Novel 3-substituted-1-aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4- ones: Docking, synthesis and pharmacological evaluation as a potential anti-inflammatory agents

Article abstract of DOI:10.1016/j.bmcl.2012.08.119

Novel 3-substituted-1-aryl-5-phenyl-6-anilino-pyrazolo[3,4-d]pyrimidin-4- ones of pharmacological significance were synthesized by the reaction of ethyl-(5-amino-3-methylthio-1-aryl-5-phenyl-2H-pyrazole)-4-carboxylates 3a-c with S-methyl diphenyl thiourea independently to produce 1-aryl-3-thiomethyl-5- phenyl-pyrazolo[3,4-d]pyrimidines 4a-c in DMF with catalytic amount of K ₂CO₃, which on further treatment with different aromatic amines independently under same reaction conditions generated for compounds 5a-l. The compounds were screened for the anti-inflammatory activity and evaluated for ulcerogenic potential. The compounds 5i exhibited superior anti-inflammatory activity in comparison with diclofenac sodium and comparable activity with celecoxib at a dose of 25 mg/kg. The other compounds 4c, 5c, 5f and 5l were found as active with inhibition of edema in the range of 35-39 after 3 h of administration of test compounds. The ulcerogenic potential of active compounds was observed to be quite lesser as compared to standard. COX-2 docking score of the active compound 5i was found to be better than standard celecoxib.

Full text of DOI:10.1016/j.bmcl.2012.08.119

Bioorganic & Medicinal Chemistry Letters 22 (2012) 6616–6620
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Bioorganic & Medicinal Chemistry Letters
journal homepage: www.elsevier.com/locate/bmcl
Novel 3-substituted-1-aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4-ones:
Docking, synthesis and pharmacological evaluation as a potential
anti-inflammatory agents
Sandeep B. Yewale a, Saurabh B. Ganorkar b, Kamalkishor G. Baheti a, , Rupesh U. Shelke c
⇑
a Y.B. Chavan College of Pharmacy, Rauza Baugh, Aurangabad 431001, MS, India
b R.C. Patel Institute of Pharmaceutical Education and Research, Shirpur 425405, MS, India
c Governrnent College of Pharmacy, Aurangabad 431001, MS, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Novel 3-substituted-1-aryl-5-phenyl-6-anilino-pyrazolo[3,4-d]pyrimidin-4-ones of pharmacological
significance were synthesized by the reaction of ethyl-(5-amino-3-methylthio-1-aryl-5-phenyl-2H-
pyrazole)-4-carboxylates 3a–c with S-methyl diphenyl thiourea independently to produce 1-aryl-3-thio-
methyl-5-phenyl-pyrazolo[3,4-d]pyrimidines 4a–c in DMF with catalytic amount of K2CO3, which on
further treatment with different aromatic amines independently under same reaction conditions
generated for compounds 5a–l. The compounds were screened for the anti-inflammatory activity and
evaluated for ulcerogenic potential. The compounds 5i exhibited superior anti-inflammatory activity in
comparison with diclofenac sodium and comparable activity with celecoxib at a dose of 25 mg/kg. The
other compounds 4c, 5c, 5f and 5l were found as active with inhibition of edema in the range of
35–39 after 3 h of administration of test compounds. The ulcerogenic potential of active compounds
was observed to be quite lesser as compared to standard. COX-2 docking score of the active compound
5i was found to be better than standard celecoxib.
Received 12 May 2012
Revised 9 August 2012
Accepted 30 August 2012
Available online 13 September 2012
Keywords:
Pyrazolo[3,4-d]pyrimidin-4-ones
COX-2 Selectivity
Docking
Anti-inflammatory activity
Ulcerogenic potential
Ó 2012 Elsevier Ltd. All rights reserved.
Pyrazole ring being predominant pharmacophore for the anal-
gesic and anti-inflammatory activity as evoked in many drugs such
as phenylbutazone, sulfinpyrazone, celecoxib.1,2 Literature survey
also revealed the importance of this ring in biology and proved
its biological significance as anti-inflammatory,3 COX inhibitory,4
antimicrobial,5 CDK inhibitory,6 hypoglycemic7 and CB1 receptor
antagonist8 activities.
Condensed pyrimidines are reported in literature for array of
biological activities. The annelation of the pyrazole ring on the
pyrimidine nucleus lead to pyrazolopyrimidine which can be
looked upon as the bio-isostere of purines (imidazole-pyrimidine).
The biological significance of purine nucleus is well established;
allopurinol and its congener oxypurinol and thiopurinol which
contain pyrazolo[3,4-d]pyrimidine ring inhibit enzyme xanthine
oxidase and interfere with the biosynthesis of uric acid, the causa-
tive agent for gout.1 Pyrazolo[3,4-d]pyrimidine also exhibit analge-
sic and anti-inflammatory,9,10 antifungal,11 antimicrobial,12
antiproliferative,13 anticoagulant,14 antiviral15,16 and adenosine
antagonistic17 activities. The annual death rate amongst patients
with rheumatoid and osteoarthritis due to serious adverse conse-
quences of gastro duodenal ulceration (perforation and hemor-
rhage) has been estimated to be very high.18 Hence, it put forth
great need of NSAIDs to treat arthritis, osteoarthritis, acute pain,
migraine, post operative pain and accidental pain with minimum
adverse effects such as gastric ulcers. The present study describes
the docking, synthesis and evaluation of novel 3-substituted-1-
aryl-5-phenyl-6-anilinopyrazolo[3,4-d]pyrimidin-4-ones for anti-
inflammatory activity and ulcerogenic potential which will further
expand the scope of pyrazolopyrimidines (see Table 1 and Fig. 1).
In an attempt to design and develop novel potential anti-
inflammatory agents, we synthesized target compounds by
reacting ethyl bismethylthio-2-cyanoacrylate19 1 and aromatic
hydrazines 2a–c independently. The reaction was carried out in
dimethyl formamide in the presence of catalytic amount of anhy-
drous K2CO3 for 1.5 to 2 h resulting in ethyl-(5-amino-3-methyl-
thio-1-aryl-5-phenyl-2H-pyrazole)-4-carboxylates 3a–c, which on
independent treatment with S-methyl diphenyl thiourea20 inde-
pendently afforded the structurally diverse 6-anilino substituted
pyrazolo[3,4-d]pyrimidines 4a–c. Synthesis of intermediates and
target compounds has been carried out as depicted in the Scheme 1.
The compounds 4a–c were reacted individually with aromatic
amines like aniline, p-nitroaniline p-toludine and p-chloroaniline
to produced the titled compounds 3-substituted-1-aryl-5-phenyl-
6-anilino pyrazolo[3,4-d]pyrimidin-4-ones 5a–l by nucleophilic
substitution reaction.
⇑
Corresponding author. Tel.: +91 9422340342; fax: +91 240 2381129.
E-mail address: nk_baheti@yahoo.com (K.G. Baheti).
0960-894X/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.bmcl.2012.08.119

S. B. Yewale et al. / Bioorg. Med. Chem. Lett. 22 (2012) 6616–6620
6617
Table 1
where
D
Vc and
D
Vt is arithmetic mean of the increase in paw
Physical characterization of synthesized compounds 3a–c, 4a–c and 5a–l
volume in the control and treated group respectively. The data
was then analyzed statistically using ANOVA followed by
Dunnett’s test. All the results are expressed as mean S.E.M. The
results are expressed as a percentage inhibition of edema forma-
tion (Table 2).
Compd
Mol. Formula
Mol. Weight
% Yield
M.P. (°C)
Rf value
3a
3b
3c
4a
4b
4c
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
C
C
C
C
13H15N3O2S
13H14N4O4S
13H16N4O4S2
24H19N5OS
277
322
356
425
470
504
470
515
549
515
560
594
484
529
563
504
549
584
86
80
76
86
85
89
69
96
72
77
64
70
88
65
71
89
55
68
95–97
0.61
0.70
0.85
0.54
0.60
0.85
0.66
0.32
0.67
0.74
0.59
0.67
0.65
0.58
0.73
0.65
0.44
0.63
161–165
230–233
200–203
300–302
240–242
250–253
325–327
260–265
265–268
341–344
270–275
253–256
333–337
255–257
250–254
346–349
272–274
To predict the COX-2 selectivity, synthesized compounds 4a–c
and 5a–l, standard compounds diclofenac and potent COX-2 inhib-
itor celecoxib were subjected to molecular docking studies on
COX-2 receptor bonded with SC-588 in I 222 space group.24 For
the purpose of assessment of docking of ligands to protein active
sites for estimation of binding affinities of docked compounds, an
advanced molecular docking programme GLIDE (Schrodinger Inc.,
USA) version 4.5 was used. GLIDE; the Grid-based ligand docking
with energetics algorithm approximates a systematic search of
positions, orientations and conformations and eliminates un-
wanted conformations using scoring in the enzyme pocket via a
series of hierarchical filters. Finally the conformations were refined
via Monte Carlo sampling of pose conformation.25,26 X-ray crystal
structure of COX-2 was taken from PDB entry 6 COX having reso-
lution of 2.80 Å (Angstroms). For docking studies all structures
were prepared using protein preparation wizard in Maestro 9.0.
Protein preparation was carried out in two steps viz. preparation
and refinement. Chemical correctness was ensured and water mol-
ecules in crystal structure were deleted and hydrogen atoms were
added at missing positions and bond order for crystal ligand and
protein was adjusted and minimized up to 0.30 Å RMSD. Ligprep
2.2 module in maestro 9.0 build panel was used for ligand prepa-
ration which produced low energy conformations of ligand using
OPLS 2005 force field. Glide provides three different levels of dock-
ing precisions viz. High Throughput Virtual Screening, HTVS; Stan-
dard precision, SP and Extra precision, XP. We carried out our
calculations using XP docking mode as the tool is designed for bet-
ter refinement in ligands.
C24H18N6O3S
C
C
C
C
C
C
C
C
C
C
C
C
C
24H20N6O3S2
29H22N6O
29H21N7O3
29H23N7O3S
29H21N7O3
29H20N8O5
29H22N8O5S
30H24N6O
30H23N7O3
30H25N7O3S
29H21ClN6O
29H20ClN7O3
29H22ClN7O3S
% Yield: refers to the isolated pure compound.
Rf value-mobile phase used was either n-henxane: ethyl acetate 80:20 or chloro-
form: methanol 30:70.
Melting points were determined for isolated pure compounds and are uncorrected.
F
H
N
O
F
F
Ph
N
H
N
CH3
N
N
N
Ph
N
N
S
CH3
S
O
O
O
O
H2N
Celecoxib
NH2
Compound 5i
Active compounds amongst 4a–c and 5g–i were selected for the
ulcerogenic potential studies. The gastric lesions were counted and
an ulcer index (UI) was calculated according to Szelenyl and
Thiemer.21,22
Figure 1. Pharmacophoric pattern of celecoxib and newly synthesized potent anti-
inflammatory compound 5i.
UI ¼ ðn lesions IÞ ꢁ 1 þ ðn lesion IIÞ ꢂ 2 þ ðn lesions IIIÞ ꢁ 3
where I = presence of edema, hyperemia and single, submuco-
sal, punctiform hemorrhages; II = presence of submucosal, hemor-
rhagic lesions with small erosions and III = presence of deep ulcer
with erosions and invasive lesions.
Having secured the intermediate carboxylates 3a–c, pyrazolo-
pyrimidines 4a–c and series of 3-substituted-1-aryl-5-phenyl-6-
anilino pyrazolo[3,4-d]pyrimidin-4-ones 5a–l, in order to search
for the potent compounds, newly synthesized molecules 4a–c
and 5a–l were screened for anti-inflammatory activity and ulcero-
genic potential of most active compounds was determined in order
to investigate their potency and associated side effect.
All the experimental procedures and protocols for anti-inflam-
matory and ulcerogenic potential activities were reviewed and ap-
proved by the Institutional Animal Ethical Committee (IAEC) of Y.B.
Chavan College of Pharmacy, Aurangabad, constituted in accor-
dance with the guidelines of the Committee for the Purpose of
Control and Supervision of Experiments on Animals (CPCSEA),
Government of India. The anti-inflammatory activity of the test
compounds (4a–c and 5a–l) was evaluated using carrageenan-
induced rat paw edema method as described by Winter et al.21
Few of the final compounds from the series (4a–c and 5g–i) were
selected for the determination ulcerogenic potential studies. The
gastric lesions were counted and an ulcer index (UI) was calculated
according to Szelenyl22 and Thiemer.23 Diclofenac sodium and
celecoxib was used as a standard to compare anti-inflammatory
activity and ulcerogenic potential of the test compounds. The
percentage inhibition of edema in each test treated group was
calculated using the formula as given below:
In-vivo anti-inflammatory activity of 3-methylthio-1-aryl-5-
phenyl-6-anilino-2H-pyrazolo[3,4-d]pyrimidin-4(5H)-one 4a–c,
1-aryl-5-phenyl-3-substituted-6-anilino-2H-pyrazolo[3,4-d]pyr-
imidin-4(5H)-one 5a–l derivatives has been presented in Table 2
and some interesting trends were observed as to the effect of ann-
elation and corresponding substitutions. It was found from the re-
sults that the nature of various substituent used affected the
biological activity of the synthesized analogues. The activity data
depicts the anti-inflammatory potential of synthesized compounds
and majority of analogues were found to be active. Derivatives 3-
methylthio-1-aryl-5-phenyl-6-anilino-2(H)-pyrazole[3,4-d]pyrim-
idin-4-(5H)-ones 4a–c proved to be active variably, among them
compound 4c has percent inhibition of 68% as compared to diclofe-
nac sodium having 75% after 1 h. This creates an emphasis for the
presence of p-sulfamoyl substituted phenyl ring on first nitrogen
atom of pyrazole nucleus in this series. This was further proved
when we observed the similar pattern of the activity in the com-
pounds 5c, 5f, 5i and 5l which also possess the p-sulfamoyl
(–SO2NH2) phenyl substituent. All these derivatives exhibited com-
parable activity to diclofenac sodium and celecoxib at same dose
level. The most active derivative 5i possess all the substituents
present in a well known molecule celecoxib. It exhibited the
%Inhibition ¼ 100ð1 ꢀ
D
Vt=D
VcÞ

6618
S. B. Yewale et al. / Bioorg. Med. Chem. Lett. 22 (2012) 6616–6620
O
O
C
SCH3
C2H5O
C
C N
+ H2NHN
SCH3
C2H5O
H3CS
DMF
K2CO3
R
N
H2N
N
R
1
2a-c
3a-c
DMF
N,N-diphenyl
K2CO3
s-methyl thiourea
Ar
N
O
O
Ph
Ph
SCH3
N
N
H
H
H
K CO
DMF,
N
2
3
N
N
Ph
N
Ph
N
N
N
R
N
ArNH2
5a-l
4a-c
R
Compd.
2a
R
Compd.
4b
R
Ar
Compd.
R
Ar
H
NO2
SO2NH2
H
---
---
5f
5g
5h
5i
SO2NH2 p-Nitro phenyl
2b
NO2
SO2NH2
H
4c
H
p-Tolyl
p-Tolyl
2c
5a
Phenyl
Phenyl
NO2
3a
5b
NO2
SO2NH2 p-Tolyl
3b
NO2
SO2NH2
H
5c
SO2NH2
H
NO2
Phenyl
p-Nitro phenyl
p-Nitro phenyl
5j
H
NO2
p-Chlorophenyl
p-Chlorophenyl
3c
5d
5k
5l
4a
5e
SO2NH2 p-Chlorophenyl
Scheme 1. Synthesis of ethyl-5-amino-3-methylthio-1-aryl-2H-pyrazole)-4-carboxylate (3a–c), 3-methylthio-1-aryl-5-phenyl-6-anilino-2H-pyrazolo[3,4-d]-pyrimidin-4-
one (4a–c) and 3-substituted-1-aryl-5-phenyl-6-anilino pyrazolo[3,4-d]pyrimidin-4-ones(5a-l).
Table 2
% Inhibition of rat paw edema and XP docking glide scores for test compounds and standards
Compd
% Inhibition SEM after 1 h
% Inhibition SEM after 2 h
% Inhibition SEM after 3 h
Glide score⁄⁄
4a
4b
4c
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
46.09 1.0⁄
42.14 0.7
68.85 1.2⁄
48.13 2.5⁄
43.94 0.8
60.24 1.2⁄
29.41 0.7⁄
23.87 2.5⁄
66.98 1.0⁄
55.70 0.9⁄
46.64 0.7
77.04 0.5⁄
47.55 1.3⁄
39.56 1.4⁄
69.79 0.7⁄
0.85 0.01
36.63 0.7⁄
37.68 0.8⁄
54.11 1.0⁄
43.38 0.8⁄
40.80 0.6⁄
54.84 0.5⁄
28.96 0.6⁄
19.38 0.9⁄
55.31 1.3⁄
53.40 1.3⁄
39.78 1.0⁄
63.38 0.7⁄
44.00 1.1⁄
38.97 0.4⁄
56.33 1.1⁄
1.11 0.02
57.19 0. 7⁄
58.59 0.5⁄
25.44 2.4
26.57 1.6⁄
35.2 0.6⁄
ꢀ5.6666
ꢀ4.7862
ꢀ7.2379
ꢀ3.6530
ꢀ6.3698
ꢀ6.4872
ꢀ3.3231
ꢀ3.1175
ꢀ3.5942
ꢀ3.5431
ꢀ3.7546
ꢀ6.5485
ꢀ3.6397
ꢀ3.6850
ꢀ7.7415
ꢀ
17.07 2.0⁄
14.11 1.6⁄
39.65 1.0⁄
15.08 1.0⁄
16.76 0.7⁄
39.09 1.5⁄
32.92 0.6⁄
30.24 0.6⁄
43.66 0.6⁄
28.65 0.7⁄
20.63 0.7⁄
38.30 0.3⁄
1.08 0.41
42.83 2.3⁄
39.62 1.1⁄
Control
Diclofenac
Celecoxib
75.77 0.6⁄
78.09 0.7⁄
ꢀ4.8753
ꢀ5.9177
n = 6, mean paw volume SEM anaylsed by ANOVA followed by Dunnett’s test ⁄p <0.05, ⁄⁄—denotes g-score or docking score obtained for XP docking with 6 COX (PDB ID).
percent inhibition of 77%, 63% and 43% after 1, 2 and 3 h of
administration.
itself that is ꢀ5.9177. Among the other synthesized compounds,
4c, 5b, 5c, 5i, and 5l predicted to have better COX-2 affinity than
celecoxib with 4a depicting COX-2 affinity comparable to cele-
coxib. Molecules 4c and 5l have exceptionally high docking scores
in series which are ꢀ7.2379 and ꢀ7. 7415. Rest of the derivatives
viz 4b, 5a, 5d-h, 5j and 5k were shown docking scores in between
ꢀ3.1175 to ꢀ4.7862 which is less than the score obtained for dic-
lofenac which predicts their nonselective nature. Study of Binding
Prediction of COX-2 selectivity of compounds was evaluated
with potent and selective COX-2 inhibitor celecoxib and to ascer-
tain non-selective nature of synthesized derivatives; diclofenac
was also subjected to COX-2 docking studies which revealed that
the potent anti-inflammatory and less ulcerogenic molecule 5i
showed glide score ꢀ6.5485 which is more than that of celecoxib

S. B. Yewale et al. / Bioorg. Med. Chem. Lett. 22 (2012) 6616–6620
6619
Table 3
Evaluation of ulcer index
USA). All India Council for Technical Education, (AICTE) New Delhi
for financial assistance towards purchase of docking software,
Schrodinger Maestro-9.0 with GLIDE (Schrodinger Inc., USA) ver-
sion 4.5 and Ethicon (Johnson and Johnson Ltd.), Aurangabad,
(MS), India for providing Wistar Albino Rats to encompass pharma-
cological screening.
Compd
Dose(mg/kg)
Time(days)
Ulcer Index
Control
Diclofenac
Celecoxib
4a
4b
4c
5g
5h
5i
–
4
4
4
4
4
4
4
4
4
0
75
75
75
75
75
75
75
75
39.17 1.08⁄
9.58 0.71⁄
4.66 1.14⁄
7.50 1.26
7.83 1.17⁄
3.20 1.27⁄
16.72 0.48⁄
9.50 1.84⁄
References and notes
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Jersy, 2003; vol. 4, pp 235–244.
Each value represent the mean SEM, n = 6 analyzed by ANOVA followed by
Dunnett’s test ⁄p <0.05.
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modes of the synthesized test compounds 4a–c and 5a–l depicts
pie-pie stacking between benzene rings and amino acids Proline
(Pro A:538) of 6 COX, along with same type interaction for pyrazole
nucleus of all synthesized derivatives with amino acid Phenyl Ala-
nine (Phe B:142) as a common interaction. When docking interac-
tions pertaining to discrete chemical substitutions attached were
compared we observed that; the compounds substituted with p-
nitro phenyl moiety on first nitrogen of pyrazole nucleus have ionic
interactions with either Asparagine B:537 as in 5d, 5e, 5f or Valine
B:228 and with both as in case of compound 4a, 4c. Some of the
typical binding modes noticed for molecules with high glide score
were; for 4c; amino function and oxygen belonging to sulphona-
mide group formed hydrogen bonding with Valine (Val A:228)
and Histidine (His A:226).
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Selected compounds 4a–c and 5g–i when tested for the possible
ulcerogenic potential, the findings were that the compounds with
phenyl substitution at first position and p-toludinyl substitution
at third position showed very few sign of redness. Among the
tested compounds, 5g found to be least ulcerogenic with ulcer in-
dex of 3.20. The most active compound of the series 5i showed the
ulcer index of 9.5 whereas diclofenac sodium exhibited ulcer index
of 39.17 and celecoxib exhibited of ulcer index with value 9.58.
Ulcerogenic potential of substituents of compounds can be sum-
marized as COOH > NO2 > SO2NH2 > Phenyl > tolyl Table 3.
In summary, a series of novel 3-substituted-1-aryl-5-phenyl-6-
anilino pyrazolo[3,4-d]pyrimidin-4-ones has been prepared and
assigned structures by analytical and spectral data. The results of
the anti-inflammatory activity of the series showed that the com-
pounds exhibited moderate to good anti-inflammatory activity.
The compound 5i was found to be superior to reference drug dic-
lofenac sodium and comparable to celecoxib where as compound
4c, 5c, 5f and 5l showed comparable activity diclofenac sodium.
The ulcer index of the compound 5i was found to be less than cele-
coxib and diclofenac sodium. The COX-2 docking score of com-
pound 5i was found to be better than celecoxib. Hence this series
could generate precursors which can be further optimized and
developed for a novel lead compounds for emerging drug design
and drug discovery of anti-inflammatory compounds.
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Notes-Pharmacological Screening-Healthy Wistar Albino rats of either sex
weighing 150–180 g were used for study. Diclofenac sodium and celecoxib at
25 mg/kg was administered orally as a standard drug for comparison of anti-
inflammatory activity and ulcerogenic potential. The test compounds were
administered orally at a dose of 25 mg/kg suspended in 1% Tween 80 with
distilled water. The paw volumes were measured using the mercury
displacement technique with the help of Ugo Basile Digital Plethysmometer
at 0, 1, 2 and 3 h after carrageenan injection(0.1 ml, 1%w/v solution).
Docking-2D structures were converted to 3D stereoisomers were generated,
charged structures were neutralized and most probable ionization state at user
defined pH was determined. Conformations were generated using rapid torsion
angle search approach followed by minimization in OPLS force field 2005.
Evaluation is done with glide score (docking score) and single best pose is
Acknowledgments
Authors are grateful to Padmashree Mrs. Fatma Rafiq Zakaria,
Chairman, Maulana Azad Educational Trust, Aurangabad for pro-
viding the facilities, Dr. Jagdish Baheti and Prof. Vishal Gulecha of
Department of Pharmacology, SSDJ College of Pharmacy, Chand-
wad, (MS), India for their help in evaluation of anti-inflammatory
activity, Dr. S.J. Suarana, Principal, R.C. Patel Institute of Pharma-
ceutical Education and Research, Shirpur, (MS), India for providing
advanced molecular docking programme Glide (Schrodinger Inc.,
generated as output for particular ligand.
G Score is expressed as
Gscore = a ꢁ vdW + b⁄coul + Lipo + H bond + Metal + Bury P + Rot B + Site
Where, vdW is Van der Waal’s energy, Coul is coulomb energy, Lipo is
lipophilic contact term, H-Bond is hydrogen-bonding term, Metal is metal
binding term, BuryP is penalty for buried polar groups, RotB is penalty for
freezing rotatable bonds, Site is polar interactions at the active site and the
coefficients of vdW and Coul are a = 0.0065, b = 0.130. Chemscore and atom-
atom pair function assigns score to lipophilic ligand atoms based on
summation over a pair function; each term of which depends upon inter

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atomic distance between a ligand atom and a neighboring lipophilic protein
atom.
Evaluation of Ulcerogenic Potential-The male Wistar Albino rats weighing 170–
200 g were divided into eight groups each comprising of six rats, including a
control and standard group. The test compounds and standard diclofenac
sodium (dose 75 mg/kg/day) were suspended separately in 4 ml of 1% w/v
solution of tween 80 with water and administered orally on all 4 days. The rats
of all groups were fasted for 12 h after the administration of last dose,
thereafter they were sacrificed by decapitation and stomach was removed and
opened along with greater curvature and washed with distilled water and
Krebs solution.