MEDICINAL CHEMISTRY RESEARCH
Med Chem Res (2012) 21:4512–4522 DOI 10.1007/s00044-012-9979-z
ORIGINAL RESEARCH
Synthesis of new olefin chalcone derivatives as antitumor, antioxidant and antimicrobial agents Babasaheb P. Bandgar • Shivkumar S. Jalde • Laxman K. Adsul • Sadanand N. Shringare • Shrikant V. Lonikar • Rajesh N. Gacche Nagesh A. Dhole • Shivraj H. Nile • Amol L. Shirfule
•
Received: 11 September 2011 / Accepted: 17 January 2012 / Published online: 24 February 2012 Springer Science+Business Media, LLC 2012
Abstract Chalcone is a unique template that is associated with several biological activities. Claisen–Schmidt condensation of olefin aldehyde 3 and various mono, disubstituted and heterocyclic acetophenones afforded novel olefin chalcones. Synthesized compounds were subjected for ADME prediction by computational method which revealed that these molecules can be considered as a potential drug. Out of the 21 compounds screened, compounds 5u, 5g, 5c and 5e have shown significant cytotoxicity against Hep 3BPN 7, compounds 5j, 5i, 5n and 5o showed good cytotoxicity against HL 60 P 58. Compounds 5f, 5c, 5e and 5b showed potent cytotoxicity against Hela B 75. Antioxidant activity was assessed using three methods, namely, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical scavenging and ferric reducing antioxidant power (FRAP). The result shows that all these compounds possess significant antioxidant activity. Compounds 5k, 5s, 5a and 5c showed promising antibacterial activity. Compounds 5k, 5u and 5f could be considered as chemopreventive agents.
B. P. Bandgar L. K. Adsul S. N. Shringare S. V. Lonikar Medicinal Chemistry Research Laboratory, School of Chemical Sciences, Solapur University, Solapur 413255, Maharashtra, India B. P. Bandgar (&) S. S. Jalde Organic Chemistry Research Laboratory, School of Chemical Sciences, SRTM University, Nanded 431606, Maharashtra, India e-mail:
[email protected] R. N. Gacche N. A. Dhole S. H. Nile Biochemistry Research Laboratory, School of Life Sciences, SRTM University, Nanded 431606, Maharashtra, India A. L. Shirfule Food and Drug Toxicology Research Centre, National Institute of Nutrition, Hyderabad 500007, India
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Keywords Chalcones Cytotoxicity Antimicrobial Lipinski rule Antioxidant
Introduction Chalcones are a family of bicyclic flavonoids, defined by the presence of two aromatic rings joined by a three carbon unit containing an a,b-unsaturated carbonyl group. They are also a precursor to many flavonoids. The chalcones display wide range of biological activities. In fact, not many structural templates can claim association with a diverse range of pharmacological activities such as cytotoxicity, antitumor, anti-inflammatory, antiplasmodial, immunosupression and antioxidant (Dimmock et al., 1999). The tumour inhibiting properties of chalcone are of special interest and have been found to arise from their effects on malignant cell proliferation through tumour angiogenesis (Nam et al., 2003), interference with p53–MDM2 interaction (Stoll et al., 2001), induction of apoptosis (Reddy et al., 2011), disruption of cell cycle by inhibiting cell cycle check points such as cyclin-dependent kinases (CDKs) (Liu et al., 2007), or binding with tubulin and inhibiting the tubulin polymerization (Lawrence et al., 2000), or inhibiting depolymerization of microtubules (Tu et al., 2010). Chalcones have a preferential reactivity towards thiols in contrast to amino and hydroxyl groups. Thus, interactions with nucleic acids may be absent which could eliminate the problems of mutagenicity and carcinogenicity common in various chemotherapeutics (Dimmock et al., 1999). Polymethoxylated chalcones have potent antimitotic activity (Lawrence et al., 2000) as they possess a methoxylation pharmacophore similar to known tubulin polymerization inhibitors, such as combretastatin A4, colchicine and podophyllotoxin. Liu and Go (2006) described the synthesis of
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membrane to exert its lethal disruptive effect. Tomar et al. (2007) has synthesized chalcones containing piperazine or 2,5-dichlorothiophene and some of the compounds to show good antibacterial activity. Liu et al. (2008) has synthesized chalcones containing basic functionalities (VI) and evaluated these for antibacterial activity against drug-sensitive Staphylococcus aureus. The SAR study indicate that the presence of 1-methyl-4-piperidine and 2-hydroxy group is necessary for antibacterial activity with IC50 6.3 lM for the most active compound. In continuation of our studies in synthesizing various biologically active compounds (Bandgar et al., 2011), in the present study we have synthesized and characterized several novel olefin chalcones and subjected these for prediction of ADME by computational tools and evaluated for cytotoxicity, antioxidant and antimicrobial activities. Flavopiridol (I, Fig. 1), a pioneering benchmark CDKs inhibitor, induces cell cycle arrest at both G1 and G2 phases, and is a potent inhibitor of CDK1, 2, 4 and 6 in a competitive manner with respect to ATP (Senderowicz, 2003). Structure–activity relationship (SAR) study of flavopiridol analogue by Murthi et al. (2000) revealed that a simpler analogue, olefin (II) shows good CDKs inhibitory activity. Schoepfer et al. (2002) has designed and synthesized 2-benzylidene-benzofurano-3-one (III) as flavopiridol mimics. These compounds have 1-methyl piperidine substituent without hydroxyl group on the piperidine ring. They reasoned that hydroxyl group is not very much critical for CDK inhibitory activity. These compounds show significant inhibition of CDKs 1, 2 and 4 enzymatic activities and have selectivity against CDK4. Hampson et al. (2006) has synthesized olefin analogues of flavopiridol and found that they are potent inhibitors of glyocogen phosphorylase (II). Keeping in view of above-mentioned
methoxylated chalcones bearing N-methylpiperidine substituent to improve the aqueous solubility and drug like character and have been shown to possess good antiproliferative activity with an IC50 \ 5 lM. The presence of piperidinyl substituent gives specificity to the mechanism of antiproliferative activity. In another report, same research group synthesized the chalcones with different basic functionalities and evaluated for antiproliferative activity and found that chalcones with single basic functionality had better antiproliferative activity than those with more than one basic group (Liu and Go, 2007). The population of Staphylococcus aureus resistant to traditional antibiotics such as methicillin, oxacillin or nafcillin continues to rise and is now more than 50% in intensive care units in United States (NNIS, 1999). It has been reported that Vancomycin was the last resort for the treatment of multiple drug resistant S. aureus (Sievert et al., 2002). Liquorice (root and rhizome of Glycyrrrhiza spp.) is currently used in tobacco, confectionary and pharmaceutical industries. Among the retrochalcone (chalcones which do not have an oxygen function at the 2-position) isolated from Glycyrrhiza inflata licochalcone A (IV, Fig. 1) showed potent antibacterial activity especially to Bacillus subtilis, Staphylococcus aureus and Micrococcus luteus (Tsukiyama et al., 2002). Nielson et al. (2005) has synthesized cationic chalcones (V) which possess basic functionalities at both rings A and B. They designed these compounds based on membrane active cationic peptide antibiotics. They postulated that chalcones with basic functionalities are protonated at physiological pH. Bacterial membranes are rich in negatively charged phospholipids and thus would attract positively charged molecules, following initial electrostatic attraction. The agents would then permeate and insert itself into bacterial
Fig. 1 Flavopiridol and its analogues, synthetic and naturally occuring chalcones
OH
OH
O
O
OH
O R2
HO
O
HO
R
O
R
O
HO
OH R= 2-Cl Phenyl N
N
I R= 2-Cl Phenyl
II
R= 3-Cl Phenyl R= 4-Cl Phenyl R= Phenyl
R1
N
1 R 1= NO 2, R2 =H II I 2 R1= SO2NH 2, R2= H
H N O
O O
HO
O
OH
N
O
OH R1 1 R1 = 4-Me, R2 = H 2 R1 = H, R2 = 3-Cl
N H N
IV Licochalcone A
V Cationic Chalcone
O R2
N
Antibacterial Basic VI chalcones
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Med Chem Res (2012) 21:4512–4522
Scheme 1 Synthesis of novel olefin chalcones. Reagents and conditions: (a) N-methyl piperidone, HCl, AcOH, 85–90 C, 3.5 h; (b) DMF, POCl3, rt, 2 h; (c) NaOH, EtOH, rt, 24 h
O
O
O
a O
CHO
b O
O
1
O
O
O
N
N
2
3
O
O O
CHO
+ O
c
O
R
R
O
O
O
N
N
activity of flavopiridol and its olefin analogues, we have synthesized chalcones containing olefin moiety. The title compounds were prepared as shown in Scheme 1. Compound 2 (olefin) was prepared by reacting 1,3,5-trimethoxy benzene with 1-methyl-4-piperidone in presence of hydrogen chloride gas in glacial acetic acid (Hampson et al., 2006). Compound 2 on Vilsmeier–Hack formylation gave 2,4,6-trimethoxy-3-(1-methyl-1,2,3,6-tetrahydropyridin-4-yl)benzaldehyde (olefin aldehyde) 3. Compound 3 on Claisen–Schmidt condensation with various mono, disubstituted and heteroaromatic acetophenones under basic media afforded a product, which on purification by recrystalization with suitable solvent gave title compounds in good to excellent yields (Table 1). All the synthesized novel olefin chalcones were characterized by IR, 1H NMR and mass spectral analyses and evaluated for cytotoxicity, antioxidant and antimicrobial activities.
Materials and method Chemistry All the chemicals were purchased from Aldrich Chemical Co., USA. All the solvents were purchased from S. D. Fine chemicals. Thin layer chromatography plates were purchased from Merks kiesegel 60F254, 0.2 mm thickness sheet and media for antimicrobial study was purchased from HiMedia Chemicals Pvt. Ltd., Mumbai (MS), India. Melting points were recorded in open capillaries with electrical melting point apparatus and were uncorrected. IR spectra (KBr disks) were recorded using a Perkin–Elmer 237 spectrophotometer. 1H NMR spectra were recorded on Bruker Advance (300 and 400 MHz) spectrometer using DMSO-d6 as solvent, with TMS as an internal reference. Mass spectra were recorded on a Shimadzu LCMS-QP
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5a-u
4a-u
3
Table 1 Synthesis of novel olefin chalcones O R
B
O A
O
O N
Entry
R
Product
Yielda (%)
MP (C)
1
C6H5
5a
92
151–153
2
4-BrC6H4
5b
89
175–177
3
4-FC6H4
5c
95
139–141
4 5
3,4-OmeC6H3 C4H3S
5d 5e
91 81
99–101 140–142
6
3,4-ClC6H3
5f
78
98–100
7
4-NO2C6H4
5g
96
168–170
8
4-ClC6H4
5h
93
162–164
9
3,4-FC6H3
5i
90
169–171
10
2,4-OCH3C6H3
5j
83
142–144
11
3-NH2C6H4
5k
85
216–218
12
4-NH2C6H4
5l
78
194–196
13
2,5 OmeC6H3
5m
75
122–124
14
4-Me C6H4
5n
84
175–177
15
2-OmeC6H4
5o
81
126–128
16
4-OmeC6H4
5p
87
162–164
17
4,6-Ome,2-OHC6H1
5q
85
68–70
18
2,4,-ClC6H3
5r
71
140–142
19 20
2,4,6-OmeC6H1 2,5,-ClC6H3
5s 5t
77 69
145–147 110–112
21
C4H4N
5u
61
220–222
a
Isolated yield
1000 EX. TLC was performed on silica gel coated plates for monitoring the reactions. The spots could be visualized easily under UV light.
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Synthesis of 2,4,6-trimethoxy-3-(1-methyl-1,2,3,6tetrahydropyridin-4-yl)benzaldehyde 3
1H), 3.93 (s, 3H), 3.84 (s, 3H), 3.68 (s, 3H), 2.90 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 412 [M??1].
Olefin 2 (1.0 g, 4 mmol) was dissolved in dry DMF (13.3 ml) under anhydrous condition. It was cooled to 0C, POCl3 (7.2 ml) was added dropwise for 30 min and stirring continued for 2 h at 25C. After completion of reaction (TLC) reaction mass was poured over crushed ice (50 g), basified with Na2CO3, extracted with chloroform, dried over anhydrous Na2SO4 and purified through silica gel column using 0.5–1% methanol ? 1% liquor ammonia in chloroform as eluting solvent afforded product 3 in 51% yield.
1-(3,4-Dimethoxy-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5d) IR (KBr) cm-1: 2935, 1640, 1595, 1556, 1460, 1393, 1240, 1105, 777. 1H NMR (DMSO, 400 MHz) d: 7.60 (d, 1H, J = 16 Hz), 7.50 (d, 1H, J = 16 Hz), 7.32 (m, 2H), 7.00 (s, 1H), 6.55 (s, 1H), 5.49 (s, 1H), 3.93 (s, 3H), 3.83 (s, 3H), 3.72 (s, 3H), 3.56 (s, 3H), 3.30 (s, 3H,), 2.89 (s, 2H), 2.53 (s, 2H), 2.25 (m, 5H). MS: m/z 454 [M? ?1].
Synthesis of novel olefin chalcones (5a–5u) A mixture of substituted acetophenones (2 mmol) was dissolved in 15 ml of ethanol under stirring, to this 4 ml (20%) aqueous NaOH was added and stirred for 10 min. To this reaction mixture 3-(1,2,3,6-tetrahydro-1-methylpyridin-4-yl)-2,4,5-trimethoxybenzaldehyde (291 mg, 1 mmol, 2) was added and stirring continued for 24 h at room temperature. After completion of reaction (TLC), the reaction mixture was poured over crushed ice and stirred. The light yellow solid obtained was filtered, washed with water and dried. The crude yellow solid products were purified by recrystalization using methanol to afford pure compounds 5a–5u (Scheme 1).
1-Thiophene-2yl-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3,6tetrahydro-pyridin-4yl)-phenyl]-propenone (5e) IR (KBr) cm-1: 2926, 1639, 1580, 1553, 1464, 1393, 1240, 1103. 1H NMR (DMSO, 400 MHz) d: 7.89 (d, 1H, J = 16 Hz), 7.76 (d, 1H, J = 16 Hz), 7.50 (s, 2H), 6.84 (s, 1H), 6.54 (s, 1H), 5.47 (s, 1H), 3.96 (s, 3H), 3.84 (s, 3H), 3.75 (s, 3H), 2.96 (s, 2H), 2.45 (s, 2H), 2.27 (m, 5H). MS: m/z 400 [M??1]. 1-(3,4-Dichloro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1, 2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5f) IR (KBr) cm-1: 2925, 1634, 1560, 1464, 1323, 1203, 1108, 936, 744, 648. 1H NMR (DMSO, 400 MHz) d: 8.01 (s, 1H), 7.82 (m, 2H), 7.76 (m, 2H), 6.55 (s, 1H), 5.55 (s, 1H), 3.98 (s, 3H), 3.83 (s, 3H), 3.76 (s, 3H), 2.90 (s, 2H), 2.50 (s, 2H), 2.25 (m, 5H). MS: m/z 462 [M?].
1-Phenyl-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5a) IR (KBr) cm-1: 2925, 1640, 1580, 1464, 1105. 1H NMR (DMSO, 400 MHz) d: 8.03 (m, 3H), 7.89 (d, 1H, J = 16 Hz), 7.60 (m, 3H), 6.55 (s, 1H), 5.55 (s, 1H), 3.96 (s, 3H), 3.82 (s, 3H), 3.63 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 394 [M??1].
1-(4-Nitro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5g) IR (KBr) cm-1: 2934, 1650, 1594, 1551, 1456, 1394, 1240, 1104, 852, 718. 1H NMR (DMSO, 400 MHz) d: 8.20 (d, 2H, J = 8 Hz), 8.12 (d, 1H, J = 16 Hz), 7.95 (d, 2H, J = 8 Hz), 7.79 (d, 1H, J = 16 Hz), 6.55 (s, 1H), 5.50 (s, 1H), 3.93 (s, 3H), 3.84 (s, 3H), 3.65 (s, 3H), 2.90 (s, 2H), 2.55 (s, 2H), 2.26 (m, 5H). MS: m/z 439 [M??1].
1-(4-Bromo-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5b) IR (KBr) cm-1: 2925, 1650, 1580, 1146, 1108, 765, 635. 1H NMR (DMSO, 400 MHz) d: 7.86 (d, 1H, J = 16 Hz), 7.76 (d, 1H, J = 16 Hz), 7.58 (d, 2H, J = 8 Hz), 7.42 (d, 2H, J = 8 Hz), 6.52 (s, 1H), 5.46 (s, 1H), 3.94 (s, 3H), 3.88 (s, 3H), 3.72 (s, 3H), 2.97 (s, 2H), 2.48 (s, 2H), 2.27 (m, 5H). MS: m/z 474 [M??2].
1-(4-Chloro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5h) IR -1 (KBr) cm : 2925, 1634, 1560, 1464, 1323, 1203, 1108, 805, 740. 1H NMR (DMSO, 400 MHz) d: 7.95 (d, 1H, J = 16 Hz), 7.84 (d, 1H, J = 16 Hz), 7.68 (d, 2H, J = 8 Hz), 7.45 (d, 2H, J = 8 Hz), 6.54 (s, 1H), 5.55 (s, 1H), 3.92 (s, 3H), 3.78 (s, 3H), 3.68 (s, 3H), 2.90 (s, 2H), 2.48 (s, 2H), 2.27 (m, 5H). MS: m/z 428 [M??1].
1-(4-Fluoro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5c) IR (KBr) cm-1: 2935, 1646, 1598, 1554, 1455,1393, 1240, 1102, 1012, 765, 635. 1H NMR (DMSO, 400 MHz) d: 8.09 (d, 2H, J = 8 Hz), 7.96 (d, 1H, J = 16 Hz), 7.89 (d, 1H, J = 16 Hz), 7.39 (d, 2H, J = 8 Hz), 6.55 (s, 1H), 5.55 (s,
1-(3,4-Difluoro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1, 2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5i) IR (KBr) cm-1: 2925, 1634, 1560, 1464, 1325, 1203, 1108, 936, 744, 648. 1H NMR (DMSO, 400 MHz) d: 7.94 (d, 1H, J = 16 Hz), 7.87 (d, 1H, J = 16 Hz), 7.82 (s, 1H), 7.76 (s, 1H), 7.32 (s, 1H), 6.55 (s, 1H), 5.53 (s, 1H), 3.94 (s, 3H),
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3.84 (s, 3H), 3.64 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.27 (m, 5H). MS: m/z 430 [M??1]. 1-(2,4-Dimethoxy-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5j) IR (KBr) cm-1: 2935, 1646, 1595, 1556, 1460, 1393, 1240, 1105, 777. 1H NMR (DMSO, 400 MHz) d: 7.79 (d, 1H, J = 16 Hz), 7.74 (d, 1H, J = 16 Hz), 7.55 (d, 1H, J = 8.8 Hz), 6.63 (m, 2H), 6.52 (s, 1H), 5.50 (s, 1H), 3.93 (s, 3H), 3.83 (s, 3H), 3.82 (s, 3H), 3.60 (s, 3H), 3.32 (s, 3H), 2.95 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 454 [M??1]. 1-(3-Amino-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5k) IR (KBr) cm-1: 3407, 3334, 2933, 1645, 1591, 1458, 1390, 1312, 1099. 1H NMR (DMSO, 400 MHz) d: 7.92 (d, 1H, J = 16 Hz), 7.82 (d, 1H, J = 16 Hz), 7.16 (m, 2H), 7.10 (d, 1H, J = 8 Hz), 6.79 (d, 1H, J = 8 Hz), 6.55 (s, 1H), 5.52 (s, 1H), 5.38 (s, 2H, –NH2), 3.97 (s, 3H), 3.83 (s, 3H), 3.63 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.27 (m, 5H). MS: m/z 409 [M??1]. 1-(4-Amino-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3, 6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5l) IR (KBr) cm-1: 3407, 3334, 2933, 1645, 1591, 1458, 1390, 1312, 1099. 1H NMR (DMSO, 400 MHz) d: 7.92 (d, 1H, J = 16 Hz), 7.82 (d, 1H, J = 16 Hz), 7.75 (d, 2H, J = 8.4 Hz), 6.61 (d, 2H, J = 8.4 Hz), 6.55 (s, 1H), 6.07 (s, 2H, –NH2), 5.52 (s, 1H), 3.96 (s, 3H), 3.82 (s, 3H), 3.62 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.27 (m, 5H). MS: m/z 409 [M??1]. 1-(2,5-Dimethoxy-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5m) IR (KBr) cm-1: 2935, 1646, 1595, 1556, 1460, 1393, 1240, 1105, 777. 1H NMR (DMSO, 400 MHz) d: 7.72 (d, 1H, J = 16 Hz), 7.56 (d, 1H, J = 16 Hz), 7.09 (m, 2H), 6.98 (s, 1H), 6.52 (s, 1H), 5.49 (s, 1H), 3.93 (s, 3H), 3.82 (s, 3H), 3.79 (s, 3H), 3.73 (s, 3H), 3.56 (s, 3H), 2.94 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 454 [M??1]. 1-p-Tolyl-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5n) IR (KBr) cm-1: IR (KBr) cm-1: 2935, 1646, 1595, 1556, 1460, 1393, 1240, 1105. 1H NMR (DMSO, 400 MHz) d: 8.01 (d, 1H, J = 16 Hz), 7.89 (m, 3H), 7.20 (d, 2H, J = 8 Hz), 6.55 (s, 1H), 5.55 (s, 1H), 3.93 (s, 3H), 3.83 (s, 3H), 3.68 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.39 (s, 3H), 2.26 (m, 5H). MS: m/z 408 [M??1]. 1-(2-Methoxy-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2, 3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5o) IR (KBr) cm-1: 2935, 1646, 1598, 1554, 1455, 1393, 1240, 1102, 765, 635. 1H NMR (DMSO, 400 MHz) d: 7.70 (d,
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Med Chem Res (2012) 21:4512–4522
1H, J = 16 Hz), 7.54 (d, 1H, J = 16 Hz), 7.49 (d, 1H, J = 7.6 Hz), 7.42 (m, 1H), 7.16 (d, 1H, J = 8 Hz), 7.03 (ddd, 1H, J = 7.6, 6.8, 1.3), 6.52 (s, 1H), 5.49 (s, 1H), 3.92 (s, 3H), 3.84 (s, 3H), 3.82 (s, 3H), 3.56 (s, 3H), 2.94 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 424 [M??1]. 1-(4-Methoxy-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2, 3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5p) IR (KBr) cm-1: 2935, 1646, 1598, 1555, 1460, 1393, 1242, 1103, 777, 648. 1H NMR (DMSO, 400 MHz) d: 7.90 (d, 1H, J = 16 Hz), 7.78 (d, 1H, J = 16 Hz), 7.65 (d, 2H, J = 8 Hz), 6.84 (d, 2H, J = 8 Hz), 6.50 (s, 1H), 5.50 (s, 1H), 3.93 (s, 3H), 3.82 (s, 3H), 3.70 (s, 3H), 3.65 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 424 [M??1]. 1-(2-Hydroxy-4,6-dimethoxy-phenyl)-3-[2,4,6-trimethoxy3-(1-methyl-1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5q) IR (KBr) cm-1: 3450, 2935, 1646, 1595, 1556, 1460, 1393, 1240, 1105, 777. 1H NMR (DMSO, 400 MHz) d: 14.22 (s, 1H), 7.79 (d, 1H, J = 16 Hz), 7.74 (d, 1H, J = 16 Hz), 6.63 (m, 2H), 6.52 (s, 1H), 5.50 (s, 1H), 3.93 (s, 3H), 3.83 (s, 3H), 3.82 (s, 3H), 3.60 (s, 3H), 3.32 (s, 3H), 2.95 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 470 [M??1]. 1-(2,4-Dichloro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5r) IR (KBr) cm-1: 2925, 1634, 1560, 1464, 1323, 1203, 1108, 936, 744, 648. 1H NMR (DMSO, 400 MHz) d: 7.98 (s, 1H), 7.82 (m, 2H), 7.57 (m, 2H), 6.47 (s, 1H), 5.47 (s, 1H), 3.89 (s, 3H), 3.78 (s, 3H), 3.72 (s, 3H), 2.89 (s, 2H), 2.50 (s, 2H), 2.24 (m, 5H). MS: m/z 462 [M?]. 3-[2,4,6-Trimethoxy-3-(1-methyl-1,2,3,6-tetrahydro-pyridin4-yl)-phenyl]-1-(2,4,6-trimethoxy-phenyl)-proenone (5s) IR (KBr) cm-1: 2935, 1646, 1595, 1556, 1460, 1393, 1240, 1105, 777. 1H NMR (DMSO, 400 MHz) d: 7.80 (d, 1H, J = 16 Hz), 7.56 (d, 1H, J = 16 Hz), 6.70 (s, 2H), 6.50 (s, 1H), 5.57 (s, 1H), 3.93 (s, 3H), 3.82 (s, 3H), 3.79 (s, 3H), 3.73 (s, 3H), 3.56 (s, 3H), 3.40 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 484 [M??1]. 1-(2,5-Dichloro-phenyl)-3-[2,4,6-trimethoxy-3-(1-methyl1,2,3,6-tetrahydro-pyridin-4yl)-phenyl]-propenone (5t) IR (KBr) cm-1: 2925, 1634, 1560, 1464, 1323, 1203, 1108, 936, 744, 648. 1H NMR (DMSO, 400 MHz) d: 8.02 (s, 1H), 7.89 (m, 2H), 7.78 (m, 2H), 6.45 (s, 1H), 5.55 (s, 1H), 3.93 (s, 3H), 3.87 (s, 3H), 3.75 (s, 3H), 2.90 (s, 2H), 2.54 (s, 2H), 2.25 (m, 5H). MS: m/z 462 [M?]. 1-(1H-Pyrrol-2yl)-3-[2,4,6-trimethoxy-3-(1-methyl-1,2,3,6tetrahydro-pyridin-4yl)-phenyl]-propenone (5u) IR (KBr) cm-1: 3338, 2915, 1672, 1580, 1464, 1389, 1105, 801, 675.
Med Chem Res (2012) 21:4512–4522 1
H NMR (DMSO, 400 MHz) d: 11.88 (s, 1H), 7.88 (d, 1H, J = 16 Hz), 7.69 (d, 1H, J = 16 Hz), 7.11 (s, 1H), 7.01 (s, 1H), 6.53 (s, 1H), 6.23 (s, 1H), 5.52 (s, 1H), 3.97 (s, 3H), 3.82 (s, 3H), 3.63 (s, 3H), 2.96 (s, 2H), 2.50 (s, 2H), 2.26 (m, 5H). MS: m/z 383 [M??1].
4517
Biological activities
150 ll of (0.17 M) H2O2 and 1.5 ml of test compound (100 lg which is dissolved in 0.05% DMSO). The reaction mixture was kept at room temperature for 5 min incubation and absorbance was measured at 560 nm using the UV– Visible spectrophotometer. Ascorbic acid was used as a reference compound. All the measurements were taken in triplicate and the mean values were calculated.
Cytotoxic activity
% Activity ¼ 1
The cytotoxicity assay was performed as per the earlier reported method with slight modification (Wahab et al., 2009). The cells were harvested (2.5–3 9 104 cells/well) and inoculated in 96-well microtitre plate. The cells were washed with phosphate buffer saline (PBS) and the cultured cells were then incubated in with and without test compound (100 lg). After 72 h incubation, the medium is aspirated. 10 ll of MTT solution (5 mg/ml in PBS, pH 7.2) is added to each well and the plates are incubated for 4 h at 37C. After incubation 100 ll of DMSO (\0.5%) was added to the wells followed by gentle shaking to solublize the formation of dye for 15 min. Absorbance was read at 540 nm and surviving cell fraction was calculated. Methotrexate was used as a reference drug. All the measurements were taken in triplicate and the mean values were calculated. The inhibition of cell viability was calculated as follows
Ferric reducing antioxidant power (FRAP) assay
% Inhibition ¼ 1
T 100 C
where T is absorbance of treated cells and C is absorbance of untreated cells.
In the ferric to ferrous reduction assay, the electron donation capacity (reflecting the electron transfer ability) of the compounds was assessed. The ferric reducing power of synthesized novel olefin chalcones was determined by using previously published protocol of Queiroz (Queiroz et al., 2007). The reaction mixture contained 2.5 ml of individual compounds (100 lg), sodium phosphate buffer (200 lM, pH 6.6) and 2.5 ml of 1% potassium ferricyanide. The mixture was incubated at 50C for 20 min. The reaction was quenched by the addition of 2.5 ml trichloroacetic acid (10% w/v). Finally the reaction mixture was centrifuged at 650 rpm for 10 min. 5 ml of supernatant was mixed with equal volume of distilled water and 1 ml ferric chloride (0.1%) was added. The absorbance was measured at 700 nm using UV–Visible spectrophotometer. Increase in the absorbance of the reaction mixture indicates higher reducing power. Ascorbic acid was used as a standard. All the measurements were taken in triplicate and the mean values were calculated. % Activity ¼ 1
DPPH radical scavenging activity
Absorbance of test compound 100 Absorbance of control
Absorbance of test compound 100 Absorbance of control
Antimicrobial activity (agar diffusion method) The DPPH radical scavenging activity of chalcones was measured according to the procedure of Blois (1958) with minor modification (Bandgar et al., 2010a). The reaction mixture contained test compound (100 lg) with equal volume of DPPH radical (10-4 M in absolute ethanol) solution. After 20 min reaction time, the absorbance was recorded at 517 nm using UV–Visible spectrophotometer. Ascorbic acid was used as a standard antioxidant agent. All the measurements were taken in triplicate and the mean values were calculated. Hydroxyl radical scavenging activity Hydroxyl radical scavenging activity was determined by using the earlier reported method (Gacche et al., 2008) with slight modification. The reaction mixture contained 60 ll of (1 mM) FeCl3, 90 ll of (1 mM) 1,10-phenanthroline, 2.4 ml of (0.2 M) phosphate buffer (pH 7.8),
The antimicrobial activity was tested through agar diffusion method (Bandgar et al., 2010a, b). All the bacterial strains such as Escherichia coli (DH5-a), Proteus vulgaris (MTCC 1751), Staphylococcus aureus (MTCC 96) and fungal strain Candida albicans (MTCC 3017) used were procured from Institute of Microbial Type Culture Collection (IMTCC), Chandigarh, India and National Collection of Industrial Microorganisms (NCIM), Pune (MS), India. All the synthesized compounds were dissolved to prepare a stock solution of 1 mg/ml using DMSO (0.05%). Stock solution was aseptically transferred and suitably diluted to have solutions of concentration ranging 50–100 lg. For antifungal activity, Candida albicans spore suspension in sterile distilled water was adjusted to give a final concentration of 106 cfu/ml. Inoculum of 0.1 ml spore suspension of selected fungus was spread on Sabouraud’s Dextrose agar plates. For antibacterial activity,
123
4518
Muller Hinton agar was seeded with 0.1 ml of respective bacterial strains suspension prepared in sterile saline (0.85%) of 105 cfu/ml dilution. The wells of 6 mm diameter were filled with 0.1 ml each test compound separately for fungus and bacterial strain. The DMSO (0.05%) alone was used as a controller. The antibiotics streptomycin and flucanozole were used as a reference for antibacterial and antifungal, respectively. Inoculated plates in duplicate were then incubated at 37 ± 0.5C for antibacterial activity for 24 h and at 28 ± 0.2C for antifungal activity for 48 h. After incubation, the antimicrobial activity was measured in terms of the zone of inhibition in millimetre. Calculation of physicochemical properties The physicochemical properties of the compounds such as molecular weight, cLog P, HBA, HBD and Drug likeness were studied from online Osiris property explorer for drug bioavailability of chemical compounds (Miteva et al., 2006). Quantum chemical descriptors such as energy of highest occupied molecular orbital (EHOMO) and of lowest unoccupied molecular orbital (ELUMO) of the synthesized compounds were calculated using a BioMed CaChe 6.1 (Fujitsu Ltd.). Number of rotatable bonds and topological polar surface area (TPSA) were calculated from online Molinspiration chemoinformatics software. Aqueous solubility of the synthesized compounds was studied from online ALOGPS software.
Results and discussion MTT microdilution assay was used for the evaluation of cytotoxic properties of the novel olefin chalcones. The growth inhibitory effect was assessed using three human cancer cell lines, Hep 3BPN 7 (liver), HL 60 P 58 (leukaemia), HeLa B 75 (cervix) and one normal cell line PN-15C-12 (normal chang liver cell line). The results are summarized in Table 2. All the tested compounds exhibited cytotoxic effect on the cancer cell lines selected in this study. Compounds 5u, 5g, 5c, 5e, 5f, 5b and 5a have shown significant cytotoxicity against Hep BPN 7 (80.13–78.06%) as compared to the standard methotrexate (64.60%,), whereas, rest of the compounds have shown moderate cytotoxicity. SAR study of these compounds with respect to liver cancer cell line revealed that in general, compounds with electron withdrawing groups on aromatic B ring are more cytotoxic than their counterparts containing electron donating groups. The bioisosteric replacement of phenyl (5a) with pyrrole (5u) showed an increase in cytotoxicity. Compounds 5j, 5i, 5n, 5o, 5k and 5u exhibited good cytotoxicity against HL 60 P 58 (78.48–66.55%) as compared to the standard methotrexate (54.08%,), while other
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Med Chem Res (2012) 21:4512–4522 Table 2 Cytotoxicity profile of novel olefin chalcones Compound
Hep 3BPN7
HL60 P58
Hela B75
PN-5C-12
5a
78.06 ± 1.28 63.52 ± 1.33 84.15 ± 2.46 61.79 ± 1.48
5b
78.93 ± 1.8
5c
79.86 ± 1.18 62.18 ± 2.93 85.04 ± 2.33 69.43 ± 1.53
5d
79.46 ± 3.01 62.77 ± 2.23 84.84 ± 1.08 65.21 ± 1.23
62.68 ± 1.83 84.84 ± 1.76 66.40 ± 2.11
5e
79.8 ± 1.68 54.28 ± 2.75 84.91 ± 2.03 67.19 ± 1.28
5f
79.8 ± 243 65.04 ± 1.75 85.93 ± 2.44 67.19 ± 3.11
5g
80.13 ± 2.29 65.88 ± 1.43 83.67 ± 1.88 70.09 ± 1.21
5h
77.4 ± 2.48 65.04 ± 2.18 83.74 ± 1.16 67.98 ± 2.22
5i
76.93 ± 3.19 70.50 ± 1.65 82.85 ± 2.28 65.48 ± 1.93
5j
77 ± 2.42 78.48 ± 1.24 83.40 ± 1.57 47.82 ± 3.16
5k
76.33 ± 2.78 66.72 ± 1.73 82.64 ± 2.26 44.53 ± 1.88
5l
75.06 ± 1.84 61.17 ± 1.88 79.28 ± 2.67 49.67 ± 3.33
5m
73.40 ± 2.26 66.30 ± 1.46 82.09 ± 2.72 41.10 ± 1.38
5n
72.53 ± 1.86 69.49 ± 3.42 82.23 ± 2.51 44.26 ± 1.71
5o
71.33 ± 1.49 68.40 ± 1.85 81.13 ± 1.29 46.77 ± 1.50
5p
72.33 ± 1.81 56.97 ± 1.55 80.86 ± 1.18 46.11 ± 1.73
5q
71.40 ± 2.02 64.20 ± 1.24 79.69 ± 2.44 44.13 ± 1.82
5r
71.26 ± 3.09 58.99 ± 1.72 79.42 ± 2.59 50.98 ± 1.51
5s
70.53 ± 1.82 65.04 ± 1.27 78.73 ± 1.40 59.81 ± 1.48
5t
70.8 ± 1.27 65.63 ± 1.29 79.97 ± 2.33 60.47 ± 3.02
5u
80.13 ± 2.43 66.55 ± 1.50 77.77 ± 2.29 57.57 ± 1.88
Methotrexate 64.60 ± 1.29 54.08 ± 2.37 78.66 ± 1.87 53.85 ± 3.42 Hep 3BPN7: Liver, HL60 P58: Human leukaemia, Hela B75: Cervical, PN-15C-12: Normal liver, the results are the mean values of n = 2, all the compounds tested at 100 lg. Values are mean ± SEM of three parallel measurements
test compounds showed lower cytotoxicity. The SAR study of these compounds with respect to human leukaemia cell line revealed that compounds with electron donating groups on aromatic ring B have higher cytotoxicity than their counterpart containing electron withdrawing groups with the exception of 5i. Introduction of one more methoxy group on aromatic ring B (5j) (78.48%) resulted in decrease in cytotoxicity (5s) (65.04). Position of methoxy group is also important for cytotoxicity, changing it from 2,4-position on aromatic B ring (5j) to 2,5-position (5m) lower the cytotoxicity. Compounds 5f, 5c, 5e, 5b, 5d, 5a and 5h showed potent cytotoxicity against Hela B 75 (85.93–83.67%) as compared to the standard methotrexate (78.66%,), rest of the compounds have shown moderate cytotoxicity. Compounds containing electron withdrawing groups on aromatic ring B displayed higher cytotoxicity than their counterpart containing electron donating groups on aromatic ring B with the exception of 5d. Changing the position of chlorine from 3,4-position (5f) to 2,5-position of aromatic ring B (5t) resulted in decrease in activity. All the synthesized compounds under study presented good cytotoxicity against tumour cell lines. However, they are
Med Chem Res (2012) 21:4512–4522
minimally cytotoxic to normal cell line as indicated by less inhibition of growth of normal cell line under study. The involvement of reactive oxygen species (ROS) and the free radical-mediated oxidative damage of cell membranes, DNA and proteins in degenerative process related to ageing, cancer, inflammation, atherosclerosis, is a cause of concern. Therefore, there is increasing interest in the protective and preventative functions of foods and their constituents against oxidative damage caused by ROS and free radicals (Glucin, 2010). We have evaluated antioxidant activity of novel olefin chalcones against DPPH stable free radical. Free radical scavenging activity was measured in terms of DPPH reduction and the results are presented in Table 3. All the synthesized compounds showed good to moderate free radical scavenging activity. Compounds 5k (94.50%), 5l (89.60%) exhibited similar radical scavenging activity as the standard ascorbic acid (95.76%), whereas compounds 5u, 5j, 5i and 5n showed moderate radical scavenging activity and rest of the compounds showed minimum activity. Amino functionality and heterocyclic aromatic ring seem to favour the antioxidant activity. Substantial evidence exists to support the role of both oxygen and organic-free radical intermediates in the biomolecular interactions which contribute to the initiation, promotion and/or progression stages of chemical carcinogenesis (Trush and Kensler, 1991). Chemoprevention was described as the use of natural or synthetic chemicals allowing suppression, retardation or inversion of carcinogenesis. Curcumin is a well-known chemopreventive agent which has good antioxidant and potent cytotoxicity against various human cancer cell lines (Duvoix et al., 2005). In the present study, compounds 5k, 5u and 5f have shown good antioxidant activity and significant cytotoxicity and hence these compounds could be considered as chemopreventive agents. Hydroxyl radical is known to react with all components of DNA molecule, damaging both the purine and pyrimidine bases and also deoxyribose backbone (Halliwell and Gutteridge, 1999). Hydroxyl radicals are among the most hyper ROS and are considered to be responsible for some tissue damage occurring in inflammation. Results of hydroxyl radical (HO•) scavenging activity of synthesized chalcones are given in Table 3. These results revealed that the synthesized compounds have shown moderate to minimum HO• scavenging activity. Compounds 5u, 5n, 5o, 5f, 5j and 5p showed moderate HO• radical scavenging activity (63.15–57.89%) as compared to the standard ascorbic acid (88.54%), whereas rest of the compounds have minimum activity. Compounds containing electron donating groups on aromatic ring B revealed higher HO• scavenging activity as compared to their counterparts containing electron withdrawing groups, with the exception of 5f. Heteroaromatic compound (5u) has higher HO•
4519 Table 3 Antioxidant activity of novel olefin chalcones Compound
% DPPH inhibition
% •OH inhibition
Reducing powerb
5a
27.88 ± 2.20
41.35 ± 1.35
58.38 ± 1.87
5b
23.26 ± 1.73
44.36 ± 2.66
50.32 ± 2.09
5c
22.88 ± 3.09
38.72 ± 1.83
48.30 ± 2.29
5d
22.30 ± 2.38
34.96 ± 1.51
50.72 ± 2.37
5e
22.69 ± 1.62
36.46 ± 1.43
59.59 ± 1.05
5f
56.92 ± 3.11
59.77 ± 1.71
46.69 ± 2.46
5g 5h
25 ± 2.83 20.38 ± 1.87
51.50 ± 1.27 16.91 ± 1.30
46.29 ± 1.37 41.85 ± 1.83
5i
58.84 ± 1.99
52.25 ± 2.28
43.87 ± 2.19
5j
60.57 ± 1.76
59.02 ± 3.01
53.15 ± 2.56
5k
94.50 ± 3.12
55.63 ± 2.88
64.83 ± 2.10 48.30 ± 2.92
5l
89.60 ± 3.35
54.13 ± 3.06
5m
57.69 ± 1.60
54.88 ± 1.80
66.45 ± 1.37
5n
58.46 ± 1.26
59.77 ± 1.11
68.06 ± 1.55
5o
60.00 ± 2.38
59.77 ± 1.92
60.80 ± 2.37
5p
55.57 ± 3.25
57.89 ± 3.44
67.66 ± 2.92
5q
57.30 ± 2.09
51.12 ± 1.85
69.27 ± 1.44
5r
56.73 ± 2.62
48.12 ± 1.61
63.62 ± 3.20
5s
56.15 ± 2.19
46.61 ± 173
58.79 ± 1.46
5t
55.38 ± 2.84
48.49 ± 3.22
62.41 ± 1.37
5u
68.65 ± 2.46
63.15 ± 1.27
61.20 ± 1.05
AAa
95.76 ± 3.31
88.34 ± 1.96
78.17 ± 1.88
Values are mean ± S.E.M. of three parallel measurements a
Standard, Ascorbic acid at 1 mM
b
Ferric reducing antioxidant power (FRAP) assay, all the compounds tested at 100 lg
radical scavenging activity than its aromatic counterpart (5a). FRAP assay measures the ability of a compound to reduce the Fe[(CN)6]3- to Fe[(CN)6]2-. The reducing power associated with antioxidant activity reflects the electron donating capacity of bioactive compounds (Xing et al., 2005). The results of the reducing power of novel olefin chalcones are presented in Table 3. These results revealed that the compounds under study have promising reducing ability. Compounds 5q, 5n, 5p, 5m and 5k (69.27–64.83%) exhibited good reducing power as compared to standard ascorbic acid (78.17), whereas compounds 5r, 5t, 5u, 5o, 5e and 5s have shown moderate activity and rest of compounds showed very low activity. The SAR study revealed that compounds containing electron donating groups on aromatic ring B have higher reducing power than their counterpart containing electronwithdrawing groups with the exception of the compounds 5r and 5t. The presence of hydroxyl group imparts the reduing power (5q), methylation of hydroxyl group (5s) resulted in decreases activity. The bioisosteric replacement
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4520
of phenyl group (5a) by heterocyclic ring resulted in increase in the reducing power (5u and 5e). All the synthesized compounds were subjected to antimicrobial activity by disk diffusion method against Escherichia coli (DH5-a), Proteus vulgaris (MTCC 1751), Staphylococcus aureus (MTCC 96) and Candida albicans (MTCC 3017). Streptomycin and flucanazole are used as standard drugs against bacteria and fungus, respectively. The results of antimicrobial activity of novel olefin chalcones are presented in Table 4. Compounds 5k, 5s, 5a, 5c, 5n, 5m, 5p, 5o and 5j have shown good antibacterial activity and inhibited the growth of both gram positive and gram negative bacteria under study. The SAR study of these compounds have shown that compounds containing electron donating groups on aromatic ring B have higher antibacterial activity than the compounds containing electron withdrawing groups with the exception of 5c. Compounds with heteroaromatic ring 5u and 5e have lower antibacterial activity than their aromatic counterpart (5a). Compounds with methoxy group on aromatic ring B have higher antibacterial activity (5s, 5m, 5p, 5o and 5j). Compounds 5k and 5f showed good activity against Candida albicans, while, compounds 5a and 5c have moderate antifungal activity. Interestingly, compound 5l has moderate antifungal activity, however, changing the position of amino group on aromatic ring B from meta (5k) to para postion (5l) there is a significant decrease in the activity. It seems that the meta substitution in the compounds is necessary for antifungal activity. In general most of the chalcones under study are inactive against Candida albicans. About 30% of oral drugs fail in development due to poor pharmacokinetics (Waterbeemd and Gifford, 2003). Among the pharmacokinetic properties, a low and highly variable bioavailability is indeed the main reason for stopping further development of the drugs. An in silico model for predicting oral bioavailability is very important, both in the early stage of drug discovery to select the most promising compounds for further optimization and in the later stage to identify candidates for further clinical development. In silico prediction of oral bioavailability is pioneered by Lipinski et al. (1997) who put forwarded the rule of five to determine the oral bioavailability of compounds. The rule of five defines four simple physicochemical parameters for poor drug absorption and permeation which are molecular weight [ 500, cLogP [ 5, hydrogen bond acceptor [ 10 and hydrogen bond donor [ 5. Results of physicochemical properties of synthesized novel olefin chalcones are presented in Table 5. These results revealed that all the compounds obey the Lipinski rule of five. In addition to the molecular properties discussed by Lipinski, Navia and Chaturvedi (1996) has discussed other properties in regard to oral bioavailability. They postulated the desirability of
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Med Chem Res (2012) 21:4512–4522 Table 4 Antimicrobial activity of novel olefin chalcones Compound
Zone of inhibition (mm) EC
5a 5b 5c
SA
5.5 ± 1.10
PV
5 ± 1.47 2.5 ± 1.34
2 ± 2.29 0.5 ± 1.28 NR 4.5 ± 1.76
2 ± 1.21 7.5 ± 1.41
CA 3.5 ± 1.70 0.5 ± 2.61 3.5 ± 1.58
5d
2 ± 1.39 0.5 ± 2.16 5.5 ± 1.36
1.5 ± 1.34
5e
1.1 ± 1.83 2.5 ± 1.30 6.5 ± 1.20
1.5 ± 2.29
5f
1.5 ± 1.77
5g 5h
5 ± 1.52 9.1 ± 1.16
2 ± 2.38 5 ± 1.38 4 ± 1.48 3 ± 1.51 2.5 ± 1.43 3 ± 2.27
5.5 ± 1.03 2 ± 1.56 ND
5i
2 ± 1.19 2.5 ± 2.37 4 ± 1.15
5j
3.15 ± 1.72 2.5 ± 1.35 3.5 ± 1.23
1.1 ± 2.12
5k
3.5 ± 1.41 3.5 ± 1.66 7 ± 1.05
6.30 ± 1.30
5l
6.5 ± 1.04 1.5 ± 2.76 5 ± 2.61
2.9 ± 1.19
5m
2.5 ± 2.24
5 ± 1.62 5 ± 1.82
ND
5 ± 2.18 10.2 ± 1.11 0.1 ± 2.12
ND
5n
2.5 ± 1.20
5o
3.5 ± 1.63 2.5 ± 1.20 3 ± 1.08
ND
5p
3.5 ± 1.25 2.5 ± 1.52 7 ± 1.45
ND
5q
2 ± 1.37 1.5 ± 1.80 9.5 ± 1.55
5r
2.5 ± 2.64 1.1 ± 2.16 5.5 ± 1.72
1.1 ± 1.02
5s
3.5 ± 1.61 3.5 ± 1.27 3.5 ± 2.61
ND
5t
1.5 ± 1.43 1.5 ± 2.61 6.5 ± 1.35
ND
1.5 ± 1.42
6.25 ± 1.01 1.1 ± 1.11 3 ± 1.23
1.5 ± 1.20
Streptomycina 2.5 ± 1.45 2 ± 1.57 2.4 ± 1.4 Flucanozoleb – – –
– 6.5 ± 1.29
5u
Values are mean ± SEM of three parallel measurements ND not determined, data represent mean of two replicates; EC Escherichia coli; SA Staphylococcus aureus; PV Proteus vulgaris; CA Candida albicans a
Standard at 20 lg, 100 lg
b
standard at 10 lg, all the compound tested at
molecular flexibility for membrane permeation which is measured by the number of rotatable bonds. Compounds with 10 or fewer rotatable bonds will have probability of good oral bioavailability. The compounds under study have the number of rotatable bonds less than 10 with the exception of compound 5s which has 10 rotatable bonds. Polar surface area (PSA) of a molecule encodes more hydrogen bonding information, it refers to surface area of the oxygen, nitrogen, sulphur and attached hydrogen atom, and it has been shown to correlate well with drug transport properties (Veber et al., 2002). A new and fast methodology has been developed to calculate the PSA from fragment contribution which is termed as TPSA. The TPSA ˚ 2 will have high probability of equal to or less than 140 A good oral bioavailability. Results from Table 5 showed that compounds under study have TPSA in the range 48.01–93.83. Drug likeness can be defined as a delicate balance among the molecular properties of compound that
Med Chem Res (2012) 21:4512–4522
4521
Table 5 Physicochemical properties of novel olefin chalcones Compound
AlOGPSa in mg/l
cLog P
MW
HBA
HBD
EHOMO
ELUMO
TPSAb
nRBc
5a
-4.72 (7.58)
3.53
393.19
5
0
-9.231
-0.456
48.01
7
5.62
5b
-5.55 (1.32)
4.23
471.10
5
0
-9.454
-0.337
48.01
7
0.72
5c
-4.97 (4.41)
3.59
411.18
5
0
-9.574
-0.280
48.01
7
1.98
5d
-4.96 (5.02)
3.32
453.22
7
0
-9.475
-0.461
66.47
9
1.98
5e
-5.20 (2.53)
3.37
399.15
6
0
-9.247
-0.678
48.01
7
1.37
5f
-5.69 (0.95)
4.76
461.12
5
0
-9.354
-0.567
48.01
7
5.89
5g
-5.47 (1.60)
3.90
438.87
8
0
-8.348
-0.348
93.83
8
5.85
5h
-5.27 (2.28)
4.14
427.16
5
0
-9.789
-0.658
48.01
7
0.80
5i
-5.12 (3.23)
3.65
429.18
5
0
-9.249
-0.456
48.01
7
1.15
5j
-4.96 (4.97)
3.32
453.22
7
0
-9.347
-1.472
66.47
9
1.44
5k 5l
-4.60 (10.18) -4.66 (8.92)
2.81 2.81
408.20 408.20
5 5
2 2
-8.974 -9.234
-0.423 -0.469
74.03 74.03
7 7
0.29 0.69
5m
-4.67 (4.91)
3.32
453.22
7
0
-9.678
-0.434
66.47
9
1.49
5n
-4.91 (5.05)
3.85
407.21
5
0
-9.367
-0.428
48.01
7
1.08
Drug likeness
5o
-4.79 (6.87)
3.43
423.20
6
0
-9.446
-0.449
57.24
8
0.84
5p
-4.83 (6.229)
3.43
423.20
6
0
-9.167
-0.443
57.24
8
1.43
5q
-4.87 (6.32)
3.02
469.21
8
1
-9.379
-0.478
86.70
9
0.96
5r
-5.70 (0.93)
4.76
461.12
5
0
-9.334
-0.464
48.01
7
0.62
5s
-3.82 (72.53)
3.09
483.23
8
0
-9.647
-0.446
75.71
10
0.95
5t
-5.71 (0.90)
4.76
461.12
5
0
-8.867
-0.388
48.01
7
0.62
5u
-3.65 (85.77)
2.31
382.19
5
1
-9.237
-0.412
63.80
7
1.02
a
Aqueous solubility,
b
Topological Polar Surface Area,
c
number of rotatable bonds
influence its pharmacodynamics and pharmacokinetics and ultimately affect their absorption, distribution, metabolism and excretion in human body (Vistolli et al., 2008). Compounds under study showed good drug likeness score in the range 0.20–5.85. The importance of aqueous solubility for drug design can be recognized at all stages of drug development. The solubility is extremely important as it determines uptake, movement and elimination of the substances from the body (Balakin et al., 2006). We have calculated the aqueous solubility of synthesized compounds as ALOGPS and all compounds possess good water solubility in the range 0.90–85.77 mg/l. Overall, all the synthesized compounds comply with the rules of Lipinski and other parameter such as number of rotatable bonds, TPSA and aqueous solubility. Hence in principle, all of these compounds could be considered as good oral candidates.
antioxidant and antimicrobial activities. Compounds 5u, 5g, 5c and 5e have shown significant cytotoxicity against Hep 3BPN 7, electron withdrawing groups on aromatic ring B had higher cytotoxicity. Compounds 5j, 5i, 5n and 5o showed good cytotoxicity against HL 60 P 58, electron donating groups on aromatic ring B enhance the cytotoxicity. Compounds 5f, 5c, 5e and 5b showed potent cytotoxicity against Hela B 75. The present study revealed that these chalcones were potent cytotoxic agents against tumour cell lines without being more toxic to normal cells. Compounds 5k and 5l have shown good free radical scavenging activity. Compounds 5k, 5s, 5a and 5c showed promising antibacterial activity. Compounds 5k, 5u and 5f could be considered as chemopreventive agents.
References Conclusion In this study, we have synthesized a series of novel olefin chalcones and screened for ADME and drug likeness, all the compounds have shown good ADME and drug likeness profile could be considered as good oral drug candidates. Synthesized compounds were evaluated for cytotoxicity,
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