Hypolipidemic Activity of 3-Amino-1-(2,3,4-mononitro-, mono-, or dihalophenyl)propan-1-ones in Rodents

A series of 3-amino-1-(2,3,4-mononitro-, mono-, or dihalophenyl)propan-1-ones were synthesized and shown to be effective in lowering both serum cholesterol and triglyceride levels significantly in CF₁ mice and Sprague-Dawley rats. All analogs showed better activity than the standard drugs, lovastatin and clofibrate, in reducing the serum cholesterol and triglyceride levels in mice at 8 mg/kg/day intraperitoneally. The best active analogs, 3-morpholino-1-(3-nitrophenyl)propan-1-one ( 4 ) and 3-piperidino-1-(3-nitrophenyl)propan-1-one ( 5 ), exhibited 58% and 67% reduction of serum cholesterol levels, respectively, and 42% and 46% reduction of serum triglyceride levels, respectively, after 16 days of administration at 8 mg/kg/day intraperitoneally in CF₁ mice. In Sprague-Dawley rats at 8 mg/kg/day oral administration, both compounds ( 4 and 5 ) significantly decreased the serum cholesterol and triglyceride levels. Rat tissue lipid levels were reduced significantly by compound 4, while less effects resulted from compound 5. The cholesterol and triglyceride levels in chylomicrons, VLDL, and LDL fractions were reduced by both analogs while the HDL cholesterol levels were significantly increased. Compound 5 was also effective in lowering serum cholesterol and triglyceride levels in hyperlipidemic mice, at 8 mg/kg/day intraperitoneally, but not effective in hyperlipidemic rats at 8 mg/kg/day intraperitoneally, but not effective in hyperlipidemic rats at 8 mg/kg/day orally. Cholesterol and triglyceride lowering effects of the agents were correlated with inhibition of the activities of liver acetyl CoA synthetase, HMG CoA reductase, phosphatidylate phosphohydrolase, and lipoprotein lipase, and with elevation of the activity of cholesterol ester hydrolase.     

Investigation of 3,5-Isoxazolidinediones as Hypolipidemic Agents in Rodents

A series of 2-benzoyl-4,4-dialkyl-3,5-isoxazolidinediones proved to have potent hypolipidemic activity, lowering both serum cholesterol and triglyceride levels at 10 or 20 mg/kg/day, IP and orally in rodents. 2-(3,4,5-Trimethoxybenzoyl)-4,4-diethyl-3,5-isoxazolidinedione (4) afforded the best hypolipidemic activity lowering normolipidemic CF_l mouse serum cholesterol levels 49% and serum triglyceride levels 34% at 20 mg/kg/day, IP. Compound 4 was selected as a typical derivative of the chemical class for further detailed studies. Serum cholesterol levels in normolipidemic Sprague Dawley male rats were reduced 45% after 8 weeks at 10 and 20 mg/kg/day of compound, orally. Serum triglyceride levels were reduced 38–49% at 10 and 20 mg/kg/day, orally. In vitro liver enzyme activities studies in normolipidemic CF_l mice showed the compound inhibited mitochondrial citrate exchange, acetyl CoA synthetase, HMG CoA reductase, acyl CoA cholesterol acyl transferase, acetyl CoA carboxylase, sn-glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase and heparin-induced lipoprotein lipase activities with increases in the activities of cholesterol ester hydrolase and ATP-dependent citrate lyase. Similar enzyme activities were inhibited in vivo except HMG CoA reductase activity was not inhibited in rat liver or small intestinal mucosa after 8 weeks drug administration. Cholesterol levels were reduced in tissues after 8 weeks administration of compound 4 in normolipidemic rats. Bile cholesterol and triglyceride levels were elevated after two weeks administration to rats at 20 mg/kg/day. Serum lipoprotein levels in normolipidemic and hyperlipidemic rats showed the cholesterol levels in VLDL and LDL fractions after 4, 6 and 8 weeks at 10 and 20 mg/kg/day were reduced whereas HDL-cholesterol levels were significantly elevated. Studies demonstrated that ³H-cholesterol and ¹⁴C-palmitic acid incorporation into lipids of the lipoprotein fraction was reduced by the drug but ³²P-incorporation was generally elevated. The agent demonstrated no observable toxicity in rats after 8 weeks administration, orally. The acute toxicity study in normolipidemic mice at 20, 40 and 100 mg/ kg/day, IP, demonstrated no observable harmful effects of the drug.     

Hypolipidemic activity of indan-1,3-dione derivatives in rodents

A series of 2-substituted indan-1,3-dione derivatives, including alkyl (C-1-C-5), mono- and disubstituted phenyl, and other 2-aryl derivatives, were tested for hypolipidemic activity of CF1 male mice at 20 mg/kg per day. These derivatives reduced both serum cholesterol and triglycerides after 16 days of administration intraperitoneally. 2-(4-Methoxyphenyl)indan-1,3-dione was one of the more active compounds with 41% reduction of serum cholesterol and 58% reduction of serum triglyceride levels on day 16. This activity was confirmed in the rat after oral administration. 2-(2-Methylphenyl)- and 2-(4-chlorophenyl)indan-1,3-dione were effective in reducing serum triglyceride levels 58% and 53%, respectively, in mice. Serum cholesterol on day 16 was effectively reduced 46% by 2-(2,4-dimethylphenyl)indan-1,3-dione. The indan-1,3-dione derivatives were more effective than clofibrate in lowering lipid levels in mice. A more detailed study on the effects of 2-(4-methoxyphenyl)indan-1,3-dione demonstrated that key enzymes in the de novo synthesis of lipids were inhibited by the drug lowering tissue levels of lipids but raising those in the feces. The alterations in lipid content of rat lipoprotein fractions by the drug appeared favorable.     

Synthesis and Hypolipidemic Activity of 3-Imino-l-oxoisoindolines in Rodents

A series of substituted 3-imino-l-oxoisoindolines derivatives demonstrated significant hypolipidemic activity, lowering both serum cholesterol and triglycerides levels after 16 days of dosing at 20 mg/kg/ day ip in CF₁ mice. 2-Butyl-3-butylimino-l-oxoisoindoline lowered serum cholesterol levels 52% and serum triglyceride 42%. 2-Pentyl-3-imino-l-oxoisoindoline lowered serum cholesterol levels 42% and serum triglyceride 61%. These derivatives resulted in better activity than the parent compound, 3-imino-1-oxoisoindoline. These studies showed that compounds with N-alkyl substitution of nitrogen atoms in the ring and outside the ring possessed potent hypolipidemic activity at the low dose of 20 mg/kg/day ip in normolipidemic CF₁ mice. Studies with 2-butyl-3-butylimino-l-oxoisoinodine in rats showed that serum cholesterol was reduced 60% and serum triglyceride 43% after 14 days of dosing at 20 mg/kg/day, orally. Treatment with this agent lowered lipid levels in the liver and aorta tissue, with increases in lipid levels in the small intestine tissue. Higher levels of cholesterol and phospholipids were excreted in the feces of treated animals compared to the control. Cholesterol levels of the very low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) fractions were reduced, whereas the HDL cholesterol levels were elevated significantly. This ratio of low-density lipoprotein (LDL) cholesterol:HDL cholesterol levels suggests that the agent may be effective in treating hyperlipidemic states in humans.     

Heterocyclic analogues of chlorcyclizine with potent hypolipidemic activity

A series of [alpha-(heterocyclyl)benzyl]piperazines was synthesized and their effect of reducing serum cholesterol and triglyceride levels in the rat was evaluated. A systematic exploration of the structure-activity relationships led to the synthesis of (R,S)-(3,5-dimethylisoxazol-4-yl)[4-(1-methylethyl)phenyl] (4-methylpiperazin-1-yl)methane dihydrochloride (M&B 31 426), which had potent activity in lowering serum lipid levels at a daily oral dose of 2 mg/kg and was 100 times more potent than clofibrate.     

The Hypolipidemic Activity of 3-Iminophthalimidine in Rodents

3-Immophthalimidine (3-imino-2,3-dihydroisoindol-l-one) was examined for its hypolipidemic activity in rodents as a chemical modification of the phthalimide nucleus. Administration of 3-iminophthalimidine for 16 days, at 20 mg/kg/day, demonstrated potent hypolipidemic activity, decreasing serum cholesterol and triglyceride levels by 44 % and 41 %, respectively. No effects on organ or body weight, or food consumption were noted as a result of administration of this agent to rats. However, reductions of liver lipid levels, i. e., triglycerides and neutral lipids, as well as lipid content of serum lipoprotein fractions, i. e., cholesterol, triglyceride and neutral lipids, were observed following administration of this agent. An increase was noted in fecal excretion of cholesterol and/or its metabolites. This effect was not correlated with an increase in bile acid synthesis, but may due in part to increased biliary excretion of cholesterol. Significant inhibitory effects of 3-iminophthalimidine on liver enzyme activities were noted, including acetyl CoA carboxylase and sn-glycerol-3-phosphate acyl transferase. Mitochondrial citrate exchange was also greatly reduced at low concentrations of the agent. Inhibition at these sites could account for the reduction in serum triglyceride levels observed after treatment in rodents.     

The Hypolipidemic Activity of Benzenetricarboxylic Acids in Rodents

A series of benzenetricarboxylic acids was shown to be potent hypolipidemic agents in rodents. Terephthalic acid proved to be one of the more potent agents, lowering serum cholesterol 42% and serum triglyceride 33 % at 20 mg/kg/day for 16 days. The ability to lower serum lipids by this agent appeared to be due to multiple modes of action: (1) terephthalic acid suppressed the activities both in vivo and in vitro of a number of regulatory enzymes involved in cholesterol, fatty acid, and triglyceride syntheses; (2) the drug inhibited cholesterol absorption from the GI tract by 43 %; and (3) the drug accelerated lipid excretion in the feces leading to a reduction of cholesterol in the tissue. Terephthalic acid was effective in lowering lipids in normal and hyperlipidemic animals and possessed a safe therapeutic index.     

Hypocholesterolaemic and antiatherosclerotic effects of tetra-iso-propyl 2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethyl-1,1-diphosphonate (SR-9223i)

Tetra-iso-propyl 2-(3,5-di-tert-butyl-4-hydroxyphenyl)ethyl-1,1-diphosphonate (CAS 126411-13-0, SR-9223i) is a member of a new class of compounds with multiple antiatherosclerotic activities. This report not only describes the cholesterol-lowering properties in four species of animals fed normocholesterolaemic diets but also reductions in lipid deposition in the arteries of cholesterol-fed New Zealand white rabbits following the administration of SR-9223i. Plasma cholesterol concentrations were reduced in mice by 27% (200 mg/kg/day administered in the diet for 10 days), in hamsters by 33% (200 mg/kg/day administered in the diet for 8 days), in dogs by 16% (25 mg/kg/day p.o. for 28 days) and 23% (75 mg/kg/day p.o. for 28 days) and in monkeys by 22% (25 mg/kg/day p.o. for 28 days). Further, the deposition of cholesterol, especially in the esterified form, in the aortae of cholesterol-fed New Zealand white rabbits was inhibited by SR-9223i (50 and 100 mg/kg/day p.o.). At the higher dose, the cholesteryl ester content of the aorta was half that of control animals. SR-9223i, at both doses, also inhibited the accumulation of cholesterol in the liver. SR-9223i has been shown to suppress HMG CoA reductase activity, inhibit ACAT activity and prevent lipid oxidation. These activities, demonstrated in vitro, have now been shown to translate into lipid lowering and antiatherosclerotic activities in vivo.     

The Hypolipidemic Activity of Furoic Acid and Furylacrylic Acid Derivatives in Rodents

2-Furoic acid, 3-furoic acid, 3,4-furan dicarboxylic acid and furyl-acrylic acid were evaluated for hypolipidemic activity in mice and rats. 2-Furoic acid was the most potent agent of the four tested, lowering serum cholesterol levels 41 % and serum triglyceride levels 56 % at 20 mg/kg/day in mice and serum cholesterol 50 % and serum triglyceride levels 42 % in rats. 2-Furoic acid effectively suppressed liver mitochondrial citrate exchange, ATP dependent citrate lyase, acetyl CoA synthetase, acyl CoA cholesterol acyl transferase, sn-glycerol-3-phosphate acyl transferase, phosphatidate phosphohydrolase and hepatic lipoprotein lipase enzymatic activities. Lipid levels after 16 days in mice were reduced in the liver. In the rat cholesterol content of the HDL fraction was elevated and lowered in the chylomicron fraction. 2-Furoic acid administration for 14 days resulted in a large portion of ³H-cholesterol being excreted by the biliary route. The furoic acid derivatives appear to have promise as hypolipidemic agents and further studies on their ability to lower lipids are warranted.     

Hypolipidemic and antioxidant activity of the novel acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor KY-455 in rabbits and hamsters

The hypolipidemic and antioxidant effects of N-(4,6-dimethyl-1-pentylindolin-7-yl)-2,2-dimethylpropanamide (CAS 178469-71-1, KY-455), a novel acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor, were examined in hyperlipidemic rabbits and normolipidemic hamsters. KY-455 inhibited rabbit intestinal, hepatic, macrophage and adrenal ACAT with IC50 values of 0.4, 0.9, 2.9 and 4.1 micromol/l, respectively. KY-455 also inhibited rabbit plasma and LDL-peroxidation (IC50: 0.4 and 1.7 micromol/l, respectively). In rabbits fed a high-cholesterol diet, treatment with KY-455 (30 mg/kg/day) for 8 days markedly lowered serum esterified, free, low-density lipoprotein (LDL)-cholesterol, and hepatic esterified cholesterol levels. KY-455 tended to inhibit ex vivo hepatic ACAT activity 5 h after the final administration. KY-455 also inhibited ex vivo peroxidation of plasma lipids 1 and 5 h after the final administration in rabbits. In normolipidemic hamsters fed a regular diet, treatment with KY-455 (30 mg/kg, twice a day) for 4 days significantly reduced serum esterified, free and LDL-cholesterol, and hepatic esterified and free cholesterol levels. A single administration of KY-455 (30 mg/kg) significantly inhibited ex vivo hepatic ACAT activity in hamsters. In conclusion, KY-455 showed in vitro inhibitory effects on LDL-peroxidation and macrophage ACAT activity at similar concentrations, and in vivo hypolipidemic and ex vivo antioxidative effects at the same dose. Long-term administration of KY-455 is expected to prevent the progress of atherosclerosis by lowering plasma lipid levels, inhibiting both LDL-oxidation and accumulation of cholesterol in macrophages.     

Hypolipidemic activity of phthalimide derivatives. 3. A comparison of phthalimide and 1,2-benzisothiazolin-3-one 1,1-dioxide derivatives to phthalimidine and 1,2-benzisothiazoline 1,1-dioxide congeners

Previously it has been observed that N-substituted phthalimide derivatives with chain lengths of four carbon or oxygen atoms showed potent hypolipidemic activity in rodents at 20 (mg/kg)/day ip. The 1,2-benzisothiazolin-3-one 1,1-dioxide (saccharin) nucleus, itself, had also been observed to be active at the same dose. An investigation was undertaken to examine a series of 1,2-benzisothiazolin-3-one 1,1-dioxide analogues for their hypolipidemic activity in mice and to compare them to their respective phthalimide congeners. In addition, a series of 1,2-benzisothiazoline 1,1-dioxide and phthalimidine analogues was prepared, and their hypolipidemic activity was compared to the phthalimide analogues. These studies show that the respective congeners of 1,2-benzisothiazolin-3-one 1,1-dioxide compared favorably to phthalimide congeners in reducing serum triglyceride and cholesterol levels in male CF1 mice at 20 (mg/kg)/day ip. Of the saccharin derivatives, 3-oxo-1,2-benzisothiazoline-2-propionic acid 1,1-dioxide was the most effective in lowering serum cholesterol levels by 53% after 16 days dosing and 3-oxo-1,2-benzisothiazoline-2-valeric acid 1,1-dioxide lowered serum triglycerides 56% after 14 days dosing. The 1,2-benzisothiazoline 1,1-dioxide and phthalimidine compounds were less active as hypolipidemic agents than their 1,2-benzisothiazolin-3-one 1,1-dioxide and phthalimide analogues, respectively.     

Hypolipidemic Agents of Phthalimide Derivatives 6. Effects of Aromatic vs. Non-Aromatic Imides

A number of substituted phthalimide, 1, 8-naphthalimide, succinimide and glutarimide derivatives demonstrated significant hypolipidemic activity at 20 mg/kg/ day, I.P. after 16 days dosing. The N-(n-pentyl) succinimide proved to be the most potent analogue of the new compounds, lowering serum triglyceride levels 51 % and serum cholesterol 47 % after 16 days dosing in mice. For the N-substituted derivatives, i. e., n-butyl, butanone, and propionic acid, of these four cyclic imides, there appeared to be no obvious trend in ability to reduce serum lipid levels. In general, the 1,8-naphthalimide and glutarimide derivatives appeared to be less active than phthalimide and succinimide. However, the -phenylsuccinimide afforded less activity than the -phenylglutarimide. Most of the derivatives at 20mg/kg/day demonstrated improved activity over clofibrate at 150mg/kg/day.     

Bicyclol, a synthetic dibenzocyclooctadiene derivative, decreases hepatic lipids but increases serum triglyceride level in normal and hypercholesterolaemic mice

Bicyclol is used for the treatment of chronic hepatitis B in China. In this study, the effects of bicyclol (100 or 300 mg kg(-1), p.o.) on serum and liver lipid contents were investigated in both normal and experimentally induced hypercholesterolaemic mice. Hypercholesterolaemia was induced by either oral administration of cholesterol/bile salt or feeding a diet containing lard/cholesterol. Daily administration of bicyclol for 7 days dose-dependently increased the serum triglyceride level (29-80%) but slightly decreased the hepatic total cholesterol level (12-17%) in normal mice. Co-administration of bicyclol with cholesterol/bile salt decreased the hepatic triglyceride and total cholesterol levels (7-15% and 25-31%, respectively), when compared with the drug-untreated and cholesterol/bile salt-treated group. Bicyclol treatment for 7 days decreased hepatic triglyceride (5-76%) and total cholesterol (5-48%) levels in mice fed with high-fat/cholesterol diet. In contrast, bicyclol treatment increased the serum triglyceride level (18-77%) in mice treated with cholesterol/bile salt or fed with high-fat/cholesterol diet. Bicyclol treatment also caused an increase in hepatic index of normal and hypercholesterolaemic mice (3-32%). The results indicate that bicyclol treatment can invariably decrease hepatic lipid levels and increase serum triglyceride levels in normal and hypercholesterolaemic mice.     

Lipid‐lowering effects of the squalene epoxidase inhibitor FR194738 in dogs,hamsters, and rats

Squalene epoxidase is a microsomal enzyme that catalyzes the conversion of squalene to 2,3‐oxidosqualene and is an important control site in the cholesterol synthetic pathway. FR194738 is a potent inhibitor of hepatic squalene epoxidase from dogs, hamsters, and rats with IC₅₀ values of 49, 14, and 68 nM, respectively. In dogs, FR194738 at 10 and 32 mg/kg/day decreased serum total cholesterol levels by 26% and 40%, and serum triglyceride levels by 47% and 76%, respectively. Pravastatin, an inhibitor of 3‐hydroxy‐3‐methylglutaryl coenzyme A reductase, at 3.2 and 10 mg/kg/day also decreased serum total cholesterol levels by 32% and 36%, and serum triglyceride levels by 56% and 50%, respectively. Both FR194738 and pravastatin preferentially decreased low‐density lipoprotein cholesterol levels among the lipoprotein fractions examined. In hamsters, FR194738 decreased serum total cholesterol levels by 22% and led to a decrease in serum triglyceride levels of 9% at 100 mg/kg/day, whereas pravastatin did not decrease total serum cholesterol levels up to 100 mg/kg/day even though it decreased serum triglyceride levels at doses as low as 3.2 mg/kg/day. In rats, both FR194738 and pravastatin failed to decrease total serum cholesterol levels up to 100 mg/kg/day. FR194738 dose‐dependently decreased serum triglyceride levels by 30%, 41%, and 65% at 10, 32, and 100 mg/kg/day, respectively, whereas pravastatin decreased them only by 19% at 100 mg/kg/day. These results clearly showed a species difference in cholesterol and triglyceride metabolism, and suggest that dogs are the most appropriate animal model for evaluating hypocholesterolemic drugs. FR194738 that induced comparable effects with pravastatin in the dog model may provide another treatment for hypercholesterolemia in men. Drug Dev. Res. 54:202–208, 2001. © 2002 Wiley‐Liss, Inc.     

Subchronic toxicity studies on perfluorooctanesulfonate potassium salt in cynomolgus monkeys.

This study was conducted to determine the earliest measurable response of primates to low-level perfluorooctanesulfonate (PFOS) exposure and to provide information to reduce uncertainty in human health risk assessment. Groups of male and female monkeys received 0, 0.03, 0.15, or 0.75 mg/kg/day potassium PFOS orally for 182 days. Recovery animals from each group, except the 0.03 mg/kg/day dose group, were monitored for one year after treatment. Significant adverse effects occurred only in the 0.75 mg/kg/day dose group and included compound-related mortality in 2 of 6 male monkeys, decreased body weights, increased liver weights, lowered serum total cholesterol, lowered triiodothyronine concentrations (without evidence of hypothyroidism), and lowered estradiol levels. Decreased serum total cholesterol occurred in the 0.75 mg/kg/day dose group at serum PFOS levels > 100 ppm. Hepatocellular hypertrophy and lipid vacuolation were present at term in the 0.75 mg/kg/day dose group. No peroxisomal (palmitoyl CoA oxidase) or cell proliferation (proliferating cell nuclear antigen immunohistochemistry) was detected. Complete reversal of clinical and hepatic effects and significant decreases in serum and liver PFOS occurred within 211 days posttreatment. Liver-to-serum PFOS ratios were comparable in all dose groups, with a range of 1:1 to 2:1. Serum concentrations associated with no adverse effects (0.15 mg/kg/day) were 82.6 +/- 25.2 ppm for males and 66.8 +/- 10.8 ppm for females. Comparison of serum PFOS concentrations associated with no adverse effect in this study to those reported in human blood samples (0.028 +/- 0.014 ppm) indicated an adequate margin of safety.     

RPR 101821, a new potent cholesterol-lowering agent: inhibition of squalene synthase and 7-dehydrocholesterol reductase

RPR 101821 (trans-2-[4-(benzoxazol-2-yl)phenylmethoxy] amino cyclohexane hydrochloride) is a potent cholesterol-lowering agent in rodents and marmoset. The compound inhibited rat liver microsomal squalene synthase (IC₅₀ = 1 nM) and 7-dehydrocholesterol (7DHC) reductase (IC₅₀ = 1 M; Lewis et al. 1995). When RPR 101821 (10 mg/kg), the 7DHC reductase inhibitor BM 15.766 (4[2-[4-(4-chlorocinnamyl)piperazine-1-yl]ethyl] benzoic acid; 10 mg/kg) or the HMG-CoA reductase inhibitor lovastatin (30 mg/kg) was given orally to rats at –29 h, – 21 h and – 5 h, serum cholesterol was reduced by 56%, 46% or 15%, respectively. The reduction in cholesterol with RPR 101821 was associated with an accumulation of 7DHC in serum, suggesting an inhibition of 7DHC reductase. In the presence of BM 15.766, RPR 101821 reduced the serum accumulation of 7DHC in a dose-dependent manner, with complete inhibition at 30 mg/kg, p.o. In Balb-cJ mice, RPR 101821 and lovastatin (50 mg/kg, b.i.d., p.o., for 14 days) lowered serum cholesterol by 67% and 2%, respectively. In marmosets, RPR 101821 and lovastatin (both at a dose of 10 mg/kg, p.o., b.i.d., for 7 days) reduced cholesterol by 28% and 19%, respectively.In summary, RPR 101821 is an orally effective potent cholesterol-lowering agent in rodents and a small primate species. The suggested mechanism of hypocholesterolemic effect is the inhibition of squalene synthase and 7DHC reductase.     

The Hypolipidemic Effects of l-Acetyl-4-phenyl-l,2,4-triazolidine-3,5-dione in Rodents

l-Acetyl-4-phenyl-l ,2,4-triazolidine,5-dione (APTD), a potent hypolipidemic agent, lowered both serum cholesterol and triglyceride levels in normo- and hyperlipidemic rats at 10 or 20 mg/kg/day. The agent effectively lowered VLDL-cholesterol (VLDL-C) and LDL-C content and raised HDL-C content in normal and hyperlipidemic rats treated from 4 to 8 weeks. Similar effects on the incorporation of cholesterol into the lipoprotein fractions were observed after drug treatment. Tissue lipids, e.g. cholesterol, were lowered, whereas fecal cholesterol levels were increased. APTD's primary targets were acyl CoA cholesterol acyl transferase (ACAT) for cholesterol ester synthesis and sn-glycerol-3-phosphate acyl transferase (GPAT) and phosphatidylate phosphohydrolase (PPH) for triglyceride synthesis.     

The Hypolipidemic Activity of a Series of 2,3-Dihydrophthalazine-l,4-dione Derivatives in Rodents

A series of substituted 2,3-dihydrophthalazine-l,4-dione derivatives as well as the corresponding N,N-diaminophthalamides were prepared and were demonstrated to have potent hypolipidemic activity, lowering both serum triglyceride and cholesterol levels significantly at 20 mg/kg/day after 16 days of dosing in CF₁ male mice. The parent compound, 2,3-dihydrophthalazine-l,4-dione, lowered serum cholesterol 51% and serum triglyceride 43%. 2-(2-Carboxyethyl)-2,3-dihydrophthalazine-l,4-dione demonstrated the best hypocholesterolemic activity, with a 66% reduction after 16 days. The 2-(p-chlorophenyl) derivative demonstrated good activity (>40% reduction) in both screens, as did the 6-methyl-2,3-dihydrophthalazine-l,4-dione derivative. Of the amides, 4-methyk N,N-diaminophthalamide demonstrated the best hypolipidemic activity, affording a greater than 40% reduction. 2,3-Dihydrophthalazine-l,4-dione was found to inhibit the enzyme activity of acetyl CoA synthetase, ATP-dependent citrate lyase, sn-glycerol-3-phosphate acyl transferase, phosphatidylate phosphohydrolase, and mitochondrial citrate exchange of liver. In mice after 16 days of dosing, there was a reduction of cholesterol, triglycerides, neutral lipids, and phospholipids in the liver. Cholesterol and neutral lipids were reduced in rat chylomicrons, very low-density lipoproteins, and low-density lipoproteins. The cholesterol content of the high-density lipoprotein fraction was slightly elevated, but reductions in the triglycerides and phospholipids were observed in this lipoprotein fraction. ³H-Cholesterol distribution studies showed a lower concentration in the major organs and plasma, with a higher ³H-cholesterol content in the stomach and large intestine.     

Synthesis and antihyperlipidemic activity of some novel 4-(substitutedamino)-5-substituted-3-mercapto- (4H)-1,2,4-triazoles

Hyperlipidemia is considered one of the key factors for cardiovascular diseases. Based on earlier work on a series of 5-alkyl-4-aryl-3-mercapto-(4H)-1,2,4-triazoles, for further lead modification, a series of 4-(substituted)amino-5-substituted-3-mercapto-(4H)-1,2,4-triazoles was designed. Target compounds were synthesized by the well known Hoggarth synthesis of substituted 1,2,4-triazoles. Synthesized compounds were screened for lipid lowering activity using the "Poloxamer 407 induced hyperlipidemia in rats" model at a dose of 100 mg/kg p.o. Compounds were found to alter serum lipid levels significantly. Most of the compounds significantly reduced serum cholesterol and triglyceride levels. Some of the compounds were found to reduce triglycerides and elevate high density lipoprotein (HDL) levels more than the standard drug atorvastatin (CAS 134523-03-8). Compounds with chloro substitution on aryl rings were found more active in reducing serum lipid levels than other substitutions.     

The Hypolipidemic Activity of N-(p-Chlorobenzoyl)-sulfamate in Rodents and its Effect on Lipid Metabolism

N-(p-Chlorobenzoyl)-sulfamate was observed to produce potent hypolipidemic activity in rodents at 10 to 60 mg/kg/day. Liver phosphatidate phosphohydrolase and sn-glycerol-3-phosphate acyl transferase activities were suppressed by the agent in vitro and in vivo, and ATP dependent citrate lyase and acetyl CoA carboxylase activities were reduced in vivo. N-(p-Chlorobenzoyl)-sulfamate reduced cholesterol, neutral lipids, and triglycerides in the liver and increased excretion of cholesterol and neutral lipids in the bile and feces. Drug treatment reduced the neutral lipid and triglyceride content of serum chylomicrons, VLDL and LDL, and cholesterol content was reduced in the chylomicron and HDL fractions.