Pharmacology & Pharmacy, 2013, 4, 684-688
Published Online December 2013 (http://www.scirp.org/journal/pp)
http://dx.doi.org/10.4236/pp.2013.49095
Open Access PP
Isolation and Spasmolytic Evaluation of New Alkaloids
from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae)
Amenan Geneviève N’guessan-Irié1,2, Joël Dade1, Pierre Champy1,3, N’doua Gisèle Siransy-Kouakou2,
Véronique Leblais3,4
1Chimie des Substances Naturelles, CNRS UMR 8076 BioCIS, Châtenay-Malabry, France; 2Laboratoire de Pharmacologie et Physiologie,
UFR Sciences Pharmaceutiques et Biologiques, Université Félix Houphouët-Boigny, Abidjan, République de Côte d’Ivoire; 3Faculté
de Pharmacie, Université Paris-Sud 11, Châtenay-Malabry, France; 4INSERM UMR-S 769, Châtenay-Malabry, France.
Received September 23rd, 2013; revised October 28th, 2013; accepted November 15th, 2013
Copyright © 2013 Amenan Geneviève N’guessan-Irié et al. This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
ABSTRACT
Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae) root bark is used in Ivorian Traditional Medicine to treat asthma,
which is a respiratory disorder characterized by inflammation and the restriction of tracheal muscles obstructing the air
circulation. The tracheal relaxant effect of a crude aqueous-alcoholic extract of the plant root bark was previously
shown. For the present study, alkaloids were isolated from the same extract and investigated ex vivo in C57Bl/6j mice
isolated trachea contracted with carbachol 1 µM, in comparison with a reference bronchodilatator, i.e. salbutamol. Two
extraction procedures allowed isolating 2 Alkaloids that monodimensional and bi-dimensional nuclear magnetic reso-
nance (NMR) and mass specters allowed identifying a pyrolidine structure type nucleus with a long bi-hydroxyled alkyl
chain. Alkaloid 1, carrier of a sugar, is a glycoside of Alkaloid 2. Both alkaloids induced similar spasmolytic effects,
but Alkaloid 1 was more effective than Alkaloid 2 at 9 × 10−6 M (p ˂ 0.01), 3 × 10−5 M, and 9 × 10−5 M (p ˂ 0.001).
Salbutamol induced its spasmolytic effect in a different way, and its maximal effect Emax (less than 30%) was obtained
at 9 × 10−6 M, while Emax of both alkaloids (100%) was obtained at 3 × 10−4 M.
Keywords: Alkaloids Isolated; Plant; Spasmolytic; Asthma
1. Introduction
Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae),
among others numerous plants, is commonly used, alone
or in association with other plants, in African Traditional
Medicine. The ethnobotanic inquiries state that the roots
of this plant are astringent and used in rheumatism, uri-
nary calculi and renal troubles [1]; in Togo, the root de-
coction is administered by oral route in abscesses [2]. In
Ivory Coast, whereas the root decoction is used as
mouthwash in case of tooth decays by people of the
North, people of the South use it to treat asthma [3]. As
asthma is a respiratory disorder which is essentially
characterized by the restriction of tracheal muscles ob-
structing the air circulation [4], the tracheal relaxant ef-
fect of a crude aqueous-alcoholic extract of the plant root
bark was previously shown [5]. Besides, bisnordihydro-
toxiferine, a tertiary indole alkaloid isolated from the root
of Strychnos divaricans was shown to antagonize ace-
tylcholine-induced contractions in rat uterus and in guinea-
pig ileum [6]; other alkaloids were also shown to have
spasmolytic effects on guinea-pig isolated trachea con-
tracted by carbachol, histamine, or KCl [7]. For the pre-
sent study, alkaloids were isolated from the root bark
extract and investigated ex vivo in mice isolated trachea
in comparison with a reference bronchodilatator, i.e. sal-
butamol.
2. Materials and Methods
2.1. Plant Material
The roots of D. cinerea were collected in September
2009 in the South-East of Ivory Coast in bushes near
Grand-Bassam. The plant was authenticated by Professor
Aké-Assi Laurent, a taxonomist at the Centre National de
Floristique (Ivory Coast), in comparison with identified
specimens and vouchers were deposited there. The barks

Isolation and Spasmolytic Evaluation of New Alkaloids from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae) 685
were removed from the roots, washed in distilled water,
air-dried at air-conditioning temperature (18˚C) for two
weeks, and pulverized. Dehydration yield was 55.2%.
2.2. Extraction Procedure
The research for alkaloids in the crude extract was made
by reactions of characterization in tube with the reactive
of Valsen-Mayer, then on Thin Layer Chromatography
plates revealed by the reactive of Dragendorff.
After that, two ways were used to isolate alkaloids
from the crude aqueous-alcoholic extract of the plant root
bark: direct division and division after acidification then
alkalinisation (Figure 1).
2.3. Pharmacological Tests
Alkaloids isolated from D. cinerea root bark were per-
formed on mice isolated trachea pre-contracted with car-
bachol 1 µM in the aim to evaluate their spasmolytic effect.
Extraction : ether petroleum, 500 mL, 2 × 48 h
ether petroleum Filtrat
Negative in reactive of Dragendorff *
Marc
CH
2
Cl
2
Filtra t
Positive in reactive of Dragendorff
Marc
1. Alca linisa tion NH
4
OH (pH 9),
2. Extraction CH
2
Cl
2
(500 mL) , 2 × 48 h
1. Alca linisa tion NH
4
OH (pH 9),
2. Extraction MeOH (500 mL) , 2 × 48 h
MeOH Filtrat
Negative in reactive of Dragendorff
Marc
CH
2
Cl
2
Extract A
6.2 g
«Residue II »
3.1 g
«Residue I »
3.1 g
Separation of Ain 2
1. Flash Chromatography
on silica gel,
EtOH /CH
2
Cl
2
4:6
2. Preparative Chromatography
on silica pa tch,
MeOH/CH
2
Cl
2
3:7
3. Chromatography
on Sephadex
®
LH-20 gel,
MeOH
Alkaloid 2
29.7 mg
Alkaloid 1
4.2 mg
1. Acidification HCl 1 N (200 mL, pH 2)
2. liquid / liquid Extraction,
CH
2
Cl
2
(3 ×150 mL)
Acid aqueous phase CH
2
Cl
2
Phase
Negative in reactive of Dragendorff *
1. Alca linisa tion NH
4
OH (pH 9)
2. liquid / liquid Extraction, CH
2
Cl
2
(3 × 150 mL)
Aqueous
phase
CH
2
Cl
2
Phase
Positive in reactive of Dragendorff *
Dried residue
1.87 g
Alkaloid 2bis, identical to alkaloid 2
15.3 mg
1. Flash Chromatography on silica gel, EtOH /CH
2
Cl
2
4:6
2. Chromatography on Sephadex
®
LH-20 gel, MeOH
* Test in reactive of Dragendorff realized
on an against acid aqueous extract
evaporation
évaporation
Dichrostachys cinerea
Pulverized root bark (300 g)
Figure 1. Pure alkaloids extraction scheme.
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Isolation and Spasmolytic Evaluation of New Alkaloids from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae) 686
2.3.1. Preparation of Solutions
Alkaloids isolated, as well as the reference product (sal-
butamol), were extemporaneously dissolved and serially
diluted in distilled water (3 × 10−5, 3 × 10−4, 3 × 10−3 and
3 × 10−2 M).
2.3.2. Chemicals
Salbutamol and carbachol were purchased from Sigma-
Aldrich Chemicals, France; all salts (NaCl, KCl, KH2PO4,
MgSO4, CaCl2 and NaHCO3) and d-glucose from Pro-
labo.
2.3.3. Animals
All experiments were performed in accordance with the
European Community guiding principles in the care and
use of animals (86/609/CEE, CE Off. J. no. L358, 18th
December 1986), the European Ethics Committee
(CREEA Ile-de-France Sud) guidelines, and the French
Decree no. 87 - 848 (J Off République Française, 20 Oc-
tober 1987: pp 12245-12248). Experiments were per-
formed on male C57BL/6J mice at 7 - 8 weeks of age (25
- 30 g; Elevage Janvier, Le Genest Saint Isle, France).
2.3.4. Preparation of Trachea Rings and ex Vivo
Procedure
Mice were anesthetized with pentobarbital (60 mg/kg
i.p.). The upper respiratory tract and associated alimen-
tary tissue were rapidly excised and placed in ice-cold
Krebs bicarbonate solution containing: NaCl 117 mM,
KCl 5.36 mM, NaHCO3 25 mM, KH2PO4 1.03 mM,
MgSO4 0.57 mM, CaCl2 2.5 mM, D-glucose 11.1 mM.
The tracheas were dissected free from surrounding tissue
and cut into 2-mm length segments, which were sus-
pended isometrically between 2 stainless steel hooks in
organ chambers containing 5 mL Krebs bicarbonate so-
lution at 37˚C and continuously gassed with a mixture of
95% oxygen and 5% carbon dioxide. Isometric tension
was recorded in real time by a force-displacement trans-
ducer connected to the PowerLab® data acquisition sys-
tem controlled by the Chart® version 5 data analysis
software (AD Instruments, Bella Vista, Australia). The
rings were stretched in a stepwise manner to a resting
value of 0.6 g for at least 1 hour. Tracheal rings were
then challenged with 10−5 M carbachol (Sigma-Aldrich
Chemicals, France) to evaluate their functional integrity.
After a 45-minutes washout period, tracheal preparations
were precontracted with a submaximal concentration of
carbachol (10−6 M). After stabilization of the contraction,
cumulative additions of the different products and of
distilled water as control vehicle were performed.
2.3.5. Data Analysis and Statistics
Chemically, isolated components’ structure has been ana-
lyzed using monodimensional NMR (1H, 13C), bi-dimen-
sional NMR (DEPT, COSY, HMBC, HSQC, NOESY),
and mass (ESI, APCI, high resolution) specters.
Biologically, the relaxant response of the tracheal
rings was expressed as percentage of the precontractile
tone induced by carbachol. The effect of vehicle (dis-
tilled water) was systematically subtracted from the ef-
fect of the products.
Results are expressed as mean ± standard errors of the
mean (S.E.M) of 6 experiments. Emax is the maximal re-
laxation obtained and CEX is the concentration of product
which induces X% relaxation. Data were analyzed with
Sigmaplot® software by an unpaired Student’s t-test or
by one way analysis of variance (ANOVA) followed by
Holm-Sidak or Bonferroni-test, with criterion set for sta-
tistical significance at p < 0.05.
3. Results and Discussion
The analysis of the root bark extract highlighted the
presence of an alkaloid fraction (tests in reactive of Val-
sen-Mayer and in reactive of Dragendorff were positive)
which purification allowed obtaining 49.2 mg of total
alkaloids, purification yield being 0.0164%.
The division allowed isolating 2 majority pure prod-
ucts. Their monodimensional and bi-dimensional nuclear
magnetic resonance specters (NMR) allowed identifying
a new structure in alkaloids’ serial: pyrolidin with a
bi-hydroxyled long alkyl chain (Figures 2 and 4) con-
firmed by mass spectrometry. These compounds are
called Alkaloid 1 (4.2 mg; y = 0.0014%), Alkaloid 2
(29.7 mg; y = 0.0099%) and Alkaloid 2 bis (15.3 mg; y =
0.0051%), alkaloids 2 and 2 bis being identical com-
pounds isolated by two different ways.
These data allow proposing the fact that Alkaloid 1,
carrier of a sugar, is a glycoside of Alkaloid 2 (baptized
JEMIGRACINE by our care).
Not aromatic, these isolated alkaloids probably arise
from lysine metabolism [8].
Both alkaloids 1 and 2 induced almost similar regular
spasmolytic effects (Emax value in Table 1). However,
Alkaloid 1 was more effective than Alkaloid 2 at 9 ×
10−6 M (p ˂ 0.01), 3 × 10−5 M and 9 × 10−5 M (p ˂ 0.001)
just like indicated on Figure 3 and in Table 1 (lowest
EC25 and EC50 for alkaloid 1), probably because of the
sugar component which could make the cell entry easier,
NO
CH3
OOH
OH
OH
HO
OH
H
Figure 2. Structure of alkaloid 1 = [5-hydroxy-12-(1-me-
thylpyrrolidin-2-yl)dodecyl hexopyranoside].
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Isolation and Spasmolytic Evaluation of New Alkaloids from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae) 687
Table 1. Emax, EC50 and EC25 of isolated alkaloids and sal-
butamol.
E
max (%) EC25 (×10−5 mol/L) EC50 (×10−5 mol/L)
Alkaloid 1 104.5 ± 0.9 2.22 ± 0.25 5.22 ± 0.77
Alkaloid 2 104.2 ± 1.8 4.32 ± 0.41 9.27 ± 0.8
Salbutamol 28.1 ± 3.2 6.87 ± 0.22 n.d
‐10
10
30
50
70
90
110
3,00E‐08 3,00E‐07 3,00E‐06 3,00E‐05 3,00E‐04
Alkaloid1
Alkaloid2
Salbutamol
%Relaxation
Log [alkaloidsandsalbutamol concentrations(mol/L)]
**
** ** ** ** **
Figure 3. Relaxant effects of alkaloids isolated from D. cine-
rea and salbutamol; **: statistically significance p ≤ 0.01.
NOH
CH3
OH
H
Figure 4. Structure of alkaloid 2 = [12-(1-méthylpyrrolidin-
2-yl) dodecane-1,5-diol].
like the numerous hydroxyls of aminosides (amino-gly-
cosides) that modulate the penetration of the antibiotic in
the bacterium and so play on the specter of action by
widening it. Emax for salbutamol (less than 30%) was
obtained at 9 × 10−6 M while the one of both alkaloids,
corresponding to a total deletion of contractions, was
obtained at 3 × 10−4 M.
Differences between Alkaloids’ effects and salbuta-
mol’s ones were significant. Thus from 3 × 10−8 to 9 ×
10−6 M, salbutamol was more effective than both alka-
loids; at 3 × 10−5 M, salbutamol was more effective than
alkaloid 2 but less effective than alkaloid 1; for the two
highest concentrations tested (9 × 10−5 and 3 × 10−4 M)
salbutamol was less effective than both alkaloids (Figure
3).
Salbutamol induced its spasmolytic effect in a differ-
ent way [from the lowest concentrations its relaxant ef-
fect appeared and reached the maximal level at 9 × 10−6
M, then decreased for the highest concentrations (Figure
3)], due to a difference in the mechanisms of action. In-
deed, the spasmolytic effect of the crude extract from
which alkaloids were isolated was not inhibited by
β2-blockers, but was sustained by hyperpolarization [5];
however salbutamol is known to have a β2-mimetic ac-
tion [9]. Besides, the increase of salbutamol’s spasmo-
lytic effect, for its lowest concentrations, testimonies
β2-receptors sensitation. The decrease of this effect, for
its highest concentrations, might be due to β2-receptors
saturation, with desensitation of the subsequent signaling
cascade [10]. Nevertheless this probable saturation might
not do prejudice to the molecule activity, as salbutamol is
well known for its neutralizing action of bronchitis spasm
during asthma crisis. Concerning the isolated alkaloids,
the steadiness of relaxation going until to a total inhibi-
tion of the carbachol-induced pre-contractions is-it in
relation with a potent spasmolytic effect? In this connec-
tion, it is important to note that authors defend the thesis
that herbal in vitro data are questionable in absence of in
vivo observations [11]. As a matter of fact, factors like
absorption or metabolism of those substances are liable
to great differences between their in vitro and in vivo
activities [12].
The Emax value is the percentage of relaxation obtained
at the maximal tested concentration. The ECx value is
defined as the concentration of extract that induces x%
relaxation. n.d is not determined value.
4. Conclusion
This study allowed isolating new structures of alkaloids
from plants. Those new components exerted a good ex
vivo activity on contracted trachea. Nevertheless, further
investigations will be required to completely identify
these components, and to confirm their real potency with
in vivo bronchodilatation tests.
5. Acknowledgements
The authors are grateful to Pr. L. Aké-Assi (Centre Na-
tional de Floristique d’Abidjan) for botanical identifica-
tion, to Dr. V. Domergue-Dupont (IFR141, Châtenay-
Malabry, France) and her staff for animal care, to Mrs. F.
Lefebvre (UMR-S 769, Châtenay-Malabry, France) for
technical assistance, to Pr. Attioua (Laboratoire de Chimie
Organique Biologique, UFR Sciences des Structures de
la Matière et Technologie, Université Félix Houphouët-
Boigny, Côte d’Ivoire) and Pr. M. Ouattara (Laboratoire
de Chimie Thérapeutique et Biomolécules, UFR Sciences
Pharmaceutiques et Biologiques, Université Félix Hou-
phouët-Boigny, Côte d’Ivoire) for their chemical help.
Financial supports were provided by the “Centre Na-
tional de la Recherche Scientifique”, the “Institut Na-
tional de la Santé et de la Recherche Médicale” and the
“Université Paris-Sud 11”.
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Isolation and Spasmolytic Evaluation of New Alkaloids from Dichrostachys cinerea (L.) Wight et Arn. (Fabaceae)
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