Hypolipidemic activity of phthalimide derivatives. 2. N-phenylphthalimide and derivatives

Antihyperlipidemic activity of glycoconjugated phthalimides in mice submitted to a model of dyslipidemia and insulin resistance

Alterations in lipid and lipoprotein metabolism are factors that trigger several negative metabolic complications. Hyperlipidemia is the starting point for the development of comorbidities of the cardiovascular system, such as atherosclerosis. The search for compounds that reduce high levels of total cholesterol and triglycerides has been widely reported in several publications in the literature. Phthalimide derivatives have been extensively researched with various biological actions. In this study we evaluated the antihyperlipidemic ability of three phthalimide derivatives (FGT-2, FGT-3 and FGT-4) on a model of obesity and insulin resistance in mice. The animals were submitted to a hyperlipid diet for 60 days. On the thirtieth day they were treated with phthalimides (20 mg/kg). The positive control group was treated with Simvastatin (20 mg/kg) and the negative control received only the carboxymethylcellulose vehicle. Biochemical and histological analyzes of all groups were analyzed. The animals treated with phthalimidic derivatives had a reduction in total cholesterol, low density and very low density lipoproteins (LDL-c and VLDL-c), triglycerides and fasting glycemia when compared to the negative control group. The treated animals also showed good results when analyzing the atherogenic indexes Castelli i and II and the ratio Triglycerides/HDL-c. In the oral glucose tolerance test and in the insulin tolerance test, animals treated with phthalimides were more sensitive to the action of the hormone regulating carbohydrate uptake. In the evaluation of the transaminases (AST/ALT), the animals of the group treated with phthalimides presented a lower elevation than the other groups of the experiment, the same observed with the uric acid evaluation. Histological analyzes were performed on liver, kidney, heart and pancreas samples. The groups treated with the compounds FGT-2 and FGT3 presented discrete alterations in the liver and kidney. FGT-4 did not present histological alterations for both tissues and the three phthalimide derivatives did not cause alterations in the other organs. These results suggest that the phthalimides tested can act as antihyperlipidemic agents and have a pleiotropic action, by acting also reducing glycemia in insulin resistance model mimicking diabetes mellitus type 2. These compounds may appear as a new approach in the treatment of obesity and complications, which are multifaceted.

Equivalent Loading of Directed Arenes in Pd(II)-Catalyzed Oxidative Cross-Coupling of Aryl C-H Bonds at Room Temperature

The unsymmetrical biaryls (Ar¹-Ar²) produced by the catalytic cross-couplings of aryl halides (Ar¹-halo) with aryl metallics (Ar²-M) in the loading ratio of 1:1 are popular in chemical synthesis. In contrast, there has been less precedence on the same biaryls produced effectively from two normal aryl C-H bonds with equivalent loading. Here, we report that, in a palladium/oxidant/acid catalytic system at room temperature, one arene (Ar¹-H, 1 equiv) can highly selectively couple with the other one (Ar²-H, 1 equiv) to afford the target Ar¹-Ar² just by controlling the directing groups and the substituted groups on their phenyl rings. The utility of this one-one cross-coupling is also demonstrated by synthesis of a few bioactive molecules.

Insights into the spontaneity of hydrogen bond formation between formic acid and phthalimide derivatives

We evaluated a group of phthalimide derivatives, which comprise a convenient test set for the study of the multiple factors involved in the energetics of hydrogen bond formation. Accordingly, we carried out quantum chemical calculations on the hydrogen bonded complexes formed between a sample of phthalimide derivatives with formic acid with the intent of identifying the most important electronic and structural factors related to how their strength and spontaneity vary across the series. The geometries of all species considered were fully optimized at DFT B3LYP/6-31++G(d,p), RM1, RM1-DH2, and RM1-D3H4 level, followed by frequency calculations to determine their Gibbs free energies of hydrogen bond formation using Gaussian 2009 and MOPAC 2012. Our results indicate that the phthalimide derivatives that form hydrogen bond complexes most favorably, have in their structures only one C=O group and at least one NH group. On the other hand, the phthalimide derivatives predicted to form hydrogen bonds least favorably, possess in their structures two carbonyl groups, C=O, and no NH group. The ability to donate electrons and simultaneously receive one acidic hydrogen is the most important property related to the spontaneity of hydrogen bond formation. We further chose two cyclic compounds, phthalimide and isoindolin-1-one, in which to study the main changes in molecular, structural and spectroscopic properties as related to the formation of hydrogen bonds. Thus, the greatest ability of the isoindolin-1-one compound in forming hydrogen bonds is evidenced by the larger effect on the structural, vibrational, and chemical shifts properties associated with the O-H group. In summary, the electron-donating ability of the hydrogen bond acceptor emerged as the most important property differentiating the spontaneity of hydrogen bond formation in this group of complexes.

Structure-activity relationships for lipoprotein lipase agonists that lower plasma triglycerides in vivo

The risk of cardiovascular events increases in individuals with elevated plasma triglyceride (TG) levels, therefore advocating the need for efficient TG-lowering drugs. In the blood circulation, TG levels are regulated by lipoprotein lipase (LPL), an unstable enzyme that is only active as a non-covalently associated homodimer. We recently reported on a N-phenylphthalimide derivative (1) that stabilizes LPL in vitro, and moderately lowers triglycerides in vivo (Biochem. Biophys. Res. Commun.2014, 450, 1063). Herein, we establish structure-activity relationships of 51 N-phenylphthalimide analogs of the screening hit 1. In vitro evaluation highlighted that modifications on the phthalimide moiety were not tolerated and that lipophilic substituents on the central phenyl ring were functionally essential. The substitution pattern on the central phenyl ring also proved important to stabilize LPL. However, in vitro testing demonstrated rapid degradation of the phthalimide fragment in plasma which was addressed by replacing the phthalimide scaffold with other heterocyclic fragments. The in vitro potency was retained or improved and substance 80 proved stable in plasma and efficiently lowered plasma TGs in vivo.

Novel phthalimide derivatives with TNF-α and IL-1β expression inhibitory and apoptotic inducing properties

24 compounds were synthesized and their immunomodulation of TNF-α and IL-1β was evaluated.

The use of tri-O-acetyl-D-glucal and -D-galactal in the synthesis of omega-aminoalkyl 2-deoxy- and 2,3-dideoxy-d-hexopyranosides

We report a simple, efficient, and mild method for the synthesis of omega-aminoalkyl 2-deoxy-d-arabino/lyxo-hexopyranoside and 2,3-dideoxy-alpha-d-erythro-hexopyranoside. The total synthesis is accomplished in two sequential reactions. The first step consists of an addition reaction of N-(omega-hydroxyalkyl)phthalimide and N-(omega-hydroxyalkyl)succinimide to peracetylated d-glycals, which is promoted by triphenylphosphine hydrobromide or borontrifluoride/diethyl etherate. The second step involves reacting the appropriate glycoside with methylamine.

Synthesis of N-phenylphthalimide derivatives as alpha-glucosidase inhibitors

Sixteen N-phenylphthalimide derivatives were synthesized and their ability to inhibit alpha-glucosidase was investigated. N-(2,4-dinitrophenyl)phthalimide was a potent inhibitor of yeast alpha-glucosidase (IC50; 0.158 +/- 0.005 mM) and maltase (IC50; 0.051 +/- 0.008 mM), whereas it did not inhibit sucrase. From a Lineweaver-Burk plot of alpha-glucosidase kinetics, N-(2,4-dichlorophenyl)phthalimide was found to be a competitive inhibitor of yeast alpha-glucosidase. These results indicate that N-(2,4-dinitrophenyl)phthalimide could be a representative of a new group of alpha-glucosidase inhibitors.

Synthesis and hypolipidemic activity of N-substituted phthalimides. Part V

A series of N-aryl- or N-(1,2,4-triazol-yl)-phthalimides (4a-4i) have been synthesized starting from phthalic anhydride (1) and an appropriate amine (2a-2i). All compounds presented hypolipidemic activity, but compound 4d proved to be the most active and reduced plasma cholesterol and triglyceride levels in Swiss white mice significantly.

Acute toxic and teratogenic effects of cyclic imides in rodents

Four structurally different cyclic imides or related derivatives (o-(N-phthalimido)acetophenone (1), 2,3-dihydrophthalazine-1,4-dione (2), N-(4-methylphenyl)diphenamide (3), and 4,6-dihydro-5H-dibenz[c,e]azepine (4) were examined for acute toxicity in mice at multiple doses, for long term toxicity at a single dose in rats, and for deleterious effects on fertility and pup development in rodents. No deleterious effects were observed when mice were administered agents at 20, 50, and 100 mg/kg/day for seven days. All other measured characteristics and values were normal for the four compounds. The principle effect of the compounds was to reduce the percent pregnancies in treated mice compared to the controls. Compound 2 afforded the greatest reduction of pregnancy (54%) at 100 mg/kg/day. Compounds 3 and 4 caused a minor reduction in pregnancy (12-20%). The compounds did not appear to cause measureable teratogenic effects; pups of treated rodents thrived and survived as well as controls. There were no effects on murine male fertility when compounds were administered at 20, 50, and 100 mg/kg/day for six weeks.

Structure activity relationships of imido N-alkyl semicarbazones, thiosemicarbazones and acethydrazones as hypolipidemic agents in rodents

A series of nitrogen substituted N-butan-3-one derivatives of cyclic imides (phthalimide, substituted phthalimide, o-benzosulfimide, 1,8-naphthalimide, 2,3-dihydrophthalazine-1,4-dione and diphenimide) and their semicarbazone, thiosemicarbazone and acethydrazone derivatives were investigated for hypolipidemic activity in rodents. These compounds were generally potent hypolipidemic agents, lowering serum cholesterol levels on an average of 37% and serum triglyceride levels on an average of 29% after 16 days dosing at 20 mg/kg day intraperitoneally (I.P.) in mice. Several analogs, most notably the semicarbazone and acethydrazone derivatives of 1-N-(1,8-naphthalimido)-butan-3-one, demonstrated improved hypocholesterolemic activity relative to their ketone precursors. Similarly, the acethydrazone derivatives generally resulted in improved hypotriglyceridemic activity in each series of 2-(3-oxobutyl)-2,3-dihydrophthalazone-1,4-dione analogs tested. The thiosemicarbazones in mice generally resulted in a loss in hypolipidemic activity. Select compounds, 1-N-3-methylphthalimido butan-3-semicarbazone (Ig) and 1-(4-methoxyphthalazine-1(2H)-one)yl butan-3(N-acetyl)hydrazone (IVg), at 10 mg/kg/day orally administered to rats demonstrated potent hypolipidemic activity after 14 days. These compounds lowered liver, small intestine mucosa and aorta wall tissue lipids, e.g. cholesterol and triglycerides, and raised fecal excretion of cholesterol moderately and of triglyceride significantly. Rat serum lipoprotein fractions after treatment for 14 days showed that the two agents lowered VLDL cholesterol and raised HDL cholesterol content.

Substituted cyclic imides as potential anti-gout agents

N-substituted cyclic imides of phthalimide, 2,3-dihydrohalazine-1,4-dione, and diphenimide were shown to reduce the serum uric acid levels in normal and hyperuric mice at 20 mg/kg/day I.P. for 14 days. The agents were potent inhibitors of commercial xanthine dehydrogenase and xanthine oxidase enzyme activities with IC50 values from 10(-7) to 10(-8) M concentrations of drug.

Hypolipidemic activity of cyclic imido alkyl ethers, thioethers, sulfoxides, and sulfones

N-Substituted alkyl ethers, thioethers, sulfoxides, and sulfones of cyclic imides (e.g., phthalimide, saccharin, 1,8-naphthalimide, succinimide, and 2,3-dihydrophthalazine-1,4-dione) were shown to have potent hypolipidemic activity at doses of 10 and 20 mg/kg/d in rodents. These N-substitutions afforded no improvement over other known N-substitutions (e.g., butyl, 3-butanone, or the propionic acid derivatives of phthalimide, saccharin, and 2,3-dihydrophthalazine-1,4-dione) compared with the respective parent compounds. However, 2-(methoxyethyl)-1H-benz[de]isoquinoline-1,3-(2H)dione (3a), 2-[2-methylsulfinyl]ethyl-1H-benz[de]isoquinoline-1,3-(2H)dione (3c), 1-(2-methylsulfinyl)-2,5-pyrrolidenedione (4c), and 1-(2-methoxyethyl-2,5-pyrrolidenedione (4a) significantly improved activity compared with parent compounds, as well as previously reported N-substituted analogues, reducing serum cholesterol levels and serum triglyceride levels by 40%. The thioether of succinimide afforded a 54% reduction of serum cholesterol and a 41% reduction of serum triglyceride levels in mice after 16 d. The alkyl thioethers of 1,8-naphthalimide and succinimide significantly lowered cholesterol levels in serum VLDL and LDL, while the alkyl thioethers of succinimide elevated HDL cholesterol content. Tissue lipids were reduced in the liver and aorta by these selected derivatives. The activities of regulatory enzymes in de novo synthesis of hepatic cholesterol and triglyceride were inhibited by the selected 1,8-naphthalimide derivatives. In situ cholesterol and cholic acid reabsorption from intestines were suppressed by the presence of the agents.

The effects of phthalimide and saccharin derivatives on low-density lipoprotein (LDL) and high-density lipoprotein (HDL) receptor activity and related enzyme activities

The hypolipidemic agents, phthalimide, saccharin, o-(N-phthalimido) acetophenone, N-(p-chlorobenzoyl) sulfamate, and o-chlorobenzylsulfonamide affected low-density lipoprotein (LDL) and high-density lipoprotein (HDL) receptor activity and lipoprotein degradation. In isolated rat hepatocytes, rat aorta foam cells, and human fibroblasts, LDL receptor activity, which is dependent on apo-B and -E, was inhibited by the drugs in a dose-dependent manner. LDL degradation was accelerated in the hepatocytes, while it was inhibited in aorta cells and fibroblasts. The drugs enhanced HDL receptor activity, dependent on apo-E and -A1, and HDL degradation in the hepatocytes, whereas in fibroblasts and aorta cells HDL receptor binding and degradation were suppressed. In parallel, activities of acyl CoA acyl transferase, sn-glycerol-3-phosphate acyl transferase, and heparin-induced lipoprotein lipase decreased and activities of HMG-CoA reductase and cholesterol oleate-ester hydrolase increased. In fibroblasts the presence of drugs enhanced HDL binding of intracellular cholesterol. In vivo studies demonstrated that phthalimide and saccharin treatment enhanced the clearance of HDL and decreased the clearance of LDL from the serum of rats. The results suggest that the mode of action of the agents is to modulate the lipoprotein receptor and, thereby, the clearance of lipids from peripheral tissue as part of the hypolipidemic activity.

Hypolipidemic activity of o-(N-phthalimido)acetophenone in Sprague Dawley rats

o-(N-Phthalimido)acetophenone has proven to be an effective hypolipidemic agent in rats at 20 mg/kg/day orally. The agent suppressed the activity of the rate-limiting enzyme of the liver involved in de novo synthesis of triglycerides. The synthetic rate-limiting enzyme for cholesterol esters was also inhibited by the drug in vivo. o-(N-Phthalimido)acetophenone lowered cholesterol in the liver and the aorta wall and generally caused an increase in phospholipids in body tissues. Serum lipoproteins were modulated by the drug with a decrease in cholesterol and triglycerides in the chylomicron, very low-density lipoproteins (VLDL), and low-density lipoproteins (LDL) and an increase in high-density lipoprotein (HDL) cholesterol. The phospholipid content was increased in the chylomicron, VLDL, and LDL fractions. In hyperlipidemic rats, o-(N-phthalimido)acetophenone lowered elevated blood lipid levels at 20 mg/kg/day orally after 3 weeks of administration. The hypolipidemic rat after drug treatment had a lower LDL cholesterol and a higher HDL cholesterol content, which is therapeutically desirable to protect against cardiovascular disease.

The hypolipidemic activity of N(4-methyl-phenyl)diphenimide in rodents

N(4-Methyl-phenyl)diphenimide afforded potent hypolipidemic activity in rodents. Serum cholesterol levels were reduced 67% and serum triglyceride were lowered 66% in rats by the drug after two weeks administration orally at 20 mg/kg/day. Rate limiting enzymes in the de novo synthesis of lipids in the liver were suppressed by the drug. Cholesterol was also removed from the body due to the drug accelerating bile excretion. Lipids removed from the blood compartment were not deposited in the organs of the body. VLDL and LDL cholesterol content was significantly reduced in rats treated with the drug with marked increase in HDL cholesterol after two weeks of administration. These data suggest that the drug may be useful in hyperlipidemic states and atherosclerosis in man, thus, further investigation of this class of chemicals is warranted.

Synthesis and hypolipidemic activity of 3-imino-1-oxoisoindolines in rodents

A series of substituted 3-imino-1-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-1-oxoisoindoline lowered serum cholesterol levels 52% and serum triglyceride 42%. 2-Pentyl-3-imino-1-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-1-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.

Hypolipidemic activity of the surfactants aminimides, and their effects on lipid metabolism of rodents

A series of short chain fatty acid derivatives of aminimides were shown to possess hypolipidemic activity in rats and mice. Most of the agents tested lowered both serum cholesterol and triglyceride levels by at least 30% in mice and were effective in hyperlipidemic induced mice. 1,1-Dimethyl-1-(2-hydroxypropyl)-amine mersitimide lowered serum cholesterol levels 41% and serum triglyceride levels 56% at 20 mg/kg/day I.P. after 16 days. The same agent was active orally when administered to rats with a 38% reduction in serum cholesterol and a 52% reduction in serum triglycerides after 14 days. The agents inhibited liver acetyl CoA synthetase, ATP dependent citrate lyase and phosphatidate phosphohydrolase activities in vitro and in vivo. Reduction of cholesterol, triglycerides, neutral lipids and phospholipid levels were noted in the livers of mice treated for 16 days. In rat studies, cholesterol, triglyceride and phospholipid levels were reduced in liver, small intestine and the feces after two weeks' dosing. The cholesterol content was reduced in the very low density lipoprotein (VLDL) and low density lipoprotein (LDL) fractions but elevated in the high density lipoproteins (HDL). Triglyceride levels were lowered in the VLDL, and neutral lipid levels were reduced in the chylomicron and VLDL fractions.

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 (3)H-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.

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.

Antihyperlipidemic activity of phthalimide analogues in rodents

Phthalimide analogues have been shown to effectively lower serum cholesterol and triglyceride levels in rats and mice. The mode of action of these agents was not to suppress the appetite of animals, but rather to reduce the activities of key enzymes in the early synthesis of liver cholesterol and fatty acids in the triglyceride pathway. Phthalimide analogues were effective in accelerating biliary excretion of cholesterol and blocking its absorption from the gut. After 16 days dosing, it was evident that higher levels of lipids were being excreted than in control mice. The major serum lipoprotein fractions were reduced in cholesterol, triglyceride, and neutral lipid content, but not phospholipid content in rats after 14 days of administration.