全 文 :49 Journal of Chinese Pharmaceutical Sciences http://www.jcps.ac.cn
Determination of bergenin in rat urine, feces and tissues by RPHPLC method
YanBin Shi 1* , YanPing Shi 2 , XiaoYun Zhang 1 , QuanYi Zhao 1 , JingMan Ni 1
1. School of Pharmacy, Lanzhou University, Lanzhou 730000, China
2. Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
OH
CH 3 O
HO
O
O
O
H
H
CH 2 OH
OH
OH
5
4
3
2
1
Received date: 20081009.
Foundation items: Natural Science Foundation of Gansu Province
(Grant No. ZS021A25051N); Scientific & Technological Tackle Key
Projects of Gansu Province, China. (Grant No. 2GS035A4304801).
* Corresponding author. Tel./fax: 869318915686;
email: shiyb@lzu.edu.cn
1. Introduction
Bergenin is a Cglucoside of 4Omethyl gallic acid
(Fig. 1) that has been isolated from the rhizome of
Rodgersia aesculifolia Batalin [1] . It has been reported
that bergenin had antiarrhythmic [2] , hepatoprotective [3–5] ,
antiinflammatory [6] , antiHIV [7] , neuroprotective [8] ,
antiulcer [9] , and antitussive activities [10] .
Drug absorption, distribution, metabolism and excre
tion (ADME) is one of the key properties for the
design of a safe and effective drug. Data and infor
mation obtained from ADME studies of the bioactive
compounds of medicinal herbs could also help us to
understand the complex actions of herbal medicines
and predict a variety of events related to efficacy
and toxicity of herbs and herbal preparations [11,12] . In
our previous study, a RPHPLC method for the quanti
fication of bergenin in rat plasma has been developed
and applied successfully to the pharmacokinetic study
of bergenin. The result indicated that bergenin in rats
was distributed widely, and eliminated moderately
fast after intravenous administration [13] .
In this paper, the determination of bergenin in
urine, feces and tissues were investigated in order to
obtain more information for understanding the phar
macokinetic properties of bergenin in rats. Therefore,
Figure 1. Chemical structure of bergenin.
an analytical method based on reversedphase high
performance liquid chromatography (RPHPLC) to
determine bergenin in rat urine, feces and tissues
was developed. The methods for the quantification
of bergenin in urine and tissues were validated with
parameters such as selectivity, linearity, precision,
accuracy and recovery.
2. Materials and methods
2.1. Chemicals and animals
Bergenin (purity, 98%) was provided by Institute
of Pharmaceutics, Lanzhou University. The reference
standard of bergenin (serial number: 1532–2001)
was purchased from the National Institute for the
Control of Pharmaceutical and Biological Products
(Beijing, China). Bergenin was dissolved in 1,2
propanediol and redistilled water (1:5, v/v), and filtered
through a 0.22 µm filter before rat experiment. The
formulation used for intravenous administration
Abstract: A RPHPLC analytical method was developed for determining bergenin in rat urine, feces and tissues. The separation
was performed on a C18 analytical column with methanol–water as the mobile phase at a flow rate of 0.8 mL/min. The column
temperature was 40 ºC and the eluate was monitored at 220 nm. The calibration curve for urine analysis showed a good linearity
(r = 0.9989) over the range of 0.5–100 µg/mL, and the absolute recoveries were in the range of 90.0%–92.6%. A good linearity
(r≥0.9996) for all tested tissues was obtained over the range of 0.3–150 µg/g except for lung, which had a linearity range of
0.5–150 µg/g. The absolute recoveries from tissues were higher than 63.9%. The method was successfully applied to determine
the bergenin levels in several biological samples after rats were given bergenin formulation through tail vein injection. The results
demonstrated that the amount of bergenin recovered from urine was about 35.36% of the total dose, and that from feces was less
than 10%. Bergenin can be quickly and widely distributed in the rat, accumulating high levels in the kidney in comparison to all
other tissues investigated. It was not distributed into the brain at any significant level owing to its hydrophilic property.
Keywords: RPHPLC; Bergenin; Excretion; Distribution
CLC number: R917 Document code: A Article ID: 1003–1057(2009)1–49–6
Y. B. Shi et al. / Journal of Chinese Pharmaceutical Sciences 18 (2009) 49–54 50
consisted of a 0.25% (w/v) solution of bergenin.
HPLCgrade methanol was from Yuwang Chemical
Reagents Company (Shandong, China). All other
chemicals were of analytical grade, obtained from
Tianjin Second Reagent Factory (Tianjin, China).
Wistar rats weighing 200–250 g were purchased
from the Laboratory Animal Services Center of
Lanzhou University. The animals were housed in
metabolite cages and acclimated in the laboratory
for at least one week prior to the experiment at
ambient temperature (22–28 ºC). All procedures
involving animals and their care were carried out
according to the guidelines of the Committee on
the Use of Animal Subject in Research of Lanzhou
University. Standard rat food and tap water were
provided ad libitum.
2.2. HPLC apparatus and conditions
The analysis was carried out on a HPLC system
(Shimadzu Scientific Instruments Inc., Kyoto, Japan)
consisted of a LC10AT pump, a SPD10A UVvis
detector (wavelength range from 190 to 790 nm), and
a 7725i sample injector (CA, USA). The separation
was performed on a Diamonsil TM , C18 analytical
column (4.6 mm × 250 mm, 5 µm, Dikma, USA) with
a Securityguard TM guard cartridge (Phenomenex, USA).
The mobile phase was composed of a mixture of
methanol and water. The proportion of methanol–
water was 20:80 (v/v) for the determination of ber
genin in urine and feces samples, and 22:78 (v/v) for
tissue samples. The solvents used for mobile phase
were filtered through a 0.22 µm filter and degassed
prior to use. The flow rate was set at 0.8 mL/min.
The column temperature was 40 ºC and the eluate
was monitored at 220 nm. The signals from the
detector were collected and analyzed with a com
puter equipped with a chromatography data system
CLASSVP TM software package (Version 6.1, Shimadzu
Scientific Instruments Inc., Kyoto, Japan).
2.3. Preparation of calibration samples
A bergenin stock solution was prepared in methanol
at a final concentration of 0.5 mg/mL, and stored in
a refrigerator at 0–4 ºC. Working standard solutions
with concentrations of 0.5–100 μg/mL were prepared
by appropriate dilution of the stock solution with
methanol.
To prepare urine calibration standards, each 0.5 mL
aliquot solution of different concentrations of bergenin
(0.5–100 μg/mL) were transferred to polyethylene
tubes, dried under a gentle nitrogen stream at ambient
temperature. The residue was redissolved in 0.5 mL
blank urine with vortexmixing for 2 min, filtered
through an organic membrane with a pore diameter
of 0.22 µm. The resulting urine samples contained
bergenin in the concentrations of 0.5, 1.0, 2.0, 10,
20, 50 and 100 μg/mL. The urine sample volume
injected into HPLC was 10 µL.
To prepare tissue calibration standards, liver, kidney,
lung, heart, spleen and brain were isolated from rats and
homogenized in distilled water (1 g:1 mL) under
icewater bath. The tissue homogenates (0.5–1.0 mL)
spiked with 1.0–2.0 mL of different concentrations
of working standard solutions of bergenin were
vigorously mixed with a vortex mixer for 1 min.
Thus, the tissues containing bergenin in the concen
trations of 0.3, 0.75, 1.5, 3.0, 7.5, 15, 30, 75 and
150 μg/g were obtained, which were centrifuged at
5000 r/min for 10 min. The resulting supernatants
were collected and dried under a gentle nitrogen
stream at ambient temperature. The residues were
dissolved in 0.5 mL methanol and filtered. Filtrate
(25 μL) of each tissue sample was injected into the
HPLC system for analysis.
2.4. Precision, accuracy and absolute recovery
For intraday precision and accuracy, five replicates
of urine samples spiked at three concentrations of
1.0, 20 and 100 µg/mL and tissue samples spiked at
three concentrations of 0.75, 15 and 150 μg/g were
analyzed at five time intervals during one day,
respectively. The precision was expressed as the
relative standard deviation (RSD %) and calculated
from the standard deviation divided by the mean of the
detected concentration. The accuracy was expressed
as the relative error percentage (RE %) and calcu
lated as ((mean of measured concentrationadded
concentration)/added concentration) × 100%. Inter
day precision and accuracy were determined in five
replicates of the biological samples spiked at the
three levels mentioned above, which were analyzed
over three consecutive days. Absolute recovery at
the three levels was calculated as (the peak area of
bergenin in urine or tested tissue/peak area of bergenin
in methanol) × 100%.
2.5. Preparation of samples
Five rats were given bergenin formulation through
tail vein at a single dose of 22.5 mg/kg body weight.
Urine samples were collected just before administra
tion and at the following time intervals: 0–6, 6–12,
12–18 and 18–24 h after administration. Feces samples
were collected only once during 0–24 h. Urine samples
were frozen at –20 ºC and feces samples were firstly
dried at ambient temperature,then stored at –20 ºC
until analysis. The storage time of samples was less
than one week according to the stability of bergenin
in plasma described in literature [13] . Before analysis,
urine samples were thawed and vigorously mixed,
then diluted with blank urine if necessary. A 1.0 mL
Y. B. Shi et al. / Journal of Chinese Pharmaceutical Sciences 18 (2009) 49–54 51
aliquot of urine sample was filtered through a 0.22 µm
filter and 10 µL aliquot of filtrate was injected into
HPLC for determination. Feces sample was grinded
into fine power and transferred into glass vessels,
fivefold volume (m/v) of methanol was added, and
mixed with the content gently. The suspension was
initially homogenized with ultrasonic vibration
for 5 min and centrifuged at 3000 r/min for 5 min.
The supernatant was collected and filtered. A 10 µL
aliquot of feces filtrate was used for determination.
Another twelve rats were given bergenin formulation
through tail vein at the same dose of 22.5 mg/kg.
Three rats were sacrificed by decapitation at each
timepoint. Tissue samples including liver, kidney,
lung, heart, spleen and brain, were collected at 0.5,
2, 4 and 8 h, rinsed with 0.9% NaCl, gently cleaned
with absorbent paper to remove surface liquid, weighed,
and immediately frozen at –20 ºC until analysis. The
storage time of all samples was less than one week.
Before analysis, each sample of 0.5–1.0 g was sliced
while frozen and processed with the similar procedure
as described on the preparation of calibration samples.
3. Results
3.1. Specificity
The HPLC chromatograms of the urine and kidney
samples from the rats treated with bergenin intrave
nously, the blank samples spiked with bergenin in
vitro, and the blank samples before bergenin injection
are shown in Figures 2 and 3. There are no endogenous
interference peaks observed at the retention time
when bergenin was detected. The retention time of
bergenin was found to be around 18.0±0.5 min for
urinary samples and 13.5±0.5 min for tissue samples
because of the different mobile phases used.
Figure 2.HPLC chromatograms of bergenin in rat urine. (A) Blank urine; (B) Blank urine spiked with bergenin; (C) Urine sample after i.v. administration.
400
200
0
(A)
5 10 15
400
200
0
(B)
5 10 15 20
400
200
0
(C)
5 10 15 20
bergenin
bergenin
m
A
U
m
A
U
m
A
U
min min min
Figure 3. HPLC chromatograms of bergenin in rat kidney. (A) Blank kidney homogenate before intravenous administration; (B) Blank kidney
homogenate spiked with bergenin; (C) Kidney homogenate obtained from the rat treated with bergenin intravenously at 0.5 h after dosing.
400
300
200
100
0
(A)
5 10 15
bergenin
400
200
0
(C)
5 10 15
400
200
0
(B)
5 10 15
bergenin
m
A
U
m
A
U
m
A
U
min min min
Y. B. Shi et al. / Journal of Chinese Pharmaceutical Sciences 18 (2009) 49–54 52
3.2. Calibration curve, LOD and LOQ
The calibration curves were prepared using the
peak areas (A) of analytes versus the corresponding
concentrations (C), and expressed by the linear least
squares regression equation. Linearity was evaluated
by the correlation coefficients of the regression
equations of the calibration curves. The linearity
range should cover the possible contents of analytes
existed in the tested samples. The calibration curve
for urine analysis was C = 4.933 × 10 –5 A – 0.0623
(r = 0.9989) from 0.5 to 100 µg/mL. The limit of
detection (LOD) (signaltonoise ratio = 3) was found
to be approximately 0.17 μg/mL, and the limit of
quantification (LOQ) was 0.5 μg/mL with RSD of
8.55% and RE of 13.13% (n = 10).
The calibration curves for all tested tissues were
listed in Table 1, and the linearity was satisfactory
based on the value of correlation coefficient (r≥
0.9996). The linearity ranges for all tissue samples
were from 0.3 to 150 µg/g except for the lung,
which showed a linearity range from 0.5 to 150 µg/g.
The LODs were in the range of 0.08–0.15 μg/g,
and the LOQs were 0.3–0.5 μg/g with RSDs of
10.63%–17.35% and REs of –13.23%–7.10% (n = 8).
3.3. Precision, accuracy and absolute recovery
The parameters for validating the HPLC assay
included precision, accuracy and absolute recovery.
Table 2 showed the precision, accuracy and absolute
recovery of the method for urine analysis. The varia
tions (RSD %) at three levels for intraday assay
were between 3.11%–4.14%, for interday assay
were between 1.07%–5.68%. All of the accuracies
(RE %) were between 2.24%–9.35%. The absolute
recoveries were in the range of 90.0%–92.6%.
Table 3 showed the precision, accuracy and absolute
recovery of the method for all tested tissue analysis.
The intraday and interday precisions (RSD %) for
bergenin analysis in liver, kidney, lung, heart, spleen and
brain at three levels were in the range of 0.74%–9.46%
and 1.00%–9.24%, respectively. The intraday and
interday accuracies (RE %) were –0.96%–6.43%
and –0.81%–9.19%, respectively. The absolute recoveries
of bergenin from all tested tissues were higher than
63.9%. Among them, the absolute recovery of bergenin
from brain was between 92.2%–95.5%, which was
higher than those from other tissues.
According to the literature criteria [14] , this method
can satisfy the basic requirements for analyzing
bergenin in biological samples.
Tissue Standard curves r Linearity (μg/g) LOD (μg/g) LOQ(μg/g)
Liver
Kidney
Lung
Heart
Spleen
Brain
C = 2.289 × 10 5 A –0.2651
C = 1.867 × 10 5 A– 0.0764
C = 3.192 × 10 5 A + 0.1347
C = 3.808 × 10 5 A–0.2908
C = 3.686 × 10 5 A –0.2522
C = 1.670 × 10 5 A– 0.1833
0.9996
0.9999
0.9999
0.9998
0.9999
0.9999
0.3–150
0.3–150
0.5–150
0.3–150
0.3–150
0.3–150
0.08
0.08
0.15
0.10
0.08
0.08
0.3
0.3
0.5
0.3
0.3
0.3
Table 1. Calibration curves and sensitivity for determination of bergenin in rat tissues
Amount added (µg/mL)
Intraday Interday
Absolute recovery (%)
Amount detected(µg/mL) RSD (%) RE (%) Amount detected(µg/mL) RSD (%) RE (%)
1 1.09 4.14 9.00 1.09 5.68 9.00 92.6 ± 8.9
20 21.87 3.37 9.35 21.31 1.07 6.55 91.1 ± 1.2
100 107.83 3.11 7.83 102.24 2.12 2.24 90.0 ± 2.5
Table 2. Intraday (n = 5) and interday (3 d, n = 5) precision, accuracy and absolute recovery for urine analysis
Tissues Concentration range (µg/g)
Precision (RSD %) Accuracy (RE %)
Absolute recovery (%)
Intraday Interday Intraday Interday
Liver 0.75 – 150 1.74 – 3.07 1.00 – 4.71 1.63 – 5.88 1.12 – 3.90 69.9 – 76.7
Kidney 0.75 – 150 0.74 – 6.71 1.41 – 8.33 –0.96 – 4.07 0.09 – 4.78 73.8 – 84.5
Lung 0.75 – 150 0.95 – 2.21 1.64 – 4.66 –0.18 – 6.43 –0.81 – 9.19 76.5 – 80.1
Heart 0.75 – 150 2.83 – 8.86 2.52 – 8.31 –0.48 – 6.09 –0.33 – 8.16 63.9 – 86.4
Spleen 0.75 – 150 1.71 – 9.46 1.41 – 9.24 0.26 – 2.39 0.07 – 6.54 68.1 – 89.8
Brain 0.75 – 150 1.13 – 4.13 1.20 – 6.83 –0.89 – 5.18 0.02 – 8.07 92.2 – 95.5
Table 3. Intraday (n = 5) and interday (3 d, n = 5) precision, accuracy and recovery for the tested tissue analysis
Y. B. Shi et al. / Journal of Chinese Pharmaceutical Sciences 18 (2009) 49–54 53
3.4. Application of bergenin analysis to urine,
feces and tissue samples
The concentrations of bergenin in urine and tissues
were calculated using the corresponding calibration
curves. The result showed that there was a significant
decrease in the portion of bergenin detected from
urine as sampling periods were extended. The
amount of urinary bergenin detected from 0–6 h
following intravenous administration was 97.13% of
the whole detected amount during 0–18 h. The excre
tion ratio of kidney for bergenin was calculated using
the formula:
and the value was approximately 35.36%. The per
centage of the dose recovered in feces was about
9.34%, which was estimated using the calibration
curve for urinary bergenin analysis.
Bergenin distribution amount (Dt) in tissues was
calculated as follows:
As shown in Table 4, all tested tissues collected at
0.5 h following intravenous administration were
found to retain parent drug. The amount of bergenin
was the highest in the kidney, and then in the spleen,
lung, liver, heart and brain sequentially. The organ
of brain maintained a very low drug concentration
with a value of 0.44 ± 0.26 μg/g, which was likely
because of the hydrophilic properties of bergenin.
The order of the resident time (from longest to
shortest) in tested tissues was kidney, lung, liver,
spleen, heart and brain.
4. Discussion
A simple, practical and lowcost RPHPLC
method has been developed for the quantitative
determination of bergenin in biological samples. The
results showed that bergenin was distributed widely
and eliminated quickly in rat after intravenous ad
ministration. The fast metabolism of bergenin in rat
likely resulted in the lower plasma drug concentra
tion and excretion ratio of kidney. This observation
was in agreement with our previous pharmacoki
netic study [13] . Comparatively, kidney maintained
the highest drug concentration and the longest drug
resident time, while there were very low drug con
centrations in brain, which indicated that bergenin
tends to accumulate in kidney in comparison to all
other tissues investigated. Moreover, bergenin was
not distributed easily in brain because of its hydro
philic property.
Acknowledgements
The research is funded by Natural Science Foun
dation (Grant No. ZS021A25051N) and Scientific
& Technological Tackle Key Projects (Grant No.
2GS035A4304801) of Gansu Province, China.
We are very grateful to ZhenYing Hu and Yong
Jiang Luo (Lanzhou Institute of Animal Sciences
and Veterinary Pharmaceutics, CAAS) for their
technical assistance.
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bergenin amount ( g)
Dt = 100%
tissue weight (g)
m
´
amount detected from urine
fr = 100%
dosage administrated
´
Table 4. Bergenin concentrations in rat tissues after a single intrave
nous administration at 22.5 mg/kg body weight ( , μg/g)
Tissue
Sampling time (h)
0.5 2 4 8
Liver 1.52 ± 0.76 0.60 ± 0.39
Kidney 9.44 ± 1.41 1.53 ± 0.33 1.12 ± 0.12
Lung 2.00 ± 0.34 0.65 ± 0.44
Heart 1.49 ± 0.53
Spleen 3.64 ± 1.14 0.44 ± 0.26
Brain 0.44 ± 0.26
: not detected or lower than LOQ.
x s ±
Y. B. Shi et al. / Journal of Chinese Pharmaceutical Sciences 18 (2009) 49–54 54
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127–138.
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反相高效液相色谱法测定大鼠尿、粪便和组织中岩白菜素的含量
史彦斌 1* , 师彦平 2 , 张晓云 1 , 赵全义 1 , 倪京满 1
1. 兰州大学 药学院, 甘肃 兰州 730000
2. 中国科学院 兰州化学物理研究所,甘肃 兰州 730000
摘要: 本文建立了应用反相高效液相色谱测定大鼠尿、粪便和组织中水溶性药物岩白菜素含量的方法。色谱条件为
Diamonsil TM C18色谱柱, 甲醇–水为流动相, 流速 0.8 mL/min, 柱温 40 ºC, 检测波长 220 nm。尿中药物浓度在0.5–100 µg/mL
范围内与峰面积呈良好线性关系(r = 0.9989), 绝对回收率介于90.0%–92.6%。肺中药物浓度在0.5–150 µg/g范围内, 其它被
测组织中药物浓度在0.3–150 µg/g 范围内与峰面积具有良好线性关系(r≥0.9996), 各组织中药物绝对回收率均大于
63.9%。该方法用于测定大鼠静脉注射岩白菜素后尿液、粪便和组织中药物的浓度, 结果表明约有35.36%的服药剂量从
其尿液中回收, 不足10%的剂量从粪便中回收。原形药物能快速分布到被测组织中, 肾中药物分布最多, 而脑组织中分布
最少, 这与药物本身具有较好的水溶性相关。
关键词:反相高效液相色谱; 岩白菜素;排泄;分布