Antiplasmodial activity of steroidal chalcones: evaluation of their effect on hemozoin synthesis and the new permeation pathway of Plasmodium falciparum-infected erythrocyte membrane.
ABSTRACT Chalcone derivatives on an estradiol framework were evaluated for their ability to inhibit the growth and development of the malaria parasite Plasmodium falciparum. Out of twelve steroidal chalcones and one indanone derivative studied, three were found to have 50% growth inhibitory concentration less than 5μm and minimum inhibitory concentration for parasite development from ring to schizont stage as ≤20μm with best activity for gallic acid-based chalcone derivative 1 as 2.07 and 10μm, respectively. Two of the active derivatives 1 and 10 did not exhibit cytotoxicity against vero cells as evident by the good selectivity ratio. Study of structure-activity relationship indicated that increasing substitution in the benzoyl ring-enhanced antiplasmodial activity. Hemozoin synthesis of the parasite remained unaffected by these derivatives. These derivatives were also investigated for their effect on parasite-induced new permeation pathway in the erythrocyte membrane by sorbitol-induced hemolysis, and four derivatives 1, 2, 9, and 10 exhibited significant inhibition (>70%) at 20μm concentration. A positive correlation was also observed among the antiplasmodial activity and inhibition of new permeation pathway. These observations suggest that steroidal chalcones with selective activity for the parasite may be considered as antimalarial leads for further optimization and preclinical study.
- SourceAvailable from: Cátia Teixeira[Show abstract] [Hide abstract]
ABSTRACT: Cinnamic acid derivatives containing a 4-amino-7-chloroquinoline scaffold (blue) and substituted cinnamoyl building blocks (green) linked through an alkylamine chain (red) were found to have potent (11-59 nM) in vitro activities against erythrocytic chloroquine- resistant Plasmodium falciparum.ChemMedChem 06/2012; 7(9):1537-40. · 2.84 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Plants are known as the source of novel agents for developing new antimalarial drugs. Glabridin is a polyphenolic flavonoid, a main constituent in the roots of Glycyrrhiza glabra possesses various biological activities. However, its anti-plasmodial activity is unexplored. In the present work, it is first time demonstrated that glabridin inhibits Plasmodium falciparum growth in vitro with an IC50 23.9±0.43μM. Glabridin showed poor cytotoxicity in vitro with an IC50 246.6±0.88μM against Vero cell line and good selectivity index (9.6). In erythrocytic cycle, trophozoites stage was found to be most sensitive to glabridin. In silico study showed that glabridin inhibits Pf LDH enzyme activity by acting on NADH binding site. Glabridin induced oxidative stress by the generation of reactive oxygen and nitrogen species. Glabridin could induce apoptosis in parasite as evident by the depolarization of mitochondrial membrane potential (Δψm), activation of caspase like proteases and DNA fragmentation. These results indicate that glabridin exhibits antiplasmodial activity and suitable for developing antimalarial agent from a cheap and sustainable source.Parasitology International 12/2013; · 2.30 Impact Factor
Antiplasmodial activity of steroidal chalcones:
evaluation of their effect on hemozoin synthesis
and the new permeation pathway of Plasmodium
falciparum-infected erythrocyte membrane
Brijesh S. Sisodia1, Arvind S. Negi2,
Mahendra P. Darokar1, Upendra N.
Dwivedi3and Suman P. S. Khanuja1,*†
1Department of Molecular Bioprospection, Central Institute of
Medicinal and Aromatic Plants, Kukrail Picnic Spot Road, Lucknow
226 015, India
2Department of Analytical Chemistry, Central Institute of Medicinal
and Aromatic Plants, Kukrail Picnic Spot Road, Lucknow 226 015,
3Department of Biochemistry, University of Lucknow, Lucknow 226
*Corresponding author: Suman P. S. Khanuja, firstname.lastname@example.org
?Present address: NutraHelix Biotech Pvt. Ltd. 101, Park View
Apartments, Bldg-II Mandi Village Road, Meharuli, New Delhi 110
Chalcone derivatives on an estradiol framework
were evaluated for their ability to inhibit the
growth and development of the malaria parasite
Plasmodium falciparum. Out of twelve steroidal
chalcones and one indanone derivative studied,
three were found to have 50% growth inhibitory
concentration less than 5 lM and minimum inhibi-
tory concentration for parasite development from
ring to schizont stage as £20 lM with best activity
for gallic acid-based chalcone derivative 1 as 2.07
and 10 lM, respectively. Two of the active deriva-
tives 1 and 10 did not exhibit cytotoxicity against
vero cells as evident by the good selectivity ratio.
Study of structure–activity relationship indicated
that increasing substitution in the benzoyl ring-
enhanced antiplasmodial activity. Hemozoin syn-
thesis of the parasite remained unaffected by
these derivatives. These derivatives were also
investigated for their effect on parasite-induced
new permeation pathway in the erythrocyte mem-
brane by sorbitol-induced hemolysis, and four
derivatives 1, 2, 9, and 10 exhibited significant
inhibition(>70%)at 20 lM
positive correlation was also observed among the
permeation pathway. These observations suggest
that steroidal chalcones with selective activity for
the parasite may be considered as antimalarial
leads forfurther optimization
Key words: antiplasmodial, chalcone, hemozoin, new permeation
pathway, sorbitol-induced hemolysis
Received 10 February 2011, revised 19 November 2011 and accepted
for publication 5 December 2011.
Malaria causes an estimated 247 million clinical cases resulting in
nearly one million deaths, mostly of children under 5 years. 109
countries were declared endemic for malaria by World Health Orga-
nisation (1). Plasmodium falciparum is the leading cause of malaria
deaths. Although artemisinin and its derivatives exhibit high efficacy
against malaria parasite resistant to chloroquine and other drugs,
clinical failures of artemisinin-based therapy have also been
reported from Cambodia, and reduced susceptibility of P. falciparum is
characterized by slow parasite clearance in vivo (2). Constant emer-
gence and spread of multi-drug resistance together with the lack of
effective vaccines have accelerated the need to rapidly discover
new chemotherapeutic agents for the treatment of malaria.
Chalcones, that is, 1, 3-diphenyl-2-propen-1-ones are one of the
major classes of natural products of the flavonoid family. They are
small, non-chiral molecules with molecular weight in the range of
300–600 g⁄mol and relative high lipophilicity (Log P ?5–7). They
possess several interesting pharmacological activities including anti-
cancer and antimalarial properties (3). The discovery of antiplasmo-
dial property of licochalcone A, an oxygenated chalcone found in
the roots of the Chinese licorice, has generated interest in antima-
larial activity of chalcones. Licochalcone A was found to possess
similar in vitro activity against chloroquine sensitive and resistant
P. falciparum (4). Recently, Licochalcone A has also been reported
to enhance antimalarial activity of artemisinin in vitro (5). Several
other naturally occurring chalcones and their derivatives have been
reported to exhibit antimalarial properties.
Antimalarial activity of chalcones appears to be determined mainly by
the properties of the ring B. The size and hydrophobicity of this substi-
tuent have also been identified as critical for the activity (6). Mecha-
nism of antiplasmodial action of chalcones is still not very clear,
although several mechanisms have been suggested for different chal-
cones including inhibition of a parasite-induced permeation pathway
of erythrocyte membrane (6), glutathione (GSH)-dependent haemin
degradation (7), components of mitochondrial respiratory chain, that
is, bc1 complex and complex II, succinate ubiquinone reductase (8),
Chem Biol Drug Des 2012; 79: 610–615
ª 2012 John Wiley & Sons A/S
cyclin-dependent protein kinases (9,10), and plasmepsin II (11). Malaria
parasite induces anion-selective channels in the host erythrocyte mem-
brane (known as new permeation pathway-NPP) for increased perme-
ability. These channels are used by the parasite for the uptake of
essential nutrients including sugars, amino acids, nucleotides, etc. and
to efflux various waste substances such as lactic acid. Because proper-
ties of the NPP are significantly different from those in normal human
cells, it is considered an important antimalarial drug target (6).
Syntheses of steroidal chalcone derivatives and subsequently trans-
formed indanone derivative (Figure 1) have been reported previously
(12). Having a lipophilic steroidal framework, these chalcones are
more likely to have better affinity to plasmodial membranes. Fur-
ther, these steroidal chalcones are expected to have better bioavail-
ability than other reported chalcones because of the presence of
both hydrophobic aromatic rings and lipophilic steroidal framework
(13). In the present study, we report antiplasmodial activity of these
derivatives against P. falciparum by examining their effect on
growth and development of the parasite in vitro. These derivatives
were also evaluated for their cytotoxicity against a mammalian cell
line (Vero). We also investigated the ability of these derivatives to
interfere with hemozoin synthesis and the new permeation pathway
of P. falciparum-infected erythrocyte membrane. This is the first
report on steroidal chalcones with antiplasmodial activity.
Materials and Methods
Chemicals and materials
Human O+ erythrocytes were prepared from blood drawn from one of
the authors (BSS) with informed consent. RPMI-1640 medium, albu-
max II, fetal bovine serum and fungizone were procured from Gibco
BRL (Grand Island, NY, USA). 4-(2-hydroxyethyl)-1-piperazineethane-
sulfonic acid (HEPES) buffer, hypoxanthine, triton X-100, L-lactic acid, 3-
acetyl pyridine adenine dinucleotide (APAD), nitroblue tetrazolium
(NBT), phenazine ethosulphate (PES), antibiotic-antimycotic solution
(100X), phosphate buffered saline (PBS), neutral red, chloroquine
diphosphate, quinine, artemisinin, doxorubicin hydrochloride, haemin
chloride, and furosemide were purchased form Sigma-Aldrich (St.
Louis, MO, USA). Chemical syntheses of the steroidal chalcones inves-
tigated in this study have been reported previously (12). Log P value
of the compounds was calculated by CHEMDRAW ULTRA 8.0 Cambridge
Soft, Cambridge, MA, USA.
P. falciparum (clone NF-54) was cultured in freshly washed 5% O+
red blood cells in RPMI-1640 medium supplemented with 25 mM
HEPES, 0.2% NaHCO3, 370 lM hypoxanthine, 40 lg⁄mL gentamycin,
0.25 lg⁄mL fungizone, and 0.5% albumax II at 37 ?C using candle
jar method as described previously (14). Spent medium was
replaced every 24 h, and the culture was routinely monitored
through Geimsa staining of thin smears. The culture was synchro-
nized by 5% D-sorbitol treatment for 20 min at 37 ?C to obtain
ring-stage parasites (15).
Antiplasmodial activity against parasite growth and development
was determined in vitro by a parasite lactate dehydrogenase (pLDH)
assay (16) and schizont maturation inhibition assay (17), respec-
tively, with minor modifications. For the pLDH assay, a synchronous
culture (ring stage) with 1.5% parasitemia and 2% hematocrit was
incubated in 96-well microtitre plate with multiple concentrations of
test compounds at 37 ?C for 48 h in a candle jar. Cultures were
carefully resuspended and aliquots of 20 lL were added to another
microtitre plate containing 100 lL of Malstat reagent and 25 lL of
NBT-PES solution per well. The Malstat reagent and NBT-PES solu-
tion were prepared as described elsewhere (18). After keeping the
plate in the dark for 30 min, the absorbance was recorded at
650 nm using a SPECTRAMAX 190 microplate reader (Molecular
Devices Inc., Sunnyvale, CA, USA).
For the schizont maturation inhibition assay, 180 lL of synchronous
culture with 1% parasitemia and 3% hematocrit was transferred
into 96-well plates containing 20 lL of different dilutions (in
duplicate) of test compounds or standard drugs. The plate was
incubated for 30 h, the time required for maturation of intra-eryth-
rocytic P. falciparum (19). Geimsa-stained smears were prepared
from each well and observed microscopically to record maturation
of rings into schizonts. The concentration completely inhibiting para-
site maturation was considered as minimum inhibitory concentration
Cytotoxicity against vero cells
Vero cells (VERO C1008; ATCC CRL-1586, kidney epithelial cells from
African vervet monkey) were cultured in 75-cm2flasks in RPMI-1640
medium supplemented with 0.2% NaHCO3, 1X antibiotic-antimycotic
solution, and 10% fetal bovine serum at 37 ?C in an atmosphere of
95% humidity and 5% CO2. The assay was performed in 96-well
plate using the neutral red uptake method as described previously
(20). Doxorubicin hydrochloride was used as positive control.
Concentrations ranging from 0.1–100 lM were tested for the
derivatives and standards.
Figure 1: Chemical structures of Chalcones and Indanone.
Antiplasmodial activity of steroidal chalcones
Chem Biol Drug Des 2012; 79: 610–615
Determination of selectivity ratio
Selectivity ratio was determined from the following expression: IC50
for cytotoxicity against vero cells ⁄ IC50 for growth inhibition of
P. falciparum determined using the pLDH assay.
Ferriprotoporphyrin IX (FP) biomineralization
Chalcone derivatives showing good antiplasmodial activity were
evaluated for their ability to interfere with hemozoin synthesis by
the ferriprotoporphyrin IX (FP) biomineralization inhibition assay as
described previously (21). Chloroquine and quinine were used as
standard drugs inhibiting the process.
Sorbitol-induced hemolysis of parasite-infected
The chalcone derivatives were also studied for their effects on
P. falciparum-induced permeation pathways in erythrocytes as
described previously (6) with minor modifications. Briefly, parasite
culture at ?15% parasitemia (>95% trophozoits of 36–44 h after
invasion) was washed twice with NaCl (150 mM)-HEPES (20 mM)
solution (pH 7.4), and a cell suspension of 50% hematocrit was pre-
pared in the same solution. 20 lM concentration of each derivative
was tested. Test derivatives dissolved in dimethyl sulfoxide (DMSO)
were diluted to 200 lM with sorbitol (300 mM)-HEPES (20 mM) buf-
fer (pH 7.4). 100 lL of infected cell suspension at 50% hematocrit
was mixed with 100 lL of diluted derivatives (100 lL of sorbitol-
HEPES buffer with the same final concentration of DMSO for con-
trol) and 800 lL sorbitol-HEPES buffer (pH 7.4) in microcentrifuge
tube and incubated at 37 ?C for 30 min. Tubes were centrifuged
and 100 lL of supernatant was used to measure absorbance at
540 nm to estimate the amount of hemoglobin released. Inhibition
of hemolysis with reference to control reflects the channel-blocking
effect of the derivatives. Furosemide was used as standard inhibi-
Dose–response data analysis
Absorbance values of test derivatives and standard drugs were con-
verted to percentage inhibition using absorbance of vehicle control
wells. IC50swere calculated from dose–response curve data by non-
linear regression analysis using GRAPHPAD PRISM software version
4.0 for windows (GraphPad, San Diego, IL, USA).
Results and Discussion
Inhibition of growth and development of the parasite by twelve ste-
roidal chalcone and one indanone derivatives (Figure 1) was deter-
mined by IC50 in the pLDH assay and MIC in the schizont
maturation inhibition assay, respectively. A positive correlation was
observed in results obtained by both the assays (Table 1). Among
the thirteen derivatives evaluated, three 1, 2, and 10 exhibited
IC50s below 5.0 lM, three 9, 11, and 13 exhibited IC50s in the
range of 5.0–17.0 lM, and the remaining seven 3, 4, 5, 6, 7, 8,
and 12 did not exhibit significant antiplasmodial activity (IC50val-
ues ranging from 24–160 lM were obtained). The best activity was
exhibited by the gallic acid-based chalcone derivative 1, with an
IC50value of 2.07 lM, comparable to licochalcone A (IC50; 4.22 lM).
The IC50sfor chloroquine and artemisinin were determined to be
0.05 € 0.02 and 0.03 € 0.004 lM, respectively, in our assay condi-
tions (Table 1).
Derivatives 1 and 2 also showed potency to completely inhibit in
vitro parasite development to schizont with MIC £ 10 lM but other
three 10, 11, and 13 inhibited development with MIC £ 20 lM.
Five derivatives 3, 5, 7, 9, and 12 showed inhibition with
MICs £ 40 lM but remaining three 4, 6, and 8 were unable to
completely inhibit the schizont maturation at 100 lM, the highest
concentration used in this study. Chloroquine and artemisinin exhib-
ited their MICs at 0.2 and 0.1 lM, respectively. MIC values ranging
from 10 to >100 lM were observed for parasite development with
best activity of 10 lM for compound 1 and 2. The broad concentra-
tion range for the activity reflects structural diversity existing
among the derivatives.
All the derivatives were also evaluated for in vitro cytotoxicity
against the mammalian cell line (vero), and the selectivity ratio was
calculated for P. falciparum against vero cells (Table 1). Out of three
derivatives showing good antiplasmodial activity (IC50< 5 lM), two
1 and 10 showed a good selectivity ratio of >48.30 and >23.20,
respectively, which may be considered safe but another derivative
2 showed a relatively poor safety profile with selectivity ratio of
2.00. Derivatives 3, 6, and 7 were found to be toxic toward vero
cells as indicated by selectivity ratio of <1. Selectivity ratios for
chloroquine and artemisinin were determined to be >2000 and
>3333, respectively. Diverse cytotoxicity profiles with IC50 values
ranging from 8.39 to >100 lM again suggest structural diversity
among the derivatives.
Our previous report (12) indicated that these steroidal chalcones do
not affect osmotic fragility of normal erythrocytes at concentrations
used for antiplasmodial assays in terms of reduced mean erythro-
cyte fragility (MEF) with reference to control. It suggests that these
derivatives have no significant toxic effects on erythrocyte mem-
To investigate the mechanism of antiplasmodial action, we exam-
ined derivatives showing significant activity for their potential to
interfere with hemozoin synthesis of the parasite. During intra-
erythrocytic growth, malaria parasite digests host hemoglobin
resulting in large amounts of redox active ferriprotoporphyrin (FP) IX
which is detoxified by the parasite primarily through the process of
biomineralization of FP to hemozoin (b-hematin). Inhibition of hemo-
zoin synthesis has been reported to be a major mechanism of
action for several antimalarial drugs including chloroquine and qui-
nine. It is also considered to be a suitable target to discover new
drugs (21,22). All four derivatives 1, 2, 10, and 11 studied showed
no significant inhibition at 500 lM the highest concentration tested.
IC50values for chloroquine and quinine were observed to be 11.66
and 430.70 lM, respectively (Table 1).
Although prenylated derivatives of chalcones have been reported to
interfere with the haemin degradation process of P. falciparum, the
antiplasmodial activity and GSH-dependent haemin degradation are
Sisodia et al.
Chem Biol Drug Des 2012; 79: 610–615
not correlated, suggesting an alternative mechanism of action to
account for the observed antiplasmodial activity (7). Some chalcones
with a naphthalene as ring A and⁄or 2-hydroxyphenyl as ring B
have also been demonstrated to have good affinity for ferriprotopor-
phyrins but these chalcones do not have good antimalarial activity,
thus disassociating ferriprotoporphyrin binding and antimalarial
potency (23). The affinity of these chalcones for FP might not be
inhibiting hemozoin synthesis significantly or the toxic FP might be
detoxified by the parasite through secondary detoxification systems
including reduced glutathione, heme-binding proteins, and peroxida-
tive reactions (22). Another study (5) has also shown that licochal-
cone A does not interfere with hemozoin formation. These studies
support our observation that antiplasmodial activity of chalcones
may not be mediated by interfering with hemozoin synthesis.
The effect of these derivatives was also studied on a parasite-
induced new permeation pathway in the erythrocyte membrane in
vitro by measuring sorbitol-induced hemolysis of parasite-infected
erythrocytes. Derivatives 1, 2, 9, and 10 exhibited >70% inhibition
of hemolysis at 20 lM but other derivatives exhibited between
1.46–34.80% inhibition at the same concentration (Table 1). Furose-
mide, a known inhibitor of sorbitol-induced hemolysis exhibited
54.31% inhibition at 20 lM and its IC50 was determined to be
The structure–activity relationship (SAR) for these derivatives was
also studied. Structural variation among these derivatives was
found mainly in the benzoyl ring, while the steroidal part was intact
except in few instances where 17-hydroxyl was acetylated to a 17-
acetoxy group. Trimethoxylated derivatives 1 and 2 exhibited better
antiplasmodial activity than dimethoxylated derivative 3. In trimeth-
oxylated analogs, 17-hydroxy derivative 1 possessed better antiplas-
modial activity and higher selectivity index than the corresponding
17-acetoxy derivative 2. The mono-demethylated derivative of com-
pound 3, that is, 3-methoxy, 4-hydroxy benzoyl derivative 4 exhib-
ited lower antiplasmodial activity than 3. Among the disubstituted
benzoyl derivatives, 3, 4-methylenedioxy benzoyl derivative 5 pos-
sessed the best activity but all these derivatives exhibited poor
selectivity index. Similarly, dimethylated benzoyl derivative 7 exhib-
ited better antiplasmodial activity than the mono-methylated derivative
Table 1: Antiplasmodial activity and cytotoxicity of steroidal chalcones and their effects on ferriprotoporphyrin IX biomineralization and sor-
bitol-induced hemolysis of P. falciparum-infected erythrocytes
Vero cells (lM)
at 20 lM
2.07 € 0.37
4.19 € 0.54
4.31 € 0.75
9.10 € 0.92
12.96 € 1.23
16.39 € 1.88
24.31 € 2.80
29.51 € 2.53
30.56 € 4.25
36.52 € 3.15
97.84 € 9.28
151.65 € 10.66
160.13 € 12.54
0.05 € 0.02
0.03 € 0.004
8.39 € 0.85
21.88 € 2.31
33.59 € 2.94
55.37 € 6.12
65.04 € 7.56
15.09 € 1.36
76.96 € 8.29
21.22 € 1.64
29.86 € 3.14
4.65 € 0.49
aDetermined by pLDH assay, data are mean € SEM from three independent experiments performed in triplicates.
bThe table has been sorted by IC50values for antiplasmodial activity against P. falciparum.
cData are means from two independent experiments performed in duplicate.
dDetermined by neutral red uptake assay, data are mean € SEM from three independent experiments performed in triplicates.
eSelectivity ratio = IC50for Vero cells⁄IC50for P. falciparum.
f500 lM is the highest concentration tested. Values are means of two independent experiments performed in triplicate.
gNA, Not active at 100 lM; highest concentration tested.
hCT, Cytotoxic; value for selectivity ratio is <1.
iIC50of furosemide against sorbitol-induced hemolysis is 10.27 lM.
–, not determined.
Antiplasmodial activity of steroidal chalcones
Chem Biol Drug Des 2012; 79: 610–615
6. Among the mono-halogenated (fluoro, chloro, and bromo) ana-
logs, p-fluoro benzoyl derivative 11 exhibited good antiplasmodial
activity. 2, 4-Dichloro benzoyl analog 10 exhibited higher activity
than the corresponding mono-chloro analog 8. Overall, on increasing
substitution in the benzoyl ring-enhanced antiplasmodial activity.
Among these analogs, gallic acid-based chalcone derivative 1 was
the best hit, as it possessed the highest antiplasmodial activity
(2.07 € 0.37 lM as IC50and £10 lM as MIC) and high selectivity
ratio as >48.30. Based on our results, more methoxy substituent
may increase the activity of the compounds of the series. However,
the series may further be explored for some more substituents like
nitro group, amino group, etc. A moderate level of lipophilicity is
required in the molecule to have good bioavailability (13). A mole-
cule is considered lipophilic if it has Log P value in the range of 4–
7. Most of these analogs had calculated Log P values (Log Pcal) in
the moderate range of 5–6, so they may have good bioavailability.
However, there are several other determinants for bioavailability of
the molecules. In our study, some of the analogs exhibited moder-
ate level of antiplasmodial activity with good safety profile. How-
ever, it is expected that these analogs will be good candidates in
in vivo system with better bioavailability because of their moderate
Potential to inhibit parasite-induced new permeation pathway in
erythrocyte membrane (channel-blocking activity) was measured by
reduction in absorbance for hemoglobin released from hemolysis
induced by sorbitol treatment. Channel-blocking activity (‡70% inhi-
bition) of trimethoxylated derivatives 1 and 2 and 2, 4-dichloro ben-
zoyl derivatives 9 and 10 is in good agreement with their
antiplasmodial activity. Because antimalarial agents with newer
mechanism of action are urgently required to prevent development
of cross-resistance, active steroidal chalcones inhibiting NPP might
have added advantage for drug development. However, for 4-fluor-
ophenyl analog 11 and indanone derivative 13, antiplasmodial
activity could not be correlated with their effect on new permeation
pathway suggesting that these structurally different analogs may
act through other mechanism(s). The remainder of the derivatives
did not exhibit significant activity against P. falciparum and sorbitol-
induced hemolysis as well.
In conclusion, steroidal chalcone derivatives 17-hydroxy, trimethoxy-
lated derivative 1, 17-acetoxy, trimethoxylated derivative 2, and 2,
4-Dichloro benzoyl derivative 10 possess moderate antiplasmodial
activity. Structure–activity relationship study indicates that increas-
ing substitution in the benzoyl ring-enhanced the activity. Two
active derivatives 1 and 10 also exhibited good selectivity for
P. falciparum against mammalian cells. The broad concentration
range for activity suggests structural diversity existing among the
derivatives. These derivatives did not inhibit hemozoin synthesis of
the parasite. They showed inhibition of the parasite-induced new
permeation pathway in erythrocyte membrane, and antiplasmodial
activity was found to be correlated to inhibition of new permeation
pathway with exceptions suggesting that few structurally different
analogs may indeed act against the parasite through other mecha-
nism. Further optimization of these compounds needs to be per-
formed to obtain better lead molecule(s), which may be taken up
for further in vivo evaluation in rodent malaria model, alone and in
combination with artemisinin-derived drugs.
Authors are thankful to Dr S K Puri and Dr K Srivastava, Central
Drug Research Institute, Lucknow, India for providing NF-54 clone of
P. falciparum. Vero cell line was a kind gift from Dr A K Balapure,
Central Drug Research Institute, Lucknow, India. We are grateful to
Dr Silvia Parapini and Prof. Donatella Taramelli, University of Milan,
Milan, Italy for helping us in standardization of pLDH assay in our
laboratory.This study was supported by Council of Scientific and
Industrial Research, New Delhi, India.
Conflict of Interest
There are no conflicts of interest.
1. WHO (2008) World Malaria Report. Geneva: World Health Orga-
2. Dondorp A.M., Nosten F., Yi P., Das D., Phyo A.P., Tarning J.,
Lwin K.M. et al. (2009) Artemisinin resistance in Plasmodium fal-
ciparum malaria. N Engl J Med;361:455–467.
3. Nowakowska Z. (2007) A review of anti-infective and anti-
inflammatory chalcones. Eur J Med Chem;42:125–137.
4. Chen M., Theander T.G., Christensen S.B., Hviid L., Zhai L., Khar-
azmi A. (1994) Licochalcone A, a new antimalarial agent, inhibits
in vitro growth of the human malaria parasite Plasmodium falci-
parum and protects mice from P. yoelii infection. Antimicrob
5. Mishra L.C., Bhattacharya A., Bhasin V.K. (2009) Phytochemical
licochalcone A enhances antimalarial activity of artemisinin in vi-
tro. Acta Trop;109:194–198.
6. Go M.L., Liu M., Wilairat P., Rosenthal P.J., Saliba K.J., Kirk K.
(2004) Antiplasmodial chalcones inhibit sorbitol-induced hemoly-
sis of Plasmodium falciparum-infected erythrocytes. Antimicrob
7. Frçlich S., Schubert C., Bienzle U., Jenett-Siems K. (2005) In vitro
antiplasmodial activity of prenylated chalcone derivatives of hops
(Humulus lupulus) and their interaction with haemin. J Antimic-
8. Mi-Ichi F., Miyadera H., Kobayashi T., Takamiya S., Waki S., Iw-
ata S., Shibata S., Kita K. (2005) Parasite mitochondria as a tar-
get of chemotherapy: inhibitory effect of licochalcone A on the
Plasmodium falciparum respiratory chain. Ann N Y Acad
9. Geyer J.A., Prigge S.T., Waters N.C. (2005) Targeting malaria
with specific CDK inhibitors. Biochim Biophys Acta;1754:160–170.
10. Geyer J.A., Keenan S.M., Woodard C.L., Thompson P.A., Gerena
L., Nichols D.A., Gutteridge C.E., Waters N.C. (2009) Selective
inhibition of Pfmrk, a Plasmodium falciparum CDK, by antimalar-
ial 1, 3-diaryl-2-propenones. Bioorg Med Chem Lett;19:1982–
11. Sriwilaijaroen N., Liu M., Go M.L., Wilairat P. (2006) Plasmepsin
II inhibitory activity of alkoxylated and hydroxylated chalcones.
Southeast Asian J Trop Med Public Health;37:607–612.
Sisodia et al.
Chem Biol Drug Des 2012; 79: 610–615
12. Saxena H.O., Faridi U., Kumar J.K., Luqman S., Darokar M.P.,
Shanker K., Chanotiya C.S., Gupta M.M., Negi A.S. (2007) Syn-
thesis of chalcone derivatives on steroidal framework and their
anticancer activities. Steroids;72:892–900.
13. Menear K. (1998) Progress towards the discovery of orally active
thrombin inhibitors. Curr Med Chem;5:457–468.
14. Trager W., Jensen J.B. (1976) Human malaria parasites in con-
tinuous culture. Science;193:673–675.
15. Lambros C., Vanderberg J.P. (1979) Synchronization of Plasmo-
dium falciparum erythrocytic stages in culture. J Parasi-
16. Makler M.T., Ries J.M., Williams J.A., Bancroft J.E., Piper R.C.,
Gibbins B.L., Hinrichs D.J. (1993) Parasite lactate dehydrogenase
as an assay for Plasmodium falciparum drug sensitivity. Am J
Trop Med Hyg;48:739–741.
17. Rieckmann K.H., Campbell G.H., Sax L.J., Mrema J.E. (1978)
Drug sensitivity of Plasmodium falciparum. An in-vitro microtech-
18. Fattorusso E., Parapini S., Campagnuolo C., Basilico N., Tagliala-
tela-Scafati O., Taramelli D. (2002) Activity against Plasmodium
falciparum of cycloperoxide compounds obtained from the
sponge Plakortis simplex. J Antimicrob Chemother;50:883–888.
19. Srinivas S.D., Puri S.K. (2002) Time course of in vitro maturation
of intra-erythrocytic malaria parasite: a comparison between
Plasmodium falciparum and Plasmodium knowlesi. Mem Inst
20. Repetto G., Del Peso A., Zurita J.L. (2008) Neutral red uptake
assay for the estimation of cell viability⁄cytotoxicity. Nat
21. Deharo E., Garc?a R.N., Oporto P., Gimenez A., Sauvain M., Jul-
lian V., Ginsburg H. (2002) A non-radiolabelled ferriprotoporphyrin
IX biomineralisation inhibition test for the high throughput
screening of antimalarial compounds. Exp Parasitol;100:252–256.
22. Kumar S., Guha M., Choubey V., Maity P., Bandyopadhyay U.
(2007) Antimalarial drugs inhibiting hemozoin (b-hematin) forma-
tion: a mechanistic update. Life Sci;80:813–828.
23. Elena L.M.S. (2003) Interaction
riprotoporphyrin IX. Proceedings of 9th National Undergraduate
Research Opportunities Programme Congress, Nanyang Techno-
logical University, Singapur.
Antiplasmodial activity of steroidal chalcones
Chem Biol Drug Des 2012; 79: 610–615