped for measuring the amounts of polygalic acid,senegenin, and dehydroxypresenegenin; the main objec-tive is to find a suitable chemical marker for the quanti-tative evaluation of Radix Polygalae [26–28]. However,the usage of these markers is far from perfection. Up tothe present, work on the quantitative analysis of phenolsfrom Radix Polygalae has remained rather limited. In thecurrent study, a new method utilizing HPLC–DAD hasbeen developed for quality evaluation of Radix Polygalaethrough simultaneous determination of nine phenolcompounds in a single analysis, including sibiricose A5,sibiricose A6, glomeratose A, tenuifoliside A, glomera-tose D, 39,6-di-O-sinapoyl sucrose ester, mangiferin, poly-galaxanthone III, polygalaxanthone XI.

2 Experimental

2.1 Plant materials and chemicals

Mangiferin was purchased from the National Institutefor the Control of Pharmaceutical and Biological Prod-ucts (Beijing, China); sibiricose A5, sibiricose A6, glomera-tose A, tenuifoliside A, glomeratose D, 39,6-di-O-sinapoylsucrose ester, polygalaxanthone III, and polygalaxantho-ne XI were isolated previously from roots of P. tenuifolia,and their structures were established by comparison oftheir spectral data (UV, IR, MS, 1H NMR, and 13C NMR)with those reported in the literature [7, 14, 29, 30]. Thepurities of these isolated chemicals were determined tobe more than 98% by normalization of peak areasdetected by HPLC–DAD. All the chemical markers werestable in 70% ethanol. Acetonitrile of HPLC grade waspurchased from Merck (Darmstadt, Germany), and ultra-pure water was prepared by a Milli-Q purification system(Millipore, Molsheim, France). All other reagents were ofanalytical grade.

Four samples of Radix Polygalae were purchased in theHong Kong market; 11 samples of the roots of P. tenuifoliawere collected from Yuncheng, Jiang County, Wanrongand Xinjiang of Shanxi Province; Weinan and Hanchengof Shannxi Province; Xinmi, Yuzhou and Song County ofHenan Province; Shijiazhuang of Hebei Province; Benxiof Liaoning Province; and one sample of the roots of P.sibirica was collected from Wutai Mountain of ShanxiProvince. Cultivated plants of different ages were col-lected in June 2005 in the same field of Yuanzhi Cultivat-ing Farm in Wanrong of Shanxi Province. For samplesfrom different growing months, each sample of 2-year-old plants was collected on the 25th of every month fromJanuary to December in 2005 from the same farm. All thecollected plant materials were authenticated by one ofthe authors – Dr. Tina T. X. Dong – according to the mor-phological characteristics. The voucher specimens were

deposited in the Department of Biology, The Hong KongUniversity of Science and Technology, Hong Kong.

2.2 Sample preparation

The phenols were first dissolved in 70% ethanol at1.0 mg/mL as a stock solution. A certain amount of thestock solution was transferred to a 2-mL volumetric flaskand made up to volume with the same solvent to obtainthe appropriate concentrations. All the solutions werefound to be stable when stored at 48C in the dark for twoweeks. All the samples were dried at 608C until constantweight. A 0.5-g portion of pulverized sample was accu-rately weighed and extracted with 25 mL of 70% ethanolin an ultrasonic bath for 30 min at room temperature.After centrifuging at 30006g for 10 min, the superna-tant was filtered through a 0.45-lm membrane filterprior to injection into the HPLC system.

2.3 HPLC–DAD analysis

An HPLC system consisting of a Waters (Milford, MA) 600pump, an in-line degasser AF, a 717 auto-sampler, and aUV/VIS Photodiode Array 2996 Detector was used for allanalyses. Chromatographic separations were carried outon a Prevail C18 ODS column (250 mm64.6 mm id, 5 lm,Alltech) with a C18 Guard column (7.5 mm64.6 mm id,5 lm, Alltech). The mobile phases were composed of ace-tonitrile (A) and 0.05% phosphoric acid in water (B) usingthe following gradient program: 0–5 min, isocratic12.0% A; 5–10 min, linear gradient 12.0–16.0% A; 10–28 min, linear gradient 16.0–20.0% A; 28–50 min, lineargradient 20.0–23.0% A; 50–65 min, linear gradient23.0–25.0% A; 65–75 min, isocratic 25% A. A pre-equili-bration period of 15 min was observed between individ-ual runs. The DAD detected analytes at 258 nm and330 nm. Chromatography was performed at room tem-perature at a flow rate of 1.0 mL/min and the injectionvolume was 10 lL.

2.4 Calibration curve, limits of detection andquantification

Standard stock solutions containing nine analytes wereprepared and diluted to appropriate concentrations forthe plotting of calibration curves. At least six concentra-tions of nine analyte solutions were analyzed in tripli-cate, and then the calibration curves were constructedby plotting the peak areas versus the concentration ofeach analyte. The squares of correlation coefficients (r2)of these calibration curves were higher than 0.9995. Thediluted solutions of the analytes were further diluted togive a series of concentrations with 70% ethanol to deter-mine the limits of detection (LOD) and quantification(LOQ). The LOD and LOQ under the present chromato-


J. Sep. Sci. 2007, 30, 2583 –2589 Liquid Chromatography 2585

graphic conditions were determined at a signal-to-noiseratio (S/N) of 3 and 10, respectively.

2.5 Precision, repeatability, and accuracy

The intra- and inter-day precisions were determined byanalyzing the known concentrations of nine analytes insix replicates during a single day and by duplicating theexperiments on three successive days, respectively. Inorder to confirm the repeatability, five different workingsolutions prepared from the same sample obtained fromWanrong of Shanxi Province were analyzed. The relativestandard deviation (RSD) was taken as a measure of preci-sion and repeatability. A recovery test was used to evalu-ate the accuracy of this method. Exact amounts of nineanalytes were added to approximately 0.25 g of P. tenuifo-lia roots from Wanrong and then extracted and analyzedas described above. The average recoveries were cali-brated by the formula: recovery (%) = {(amount found –original amount)/amount spiked}6100%, and RSD (%) =(SD/mean)6100%.

3 Results and discussion

3.1 Optimization of extraction procedure

Preliminary analyses suggest that phenols belong to themajor constituents in Radix Polygalae, and could serve aschemical markers for quality assurance (Fig. 1). Thus, theoptimization of extraction was targeted on phenols. Inorder to obtain quantitative extraction of phenols fromRadix Polygalae, the variables involved in the extraction,such as solvent and extraction method, were optimized.Both methanol and ethanol were tested for their effi-

ciency as extraction solvent; the best solvent was foundto be 70% ethanol, which allowed a complete extractionof the tested phenols. In order to find the best extractionmethod, sonication for 30 min, refluxing for 2 h, andSoxhlet extraction for 5 h were tested and compared. Theresults suggested that sonication for 30 min was simplerand highly effective in extracting the phenols (data notshown). The residue after the first extraction was furtherextracted with 70% ethanol for an additional 30 min,and no phenols were detected. Therefore, ultrasonicextraction with 70% ethanol for 30 min in a single stepwas selected to prepare the sample solution.

3.2 Optimization of chromatographic conditions

The chromatographic conditions were optimized toobtain chromatograms with good resolution of adjacentpeaks. A Prevail C18 ODS column used for the analysis ofphenols in Radix Polygalae provided better separationcompared to other conventional C18 columns. The Rs val-ues for the nine phenols were, in most cases, higher than1.5. With respect to the choice of mobile phase, the addi-tion of 0.05% phosphoric acid was necessary to eliminatepeak tailing of the phenols. Because of the long retentiontimes of some of the late-eluting peaks in isocratic runs,gradient elution at 75 min was required in the HPLCanalysis.

By using the UV spectra with 3-D chromatograms ofHPLC–DAD, the absorption maxima of mangiferin, poly-galaxanthone III, and polygalaxanthone XI wereobserved at 258, 319, and 364 nm; sibiricose A5, sibirico-se A6, 39,6-di-O-sinapoyl sucrose ester at 239 and 330 nm;glomeratose A and tenuifoliside A at 309 nm, and glom-eratose D at 320 nm. As a practical consideration, two


Figure 1. Chemical structures of nine phenols (with abbreviations from 1 to 9) in Radix Polygalae.

2586 J. Li et al. J. Sep. Sci. 2007, 30, 2583 – 2589

monitoring wavelengths for quantitative determinationwere employed, 258 nm for mangiferin, polygalaxantho-ne III, and polygalaxanthone XI, and 330 nm for the

other six phenols. Figure 2 shows a typical separation ofthe phenol standards and Radix Polygalae extractobtained at 330 nm under the optimized chromato-graphic conditions. The peaks of reference compoundswere identified by comparison of their retention timesand their UV spectra with those acquired on injectingstandards under the same conditions or by spiking thesamples with stock standard solutions.

3.3 Method validation

All calibration curves showed an excellent linear regres-sion (r2 A0.9995) within the range of calibration (Table 1).The LODs (S/N = 3) and the LOQs (S/N = 10) for the ninephenols were less than 0.41 and 1.33 lg/mL, respectively.The overall intra- and inter-day variations were less than4.0% for the analytes (Table 2). Validation studies of thismethod showed a good reproducibility with RSD lessthan 5.0% (n = 5) for the nine analytes. Table 3 shows thatthe developed analytical method has an excellent accu-racy with an overall recovery from 96.0 to 104.67% (n = 5)for the analytes. Therefore, the HPLC–DAD method wasprecise, accurate, and sensitive enough for simultaneousquantitative evaluation of nine phenols in Radix Polyga-lae.

3.4 Analysis of phenols in Radix Polygalae

The newly developed quantitative method was applied tosimultaneously determine nine phenols in different sam-ples of Radix Polygalae collected at various harvestingtimes and from various cultivation regions in China. Sev-enteen samples of Radix Polygalae were collected fromdifferent sources including commercial sources in theHong Kong herbal market and the cultivation farms indifferent regions of China (Fig. 3 and Table 4). Withregard to the levels of phenols, Radix Polygalae from


Table 1. Calibration curves, LOD and LOQ for the phenol standards.

Analytea) Calibration curveb) Correlationcoefficient (r2)

Linear range(lg/mL)

LODc)

(lg/mL)LOQd)

(lg/mL)

1 y = 7872.9x – 5887.7 0.9998 5.00 –200.00 0.26 0.812 y = 15668x – 14144 0.9997 5.00 –50.00 0.34 1.063 y = 8357.4x + 11184 0.9999 50.00 –500.00 0.41 1.334 y = 6731.1x – 814.4 0.9995 2.00 –20.00 0.21 0.665 y = 4531.3x – 2452.4 0.9995 5.00 –50.00 0.35 1.186 y = 6682x – 6603.3 0.9996 5.00 –50.00 0.24 0.787 y = 13033x – 13900 0.9997 10.00 –400.00 0.38 1.288 y = 4522.3x + 5012.3 0.9996 5.00 –200.00 0.29 0.949 y = 9036.3x – 13544 0.9996 5.00 –200.00 0.28 0.98

a) The notation for analyte (phenol) refers to Fig. 1.b) The calibration curves were constructed by plotting the peak areas versus the concentration of each analyte. Each calibra-

tion curve included six data points.c) LOD refers to the limits of detection.d) LOQ refers to the limits of quantification.

Figure 2. Representative HPLC chromatograms of mixedstandards and Radix Polygalae from Wanrong in ShanxiProvince. Chromatographic separations were carried out ona Prevail C18 ODS column (250 mm64.6 mm id, 5 lm, All-tech, USA) with a C18 Guard column (7.5 mm64.6 mm id,5 lm, Alltech, USA). The mobile phases were composed ofacetonitrile (A) and 0.05% phosphoric acid in water (B) usingthe following gradient program: 0–5 min, isocratic 12.0% A;5–10 min, linear gradient 12.0–16.0% A; 10–28 min, lineargradient 16.0–20.0% A; 28–50 min, linear gradient 20.0–23.0% A; 50–65 min, linear gradient 23.0–25.0% A; 65–75 min, isocratic 25% A. Flow rate: 1.0 mL/min. The UVabsorption was at 330 nm. The notations are: (1) sibirico-se A5, (2) sibiricose A6, (3) mangiferin, (4) glomeratose A, (5)polygalaxanthone XI; (6) polygalaxanthone III, (7) 39,6-di-O-sinapoyl sucrose, (8) tenuifoliside A, (9) glomeratose D.


Shanxi and Shannxi Provinces contained significantlyhigher amounts of phenols compared to the others(Table 4). Among the analyzed phenols, 39,6-di-O-sinapoylsucrose ester was determined as the main compound at aconcentration of about 2.70–8.41 mg/g, while the totalcontent of phenols varied in a range of 7.06–24.01 mg/g.Mangiferin was present at low levels in most of the sam-ples analyzed, except sample #16 that was obtained fromthe stems of P. tenuifolia. In contrast, the stems of P. tenuifo-lia (#16) contained a very low level of other phenols.Moreover, the amounts of phenols were very similarbetween the roots of P. tenuifolia and P. sibirica.

Both P. tenuifolia and P. sibirica are listed in the ChinaPharmacopoeia as the plant origins of Radix Polygalae.However, most of the commercial sources of Radix Poly-

galae are derived from the roots of P. tenuifolia, and lessthan 5% of this TCM on the market comes from the rootsof P. sibirica, due to its rare distribution. Only one sampleof P. sibirica from Wutai Mountain of Shanxi Province wasanalyzed in the present study. The overall HPLC profile ofP. sibirica was similar to that of P. tenuifolia except for theabundances of the peaks. In the herbal market, the stemof P. tenuifolia is frequently mixed with root. Analysis ofinvestigated analytes in the stems was carried out usingthe developed method. In the stem, mangiferin wasdetermined as the main component with a content of13.77 mg/g and other phenols were detected not at all oronly in trace amounts. In order to ensure the clinical effi-cacy, it is necessary to eliminate the stem parts when har-vesting Radix Polygalae.

In order to determine the seasonal variation of RadixPolygalae, different samples of herbs were collected froma cultivating farm at Wanrong in Shanxi Province. Theamount of phenols varies considerably in different devel-opmental stages. Figure 4A shows the 2-year-old and 3-year-old plants to contain robustly higher amounts ofphenols than a 1-year-old plant. There is no significantdifference in phenol contents between 2-year-old and 3-year-old samples. In addition, the role of different har-vesting times was determined. In 2-year-old Radix Polyga-lae, the roots were collected in different months of thesame year of 2005. Figure 4B shows that the samples col-lected in March, April, and May accumulate much higheramounts of total phenols than those collected in othermonths. Therefore, the roots of P. tenuifolia should be har-vested in the spring after cultivating for 2–3 years.

4 Concluding remarks

This is a first report on simultaneous determination ofnine phenols in Radix Polygalae. Based on the validation


Table 2. Precision and repeatability of the nine analytes.

Analytea) Precision Repeatability(n = 5)

Intra-day (n = 6) Inter-day (n = 6) Mean(mg/g)

RSDb)

(%)Mean(lg/mL)

RSD(%)

Mean(l/mL)

RSD(%)

1 99.86 0.56 98.97 1.94 3.75 2.782 29.89 0.96 29.43 2.84 0.99 2.033 300.25 0.74 299.67 2.09 – –4 11.86 1.33 11.93 3.68 0.67 2.525 30.12 0.94 29.93 1.79 1.54 3.976 30.08 0.87 29.99 1.69 1.48 3.017 199.42 1.86 199.26 3.03 8.41 4.128 99.32 0.75 99.46 0.88 4.91 1.859 98.79 1.73 99.02 2.21 2.28 1.76

a) The notation for analyte (phenol) refers to Fig. 1.b) RSD (%) = (SD/mean)6100%.“–” Below the detection limit.

Table 3. Recoveries of the nine analytes.

Analytea) Original(mg)

Spiked(mg)

Found(mg)

Recovery(%)b)

RSD(%)c)

1 0.94 0.95 1.91 102.12 2.222 0.25 0.25 0.49 96.00 1.923 – 1.50 1.57 104.67 2.044 0.17 0.20 0.37 100.00 0.975 0.39 0.40 0.78 97.44 3.876 0.37 0.40 0.77 100.00 1.697 2.10 2.00 4.16 102.86 3.988 1.23 1.20 2.40 97.56 1.459 0.57 0.60 1.19 103.51 1.25

a) The notation for analyte (phenol) refers to Fig. 1.b) Recovery (%) = 1006(amount found – original amount)/

amount spiked; the data was presented as average ofthree determinations.

c) RSD (%) = 1006SD/mean.“–” Below the detection.

Figure 3. Geological locations of Radix Polygalae samplesfrom China. The denotations of two different species, P. ten-uifolia and P. sibirica, are shown.

2588 J. Li et al. J. Sep. Sci. 2007, 30, 2583 – 2589

results, the developed method proved useful and sensi-tive enough for phenol analysis under optimized condi-tions. Excellent results were obtained with respect torepeatability and recovery, as well as excellent levels ofaccuracy and precision. Therefore, the developedmethod could be used for quality assurance of Radix Pol-ygalae. As the results show, the contents of phenols aremuch higher in Radix Polygalae collected from theShanxi and Shannxi regions, and the plants should be 2-to 3-year-old plants and harvested in spring.

This research was supported by grants from University GrantsCommittee (AoE/B-10/01) and Research Grants Council(HKUST6419/06M) of the Hong Kong SAR, and Nanjing Universityof Traditional Chinese Medicine (FJK 2006011) to KWKT, and alsosupported by program for Changjiang Scholar and Innovative


Table 4. Contents in mg/g of the nine phenols in Radix Polygalae.

No.a) Source 1b) 2 3 4 5 6 7 8 9 Total

1 Hong Kong market 1.02 c) 0.39 – 0.12 0.62 0.64 3.24 1.77 0.67 8.472 Hong Kong market 0.60 0.38 – 0.15 0.57 0.56 3.60 1.38 0.85 8.093 Hong Kong market 0.63 0.37 – 0.25 0.53 0.55 3.59 1.42 0.73 8.074 Hong Kong market 2.26 0.97 tr 0.35 1.12 1.04 7.01 2.75 1.14 16.645 Xinmi, Henan 2.31 0.69 – 0.16 1.31 1.22 6.02 0.37 0.53 12.626 Yuzhou, Henan 1.72 0.79 tr 0.10 1.18 1.36 7.18 0.05 0.33 12.737 Song County, Henan 0.73 0.64 – 0.40 0.48 0.54 7.26 1.16 1.06 12.278 Shijiazhuang, Hebei 0.49 0.27 – 0.33 0.45 0.50 2.70 1.58 0.74 7.069 Benxi, Liaoning 0.69 0.49 0.26 0.31 0.37 5.42 0.99 0.71 9.25

10 Weinan, Shannxi 3.32 0.95 – 0.59 1.61 1.28 5.50 3.12 0.97 17.3411 Hancheng, Shannxi 3.34 1.26 – 0.47 1.78 1.58 7.52 5.29 0.89 22.1212 Yuncheng, Shanxi 1.76 0.90 – 0.72 0.45 0.55 6.89 2.23 1.89 15.3913 Jiang county, Shanxi 3.15 0.66 – 0.64 1.29 1.26 6.21 3.91 1.88 19.0014 Wanrong, Shanxi 3.75 0.99 tr 0.67 1.54 1.48 8.41 4.91 2.28 24.0115 Xinjiang, Shanxi 3.27 0.83 – 0.52 1.13 1.05 7.61 3.49 2.00 19.8916 Wanrong, Shanxi Tr 0.10 13.77 – 0.21 – 0.95 – – –17 Wutai Mountain, Shanxi 1.38 0.66 – 0.40 0.20 2.2 9.95 0.39 5.03 20.20

a) Sample #1 to #15 are the roots of P. tenuifolia; #16 is the stems of P. tenuifolia; #17 is the roots of P. sibirica.b) The notation for analyte (phenol) refers to Fig. 1.c) Data calculated as average of three replicates (RSD a 5%).“–” Below the detection.“tr” Below the linear range of calibration.Values are expressed as mean € SD (n = 3); SD values less than 5% are not shown for clarity.

Figure 4. Variation of phenol content in the roots of P. tenui-folia. (A): different cultivated years, and (B): different har-vesting months. Cultivated plants of different ages were col-lected in June 2005 in the same field of Yuanzhi CultivatingFarm of Wanrong, Shanxi Province, and for samples fromdifferent harvesting months, each sample of two-year-oldplants was collected on the 25th of every month from Janu-ary to December 2005 in the same farm. (1) Sibiricose A5,(2) sibiricose A6, (4) glomeratose A, (5) polygalaxanthone XI;(6) polygalaxanthone III, (7) 39,6-di-O-sinapoyl sucrose, (8)tenuifoliside A, (9) glomeratose D.


Team in University (Grant number: 985-2-063-112) and NationalKey Technology R&D Programs of China during the 11th Five-yearPlan (No.2006BAI09B05). This work is part of a project on thestudy of some common Chinese Material Medica in Hong Kongbeing undertaken by Department of Health, Hong Kong SAR Gov-ernment, China. KWKT held a visiting professorship at School ofPharmaceutical Sciences, Peking University in 2005.

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simultaneous determination of phenols in radix polygalae by high performance liquid chromatography:...

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