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2673
Table 2. Effect of N-arylphthalamic acid treatment on mice plasma cholesterol and triglyceride levels
Compd
Cholesterol (mmol/L)
Triglycerides (mmol/L)
Weight (g)
Before
After
Before
After
Before
After
a
b
c
d
e
f
g
h
2.71ꢂ0.26
2.11ꢂ0.30
2.17ꢂ0.43
2.30ꢂ0.25
3.06ꢂ0.54
3.02ꢂ0.57
2.66ꢂ0.35
2.45ꢂ0.22
2.46ꢂ0.33
2.32ꢂ0.41
3.06ꢂ0.23*
2.43ꢂ0.32*
2.48ꢂ0.54*
2.51ꢂ0.22*
3.40ꢂ0.53*
3.28ꢂ0.54*
3.17ꢂ0.22*
2.78ꢂ0.25***
2.95ꢂ0.32***
2.30ꢂ0.40
1.07ꢂ0.16
1.06ꢂ0.30
1.04ꢂ0.291.28
0.86ꢂ0.20
0.94ꢂ0.26
1.01ꢂ0.08
1.26ꢂ0.12
1.14ꢂ0.23
1.12ꢂ0.17
1.09ꢂ0.12
1.30ꢂ0.24*
1.32ꢂ0.31*
ꢂ0.33*
28ꢂ5.7
26ꢂ4.2
24ꢂ5.1
25ꢂ4.1
26ꢂ4.1
26ꢂ2.3
20ꢂ3.5
35ꢂ0.0
35ꢂ2.7
29ꢂ.1.7
29ꢂ5.7
29ꢂ4.4*
28ꢂ5.7*
28ꢂ3.5
1.06ꢂ0.22*
1.23ꢂ0.27*
1.35ꢂ0.08*
1.48ꢂ0.10*
1.58ꢂ0.32**
1.49ꢂ0.26**
1.09ꢂ0.12
30ꢂ5.0*
29ꢂ2.9*
25ꢂ6.1*
38ꢂ0.83***
39ꢂ2.82***
30ꢂ1.0
i
CMC
Values represent the meanꢂSD for six animals in each group. Significant differences: *p<0.05, **p<0.005 and ***pꢂ0.001.
the fluorophenyl series, p-fluorophenylphthalamic acid
(3g) was found to be more active in increasing the cho-
lesterol level; although meta-fluorophenylphthalamic
acid (3f) has been less effective in terms of increasing
cholesterol (9% elevation), it proved to be the most
active in developing hypertriglyceridemia (34%
increase). On the other hand, the new compound N-
[1,2,4]triazol-4-yl-phthalamic acid (3i) afforded the best
hypercholesterolemic activity (20% increase), whilst the
best hypertriglyceridemic activity was found with com-
pound N-(1H-[1,2,4]triazol-3-yl)phthalamic acid (3h)
(39% increase). Except for the control group and com-
pounds 3a and 3d, the mice body weight was sig-
nificantly increased after 14 days of drugs’ treatment
(Table 2).
Samples of plasma were used in duplicate to determine
the plasma cholesterol and triglyceride levels by using
enzymatic assay CHOD-PAP28 (by the action of cho-
lesterol esterase, cholesterol oxidase and peroxidase
contained in Merck test 1.14830.0001), Ecoline 25
reagents (diagnostica-Merck KGaA, Darmstadt, Ger-
many) and GPO-PAP29 (by the enzymes lipase, glycer-
okinase, glycerol phosphate oxidase and peroxidase
present in Merck test 1.19706.0001 System Multi-Test)
according to the manufacturer’s instructions, respectively.
The results are expressed as the meanꢂstandard error
and they were evaluated statistically using the paired
Student t-test and p<0.05 as the criterion of statistical
significance.
The preliminary results suggest that these drugs are able
to develop hyperlipidemia in mice, which may be of
interest for experimental purposes, like inducing
hypercholesterolemia and hypertriglyceridemia in ani-
mals followed by testing of new hypolipidemic drugs.
This is based on the fact that hyperlipidemic animal
models have been largely used to study coronary artery
disease, and it would be advantageous to test the biolo-
gical effect of antihyperlipidemic drugs. It is important
to mention that in recent years attempts to induce
hyperlipidemia in various animals species have been
partially successful using a variety of exogenous com-
pounds, for example: administration of polychlorinated
biphenyls,22 nicotine,23 triton WR 1339(a polyethylene
ether of alkyl phenol),24 among others;25,26 amic acids
may also be worth investigating.
Acknowledgements
We thank Brazilian National Research Council (CNPq)
and Pernambuco State Foundation for Science and
Technology (FACEPE) for financial support.
References and Notes
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The compounds tested (3a–i) were suspended in 1%
CMC and administered intraperitoneally to Swiss white
mice; the groups contained six animals weighing about
26 g each for 14 days, at a dose of 20 mg/kg/day. The
dose was chosen based on the previous experiments with
the animals treated with phthalimides resulting from
dehydration of phthalamic acids.27 The animals were
kept on fasting about 16 h before puncturing the retro-
orbital plexus for blood collection. Blood samples were
withdrawn into tubes containing ethylenediamine-
tetraacetic acid (EDTA) disodium salt (1 mg/mL)
before and after 14 days of treatment, and the plasma
was separated by centrifugation at 2500g/min. The ani-
mals were weighed every day during the treatment.