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Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
© 2013 Inforesights Publishing UK
1
Antiproliferative, antimicrobial and antioxidant activities of the
chemical constituents of Ajuga turkestanica
Nilufar Z. Mamadalieva1*, Mahmoud Z. El-Readi2, Elisa Ovidi3, Mohamed L. Ashour4,
Razan Hamoud5, Shamansur S. Sagdullaev1, Sakhnoza S. Azimova1, Antonio Tiezzi3,
Michael Wink5
1Institute of the Chemistry of Plant Substances AS RUz, Laboratory of Chemistry of Glycosides, Tashkent,
Uzbekistan.
2Department of Biochemistry, Faculty of Pharmacy, Al-Azhar University, Assiut, Egypt.
3Department for the Innovation in Biological, Agro-food and Forest systems, Laboratory of Plant Cytology and
Biotechnology, Tuscia University, Viterbo, Italy.
4Department of Pharmacognosy, Faculty of Pharmacy, Ain Shams University, Cairo, Egypt.
5Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, Heidelberg, Germany.
*Corresponding author: nmamadalieva@yahoo.com; Phone: +998 71 262 59 13; Fax: +998 71 262 73 48
Received: 12 July 2012, Revised: 11 August 2012, Accepted: 13 August 2012
Abstract
Ajuga turkestanica Rgl. Brig (Lamiaceae) is a medicinal plant from Uzbekistan.
Methanol, chloroform, butanol, and water extracts as well as isolated phytoecdyst-
eroids and iridoids were evaluated for their antioxidant, cytotoxic and antibacterial
activities. Water and butanol extracts exhibited good antioxidant activity with IC50
values of 7.24 ± 0.82 and 14.57 ± 1.64 µg/mL. The chloroform extract showed
potent cytotoxic effects against the cancer cell lines HeLa, HepG-2, and MCF-7
with IC50 values of 7.13 ± 0.85, 9.03 ± 0.92, and 10.77 ± 1.44 µg/mL, respectively.
Compared to the extracts, isolated phytoecdysteroids and iridoids showed weak
cytotoxic activity. The chloroform extract has antimicrobial properties even against
multiresistant strains like Staphylococcus aureus MRSA 1000/93 and Streptococc-
us pyogenes ATCC 12344. The methanol and chloroform extracts of A. turkestan-
ica were further investigated for their GLC-volatile components using GLC/FID
and GLC/MS. Pregna-4,9 (11)-dien-20-ol-3-on-19-oic acid lactone (19.58%), 20-
methyl-pregna-5,17-dien-3β-ol (12.93%), 3,7-dioxocholan-24-oic acid (10.53%)
and betulin (10.18%) were detected as the major compounds.
Keywords: Ajuga turkestanica; phytoecdysteroids; iridoids; HPLC; GLC; activity
Introduction
More than 45 species of the genus Ajuga L. (Lamiaceae) are found in temperate regi-
ons of the Old World and have been used in folk medicine because of their anthelmintic,
antifungal, hypoglycemic, antitumor, and antimicrobial properties (Mabberley, 2008; Israili
et al., 2009). Plants of the genus Ajuga produce a variety of biological active secondary meta-
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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bolites including phytoecdysteroids, iridoids, neoclerodane diterpenoids, sterols,
withanolid-es, anthocyanins, flavonoids, ionones, and quinones (Turkoglu et al., 2010).
In the flora of Uzbekistan, Ajuga is represented by two species: Ajuga genevensis L.,
and Ajuga turkestanica Rgl. Brig. (Sokolov et al., 1991). A. turkestanica is an endemic pere-
nnial plant and grows in areas at 600-1000 m above sea level in Southern Pamir-Аlay moun-
tains on Southwest slobes of the Hissar Mountain (Ganiev et al., 1990; Sokolov et al., 1991).
A. turkestanica has been widely used in folk medicine for enhancement of muscular strength,
against heart disease, muscle and stomach aches (Grace et al., 2008).
A. turkestanica produces a rich amount of bioactive phytoecdysteroids: 20-hydroxye-
cdysone (0.25% of dry weight), turkesterone (0.22% ) (Usmanov et al., 1973, 1975; Abduka-
dyrov et al., 2005), cyasterone (Usmanov et al., 1971), 22-acetylcyasterone (Usmanov et al.,
1978), ajugalactone (Saatov et al., 1977), ajugasterone B (Usmanov et al., 1977), -ecdyso-
ne, ecdysone 2,3-monoacetonide (Saatov et al., 1999). Further secondary metabolites are
iridoid glucosides, such as harpagide, 8-О-acetylharpagide (Kotenko et al., 1994) and carbo-
hydrates (Abdukadyrov et al., 2004). From aerial parts six neo-clerodane diterpenoids were
isolated: 14,15-dihydroajugachin B, 14-hydro-15-methoxyajugachin B, chamaepitin, ajugac-
hin B, ajugapitin, and lupulin A (Grace et al., 2008).
The phytoecdysteroids show low in vivo toxicity to vertebrates (LD50 values of 20-
hydroxyecdysone is 6.4 g/kg and >9 g/kg, i.p. and p.o. to mice). Since ecdysteroids function
as moulting hormones in insects, they can be considered as natural insecticides. Some phyto-
ecdysteroids strengthened lactation especially in conditions of hypolactation (Khalitova et al.,
1998), and possess the hypoglycemic activity (Kutepova et al., 2001). The iridoids harpagide
(5) and 8-О-acetylharpagide (6) promote bile secretion (Syrov et al., 1986). These iridoids
can be found in many other plants and have been used in phytomedicine against inflammat-
ion, pain, and microbial infections (Van Wyk and Wink, 2004).
In the present study, we report on the chemical composition of polar and non-polar
extracts and the antimicrobial, antioxidant and cytotoxic activities of root extracts (methanol,
chloroform, butanol and water) from A. turkestanica in comparison to four isolated phytoecd-
ysteroids 20-hydroxyecdysone (syn. ecdysterone) (1), turkesterone (2), cyasterone (3), 22-
acetylcyasterone (4), and two iridoid glucosides harpagide (5), 8-О-acetylharpagide (6) (Fig. 1).
HO
HO
HO
OH
HO
OH
OH
R
HO
HO
HO
HO
OH
O
O
RO
HO HO
OH
O
OH
R1OHO
O
HO OH
1 R=H
2 R=OH
3 R=H
4 R=Ac
5 R=H
6 R=Ac
Figure 1. Chemical structures of the phytoecdysteroids and iridoids from A. turkestanica.
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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Materials and methods
Plant material
Roots of A. turkestanica were collected in the Surkhan-Darya region of Uzbekistan in
the summer of 2009 and identified at the Department of Herbal Plants (Institute of the Chem-
istry of Plant Substances, Uzbekistan) by Dr. O.A. Nigmatullaev (voucher specimen number
20077092).
Preparation of A. turkestanica extracts
Roots were air-dried at room temperature before grinding them to a powder with a
Warring blender. After grinding, 100 g of plant material was extracted with solvents of meth-
anol, chloroform, butanol and water; yields of these extracts were 5.1, 1.6, 4.2 and 8.3%, res-
pectively (from the weight of the air dried roots). Extraction with each solvent was carried
out for one day at room temperature. The solvent was evaporated in a rotary vacuum evapor-
ator at 40 °C. The extracts were then kept under refrigerated conditions until further use.
Chemicals and reagents
Cell culture media, supplements, and dimethylsulfoxide (DMSO) were purchased fr-
om Roth (Karlsruhe, Germany) and Greiner Labortechnik (Frickenhausen, Germany). Doxor-
ubicin ( ≥ 98 %) and quercetin ( ≥ 98 %) were obtained from Gibco (Invitrogen, Karlsruhe,
Germany). Authentical phytoecdysteroids and iridoids were obtained from the Institute of the
Chemistry of Plant Substance, Tashkent, Uzbekistan. The purity of the tested compounds
were > 95 %, as determined by HPLC.
HPLC analysis
The contents and quantity of the phytoecdysteroids and iridoids from the roots of A.
turkestanica were investigated by HPLC. Chromatographic profiles of A. turkestanica extr-
acts were generated using a high performance liquid chromatograph LC-10ATvp connected
to a UV-VIS detector SPD-10Avp (Shimadzu Co, Kyoto, Japan). A. turkestanica extracts we-
re diluted to 1 mg/ml, filtered through 0.22 µm and 20 µl were injected. For separation of
these extracts, a Nucleosil 100-5 C18 column with a size 250 mm × 4 mm (Macherey-Nagel
GmbH & Co, KG) was used. Elution was carried out by a mobile phase consisted of A (water) and
solvent B (acetonitrile) and the gradient profile was as follows: from 0% B to 5% B in 8 min,
from 5% B to 85% B at 8-30 min, from 95% B to 100% B% at 30-35 min and at 100%B%
until40min.Flowratewas1ml/minanddetectionwasat247nmand200nm
(Abdukadyrov et al., 2005).Thequantificationsof20‐hydroxyecdysone(1),turkesterone
(2),cyasterone(3),harpagide(5)and8‐О‐acetylharpagide(6)intheextractsofA.
turkestanicawerecarriedoutusingacalibrationcurveofcorrespondingstandardsat
differentconcentra‐tions.
GLC/FID analysis
High-resolution GLC analyses were carried out on a Focus GC (Thermo Fisher
Scientific, Milan, Italy) equipped with TR1-MS fused bonded column (30 m × 0.25 mm ×
0.25 µm) (Thermo Fisher Scientific®, Florida, USA) and FID detector; carrier gas was nitro-
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
© 2013 Inforesights Publishing UK
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gen (1.5 ml/ min). The operating conditions were: initial temperature 40 ºC, for 1 min isothe-
rmal followed by linear temperature increase till 230 ºC at a rate of 4 ºC/min 230 ºC, then 5
min isothermal. Detector and injector temperatures were 300 ºC and 220 ºC, respectively.
The split ratio was 1:20. Chrom-card® chromatography data system ver. 2.3.3 (Thermo Elec-
tron Corp®, Florida, USA) was used for recording and integrating of the chromatograms.
GLC/MS analysis
The analyses were carried out on Focus GC (Thermo Fisher Scientific, Milan, Italy)
equipped with the same column and conditions mentioned for GLC/FID. The capillary colu-
mn was directly coupled to a quadrupole mass spectrometer Polaris Q (Thermo Electron
Corp®, Milan, Italy).The injector temperature was 220 ºC. Helium carrier gas flow rate was
1.5 ml/min. All the mass spectra were recorded under the following conditions: filament emi-
ssion current, 100 mA; electron energy, 70 eV; ion source, 250 ºC; diluted samples were inje-
cted with split mode (split ratio, 1:15). Compounds were identified by comparison of their
spectral data and retention indices with Wiley Registry of Mass Spectral Data 8th edition,
NIST Mass Spectral Library (December 2005), our own laboratory database and the literatu-
re (Adams, 2004; Budzikiewicz et al., 1964; Nibret and Wink, 2010).
Antioxidant activity
DPPH* radical-scavenging activity
The antioxidant and radical scavenging activities of the isolated compounds and extr-
acts were evaluated according to Brandwilliams et al. (1995) using diphenyl picryl hydrazyl
(DPPH*). Equal volumes of sample solutions containing 0.02–10 mg/mL of the samples and
0.2 mM methanolic solution of DPPH* were pipetted into 96-well plates. The absorbance
was measured against a blank at 517 nm using a Tecan Safire II Reader after incubation in
the dark for 30 min at room temperature compared with DPPH* control after background
subtraction. Quercetin was used as a positive control. The percent inhibition was calculated
from three different experiments using the following equation:
RSA (%) = [(Abs517control - Abs517sample)/ Abs517control] × 100
where RSA = radical scavenging activity; Abs517 = absorption at 517 nm; control = non-
reduced DPPH*.
Cytotoxicity studies
Cell cultures
HeLa (cervical cancer), HepG-2 (hepatic cancer), and MCF-7 (breast cancer) human
cell lines were maintained in DMEM complete media (L-glutamine supplemented with 10%
heat-inactivated fetal bovine serum, 100 U/mL penicillin, and 100 µg/mL streptomycin) in
addition to 10 mM non-essential amino acids. Cells were grown at 37 °C in a humidified
atmosphere of 5% CO2. All experiments were performed with cells in the logarithmic growth
phase.
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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Cytotoxicity assay
Sensitivity of the cancer cells to drugs was determined in triplicate using the 3-(4,5-
dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cell viability assay (Mosma-
nn, 1983). The extracts and individual substances were dissolved in dimethylsulfoxide
(DMSO) and further serially diluted with the medium in two-fold fashion into ten different
concentrations so as to attain final concentrations ranging from 0.977 to 500 µg/mL for extra-
cts and from 0.977 to 500 µM for isolated substances, in 96-well plates; each well contained
100 µL medium. The concentration of the solvent, DMSO, did not exceed 0.05% in the
medium that contained the highest concentration of extract or compound tested. Wells conta-
ining the solvent and wells without the solvent were included in the experiment. Exponenti-
ally growing cells were seeded in a 96-well plate (2×104 cells/well), the cells were cultivated
for 24 h and then incubated with various concentrations of the serially diluted tested samples
at 37 °C for 24 h and then with 0.5 mg/mL MTT for 4 h. The formed formazan crystals were
dissolved in 100 µL DMSO. The absorbance was detected at 570 nm with a Tecan Safire II
Reader. The cell viability rate (%) of three independent experiments was calculated by the
following formula:
Cell viability rate (%) = ((OD of treated cells − OD of media (blank) / (OD of control cells −
OD of media (blank)) × 100 %
where OD = optical density
Antimicrobial activity
Test microorganisms
The antimicrobial activity was evaluated against standard strains which included Gra-
m-positive bacteria such as methicillin-resistant Staphylococcus aureus MRSA ATCC
10442, vancomycin- resistant Enterococcus VanB VRE ATCC 31299 and Streptococcus pyo-
genes ATCC 12344, two clinical isolates Staphylococcus aureus MRSA 1000/93 and Entero-
coccus VanB VRE 902291, Gram-negative bacteria such as Escherichia coli ATCC 25922,
Klebsiella pneumonia ATCC 700603, and Pseudomonas aeruginosa ATCC 27853, and yeas-
ts such as Candida albicans ATCC 90028, and Candida glabrata ATCC MYA 2950. All
microorganism cultures were supplied by Medical Microbiology Laboratory, Hygiene Instit-
ute, Heidelberg University, Germany.
Culture media
Columbia with 5% sheep blood (BD) and Mueller-Hinton Broth (MHB) (Fluka) were
used in bacterial tests. All bacterial cultures were incubated at 37 °C for 24 h. CHROM agar
Candida (BD) and Sabouraud Dextrose broth (SDB) (Oxid) were used in fungal tests. All
fungal cultures were incubated at 25 °C for 48 h.
Inoculum preparation
One or two bacterial or fungal colonies from an 18-24 h agar plate were suspended in
saline to a turbidity matching 0.5 McFarland ≈1×108 CFU/mL; 1:100 dilution was performed
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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from this suspension using 900 µL broth to get 1×106 CFU/mL.
Diffusion method
1×106 CFU/mL of bacterial and fungal suspensions was spread on Colombia with 5%
sheep blood and CHROM agar Candida, respectively. Wells with diameter of 6 mm were cut
off and delivered with 40 µL of each extract (40 mg/ml) and of each pure substance (0.5
mM). DMSO, ampicillin (1 mg/mL), vancomycin (1 mg/mL), and nystatin (1 mg/mL) were
used as controls. All the plates were observed for zone of inhibition at 37 °C for 24 h (bacter-
ia) and at 25 °C for 48 h (yeasts).
Determination of minimum inhibitory concentration (MIC) and minimum microbicidal
concentration (MMC)
Microdilution method was used to determine MIC as described by NCCLS (2006).
Plant extracts were first of all dissolved in DMSO 5% to concentration of 8 mg/8 mg/ml and
the pure substances to the concentration of 1 mM and then were diluted two-fold with MHB
(bacteria) and SDB (fungi) in 96-well plates to obtain a range of concentrations between (8-
0.015 mg/mL) for plant extracts, and between (1000 and 1.5 µM) for pure substances. The
bacterial and fungal suspensions of 1×106 CFU/mL were subsequenly added and the plates
were incubated at 37 °C for 24 h (bacteria) and at 25 °C for 48 h (yeasts). MIC was defined
as the first concentration did not give visible turbidity comparing to a negative control. Each
test was performed in duplicate for each extract and substance. 3 µL of each clear well was
inoculated in appropriate agar media and incubated in the appropriate conditions. MMC was
determined as the concentration that did not yield growth on agar after incubation.
Statistical analysis
All experiments were carried out three times unless mentioned in the text. Continuous
variables were presented as mean ± SD. IC50 values were calculated using a four parameter
logistic curve (SigmaPlot 11.0) and all the data were statistically evaluated using Student’s t-
test or the Kruskal–Wallis test (GraphPad Prism 5.01; GraphPad Software, Inc., San Diego,
USA) followed by Dunn’s post-hoc multiple comparison test when the significance value is
<0.05 using the same significance level.
Results
HPLC analysis of the extracts of A. turkestanica
Chromatographic profiles for butanol, methanol, chloroform and water extracts were
generated by HPLC (Fig. 2). HPLC analysis revealed the presence of phytoecdysteroids and
iridoids as the most abundant metabolites. The following phytoecdysteroids and iridoids
could be identified unequivocally: 20-hydroxyecdysone (1) (tR=17.7 min), turkesterone (2)
(tR=16.7 min), cyasterone (3) (tR=19.0 min), harpagide (5) (tR=12.7 min), and 8-О-acetylha-
rpagide (6) (tR=15.6 min) (Fig. 2). The composition of the extracts is reported in Table 1.
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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Figure 2 Representative HPLC chromatogram of A. turkestanica (A) methanol, (B) butanol, (C) water and (D)
chloroform extracts. Peaks correspond to: 1: 20-hydroxyecdysone, 2: turkesterone, 3: cyasterone, 5: harpagide,
6: 8-О-acetylharpagide.
Table 1. Composition of water, methanol, butanol and chloroform extracts from A. turkestanica
Content of extracts (mg/ml)
Compound Retention time
(tR, min) Water Butanol Methanol Chloroform
20-Hydroxyecdysone (1) 17.7 0.01 0.065 0.046 0.034
Turkesterone (2) 16.7 0.012 0.193 0.114 n/d
Cyasterone (3) 19.0 n/d 0.027 n/d n/d
Harpagide (5) 12.7 0.061 0.016 0.049 n/d
8-О-Acetylharpagide (6) 15.6 0.148 0.098 0.125 0.002
n/d – not determined
Table 2. Identified compounds in chloroform extracted volatiles of the roots of A. turkestanica.
N
Retention
time
(min)
Compound name
Retention
indexa
(RI)
Abundance b
%
1 36.36 1,2,7,8,8a,9,10,10a-Octahydro-2,2,7,7-tetramethylphenanthrene 2045 0.58
2 38.06 4β-18-Norkaur-16-ene 2144 0.66
3 39.11 Abieta-9(11),8(14),12-trien-12-ol (Ferruginol) 2205 0.24
4 40.43 Unknown 2280 0.47
5 40.51 Abieta-6,8,11,13-tetraen-12-yl acetate 2286 0.41
6 40.63 Totarol 2293 0.36
7 40.89 Stigmast-5-en-3-ol (β-Sitosterol) 2308 0.33
8 42.32 16α,17-Epoxypregn-4-ene-3,20-dione* 2391 0.57
9 42.49 3,17-Dihydroxypregn-5-en-20-one 2401 0.76
10 43.42 Unknown 2455 0.23
11 44.64 20-Methyl-pregna-5,17-dien-3β-ol 2526 12.93
12 44.68 Unknown 2537 0.78
13 46.81 16-Dehydropregnenolone 2542 2.19
14 45.00 Pregnane-3,11,20-trione* 2550 0.98
15 48.89 5-Pregnen-3β-ol-7,20-dione* 2582 0.19
16 49.83 3,7-Dioxocholan-24-oic acid* 2587 10.53
17 50.91 Pregna-4,9 (11)-dien-20-ol-3-on-19-oic acid 2673 19.58
18 51.55 Ajuforrestine A* 2731 3.33
19 52.19
11b-Hydroxy-3,11a-dimethyl-1,9-dioxo-
3a,4,5,5a,5b,9,10,11,11a,11b,12,13-dodecahydro-3H-
naphtho[2',1':4,5]indeno[1,7a-c]furan-12-yl acetate*
2933 1.55
20 52.39 4,18-Epoxy-6,19-dihydroxy-13-cleroden-15,16-olide-19- 3103 0.98
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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acetate*
21 53.68 Stigmast-4-en-3-one 3206 3.34
22 53.74 Unknown 3225 0.83
23 53.97 4,4-Dimethylcholesta-7,9(11)-dien-3-ol 3283 8.43
24 54.18 Olean-12-en-3-one 3370 1.76
25 54.65 Betulin >3400 10.18
26 55.42 Barrigenol >3400 4.37
a - the Kovats index was calculated on TR1-MS column;
b - average of three analyses; * - tentatively identified
GLC analysis
The chloroform extract was analysed in more detail because of its pronounced biological
activities. Results of the GLC analysis of the chloroform extract are presented in Table 2 and
Fig. 3. A total of 22 components were identified in this extract. The most abundant com-
ponents were mainly sterols and oxo steroids, and triterpenes. Furthermore, abieta-, nor- and
cleroden diterpenes; meroterpene and polycyclic aromatic hydrocarbons: pregna-4,9 (11)-
dien-20-ol-3-on-19-oic acid (19.58%), 20-methyl-pregna-5,17-dien-3β-ol (12.93%), 3,7-
dioxocholan-24-oic acid (10.53%), betulin (10.18%), 4,4-dimethylcholesta-7,9(11)-dien-3-ol
Figure 3. Chromatogram of a chloroform extract of A. turkestanica by GLC.
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Figure 4. Structures of selected identified compounds from the root extract of A. turkestanica
(8.43%), barrigenol (4.37%), stigmast-4-en-3-one (3.34%), ajuforrestine A (3.33%) and 16-
dehydropregnenolone (2.19%) were identified unambiguously as major compounds (Fig. 4).
Antioxidant test
The DPPH* radical-scavenging activities of the reference substance (quercetin),
extracts and isolated secondary metabolites are documented in Table 3 and Fig. 5. All ecdy-
steroids and iridoids exhibited weak DPPH* radical scavenging activity with IC50 values
above 100 µM. Among the tested extracts, water and butanol extracts had a higher antiradical
capacity with a IC50 value 6.13 ± 0.71 and 12.23 ± 1.42 µg/mL, respectively.
Cytotoxicity analysis
A cytotoxicity screening of the methanol, chloroform, butanol extracts and isolated
phytoecdysteroids 1-4, and iridoid glucosides 5, 6 was carried out in HeLa, HepG-2, and
MCF-7 cells. The IC50 values of corresponding extracts and isolated secondary metabolites
are reported in Table 4 and Fig. 6. The phytoecdysteroids and iridoids showed a moderate in-
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Table 3. Antioxidant activity of phytoecdysteroids, iridoids, and extracts isolated from A. turkestanica using the
DPPH* radical scavenging assay. The data are represented as IC50 values (mean ± SD).
Compounds and extracts IC50 (μg/mL)
Extracts
Water 6.13 ± 0.71
Butanol 12.23 ± 1.42
Methanol 57.84 ± 4.19
Chloroform 100.5 ± 8.42
Phytoecdysteroids
20-Hydroxyecdysone (1) 142.90 ± 10.43
Turkesterone (2) 140.92 ± 12.01
Cyasterone (3) 106.31 ± 9.12
22-Acetylcyasterone (4) 114.23 ± 9.84
Iridoids
Harpagide (5) 173.48 ± 15.72
8-О-Acetylharpagide (6) 294.94 ± 30.25
Control
Quercetin 3.37 ± 0.77
Table 4. Antiproliferative activities of phytoecdysteroids, iridoids and extracts isolated from A. turkestanica on
HeLa, HepG-2 and MCF-7 cell lines. The data are represented as IC50 values (mean ± SD).
IC50 of compounds and extracts (μg/mL)
Sample HeLa HepG-2 MCF-7
Extracts
Water 234.25 ± 18.34 144.42 ± 10.07 193.04 ± 10.59
Butanol 133.11 ± 10.24 119.96 ± 8.57 130.56 ± 10.53
Methanol 72.34 ± 2.78 75.04 ± 5.80 81.94 ± 2.59
Chloroform 7.13 ± 0.85 9.03 ± 0.92 10.77 ± 1.44
Phytoecdysteroids
20-Hydroxyecdysone (1) 85.57 ± 3.25 57.10 ± 10.77 73.81 ± 10.71
Turkesterone (2) 75.17 ± 4.14 63.01 ± 7.53 105.21 ± 10.96
Cyasterone (3) 77.24 ± 10.15 52.03 ± 7.85 82.07 ± 11.69
22-Acetylcyasterone (4) 67.49 ± 8.47 71.38 ± 2.74 115.45 ± 0.38
Iridoids
Harpagide (5) 58.31 ± 10.58 51.79 ± 12.85 94.96 ± 19.07
8-О-Acetylharpagide (6) 61.59 ± 8.17 68.14 ± 11.35 86.09 ± 12.04
Control
Doxorubicin (µg/ml) 1.07 ± 0.11 0.39 ± 0.04 0.28 ± 0.02
hibition of cell proliferation with IC50 values above 50 µg/mL. Methanol and chloroform
extracts exhibited the highest level of cytotoxicity. Especially the chloroform extract strongly
inhibited cell growth in all tested cell lines (IC50 = 7.13 ± 0.85 µg/mL in HeLa, 9.03 ± 0.92
µg/mL in HepG-2, and 10.77 ± 1.44 µg/mL in MCF-7 cells).
Antimicrobial test
The extracts were tested for antimicrobial activity against several human pathogenic
bacteria and yeasts at various concentrations, ranging from 8 to 0.015 mg/mL. The correspo-
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Figure. 5 Dose-response curve for DPPH* scavenging activity of A H2O, BuOH, MeOH, and CHCl3 extracts of
A. turkestanica, B 20-hydroxyecdysone, turkesterone, C cyasterone, 22-acetyl-cyasterone, and D harpagide, 8-
O-acetylharpagide. The data shown are means ± SD obtained from three independent experiments.
nding MIC and MMC values are reported in Table 5. Pure phytoecdysteroids and iridoids
were tested at concentrations from 1.5 to 1000 µM. Growth of Enterococcus VanB VRE
ATCC 902291, E. VanB VRE ATCC 31299, Staphylococcus aureus MRSA ATCC 1000/93,
and S. aureus MRSA ATCC 10442 were not inhibited by any of the isolated secondary meta-
bolites. Only compounds 1, and 4-6 showed a MIC of 0.5 mM against E. VanB VRE ATCC
31299, and compound 1 inhibited S. aureus MRSA ATCC 10442 (MIC 0.5 mM). Compoun-
ds 1-6 have MIC values corresponding to 0.5 mM in both S. pyogenes ATCC 12344 and C.
albicans ATCC 90028. Other phytoecdysteroids and iridoids were inactive against Candida
glabrata ATCC MYA 2950 except cyasterone (3) (MIC > 0.5 mM and MMC > 0.5 mM).
Klebsiella pneumonia ATCC 700603 was inhibited by all the compounds (MIC = 0.25 mM),
except compound 1 (MIC = 0.5 mM). P. aeruginosa ATCC 27853 was inhibited by the phyt-
oecdysteroid 4, which showed the strongest activity (MIC = 0.125 mM), whereas other
compounds showed MIC values from 0.25 to 0.5 mM (Table 5).
The chloroform extract showed strong antimicrobial activity against S. aureus MRSA
ATCC 1000/93 and S. pyogenes (MIC = 0.06 mg/mL and MMC = 0.03 mg/mL), respective-
ly. C. glabrata was not inhibited by any of the tested plant extracts, whereas only chloroform
extract showed a weak inhibition (MIC>4 mg/mL) against this yeast. Butanol and methanol
extracts (MIC = 4 - 8 mg/mL) were less active.
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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13
Table 5a. Minimum inhibitory concentrations (MIC) and minimum microbicidal concentrations (MMC) of the
extracts and compounds from the plant A. turkestanica against different pathogens
Sample
Staphylococcus
aureus MRSA
ATCC 10442
Enterococcus
Vanb VRE
ATCC 31299
Staphylococcus
aureus MRSA
ATCC 1000/93
Enterococcus
Vanb VRE ATCC
902291
Streptococcus
pyogenes ATCC
12344
A. t. H2O extract I.z. 0 NA 6.05±0.05 5.1±0.1 8.8±0.1
MIC 8 NA 8 >8 4
MMC >8 NA 8 >8 >8
A. t. BuOH extract I.z. 0 NA 4.05±0.05 3.1±0.1 4.8±0.1
MIC 4 NA 4 >4 2
MMC >4 NA 8 >4 4
A. t. MeOH extract I.z. 3.15±1.15 3.8±0.2 3.9±0.1 3.8±0.1 5.9±0.1
MIC >4 2 4 >4 2
MMC >4 8 >4 >4 4
A. t. CHCl3 extract I.z. 7.1±0.1 3.4±0.2 6.85±0.15 4.8±0.2 8.2±0.2
MIC >4 >4 0.06 4 0.03
MMC >4 >4 0.5 >4 0.25
20-Hydroxy-
ecdysone (1) I.z. 0 0 NA NA 4.9±0.1
MIC* 0.5 0.5 NA NA 0.5
MMC* >0.5 >0.5 NA NA >0.5
Turkesterone (2) I.z. NA NA NA NA 3.05±0.05
MIC* NA NA NA NA 0.5
MMC* NA NA NA NA >0.5
Cyasterone (3) I.z. NA NA NA NA 4.1±0.1
MIC* NA NA NA NA 0.5
MMC* NA NA NA NA >0.5
22-O-Acetyl-
cyasterone (4) I.z. NA 3 NA NA 3.9±0.1
MIC* NA 0.5 NA NA 0.5
MMC* NA >0.5 NA NA >0.5
8-О-Acetyl-
harpagide (5) I.z. NA 0 NA NA 3.95±0.05
MIC* NA 0.5 NA NA 0.5
MMC* NA >0.5 NA NA >0.5
Harpagide (6) I.z. NA 0 NA NA 3.9±0.1
MIC* NA 0.25 NA NA 0.5
MMC* NA 0.5 NA NA >0.5
Ampicillin a I.z. 14.5±0.5 15 13.5±0.5 NA 25±1
MIC 25 1 50 NA 0.05
MMC >25 7 >50 NA 0.1
Vancomycin a I.z. 10±0.2 NT NT NA 15±1
MIC 0.8 25 7 NA 0.1
MMC 12.5 >50 12.5 NA 0.4
Nystatine a I.z. NT NT NT NT NT
MIC NT NT NT NT NT
MMC NT NT NT NT NT
A.t. – A. turkestanica; I.z. – inhibition zone, mm; MIC - mg/mL; MIC* - mM; MMC - mg/mL; MMC* - mM; NT – not tested; NA
– not active; a = MIC and MMC values in µg/ml
Discussion
A. turkestanica accumulates high levels of phytoecdysteroids (Abdukadyrov et al.,
2005; Usmanov et al., 1975; Saatov et al., 1977) and has therefore been exploited as an indu
strial source for the production of phytoecdysteroids. The main major phytoecdysteroids are
20-hydroxyecdysone (1) and turkesterone (2). The chemical analysis of the present study
confirms already reported (Abdukadyrov et al., 2005; Usmanov et al., 1971, 1975, 1978; Saa-
tov et al., 1977). Due to the substantial bioactivity of the CHCl3 extract (Table 3-5), such ext-
ract is characterized by both HPLC and GLC. In addition to compounds 1 and 6, chloroform
extract contains a number of oxo sterols (pregna-4,9 (11)-dien-20-ol-3-on-19-oic acid lacto-
ne, 3,7-dioxocholan-24-oic acid and 16δ-pregnenolone), sterols (20-methyl-pregna-5,17-dien-3β-
ol and 4,4-dimethylcholesta-7,9(11)-dien-3-ol) and triterpenes (betulin and barrigenol) (Table 2).
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
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14
Table 5b. Minimum inhibitory concentrations (MIC) and minimum microbicidal concentrations (MMC) of the
extracts and compounds from the plant A. turkestanica against different pathogens.
Sample Escherichia coli
ATCC 25922
Klebsiella
pneumonia
ATCC 700603
Pseudomonas
aeruginosa
ATCC 27853
Candida albicans
ATCC 90028
Candida glabrata
ATCC MYA
2950
A. t. H2O extract I.z. 0 0 4.5±0.1 0 NA
MIC 8 8 8 8 NA
MMC >8 >8 >8 >8 NA
A. t. BuOH extract I.z. 0 0 3 0 NA
MIC 8 8 4 4 NA
MMC >8 >8 8 >4 NA
A. t. MeOH extract I.z. 3.15±0.15 4.85±0.15 4.4±0.2 3.8±0.2 NA
MIC 8 4 4 >4 NA
MMC >8 >4 8 >4 NA
A. t. CHCl3 extract I.z. 3.3±0.1 4.8±0.2 4.9±0.1 5.75±0.25 3.9±0.1
MIC 8 8 4 2 >4
MMC >8 >8 >4 >4 >4
20-Hydroxy-
ecdysone (1) I.z. 3.1±0.1 3 3.4 3.9±0.1 NA
MIC* 1 0.5 0.25 >0.5 NA
MMC* >1 >0.5 0.5 >0.5 NA
Turkesterone (2) I.z. 3 3.8±0.2 3 4.8±0.2 NA
MIC* 1 0.25 0.5 0.5 NA
MMC* >1 0.5 1 >0.5 NA
Cyasterone (3) I.z. 3±0.1 3.9±0.1 3.05±0.15 3 3.9±0.1
MIC* 1 0.25 0.5 0.5 >0.5
MMC* >1 0.5 1 >0.5 >0.5
22-O-Acetyl-
cyasterone (4) I.z. 3.05±0.15 3.85±0.15 3.4±0.4 3 NA
MIC* 1 0.25 0.125 >0.5 NA
MMC* >1 0.5 0.25 >0.5 NA
8-О-Acetyl-
harpagide (5) I.z. 3.05±0.05 3 3.1±0.1 3.85±0.15 NA
MIC* 0.5 0.25 0.25 0 NA
MMC* >0.5 0.5 0.5 0 NA
Harpagide (6) I.z. 3 3.2±0.1 3.1±0.1 NA NA
MIC* 1 0.25 0.25 NA NA
MMC* >1 0.5 0.5 NA NA
Ampicillin a I.z. 14 - NA NT NT
MIC 12.5 25 NA NT NT
MMC 25 25 NA NT NT
Vancomycin a I.z. NA NT NA NT NT
MIC NA 25 NA NT NT
MMC NA 50 NA NT NT
Nystatine a I.z. NT NT NT 10±1.2 12±1
MIC NT NT NT 0.2 0.2
MMC NT NT NT 0.4 0.2
A.t. – A. turkestanica; I.z. – inhibition zone, mm; MIC - mg/mL; MIC* - mM; MMC - mg/mL; MMC* - mM; NT – not tested; NA
– not active; . a = MIC and MMC in µg/ml
These phytochemicals were completely different from those of previously published studies
performed on lipophilic extractions of other Ajuga species (Azizan et al., 2002; Baser et al.,
1999; 2001; Javidnia et al., 2010; Velasco-Negueruela et al., 2004; Sa-jjadi et al., 2004).
Isolated phytoecdysteroids and iridoids of A. turkestanica were ineffective for DPPH
radical scavenging activity (Table 3). This is not surprising because the structure of ecdyster-
oid molecules is unlikely to exert an antioxidant effect, as compared to the common antio-
xidative flavonoids (Harborne and Williams, 2000). In our experiments polar extracts such as
butanol and methanol extracts were more active; this activity could be due to phenolics or
other antioxidants that were not identified in our analysis. This finding is in agreement with
other studies (Miliauskas et al., 2005; Turkoglu et al., 2010).
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
© 2013 Inforesights Publishing UK
15
As shown in Table 4 none of the isolated secondary metabolites exhibited a high
cytotoxicity (IC50 above 100 µM or 50 µg/ml). The higher activity of the chloroform extract
is probably due to additional compounds that were identified by GLC and GLC-MS (Fig. 3).
Since individual substances of the CHCl3 extract were not available, we could not identify
the underlying cytotoxic principle. Lagova and Valueva (1981) found that 20-hydroxy-
ecdysone was ineffective to inhibit the growth of several tumour types, whereas it stimulated
that of mammary gland carcinomas. In this specific case, because ecdysteroids structurally
resemble sex hormones, they may bind to steroid hormone receptors in mammals and
stimulate hormone-dependent tumors. Takasaki et al. (1999) reported that phytoecdysteroids
and iridoids from Ajuga decumbens have anticancer properties. In their study cyasterone,
polypodine B, decumbesterone A, especially 8-О-acetylharpagide (6) showed strong tumour
preventive activities in vivo in a mouse-skin model, using 7,12-dimethylbenz[a]anthracene as
tumour initiator and TPA as promoter.
As shown in Table 5, phytoecdysteroids and iridoids of A. turkestanica had weak
antimicrobial activity against Gram-positive bacteria, C. glabrata ATCC MYA 2950, except
S. pyogenes ATCC 12344. Only cyasterone (3) showed activity (MIC > 0.5 mM and MMC >
0.5 mM) against C. glabrata ATCC MYA 2950. Compounds 1-6 showed stronger activity
against all Gram-negative bacteria. Acetyl group containing phytoecdysteroids such as 4 and
5 inhibited the growth of bacteria used. The maximum inhibition was observed against K.
pneumonia ATCC 700603 and P. aeruginosa ATCC 27853 having of MIC values of 0.125-
0.25 mM. According to Shirshova et al. (2006) and Volodin et al. (1999) true phytoecdyste-
roids such as ecdysone, inokosterone and 20-hydroxyecdysone (1) have weak antimicrobial
activity. But the introduction of acetyl groups into the molecule 1 can increase antimicrobial
activity against Bacillus cereus, Proteus rettgeri and Saccharomyces cerevisiae in the seque-
nce from 2-aсetate-20-hydroxyecdysone<2,3,22-tri-acetate-20-hydroxyecdysone < 2,3,22,25-
tetraacetate-20-hydroxyecdysone (Shirshova et al., 2006; Politova et al., 2001). Whereas
iridoid glucosides are rather inactive, some iridoid aglycones from the Cymbaria mongolica
showed antibacterial activity against Bacillus subtilis, Escherichia coli and Staphylococcus
aureus. Among them, 1β-methoxylmussaenin A possessed significant activity similar to that
of chloramphenicol (Dai et al., 2002). Iridoid glucosides are stored inactive prodrugs in plant
vacuoles; only after treatment with beta-glucosidase an aglycone is formed in which the
lactol rings opens. Then two reactive aldehyde groups are generated; these can interfere with
amino groups of proteins and nucleic acids (Wink, 2008; Wink and van Wyk, 2008).
Our antimicrobial tests revealed that the isolated ecdysteroids are hardly antimicr-
obial. However, the chloroform extract has antimicrobial activity even against multiresistant
strains with known resistance against antibiotics, like Staphylococcus aureus MRSA ATCC
1000/93 and Streptococcus pyogenes ATCC 12344 (Table 5).
We assume that cytotoxic and antibacterial activities of the chloroform extract of A.
turkestanica may be due to the presence of nonpolar compounds such as oxo sterols, sterols,
diterpenes, and triterpenes. According to the literature, some of pregnene and pregnadiene
derivatives were potential inhibitors of 5α-reductase type II, inhibited cell proliferation of
LNCap and PC-3 prostate cancer cells and were the most active in the 5AR2 inhibitory test
(Kim and Ma, 2009). Also some triterpenes such as betulin could act as potent antitumour
Phytopharmacology 2013, 4(1), 1-18 Mamadalieva et al.
© 2013 Inforesights Publishing UK
16
promoters, being active against colorectal (DLD-1), breast (MCF-7), prostate (PC-3) and lung
(A549) cancer cell lines (Gauthier et al., 2009).
In conclusion, whereas isolated ecdysteroids and iridoid glucosides of A. turkestanica
do not function as antioxidants or substantial cytotoxic or antimicrobial agents, the chlorofo-
rm extract with more lipophilic compound was more active. In a next step further studies
should be performed on the isolation and identification of the active compounds of the chlor-
oform extract of A. turkestanica.
Conflict of interest
The authors declare no conflict of interest.
Acknowledgements
N.Z. Mamadalieva gratefully acknowledges the support of the UNESCO-L’OREAL
and DAAD research grant.
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