Journal of Pharmaceutical Analysis 2013;3(4):241–247

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ORIGINAL ARTICLE

A simple method for the isolation and purification of

resveratrol from Polygonum cuspidatum
Dong-Geng Wanga, Wen-Ying Liub, Guang-Tong Chena,b,

a
Medical School, Nan Tong University, Nan Tong 226001, China
b
Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China

Received 31 May 2012; accepted 5 December 2012

Available online 10 December 2012

KEYWORDS Abstract Resveratrol, a polyphenol compound with strong biological activity, has been widely used in
Polygonum cuspidatum;
medicine, health products and cosmetic industries. It is also the main active component of Polygonum
Resveratrol; cuspidatum, a well-known traditional Chinese medicine. We developed a simple and effective method for
Solvent extraction; the preparation of resveratrol from P. cuspidatum. The whole preparative process consisted of reflux
Purification extraction, filtering, hydrolyzing, liquid–liquid extraction and eluting. Filtering is to remove non polar or
less polar compounds and debris fragments from the extract. Hydrolyzing is to transform polydatin to
resveratrol to improve the yield of resveratrol. Eluting is to remove impurities including strong acidic and
water-soluble compounds. By acid hydrolysis of glycoside (polydatin), the yield of resveratrol increased
about 4-fold. The extraction recovery in different stages was high, and the content of resveratrol in the
final product was over 73.8%. Compared with other methods reported, this technology is eco-friendly,
easier to perform, and also has a lower cost.
& 2013 Xi’an Jiaotong University. Production and hosting by Elsevier B.V.
Open access under CC BY-NC-ND license.

1. Introduction Pharmacopoeia [1], has been traditionally used for treatment

of various inflammatory diseases, hepatitis, tumors, and
Polygonum cuspidatum Sieb. et Zucc., a well-known traditional diarrhea in East Asian countries such as China, Korea and
Chinese medicine and officially listed in the Chinese Japan. Its major constituents are stilbenes and anthraquinones
such as polydatin, resveratrol (Fig. 1), anthraglycoside B,
n
Corresponding author at: Medical School, Nan Tong University, emodin, physcion and chrysophanol [2–4].
Nan Tong 226001, China. Tel.: þ86 513 85051049; As one of its main active components, resveratrol is also
fax: þ86 513 85051892. found in many other families of plants such as peanuts [5],
E-mail address: guangtong_chen@ntu.edu.cn (G.-T. Chen) grapes [6] and wine [7], but the content of resveratrol in
Peer review under responsibility of Xi’an Jiaotong University. P. cuspidatum is much higher than that in grape and other
plants. Now resveratrol has widely been used in medicine,
health products and cosmetic industries on account of their
various pharmaceutical properties such as anti-inflammatory,
anticancer [8] and cardioprotective activities [9].

2095-1779 & 2013 Xi’an Jiaotong University. Production and hosting by Elsevier B.V. Open access under CC BY-NC-ND license.
http://dx.doi.org/10.1016/j.jpha.2012.12.001
242 D.-G. Wang et al.

Fig. 1 Chemical structures of trans-resveratrol (A) and trans-polydatin (B).

Although there is considerable evidence that trans- All other reagents used were also of AR grade, and water was
resveratrol possesses strong biological activity, P. cuspidatum distilled three times.
has a lower level of trans-resveratrol in comparison to its The reference compounds of trans-resveratrol, polydatin
glucoside transpolydatin (piceid, trans-3,5,40-trihydroxylstil- and emodin were all of purity 499% (National Institute for
bene-3-mono-D-glycoside). In fact, the level of trans-polydatin the Control of Pharmaceutical and Biological Products).
in P. cuspidatum is 5–8 times greater than the level of trans- P. cuspidatum was purchased from a local drug store and
resveratrol. Therefore, if we can hydrolyze polydatin into identified by Dr. Li-Na Chen (School of Pharmacy, Nanjing
resveratrol, the output of resveratrol will be greatly increased. Medical University, Nanjing, China).
Because these polyphenols present a wide range of possible
health benefits, a huge effort has been made towards the 2.2. HPLC
development of isolation, purification and quantification meth-
odologies. Conventional methods entail extraction by heating
The analysis was carried out on an HPLC system (Shimadzu,
under reflux with ethanol, followed by filtration, concentration
Japan) equipped with an LC-10ATvp pump, an SPD-10Avp
and purification. This procedure is time-consuming and requires a
detector, and a CTO-10ASvp column oven. A Nucleosil 100
large amount of solvent [10]. Other authors have experimented
C18 reverse-phase column (150 mm  4.6 mm; particle size,
with molecular imprinted polymers for the selective extraction and
5 mm; Knauer, Berlin, Germany) protected by a pre-column
purification of resveratrol and piceid from the same plant [11].
was used.
Supercritical fluid extraction (SFE), which primarily uses CO2 as
For determination of samples obtained in this experiment,
its extraction medium, has been widely used for the extraction of
we used acetic acid:acetonitrile:water (2:20:80, v/v) as solvent
non polar substances such as oils from natural plants and recent
A, and 100% acetonitrile as solvent B, at a flow rate
literature has shown that it can also be used for the extraction of
of 1.0 mL/min with the following gradient: 0–30% B linear
resveratrol from P. cuspidatum when either ethanol or acetonitrile
(0–14 min), 30–100% B linear (14–18 min), 100% B
is added as a modifier [12,13]. Enzymic hydrolysis technology has
(18–23 min). This was followed by a 15 min equilibrium period
been recoursed to increase in the recovery of resveratrol [14,15].
with initial conditions prior to injection of the next sample.
Other methods such as high-speed counter-current chromatogra-
Samples were filtered (0.45 mm, Millipore) and 20 mL was
phy (HSCCC) [2,16,17] and eco-friendly extraction technology [18]
directly injected. Chromatograms were monitored at 290 nm
were also used in the preparation of resveratrol. These new
using the UV detector.
technologies mentioned above are simple and intuitive, but
Chromatographic peaks were identified through compar-
expensive and time-consuming.
ison with retention times of resveratrol, polydatin and emodin
After refluxing extraction with 95% ethanol, the dried
standards. Quantitative determination of resveratrol was
extract from P. cuspidatum contains resveratrol, polydatin,
performed using an external standard based on the area of
emodin and many other components. According to their
peak under the optimal HPLC analytical conditions.
different chemical properties such as solubility, acidity and
hydrolysis, we designed a new method for the preparation of
resveratrol from P. cuspidatum. This method not only greatly 2.3. HPLC–MS/MS and other equipments
improved the yield of resveratrol, but also reduced organic
solvent consumption and had a lower cost. In order to confirm the main component of the final product
to be resveratrol, it was purified on a preparative HPLC
system and its chemical structure was further identified by
HPLC–MS/MS and 1H-NMR.
2. Experimental The preparative HPLC system consisted of two LC-8A
pump (Shimadzu, Japan), an SPD-20A detector (Shimadzu,
2.1. Reagents and materials Japan), a Sapphire C18 column (10.0 mm  250 mm, 5 mm;
Sepax Technologies, Inc.) protected by a pre-column, and
The AR grade solvents used for the extraction were 95% N2000 workstation (Saier Tai Technology Co. Hangzhou,
ethanol, ethyl acetate, and petroleum ether (Guoyao Group China). For the preparation of resveratrol, we used methanol:
of Chemical Reagents Ltd., China). Acetonitrile (Tedia water (45:55, v/v) as the mobile phase, and the detective
Company INC., USA) and acetic acid were of HPLC grade. wavelength was set at 290 nm.
Isolation and purification of resveratrol from Polygonum cuspidatum 243

HPLC/MS/MS analyses were performed using a system a proportion of 1:30 (w/v, g/mL) were sealed in a vessel and
consisting of a Finnigan autosampler (Thermo Electron placed into the ultrasonic cleaning bath for 20 min at 50 1C.
Corporation, USA), a Finnigan LC pump, a Finnigan TSQ The mixture finally becomes a uniform suspension solution,
Quantum Ultra equipped with an electrospray ion source and and was immediately filtered at lower pressure. The aqueous
operated by XCalibur software. solution and the residue acquired were used for HPLC
1
H-NMR spectra were measured on a Bruker DRX-400 detection.
spectrometer. In order to hydrolyze polydatin to resveratrol, the aqueous
KQ5200 ultrasonic washer (Kunshan Ultrasonic Instru- solution was adjusted with hydrochloric acid to pH¼1, and
ment Co. Ltd., China) and RE 52-86A rotary evaporator hydrolyzed by refluxing in water bath for 8 h at 75 1C.
(Shanghai Yarong Instrument Co. Ltd., China) were used for
extraction. 2.5.3. Liquid–liquid extraction
Liquid–liquid extraction was carried out in a separating funnel.
2.4. Spectral data of trans-resveratrol by mass spectrometry The aqueous solution mentioned above was mixed with the same
and 1H-NMR volume of extraction solvent, and the separation between the
aqueous and organic phases was carried out by gravitational
HPLC–ESI–MS/MS was adopted to analyze trans-resveratrol. sedimentation. To achieve a high recovery extraction was
The data were shown here: parent ion [MH] m/z 227, main repeated three times. The volumes of aqueous and organic phases
product ions m/z 185, 143, 117 and 119. The molecular mass were measured and concentrations of resveratrol in each phase
of trans-resveratrol is 228 D. were analyzed with HPLC (see Eq. (2)).
In dimethyl sulfoxide (DMSO), the 1H-NMR data were as

Extraction recovery of resveratrol ð%Þ ¼ V0 C0 =Vi Ci  100%
follows: 6.11 (m, 1H, H-4), 6.37 (d, 2H, J ¼2.0 Hz, H-2, H-6),
6.76 (d, 2H, J ¼ 8.5 Hz, H-30 , H-50 ), 6.90 (d, 1H, J¼ 16.3 Hz, ð2Þ
H-a), 6.92 (d, 1H, J¼ 16.3 Hz, H-b), 7.39 (d, 2H, J ¼8.5 Hz, where V0 and C0 are the volume and concentration of resveratrol
H-20 , H-60 ), 9.17 (s, 2H, 3-OH, 5-OH), 9.52 (s,1H, 40 -OH). in organic phase after extraction respectively, Vi and Ci are the
From the above data, it was easy to confirm resveratrol. initial volume and initial concentration of resveratrol in aqueous
solution before solvent extraction.
2.5. Procedures for the preparation of resveratrol from
P. cuspidatum 2.5.4. Eluting
To remove the impurities including strong acidic and water-
Method for the preparation of resveratrol from P. cuspidatum soluble compounds, the alkaline aqueous solution with pH
was based on the chemical properties of compounds in the 8–9 (for example, 5% sodium bicarbonate solution)was added
95% ethanol extract. The whole process included reflux to the organic phase, and washed (about 2 times, v/v¼ 1) until
extraction, filtering, hydrolyzing, liquid–liquid extraction and the color of aqueous phase changed from red to almost
eluting. The flow chart is shown in Fig. 2. colorless. The mixture was directly left to complete phase
separation in a funnel. The volumes of aqueous and organic
2.5.1. Preparation of the 95% ethanol extract from phases were measured and the concentration of resveratrol in
P. cuspidatum by reflux extraction each phase was measured by HPLC.
Extraction of resveratrol from P. cuspidatum was performed
with 95% ethanol by reflux extraction according to the
method reported in literature [19]. In this process, the dried 3. Results and discussion
roots of P. cuspidatum were ground to powder (about 40
mesh) by using FZ102 plant disintegrator. One hundred grams 3.1. Extraction of resveratrol from P. cuspidatum
of powder were placed in distillation flask. After adding 95%
ethanol in a proportion of 1:6 (powder: 95% ethanol, g/mL), The yield of 95% ethanol extract acquired from P. cuspidatum
the mixture was left to rest approximately 12 h at room by refluxing extraction was 13.3%, and the content of
temperature. Then the soaked powder of P. cuspidatum was resveratrol in the extract was 3.3%.
extracted by refluxing extraction at about 80 1C. This extrac- Fig. 3(A) shows the HPLC chromatograms of the 95%
tion procedure was repeated three times and 1 h for each time. ethanol extract. It is clear that there are five major peaks in
The extract solutions obtained were combined and evaporated this chromatogram. Peaks 3 and 4 were identified as resver-
to dryness by a rotary evaporator under vacuum at 65 1C. atrol and emodin with retention time of 14.8, 21.3 min by
The yield was calculated dividing the mass of recovered dry comparison with the external standards, respectively. Peaks 1,
extract (mr) by the initial mass of P. cuspidatum powder (mi) 2 and 5 were of unknown components. It was evident that
(see Eq. (1)) and the content of resveratrol was detected by peaks with retention time over 21 min were of non polar or
HPLC. less polar compounds.


Yield ð%Þ ¼ mr =mi  100% ð1Þ
3.2. Filtration

3.2.1. Roles of filtration

2.5.2. Filtering and hydrolyzing Fig. 3(A) shows the chromatogram of 95% ethanol extract,
The 95% ethanol extract mentioned above was pulverized into Fig. 3(B and C) are the chromatograms of residue and
powder form (less than 0.9 mm). A milled sample and water in aqueous solution after filtering, respectively. It is very clear
244 D.-G. Wang et al.

Powder of P. cuspidatum
Reflux extraction with 95% ethanol, concentrating, drying

95% ethanol extract dried

Filtering [Extract:water (1:30, g/mL), Ultrasound-assisted dissolution]

Residue Aqueous solution

Hydrolyzing in acidic solution(pH=1)

Aqueous solution

Liquid-liquid extraction with methyl tert-butyl ether

Aqueous phase Organic phase

Eluting with pH 8-9 basic solution

Aqueous phase Organic phase

Drying under reduced pressure

Product

Fig. 2 Flow chart representative of the extraction and purification processes of resveratrol.

single molecular form, were still found in the filtrate and could
not be easily removed. However, compared with the first one,
the second method was very effective in eliminating the non
polar or less polar compounds. The cause might be that these
compounds existed in molecular aggregation form and thus
could be easily removed by filtering (figures were not
given here).

3.2.2. Effect of extract–water ratio on the extraction of

resveratrol
The extract–water ratio (w/v, g/mL) has a marked effect on
the resveratrol extraction. A plot of extract–water ratio versus
Fig. 3 HPLC chromatograms of samples in filtration and
the extraction recovery of resveratrol is shown in Fig. 4. The
hydrolyzing. (A) Chromatogram of 95% ethanol extract, (B)
extraction recovery of resveratrol started to increase at ratio
and (C) chromatograms of residue and aqueous solution after
1:10 and reached the maximum (86.3%) at about 1:30
filtration, (D) chromatograms of aqueous solution after hydro-
(Analysis of variance: F¼11.847, P¼0.008). But when the
lyzing for 6 h. Peak1 polydatin, 3 resveratrol, 4 emodin, 2 and 5
ratio was over 1:30, it was not significant for the change of
unknown components.
extraction recovery value (Analysis of variance: F ¼0.056,
P ¼0.946).
that resveratrol (peak3) and other compounds with TR 15 min
Obviously, this was concerned with the degree of extracts
were mostly remained in aqueous phase, while the non polar
dissolved in water. When the extract–water ratio was below
or less polar compounds with TR 21 min were mostly or
1:30, the extraction recovery of resveratrol was comparatively
completely left in residue.
lower. This might be caused by the losses of resveratrol for the
The 95% ethanol extract contains some non polar or less
formation of coarse particles in the mixture.
polar compounds such as physcion, chrysophanol, emodin
and so on. To remove these compounds and debris fragments
from the extract, the efficiency of two different filtering 3.3. Hydrolyzing
approaches was compared. The first one used direct filtration
method. The extracting solution acquired from P. cuspidatum In order to improve the yield of resveratrol, we used a
by refluxing extraction was concentrated under low pressure glycoside hydrolysis pathway. First we used sulfuric acid
until ethanol was mostly or completely evaporated. After that (pH ¼ 1), both resveratrol and polydatin can be easily oxidized
it was diluted with water and then filtrated. It was found that in this condition. Therefore, we finally used the reflux-
those non polar or less polar compounds, which might exist in hydrolysis approach under hydrochloric acid condition
Isolation and purification of resveratrol from Polygonum cuspidatum 245

Fig. 5 HPLC chromatograms of samples after liquid–liquid

extraction. (A) chromatogram of organic phase, and (B) chroma-
togram of aqueous phase.
Fig. 4 Effect of extract–water ratio (g/mL) on the extraction
recovery of resveratrol (n ¼3).

(pH ¼1). TLC results showed that after reflux-hydrolyzing for

8 h, polydatin was hydrolyzed completely.
Fig. 3(D) shows the chromatogram of aqueous solution
after hydrolyzed in acidic solution (pH ¼1) for 6 h. It was
clear that most polydatin was transformed to resveratrol.

3.4. Liquid–liquid extraction

3.4.1. Selection of extraction solvent

Any components will be distributed between two phases according
to the distribution constant, temperature, and the relative volumes Fig. 6 Effect of pH on resveratrol extraction during the eluting
of two phases. Therefore, the selection of extractants is one of the process.
most important factors in solvent extraction. Four solvents [ethyl
acetate, ethyl acetate:petroleum ether (1:1), petroleum ether and
methyl tert-butyl ether] were tested in their extraction efficiency,
and the extraction recoveries acquried were 81.877.3%,
91.776.5%, 10.674.3%, 92.679.2% (mean7SD, n¼ 3), respec-
tively. For methyl tert-butyl ether, the extraction recovery of
resveratrol was the significantly highest among the four extractants
(Analysis of variance: F¼ 93.55, P¼0.0001), thus it was finally
selected as extraction solvent. Similar results were also obtained
when ethyl acetate–petroleum ether (1/1, v/v) was used as
extractant.

3.4.2. Chromatograms after liquid–liquid extraction Fig. 7 HPLC chromatograms of samples after eluting. (A)
Fig. 5 shows HPLC chromatograms of samples after liquid– chromatogram of aqueous phase, and (B) chromatogram of
liquid extraction using methyl tert-butyl ether as extractant. It organic phase.
was evident that resveratrol (peak3) was selectively extracted
into the organic phase (Fig. 5(A)), and not found in the was used. The content of resveratrol in the dried product
aqueous phase. Impurities of water soluble compounds reached to 73.8%.
(Tro14.0 min) were mostly remained in the aqueous phase Resveratrol is a weak acid, so under a certain pH range it
(Fig. 5(B)). existed as un-ionized molecular form. When being eluted with
solution (pHo9), resveratrol still remained in the organic
phase. However, when an eluent with pH410 was used,
3.5. Eluting resveratrol (ionized form) was transferred to aqueous phase.
An increase of pH (9opHo10) brought about a considerable
3.5.1. Effects of pH on the extraction of resveratrol during the decrease of extraction recovery of resveratrol.
eluting process
Fig. 6 shows that pH had a great effect on the extraction of
resveratrol. When basic aqueous solution with pH ¼8–9 was 3.5.2. Investigation of the eluting efficiency
used as elution solvent, the extraction recovery of resveratrol Fig. 7(A and B) are the HPLC chromatograms of aqueous
was over 90%. However, the extraction recovery of resveratrol and organic phases after being eluted. Fig. 7(A) shows
decreased quickly to 0 when the elution solvent with pH410 that impurities with retention time less than 14.5 min were
246 D.-G. Wang et al.

Table 1 Comparision of methods for the isolation and purification of resveratrol from Polygonum cuspidatum.

Strategy Main steps Yields Content of Refs.

(g/100 g) resveratrol (%)

Enzymic hydrolysis Extraction, enzymic hydrolysis, – 65 [14]

purification
Macroporous resin adsorption, RP-HPLC Macroporous resin 0.14 98 [3]
High-speed counter-current chromatography (HSCCC) Extraction, HSCCC 0.0185 95 [2]
Supercritical fluid extraction (SFE) SFE-CO2 0.71 5.74 [13]
Our experiment Acid hydrolysis, alkali washing 40.90 73.8

‘‘–’’ means the data are not found.

completely eluted into the aqueous phase, while resveratrol References

(peak3) and emodin (peak4) with retention time 14.8 and
21.3 min were still remained in the organic phase as displayed [1] China Pharmacopoeia Committee, Pharmacopoeia of the People’s
in Fig. 7(B). Republic of China, the First Division of 2005 Edition, China
Chemical Industry Press, Beijing, 2005, pp. 167.
[2] X. Chu, A. Sun, R. Liu, Preparative isolation and purification of
3.6. Comparison of different technologies for the extraction five compounds from the Chinese medicinal herb Polygonum
and purification of resveratrol cuspidatum Sieb.et Zucc by high-speed counter-current chroma-
tography, J. Chromatogr. A 1097 (2005) 33–39.
[3] D.L. Zhang, X. Li, D.X. Hao, et al., Systematic purification of
According to literatures reported, there are several different
polydatin, resveratrol and anthraglycoside B from Polygonum
methods for the preparation of resveratrol from P. cuspidatum.
cuspidatum Sieb. et Zucc, Sep. Purif. Technol. 66 (2009) 329–339.
Among them four major methods are shown in Table 1. The [4] B.C. Vastano, Y. Chen, N.Q. Zhu, et al., Isolation and identifica-
conventional methods such as macroporous resin or silica gel tion of stibenes of Polygonum cuspidatum, J. Agric. Food Chem.
column chromatography are simple, but they are time-consuming 48 (2000) 253–256.
and require a large amount of organic solvents. High-speed [5] J.M. Ingham, 3,5,40 -Trihydroxystilbene as a phytoalexin
counter-current chromatography and supercritical fluid extraction from groundnuts (Arachis hypogaea), Phytochemistry 15 (1976)
are of advanced technologies, but they need expensive equipment. 1791–1793.
In this study, we used acid hydrolysis combined with alkaline [6] P. Landcake, R.J. Price, The production of resveratrol by Vitis
solution washing approach. Because of no participation of vinifera and other members of the Vitaceae as a response to
infection or injury, Physiol. Plant Pathol. 9 (1976) 77–86.
precious instrument and less consumption of organic solvents in
[7] E.H. Siemann, L.L. Creasy, Concentration of the phytoalexin
this method, its cost is naturally lower. By comparing resveratrol
resveratrol in wine, Am. J. Enol. Vitic. 43 (1992) 49–52.
yields of extracts before and after acid hydrolysis, we found the [8] A.A. Bertelli, F. Ferrara, G. Diana, et al., Resveratrol, a natural
yield of resveratrol of the latter increased about four-fold (data stilbene in grapes and wine, enhances intraphagocytosis in human
were not given here). promonocytes: a co-factor in antiinflammatory and anticancer
chemopreventive activity, Int. J. Tissue React. 21 (1999) 93–104.
[9] M.H. Li, J.K. Chen, S.S. Huang, et al., Cardioprotective effect of
4. Conclusion resveratrol, a natural antioxidant derived from grapes, Cardio-
vasc. Res. 47 (2000) 549–555.
[10] H.Y. Xiang, C.S. Zhou, Q.F. Lei, et al., Studies on separation and
In this work we developed a simple and effective method for
purification of piceid from Poligonum cuspidatum by macroporus
the preparation of resveratrol from P. cuspidatum. By compar- adsorption resin, Chin. Pharm. J. 40 (2005) 96–98 (in Chinese).
ing with some traditional and modern methods in separation [11] X. Zhuang, X. Dong, S. Ma, et al., Selective on-line extraction of
and purification science, this method brings us several advan- transresveratrol and emodin from Polygonum cuspidatum using
tages. First, it does not need column packing such as molecularly imprinted polymer, J. Chromatogr. Sci. 46 (2008)
macroporous resin or silica gel. Secondly, it requires only a 739–742.
small amount of organic solvents. And finally, it does not need [12] B. Beňová, M. Adam, P. Pavlı́kováand, et al., Supercritical fluid
expensive equipment. extraction of piceid, resveratrol and emodin from Japanese
According to this method, the yield of resveratrol increased knotweed, J. Supercrit. Fluids 51 (2010) 325–330.
about 4-fold by acid hydrolysis of glycoside, and the content [13] W. Yu, B. Shu, Y. Zhao, Supercritical CO2 extraction of
resveratrol and its glycoside piceid from Chinese traditional
of resveratrol in the final product was over 73.8%.
medicinal herb Polygonum cuspidatum, J. Sci. Food Agric. 85
(2005) 489–492.
[14] Z.F. Huang, J.H. Yi, Q.L. Liu, et al., Research of extracting and
Acknowledgments
purifying process of resveratrol from Polygonum cuspidatum
extract by enzymatic hydrolysis, Nat. Prod. Res. Dev. 21 (2009)
This work was supported by Natural Science Foundation of 1061–1064 in Chinese.
Jiangsu College & University (10KJB350003) and the Priority [15] T.L. Tian, J. Shen, M.M. Xu, et al., Biotransformation of
Academic Program Development of Jiangsu Higher Education polydatin from Polygonum cuspidatum by Rhizopus sp T-34,
Institutions (PAPD). Sichuan Daxue Xuebao 2 (2008) 437–440 (in Chinese).
Isolation and purification of resveratrol from Polygonum cuspidatum 247

[16] F.Q. Yang, T.Y. Zhang, Y. Ito, Large-scale separation of [18] M. Stefano, B. Arianna, B. Luisa, et al., A one-pot ultrasound-
resveratrol, anthraglycoside A and anthraglycoside B from Poly- assisted water extraction/cyclodextrin encapsulation of resveratrol
gonum cuspidatum Sieb. et Zucc by high speed counter-current from Polygonum cuspidatum, Food Chem. 130 (2012) 746–750.
chromatography, J. Chromatogr. A 919 (2001) 443–448. [19] D.G. Wang, W.Y. Liu, Application of Doehlert design for the
[17] M. Yang, X.J. Xu, C.Y. Xie, et al., Preparative isolation and optimization of resveratrol extraction from Polygonum cuspida-
purification of 12,13-dihydroxyeuparin from Radix Eupatorii tum, Chin. Pharm. J. 40 (2005) 1138–1142 (in Chinese).
Chinensis by high-speed counter-current chromatography,
J. Pharm. Anal. 2 (2012) 258–263.