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Quantification of Valerenic Acid in Ferula sumbul Roots
Using UPLC
SONALI BATRA, A. KUMAR* AND A. SHARMA
University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh-160 014, India
Sonali, et al.: Quantification of Valerenic Acid Using UPLC
Ferula sumbul (Umbelliferae) roots have a characteristic musk odour and it has been traditionally used for
relieving anxiety, as a sedative in hysteria and other nervous disorders. Present investigation aims to develop
and validate a simple, robust, accurate and fast analytical ultra-performance liquid chromatography
technique for the estimation of valerenic acid in F. sumbul roots. F. sumbul root extract was prepared by
refluxing the powdered roots with methanol for 30 minutes. A simple method for the estimation of valerenic
acid has been developed and validated using ultra-performance liquid chromatography with photodiode
array detector. The estimation was achieved using BEH Shield RP, C-18 column (2.1×50 mm, 1.7 μm) with
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September-October 2017
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isocratic elution of methanol and 0.5% phosphoric acid (75:25) at a flow rate of 0.25 ml/min and detection
at 218 nm. The method has been developed for the first time and is accurate with good linearity (r2>0.998).
F. sumbul roots were found to contain 12.62±0.074 µg/g valerenic acid. The developed method can be
selectively used for the estimation of valerenic acid in the roots of F. sumbul. All the validation parameters
were found to be within the permissible limits prescribed by ICH guidelines.
Key words: Ultra-performance liquid chromatography, valerenic acid, F. sumbul, validation
The genus Ferula (Umbelliferae) comprises 130 species
distributed from the Mediterranean region to Central
Asia. The genus is well documented as a good source
of biologically active compounds such as coumarins,
terpene alcohols, and sesquiterpene derivatives[1].
F. sumbul Hook. (Syn. F. moschata Reinsch.) commonly
known as sumbul (Hindi) or musk root (English)
consists of cylindrical or tapered pieces of dried roots
and rhizomes with bitter taste and slight musky odour[2].
It has been traditionally used for relieving anxiety, as
a sedative in hysteria and other nervous disorders, and
as a mild gastrointestinal stimulant. The coumarins
and bicoumarins isolated from the ethanol extract of
F. sumbul roots exhibit antiHIV activity and inhibit
cytokine release[3].
The present study involves the estimation of valerenic
acid (VA, fig. 1) content in F. sumbul roots, using
ultra performance liquid chromatography (UPLC).
VA is one of the important constituents of the drug
Valeriana officinalis[4,5] and is mainly responsible
for its anxiolytic activity. Its root extract has been
used for the treatment of anxiety, epilepsy and sleep
disorders for centuries. UPLC, a derivative of well-
known analytical technique, works on the same basic
principle of high performance liquid chromatography
(HPLC), but decreased column particle size allows
increased sensitivity, better resolution and shorter run
time[6,7]. Already established HPLC method for VA
estimation involves a complex solvent system for its
quantification[8,9]. The UPLC method described herein
has shorter run time, consumes less HPLC solvent and
reference standard, and gives better separation and
enhanced resolution.
Roots of F. sumbul were procured from Rym Exports,
Mumbai, India. They were authenticated from
NISCAIR, New Delhi, with voucher specimen number
NISCAIR/RHMD/Consult/2014/2483-62-2
dated
18/07/2014. Reference standard VA was purchased
from Sigma-Aldrich, HPLC grade methanol was
obtained from Merck Specialties Pvt. Ltd. (Mumbai,
India) and HPLC grade water was obtained from the
Millipore system (Billerica, MA, USA).
Accurately weighed 1 mg of VA was dissolved in
methanol and volume was made up to 10 ml in a
volumetric flask, to get a concentration of 100 µg/ml.
This was used as stock solution, to make the further
dilutions. The coarsely powdered roots of F. sumbul
(2 g) were refluxed for 30 min with HPLC-grade
methanol (20 ml). The extract obtained was filtered
through Whatmann filter paper (no. 10). The residue
was washed with methanol (5 ml), transferred to 25 ml
volumetric flask and the volume was adjusted to get
a concentration of 80 mg/ml. It was filtered through
0.22 µm syringe filter. The sample solution (0.50 µl)
was injected into the UPLC system. The whole process
was carried out in triplicate.
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Fig. 1: Structure of valerenic acid (VA)
Accepted 14 August 2017
Revised 28 February 2017
Received 29 June 2016
*Address for correspondence
E-mail: bashwani@pu.ac.in
September-October 2017
Indian J Pharm Sci 2017;79(5):834-838
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Analysis was performed on a Waters Acquity UPLC
H-Class system, equipped with a binary pump,
autosampler, photodiode array detector (PDA) and
Empower 2™ software (Waters, Milford, MA, USA).
The analytical method was developed using a BEH
Acquity RP, C-18 column (2.1×50 mm, 1.7 μm, Waters,
Milford, MA, USA). The mobile phase consisted
of methanol (solvent A) and 0.5% phosphoric acid
(solvent B), in the ratio of 75:25. The flow rate was set
to 0.25 ml/min, injection volume was 0.50 μl, column
temperature was maintained at 25° using a column
oven, and detection was carried out using PDA detector
at 218 nm.
The developed UPLC method was validated in
accordance with ICH (Q2 (R1)) guidelines in terms
of linearity, sensitivity, precision, accuracy, and
robustness of the study[10]. Linearity was determined
using concentration levels plotted over the range of
0.5-2.0 µg/ml. The calibration curve was developed by
plotting peak area versus concentration. The regression
coefficient, slope and intercept were calculated from
the calibration curve. Sensitivity of the method was
determined with respect to limit of detection (LOD,
S/N=3) and limit of quantification (LOQ, S/N=10).
Serial dilutions of the standard solution were injected
and, thus, LOD and LOQ values were calculated by the
UPLC system suitability software. Repeatability of the
method was analysed by injecting single concentration
of VA six times (n=6) within one day. The precision
data were expressed as percentage relative standard
deviation (%RSD). For determination of accuracy of
the method, a recovery study was carried out by adding
a known amount of individual standard at low (80%),
medium (100%) and high (120%) concentration into
coarsely powdered drug and the sample was prepared
as described earlier. The three concentrations, thus
prepared, were analysed in triplicate and the results
were expressed as the percentage recovery of the added
standard. Robustness of the method was determined
by making deliberate changes to the chromatographic
conditions, such as change in flow rate (0.25±0.02
ml/min), mobile phase composition (75:25±5) and
injection volume (0.5±0.1 µl). Each parameter was
analysed in triplicate and the variations in the retention
time were expressed as %RSD with respect to normal
retention time.
Optimal chromatographic conditions were obtained
on the Acquity BEH Acquity, RP C-18 column
and isocratic elution using different proportions of
methanol: 0.5% aqueous phosphoric acid (75:25) as
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mobile phase for the method development for VA by
UPLC. The optimised chromatographic conditions led
to well separated peak of VA in methanol extract of
F. sumbul roots, with a stable baseline.
The validation of the developed method was done by
preparing the standard curve of VA. For VA standard,
the correlation coefficient (r2) was found to be ≥0.998,
which indicates a high degree of correlation between
selected concentrations and respective peak areas, and
also indicated good linearity of the method developed.
The slope, intercept and correlation coefficient for the
standard were determined by regression analysis. The
LOD for VA was observed to be 30 ng/ml and LOQ
was 100 ng/ml implying adequate sensitivity of the
method (Table 1). The %RSD values for repeatability
studies were found to be 0.506%, which complied
with permissible limits (≤5) as per the ICH guidelines
(Table 1). Percent recovery for VA standard was found
to be in the range of 99.44-102.02 with %RSD≤1.311
(Table 2), which showed good recovery of the standard.
The %RSD values for all the deliberately made
changes in the UPLC conditions were found to be in
the acceptable range: for flow rate, 0.038-0.311; for
mobile phase composition, 0.035-0.605; for injection
volume, 0.161-0.395. For the different parameters
taken into consideration, the %RSD values were less
than 5%, which clearly indicates the robustness of the
analytical method (Table 3).
The UPLC/PDA method developed was employed for
quantification of VA in the sample of F. sumbul roots.
Fig. 2 depicts the chromatogram of the drug, VA and
blank. Mean VA content in the roots was estimated to
be 12.62±0.074 µg/g with %RSD 0.548.
Aim of the present investigation, was to develop a
fast, accurate and robust analytical method for VA
estimation. VA is considered to be the main constituent
responsible for the central nervous system activities
and has been officially reported as a marker compound
of V. officinalis[11,12]. The main purpose of the study
TABLE 1: LOD, LOQ, LINEARITY AND PRECISION
OF UPLC METHOD FOR QUANTIFYING VA
Parameter
LOD
LOQ
Linearity
Repeatability
(n=6) %RSD
Observations
30 ng/ml
100 ng/ml
Range: 0.5-2.0 µg/ml
Regression equation: y=16188x–79.30
Correlation coefficient: r2=0.998
0.507
LOD: limit of detection; LOQ: limit of quantification; %RSD:
percentage relative standard deviation
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TABLE 2: RESULTS OF RECOVERY STUDIES
Original amount in
sample (µg/ml, n=9)
1.010±0.006 (0.586)
Spiked amount
Found amount (µg, n=3)
(µg/ml)
0.8
1.804±0.016 (0.917)
1
2.027±0.002 (0.094)
1.21
2.244±0.026 (1.81)
Mean recovery
(n=3)
99.438±2.068 (2.079)
101.230±0.190 (0.187)
101.019±2.191 (2.148)
Mean recovery
(n=9)
100.896±1.322 (1.311)
All values are given as mean±SD (%RSD)
TABLE 3: ROBUSTNESS OF THE METHOD
Parameter
Variable parameter
Flow rate
0.23
(0.25±0.02)
0.27
Mobile phase composition
70:30
(75:25±5)
80:20
Injection volume
(0.50±0.1)
0.40
0.60
Sample
Test
Standard
Test
Standard
Test
Standard
Test
Standard
Test
Standard
Test
Standard
Mean retention time
3.721
3.722
3.184
3.164
5.958
5.966
3.317
2.031
3.582
3.524
3.543
3.501
%RSD
0.038
0.113
0.311
0.223
0.605
0.130
0.256
0.035
0.395
0.241
0.359
0.162
For the different parameters taken into consideration, the %RSD values were less than 5%, which clearly indicates the robustness of the
analytical method
Fig. 2: Chromatogram overlay of F. sumbul roots, VA (1 µg/ml) and blank (methanol)
▬ F. sumbul; ▬ valerenic acid; ▬ blank
was to describe a UPLC method, which could be used
for the quantification and standardization of F. sumbul
roots. The proposed method has a short run time of
7 min, with retention time of around 3.2 min. With
such a short time of analysis and good resolution,
the method offers substantial advantages over earlier
reported HPLC methods[8] and hence can be extended
for analytical purposes.
September-October 2017
Acknowledgements:
The authors acknowledge University Grants
Commission (UGC) for the financial support of this
study.
Financial assistance:
Nill.
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Conflicts of Interest:
The authors declare no conflicts of interest.
REFERENCES
1.
2.
3.
4.
5.
838
Gonzalez A, Barrera J. Chemistry and sources of mono- and
bicyclic sesquiterpenes from Ferula species. In: Herz W,
Kirby GW, Moore RE, Steglich W, Tamm C, editors. Progress
in the Chemistry of Organic Natural Products. Vol. 64. New
York: SpringerLink; 1995.
The Wealth of India. A Dictionary of Raw Materials and Industrial
Products, Raw Materials. Vol. 4, New Delhi: Publications and
Information Directorate, CSIR; 1956. p. 21-22.
Zhou P, Takaishi Y, Duan HQ, Chen B, Honda G, Itoh M, et
al. Coumarins and bicoumarin from Ferula sumbul: antiHIV
activity and inhibition of cytokine release. Phytochemistry
2000;53:689-97.
Khom S, Strommer B, Ramharter J, Schwarz T, Schwarzer
C, Erker T, et al. Valerenic acid derivatives as novel subunitselective GABA(A) receptor ligands - in vitro and in vivo
characterization. Br J Pharmacol 2010;161:65-78.
Nam SM, Choi JH, Yoo DY, Kim W, Jung HY, Kim JW, et al.
Valeriana officinalis extract and its main component, valerenic
acid, ameliorate D-galactose-induced reductions in memory,
cell proliferation, and neuroblast differentiation by reducing
corticosterone levels and lipid peroxidation. Exp Gerontol
2013;48:1369-77.
6. Bairwa K, Srivastava A, Jachak SM. Quantitative analysis of
boeravinones in the roots of Boerhaavia diffusa by UPLC/
PDA. Phytochem Anal 2014;25:415-20.
7. Kumar A, Saini G, Nair A, Sharma R. UPLC: A preeminent
technique in pharmaceutical analysis. Acta Pol Pharm
2012;69:371-80.
8. Bos R, Woerdenbag H, Hendriks H. The Essential Oil and
Valepotriates from Roots of Valeriana javanica Blume Grown
in Indonesia. Flavour Fragr J 1996;11:321-26.
9. Gao X, Björk L. Valerenic acid derivatives and valepotriates
among individuals, varieties and species of Valeriana.
Fitoterapia 2000;71:19-24.
10. https://www.ich.org/fileadmin/Public_Web_Site/ICH_
Products/Guidelines/Quality/Q2_R1/Step4/Q2_R1__
Guideline.pdf.
11. The European Pharmacopoeia. Vol. 2. Strasbourg, France:
Directorate for the Quality of Medicines & HealthCare of
Council of Europe, EDQM; 2011. p. 1269-63.
12. Indian Pharmacopoeia Commission. New Delhi: Ministry of
Health and Family Welfare; 2014. p. 3276-78.
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