9
56
Chem. Pharm. Bull.
Vol. 66, No. 10 (2018)
evaporation, 4-methyl-1H-imidazole-5-carbonyl chloride (9) in 4% DMSO/corn oil respectively. After 18h. of Triton ad-
was produced with a yield of 95%. ministration, animals were anesthetized with diethyl ether
Finally, a mixture of (9, 0.8g, 5.5mmol) of 4-methyl-1H- and blood was collected from the renal artery. The blood
imidazole-5-carbonyl chloride with (0.1g, 5.5mmol) of NaH samples were immediately centrifuged (3000rpm for 10min)
and (4, 1.3g, 6.6mmol) of 4-aminobenzophenone were dis- and the serum was used for lipid analysis using the relevant
solved in DMF and stirred for 24h at 90°C (Chart 2). Fol- profile kits for total cholesterol (TC), high density lipoprotein
lowing the removal of the precipitate by filtration, the filtrate (HDL), TG, and low density lipoprotein (LDL) were measured
was neutralized with TEA to remove any excess of HCl, con- directly using commercially available enzymatic colorimetric
centrated to dryness by evaporation under reduced pressure, assay kits by the automatic analyzer (Model Erba XL-300,
then, the crude mixture was purified by using column chro- Mannheim, Germany) at Al-Zaytoonah University of Jordan.
matography on silica gel started with n-hexane–ethyl acetate
70:30) and gradually increased polarity until n-hexane–ethyl vided into eight groups (6 animals per each group). The first,
Toxicity Study Test Forty-eight normal rats were di-
(
acetate (40:60) was reached to give the final compound (11) second, third and fourth groups received an intra-gastric
as a pale orange powder (0.3g, 16%); mp 163°C; Rf=0.35 in administration of (30mg/kg BW) of compounds 4, 6, 10 and
1
mobile phase (chloroform–methanol, 95:5); H-NMR (400Hz, 11 dissolved in 4% DMSO/corn oil respectively. While, the
DMSO-d ) δ: 12.51 (s, 1H, NH-imidazole), 10.09 (s, 1H, NH- fifth, sixth, seventh and eighth groups received an intra-gastric
6
amide), 8.04 (d, J=6.57Hz, 2H, Ar-H), 7.74 (s, 1H, imidazole- administration of the double initial dose (60mg/kg BW) of the
H), 7.71 (m, 4H, Ar-H), 7.64 (t, J=4.68Hz, 1H, Ar-H), 7.56 same compounds. The tested animals were left under observa-
1
3
(
(
t, J=5.76Hz, 2H, Ar-H), 2.50 (s, 3H, CH ) ppm; C-NMR tion for three weeks. None of the tested animals died even the
3
DMSO-d ) δ: 195.0 (1C), 162.7 (1C), 143.9 (1C), 138.1 (1C), ones who received the double dose.
6
1
(
34.0 (1C), 133.2 (1C), 132.6 (1C), 131.4 (2C), 130.1 (1C), 129.8
3C), 128.9 (2C), 119.2 (2C), 11.1 (1C) ppm; IR (KBr disc): mean± standard error of the mean (S.E.M.). Statistical analysis
ν=3363.86 (NH-amide), 1681.93 (CO-ketone), 1627.92 (CO- was carried out by Student’s t-test, using Graph Pad Prism
Statistical Analysis The results were expressed as
−1
amide) cm .
software version 7.00 (2016). p values <0.05 were considered
Water Solubility Test Ten milligrams from each of com- as statistically significant.
pounds 4, 6, 10, and 11 were dissolved separately in 5mL of
distilled water. All tested compounds showed complete dis- Results
solving forming clear solutions. The same test was performed
Synthesis Activation of both 1H-imidazole-5-carboxylic
on indole, and benzothiophene carboxamide benzophenone acid (1) and 4-methyl-1H-imidazole-5-carboxylic acid (8) in
9,11)
derivatives
that showed only partial dissolution forming to the acyl chloride was obtained by using oxalyl chloride
turbid solutions, particularly the benzothiophene derivatives.
Pharmacology
Animals and Treatment
For in vivo study, forty-eight male Wistar rats, weighing procedure reported by Berger. A solution of different amino
around 180–200g, bred, cared in the animal house of Faculty benzophenones in DMF was then added and stirred for 24h
of Pharmacy, Al-Zaytoonah University of Jordan, Amman, at 90°C. The amide formation was reached reacting 1H-imid-
Jordan, were accessed only to tap water throughout the ex- azole-5-carbonyl chloride with various amines as adapted by
in excess in the presence of few drops of DMF. The mixture
was refluxed under stirring for 90min to give the correspond-
ing imidazole carbonyl chloride (Charts 1, 2) according to a
19)
2
0)
perimental duration (18h). Rats were maintained in a 12h Seo and Chang. The corresponding amides were then iso-
light–dark cycle under constant humidity and (22± 02°C). All lated by column chromatography and characterized by using
1
13
animal experiments were carried out in accordance with the IR, H-NMR, and C-NMR.
guidelines of Animal Welfare Committee of the University.
Induction of Hyperlipidemia by Triton WR-1339
Lipid-Lowering Activity
Acute Induction of Hyperlipidemia by Triton WR-1339
To screen the hypolipidemic effect of natural or chemi- Model
cal drugs, Triton WR-1339 (Sigma-Aldrich, St. Louis, MO,
In comparison with the normal control group (NCG) tested
U.S.A.) has been widely used to induce acute hyperlipidemia animals (n=8), which received an intraperitoneal injection of
15)
in animal models in doses ranging from 200 to 400mg/kg.
normal saline, Triton WR-1339 caused a significant decrease
In this study a dose of 300mg/kg of Triton WR-1339 dissolved in plasma HDL (26%, p<0.001) and a significant increase in
16)
in water was given intraperitoneally to the rats.
Pharmacological Experimental Design
TG, LDL, and TC (2053, 203, 245%, respectively, p<0.0001)
levels in hyperlipidemic control group (HCG) after 18h of Tri-
Overnight forty-eight fasted rats were randomly divided ton WR-1339 (300mg/kg single dose) administration (Fig. 2).
into six groups each consisting of eight animals. The first
Effects of Novel Imidazole Carboxamide Derivatives and
group served as hyperlipidemic control group (HCG) receiv- Bezafibrate (BF) on Plasma Lipid Levels
ing an intraperitoneal injection of (300mg/kg body weight
The effects of novel imidazole carboxamide derivatives 4,
BW)) Triton WR-1339 dissolved in distilled water. The sec- 6, 10, 11, and BF on plasma lipid levels (TG, HDL, LDL, and
(
ond group was the standard control group (BF) and received TC) on Triton WR 1339 treated rats after 18h. were reported
an intraperitoneal injection of Triton WR-1339 followed by (Table 1). Results indicate that rats treated with 30mg/kg of
an intra-gastric administration of bezafibrate (100mg/kg the tested compounds 4, 6, 10, and 11 suppressed significantly
17,18)
BW) dissolved in 4% DMSO/corn oil.
The third, fourth, Triton WR- 1339-induced elevation in TG levels. Notably, the
fifth, and sixth groups received an intraperitoneal injection of elevated plasma TG levels after a single injection of Triton
Triton WR-1339 followed by an intra-gastric administration WR-1339 administration were significantly (p<0.0001) re-
of (30mg/kg BW) of compounds 4, 6, 10, and 11 dissolved duced in compounds 4, 6, 10, 11, and BF by 80, 86, 73, 79,