Synthesis, characterization, and anti-rheumatic potential of phthalazine-1,4-dione and its Cu(II) and Zn(II) complexes

Article abstract of DOI:10.1007/s00044-013-0827-6

Two new metal complexes derived from the reaction of 2-[(2-hydroxybenzoyl) 2,3,4a,5,10,10a-hexahydro- 5,10[1′,2′]-benzenobenzo[ g]phthalazine-1,4-dione] (HBPD) with Cu(II) and Zn(II) have been synthesized and characterized by using elemental analysis, spectral analysis (UV-Vis, IR, ¹H NMR, ¹³C NMR), conductance, thermal analysis, and magnetic moments. The in vivo collagen-adjuvant arthritis model in rats revealed a significant antioxidant, analgesic, and anti-rheumatic effects for HBPD and its copper and zinc complexes in comparison with standard piroxicam. The results showed that, the investigated Cu and Zn complexes have higher anti-inflammatory activity than the free ligand. Springer Science+Business Media 2013.

Full text of DOI:10.1007/s00044-013-0827-6

MEDICINAL
CHEMISTRY
RESEARCH
Med Chem Res (2014) 23:2536–2542
DOI 10.1007/s00044-013-0827-6
ORIGINAL RESEARCH
Synthesis, characterization, and anti-rheumatic potential
of phthalazine-1,4-dione and its Cu(II) and Zn(II) complexes
•
Yousery E. Sherif Nasser M. Hosny
Received: 17 May 2013 / Accepted: 3 October 2013 / Published online: 26 October 2013
Ó Springer Science+Business Media New York 2013
Abstract Two new metal complexes derived from the
reaction of 2-[(2-hydroxybenzoyl) 2,3,4a,5,10,10a-hexa-
hydro-5,10[10,20]-benzenobenzo[g]phthalazine-1,4-dione]
(HBPD) with Cu(II) and Zn(II) have been synthesized and
characterized by using elemental analysis, spectral analysis
Introduction
Heterocyclic compounds containing phthalazine moiety are
considered an important class of organic compounds, due
to their pharmacological activities (Al-Assar et al., 2002;
Jain and Vederas, 2004; Carling et al., 2004). Phthalazines
have wide pharmacological applications as anticonvulsant,
1
(UV–Vis, IR, H NMR, 13C NMR), conductance, thermal
analysis, and magnetic moments. The in vivo collagen-
adjuvant arthritis model in rats revealed a significant
antioxidant, analgesic, and anti-rheumatic effects for
HBPD and its copper and zinc complexes in comparison
with standard piroxicam. The results showed that, the
investigated Cu and Zn complexes have higher anti-
inflammatory activity than the free ligand.
`
(Zappala et al., 2000) cardiotonic, (Nomoto et al., 1990),
vasorelaxant agents (Watanabe et al., 1998), anti-bacterial
agents (Berghot, 1992, 2001), and hypertensive agents
(Pende et al., 1996).
Experimental evidences of research work collected by
many groups proved that, the coordination of Cu(II) by
nonsteroidal anti-inflammatory drugs (NSAIDs) improves
the pharmaceutical activity of the drugs themselves and
reduces their undesired toxicity effects. Walker et al. (1975)
have shown that the species of molecular weight below 500
will be active chemicals against rheumatoid arthritis. These
low molecular weight fractions are bonded to serum albu-
min. The anti-arthritic activity of these endogenous agents is
suggested to be through a mechanism, which encourages the
release of albumin bound copper in the blood to facilitate its
availability at the site of inflammation (Jackson et al., 1978).
The copper complexes of these low molecular weight species
are free radical scavengers of the superoxide dismutase and
their anti-oxidant activities protect the synovial tissue from
hydroxyl and superoxide radical anion O-2 (Richardson,
1976; Oyanagui, 1976; Regan et al., 2005).
Keywords Benzenobenzo[g]phthalazine-1,4-dione ꢀ
Copper and Zinc complexes ꢀ Anti-rheumatoid activity
Electronic supplementary material The online version of this
article (doi:10.1007/s00044-013-0827-6) contains supplementary
material, which is available to authorized users.
Y. E. Sherif (&)
Chemistry Department, Faculty of Science and Arts, Ulla,
Taibah University, Medina, Kingdom of Saudi Arabia
e-mail: youserysherif@gmail.com; youserysherif@hotmail.com
Sorenson showed that, the metal ion plays an important
role, in conversion the inactive substances to potent
NSAIDs when used in the form of their metal complexes
and the resulting complexes of NSAIDs are much more
effective than the free drugs (Sorenson, 1982).
Y. E. Sherif
Clinical Pharmacology Department, Faculty of Medicine,
Mansoura University, Mansoura, Egypt
N. M. Hosny
Chemistry Department, Faculty of Science, Port Said University,
Port Said, Egypt
The wide applications of phthalazines and the above
findings have prompted us to investigate the anti-rheumatic
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Med Chem Res (2014) 23:2536–2542
2537
Synthesis of the metal(II) complexes
activity of phthalazine-1,4-dione derivative and some of its
metal complexes.
A mixture containing 2-[(2-hydroxybenzoyl) 2,3,4a,5,10,
10a-hexahydro-5,10[10,20]-benzenobenzo[g]phthalazine-1,
4-dione] (HBPD) (6 mol) in 25 ml ethanol and acetate salt
of Cu(II) or Zn(II) (3 mol) in 10 ml H2O was heated under
reflux on a water bath for 6 h. The formed precipitate was
filtered off, washed with hot water, hot ethanol, diethyl-
ether, and finally dried in a vacuum desiccators over
anhydrous CaCl2.
Herein, new Cu(II) and Zn(II) complexes of 2-[(2-hy-
droxybenzoyl) 2,3,4a,5,10,10a-hexahydro-5,10[10,20]-benze-
nobenzo[g]phthalazine-1,4-dione] (HBPD) were synthesized
to investigate the effect of the coordinated metal ion on the
anti-inflammatory activity of the free ligand. The isolated
complexes have been characterized by different physico-
chemical techniques and their anti-inflammatory and anti-
oxidant activities have been studied.
[Zn (HBPD)2]
Experimental
It was obtained as white solid, m.p. 280 °C. IR 3385(br,
NH, OH), 1716(CO), 1598(CO benzoyl). 1H NMR
(DMSO-d6)3.28 (br, S, 2H, C11-H, C12-H), 4.75(br,S, 2H,
C9-H,C10-H), 6.94–7.43(m, 12H, Ar–H), 10.85(br,S,1H,
NH). 13C NMR (DMSO-d6 100 MHz) MS: m/z [M?1]?
411.1. Anal. calcd. for C25H18N2O4: C, 73.20; H, 4.0; N,
13.65. Found: C, 73.60; H, 4.40; N, 14.10. 13C NMR
(150 MHz, DMSO-d6) d(ppm) :173.4(2C,2C4),171.2(2C,
C1), 166.5(2C,C4), 162.3(2C,C3-), 143.5(2C,C5a), 143.1(2C,
C5a), 140.7(2C,C9), 132.5(2C,C6-), 130(2C,C7-), 126(4C,
C6), 125.1(4C,C7), 123.9(4C, C8), 122.6(2C,C-2 ), 118.7(2C,C4-),
49.5(C4a), 48.8(C4a), 44.9(C10a), 44.5(C10a), 40.1 (C5), 40(C5),
39.9(C10), 39.7(C10). Anal. calcd. for Zn(C25H18N2O4)2: C,
68.40; H, 4.50; N, 12.65; M, 7.50. Found: C, 68.04; H, 4.0;
N,12.91; M, 7.40.
All chemicals were of analytical grade and were used
without further purification. Melting points were recorded
on Gallenkamp electric melting point apparatus and were
uncorrected. Carbon and hydrogen contents were deter-
mined at the Microanalytical Unit of Cairo University.
Molar conductance measurements of the complexes
(10-3 M) in DMSO were carried out with a conductivity
bridge YSI model 32. Metal analysis was carried out by
standard methods (Vogel, 1961). Infrared spectra were
measured using KBr disks on a Mattson 5000 FTIR spec-
trometer. Electronic spectra were recorded on UV2 Unicam
UV–Vis spectrometer using 1-cm stoppered silica cells.
Thermal analysis measurements (TGA, DTG) were carried
out on a Shimadzu model 50 H instrument. The nitrogen
flow rate and heating were 20 cm3/min and 10 °C/min.
Magnetic measurements were carried out on a Sherwood
Scientific Magnetic Balance. 1H NMR spectra were
obtained on a JEOL Spectrophotometer at 500 MHz, using
TMS as an internal reference and DMSO-d6 as solvent.
[Cu (HBPD)(OH)2H2O]
It was obtained as green solid m.p. [300 °C. IR 3285(br,
NH, OH), 1707(CO), 1598(CO benzoyl). Anal. calcd. for
Cu(C25H23N2O7): C, 57.10; H, 4.40; N, 5.31; M,12.1.
Found: C, 57.20; H, 4.20; N,5.80; M, 11.6.
Preparation of the ligand 2-[(2-hydroxybenzoyl)
2,3,4a,5,10,10a-hexahydro-5,10[10,20]-
Pharmacological testing
benzenobenzo[g]phthalazine-1,4-dione] (HBPD)
Measurement of joint inflammation and pain tolerance
A solution of1,3-dihydroanthra[2,3-c]furan (2.76 g, 0.01 mol)
and 2-hydroxybenzohydrazide (1.52 g, 0.01 mol) in DMF
(20 ml) was refluxed for 8 h. The reaction mixture was poured
into a beaker containing ice and the separated product was
crystallized from DMF/EtOH, according to the previously
reported method (Khalil et al., 2011). It was obtained as white
solid, m.p. 238 °C. IR 3260(br, NH, OH), 1723(CO), 1659(CO
benzoyl). 1H NMR (DMSO-d6) 3.22(br, s, 2H, C11-H, C12-H),
4.80(br, s, 2H, C9-H, C10-H), 7–8.0(m, 12H, ArH), 10.8(br,
s1H, NHCO), 11.4(br, 1H, OH).13C NMR (150 MHz, DMSO-
Thirty-six Sprague–Dawley rats (200–250 g) were fed on a
standard rat chow and water ad labium. Animal care and
experiments were performed in accordance with NIH guide
to the care and use of laboratory animals. The animals were
divided into two main groups (non-arthritic control and
arthritic group). In the arthritic group, all rats were inoc-
ulated with collagen adjuvant into the left paw pad. Rats
which developed right paw arthritic manifestations after
45 days were divided into eight groups as follow, non-
arthritic non-treated, arthritic control, piroxicam treated,
ligand, acetate salt of Cu(II), acetate salt of Zn(II), Cu
complex treated, and Zn complex treated. The compounds
were given orally via gastric tube once daily in a dose
-
´
d6) d(ppm) :173.4(2C, C1, C1 ), 162.3(C4), 158.8(C3),
141.9(2C, C5), 139.0(2C, C9a), 134.8 (C6-), 129.0 (C7-),
126.8(2C, C6), 126.3(2C, C9), 124.9 (2C, C7), 124.3 (2C, C8),
119(C2-), 117(C4-), 44.4(C4a), 44.3(C10a), 39.7(C5),
39.1(C10).
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Med Chem Res (2014) 23:2536–2542
which calculated according to Paget’s table for 7 days
(Toman and Guy, 1964). Most of the previous compounds
are insoluble in water, thus it was suspended in 0.5 %
sodium carboxymethyl cellulose 1 mg per 200 g of rat
weight. This model of Collagen–Adjuvant Arthritis
(Trentham et al., 1977; Holmdahl et al., 1993; Waksman
et al., 1960) is considered a representative of rheumatoid
arthritis or ankylosing spondylitis in humans. Collagen II–
Freund’s adjuvant emulsion (0.1 ml) was injected intra-
dermally into the left hind foot paw pad of each rat (if no
arthritis developed within 4 weeks, some of the animals
were challenged by a second inoculation). After 45 days,
the systemic arthritis developed in both hind paws (Wood
et al., 1969). Joint inflammation right ankle periarticular
edema or rheumatoid index was based on severity and
extent of the erythema and edema of the periarticular tissue
and the enlargement, distortion, or ankylosis of the joints.
The inflammation was graded on a scale from one to four.
Grade four; the joint distorted and ankylosed, three;
markedly enlarged, two; erythematous with edema, and
one; normal (Randall and Selitto, 1957). Each of the six
non-arthritic, non-treated rats had a score of one. Right paw
pad thickness and joint scoring were measured at the 7th
day after starting drug treatment (52 days after complete
Freund’s adjuvant injection).
Results and discussion
The formulae [Cu(HBPD)OH.2H2O] and [Zn(HBPD)2]
represent the complexes formed from the reaction of 2-[(2-
hydroxybenzoyl) 2,3,4a,5,10,10a-hexahydro-5,10[10,20]-
benzenobenzo[g]phthalazine-1,4-dione] with Cu(II) and Zn
(II).
The isolated solid complexes are stable at room tem-
perature (25 °C), non-hygroscopic, insoluble in water and
most common organic solvents but are easily soluble in
DMF and DMSO. The complexes are non-electrolytes as
revealed from their lower values (4.0–9.0 X-1cm2mol-1
)
measured for 1 9 10-3 M in DMSO at 25 °C (Geary,
1971).
IR spectra
The most important infrared bands of the ligand and its
complexes with their probable assignments are given in
(Table 1). The ligand may exist in two possible tautomeric,
keto-enol forms (Fig. 1a, b). IR spectrum of the ligand
exhibits bands at 3425, 3260, 1723, and 1659 cm-1
attributed to m (OH), m (NH), m (4C=O), and m (-1C=O),
respectively (Khalil et al., 2011). The presence of a band
assigned to m (NH) indicates the presence of the free ligand
in the keto form.
Proximal joint (right ankle) mobilization tolerance (pain
scoring) was graded from one to four. Grade one corre-
sponds to tolerance of complete flexion 90°; degrees two,
three and four correspond to increasing degree of maltol-
erance according to a rat hind limb withdrawal, squeaking
and when the flexion becomes painful. Degree four corre-
sponds to squeaking with just initiation of flexion. Each of
the six non-arthritic, non-treated rats had a score of one
(Ghosh and Schild, 1971). This measurement of mobili-
zation tolerance was done at the 7th day of drug treatment
(52 days after complete Freund’s adjuvant injection).
The spectra of the two complexes show the disappear-
ance of the band at 3425 cm-1 assigned to m (OH), indi-
cating that this group takes part in coordination after
deprotonation. The band assigned to (-1C=O) is shifted to
the region 1598–1602 cm-1, indicating the participation of
this group in bonding. Also, the spectra of the complexes
show several new weak bands arround 455 cm-1 assigned
to m(M–O) (Nakamoto, 1970). The spectrum of Cu com-
plex [Cu(HBPD)OHꢀ2H2O] has a sharp band at 3542 cm-1
assigned to free OH (Nakamoto, 1970). From the above
findings it could be concluded that, the ligand is bonded to
Cu(II) and Zn(II) ions as mononegative (tri- and bidentate,
respectively) through carbonyl oxygen and enolic hydroxyl
after deprotonation (Figs. 2 and 3).
Measurement of oxidant stress and rheumatoid factor (RF)
Serum malondialdehyde (MDA) as lipid peroxidation was
measured by the thiobarbituric acid (TBA) test. The sample
is treated with TBA at low pH, and a pink chromogen is
measured. In the TBA reaction, one molecule of MDA reacts
with two molecules of TBA with production of a pink pig-
ment with an absorption maximum at k = 532–535 nm
(Draper and Hadley, 1990). Rheumatoid factor (RF) was
estimated using standard method (Draper and Hadley, 1990).
1H NMR
1H NMR spectrum of Zn complex recorded in DMSO-d6
shows the disappearance of the signal at 11.4 ppm assigned
to (OH) in the spectrum of the free ligand (Khalil et al.,
2011), indicating the deprotonation of this group on coor-
dination to the metal ion. The spectrum shows also singlet
signals at 3.28, 4.75 ppm and multiplet signal in the region
6.94–7.43 ppm, assigned to –CH, –CH, and phenyl rings
protons, respectively. The spectrum of Zn complex shows
singlet signal at 10.85 ppm, assigned to the amidic –CONH
proton. The presence of this signal in its position as the free
Statistical analysis
Results were expressed as mean standard error and the
data were subjected for multiregression analysis.
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Med Chem Res (2014) 23:2536–2542
2539
Table 1 IR spectra of the ligand HBPD and its metal complexes
Compound
m(OH)
m(OH)
m(NH)
m(4C=O)
m(-1C=O)
m(M–O)
free
HBPD
–
3,425
3,260
3,285
3,385
1,723
1,707
1,716
1,659
1,602
1,598
–
[Cu (HBPD).(OH).2H2O]
[Zn (HBPD)2]
3,542
–
–
–
455
460
OH
-
6
O
10
5a
-
6
9
1
10
9
5a
1
-
N2
N 3
5
-
8
-
7
2
5
-
-
8
7
NH
-
-
1
4
-
4
N 3
4
-
2
1
5a
4
7
8
-
5a
7
8
6
9a
2
5
3
-
6
9a
5
3
-
5a
6
O
9
O
5a
O
9
O
OH
OH
6
(b)
7
(a)
7
Fig. 1 Keto (a) and enol (b) tautomeric forms of the ligand
ligand indicates that, the ligand coordinates to the metal ion
in the keto form.
O
NH
N
Electronic spectra and magnetic moment of Cu
complex
O
O
The electronic spectrum of the copper(II) complex in Nujol
shows a broad band at 16891 cm-1, indicating the presence
of distortated octahedral geometry around Cu(II) (Lever,
1986). The band recorded at 22727 cm-1 is suggested to
LMCT. The magnetic moment value (1.8 B. M.) is in the
range reported for Cu(II) complexes with one unpaired
electron, the disappearance of the subnormal magnetic
moment indicates the absence of metal–metal interaction
due to polymerization and support the presence of mono-
meric form of Cu complex (Cotton and Wilkinson, 1980).
1
O
2
Cu
HO
OH2
OH2
Fig. 2 Suggested structure for Cu(II) complex
Thermal studies
O
-
10
9
6
5a
1
2
-
5
-
-
8
7
The thermal analysis (TGA and DTG) curves of the com-
plexes were carried out within a temperature range from
25 °C up to 800 °C. The determined temperature range and
percent losses in mass of the solid complexes are given in
Table 2.
NH
-
3
4
1
4
N
-
5a
7
2
6
9a
5
3
-
5a
O
9
O
O
7
6
8
Zn
8
7
6
Thermal analysis curves (TGA and DTG) of Cu com-
plex show decomposition in the temperature range
140–240 °C. This step corresponds to the loss of two
molecules of water of coordination and one hydroxo group
(calcd. 9.9 %: found 8.5 %). The second step of decom-
position lies in the temperature range 240–290 °C, corre-
sponding to loss of C24H18O3N2 and CO (calcd. 76.8 %:
found 78.0 %). The residue is CuO with estimated mass
15.5 %, close to the calculated 15.1 %.
7
O
9
5a
O
O
a
9
5
6
3
-
-
a
5
-
2
4
4
-
3 N
1
-
8
HN
5
-
7
2
-
1
a
5
9
6
10
O
Fig. 3 Suggested structure for Zn(II) complex
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Med Chem Res (2014) 23:2536–2542
Table 2 Thermoanalytical
results (TG) of Cu(II) and Zn(II)
complexes
Complex
T range (°C)
Mass loss Estd (Calcd. %)
Assignment
[Cu (HBPD)(OH).2H2O]
120–240
240–290
290–500
50–187
8.5 (9.9)
76.81 (78.0)
15.5 (15.1)
4.5 (3.8)
Loss of 2H2O ? OH
Loss of C24H18O3N2 ? CO
Residue CuO
[Zn (HBPD)2]
Loss of 2OH
187–334
334–390
390–500
41.6 (39.8)
30.0 (32.2)
23.9 (22.7)
C28H20
C16H4 C8O4
Residue ZnC6H6O4
The thermogram of zinc complex shows that, it decom-
poses in the temperature range 50–187 °C. This stage cor-
responds to the loss of 2OH (calcd. 3.8 %: found 4.5 %). The
second stage lies in the temperature range 187–334 °C and
corresponds to the loss of C28H20 (calcd. 39.8 %: found
41.6 %). The third step lies in the temperature range
334–390 °C. This stage corresponds to the loss of
C16H4C8O4 (calcd. 32.2 %: found 30.0 %). The remaining
residue is assigned to ZnC6H6O4 (calcd. 22.7 %: found
23.9 %).
NSAIDs (Sorenson, 1982). Moreover, Sorenson demon-
strated that Cu(II) complexes also have anti-ulcer effects.
It is known that zinc possess anti-ulcer effect (Fraser
et al., 1972) besides its anti-inflammatory activity (Simkin,
1976). It was noticed that most rheumatic diseases are
accompanied by low serum zinc levels. It has also been
found that complexes of zinc with some drugs as aspirin
(Singla and Wadhwa, 1994) and indomethacin (Singla and
Wadhwa, 1995) are more potent with reduced ulcerogenic
ability than their parent drugs.
For the above reasons, we have studied the anti-
inflammatory activities of the complexes derived from
Cu(II) and Zn(II) with 2-[(2-hydroxybenzoyl) 2,3,4a,5,10,
10a-hexahydro-5,10[10,20]-benzenobenzo[g]phthalazine-1,
4-dione] and compared their anti-inflammatory activities
with the free ligand and standard piroxicam.
Anti-inflammatory and analgesic effect
Metal ion complexation of naproxen is advantageous for
the transport of naproxen into the cells as supported by the
fact that the transport of organic ligands into the cells can
be facilitated by the formation of metal complexes. This
concept was invoked to explain the transport and storage of
catecholamine (Albert, 1985). It was long ago established
by Sorenson that, inactive substances can become potent
NSAIDs and much more effective than their parent drugs
when administrated in the form of Cu complexes of
The data presented in Table 3 show that piroxicam, as a
standard anti-rheumatic drug, was able to modify positively
the rheumatoid index (RI), pain tolerance, and pain scoring
against the positive control (arthritic non-treated).
Both Cu and Zn complexes treated groups appeared to
have a significant reduction in right pad thickness by the
Table 3 Influence of copper acetate, zinc acetate, standard piroxicam, the ligand, Cu and Zn complexes on rheumatoid factor, pain tolerance,
and mobilization tolerance in adjuvant-induced rheumatoid arthritis model in rats (M S.E)
Group
Dose (mg 200 g-1
according to
Paget’s tablea
)
Pain tolerance
n = 6
Proximal joint
mobilization
tolerance n = 6
MDA (nmol ml-1
n = 6
)
RF (IU ml-1
)
n = 6
Non-arthritic non-treated
Arthritic non-treated
Cu(Ac)2.2H2O
[SCMC]
[SCMC]
0.22
1.0 0.00
3.92 0.09?,=
1.00 1.18
3.3 0.6*
1.0 0.0
178 2.1
528 71.0?,=
3.7 0.22?
3.0 0.25?
2.5 0.22
4.17 0.81?
2.67 0.26
2.33 0.31
2.66 0.21
2.6 0.09?,
*
2.63 0.16?,
5.00 0.45
2.05 0.24?,
5.00 0.29
5.00 0.36
4.17 0.46
*
385 21.0?,
400.0 22.0
325 10.0?,
*
,=
,=
,=
Zn(Ac)2.2H2O
0.23
1.83 0.31
2.12 0.12?,
3.00 0.26
Piroxicam
0.36
*
*
*
,=
,=
,=
HBPD
0.36
48.0 2.1?,
40.0 2.0?,
45.0 3.0?,
*
*
*
[Cu [(HBPD)(OH).2H2O]
[Zn (HBPD)2]
0.96
2.83 0.31?,
2.50 0.43?,
*
*
0.96
SCMC 0.5 % sodium carboxymethyl cellulose
?
P \ 0.001 versus non-arthritic control
=
P \ 0.01 versus piroxicam
* P \ 0.01 versus arthritic control
a
Ghosh and Schild, 1971)
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Med Chem Res (2014) 23:2536–2542
2541
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7th day as compared with that of the arthritic non-treated
group (Table 3). It is clear that Cu and Zn complexes have
higher reduction in right pad thickness by the 7th day as
compared with the free ligand THBTD (group 6), indi-
cating that, coordination of the metal to the ligand
improved its activity. The anti-inflammatory improvement
of Cu and Zn complexes were clearly observed from the
data of the measured RF in the treated group.
Also, the results indicate that, the tested compounds did
not improve proximal joint mobilization tolerance.
Measurements of antioxidant activity of serum MDA
showed that both Cu and Zn complexes have antioxidant
activity as indicated by their lowering effect on serum
malonaldehyde level. The mechanism of the antioxidant
activity of the Cu and Zn complexes in the body involves
redox cycling at the metal center. So, it could be suggested
that the anti-inflammatory action of Cu and Zn complexes
may result from redox activity of Cu and Zn in particular
their ability to scavenge the highly reactive pro-inflam-
matory superoxide radical (Ahmad, 1995).
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Conclusion
The metal complexes of Cu(II) and Zn(II) with 2-[(2-hy-
droxybenzoyl) 2,3,4a,5,10,10a-hexahydro-5,10[10,20]-ben-
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complexes. The anti-inflammatory activity has been com-
pared with standard piroxicam. The metal complexes of
Cu(II) and Zn(II) have higher activity compared with the
free ligand HBPD.
Acknowledgments This work was supported by Taibah University,
KSA, Project No. 433/1969 year: 2012. Also, we gratefully acknowl-
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