The present invention relates to the synthesis of novel morpholine derivatives and the evaluation of their hypocholesterolemic, hypolipidemic and antioxidant activity. Especially, the present invention relates to the synthesis and pharmacochemical evaluation of morpholine derivatives of the formula I 
in which R1=CH2CH3, R2=CH3, R3, R4=H, R5=C6H5 (compound 1) or R1=CH2CH2CH2ONO2, R2=CH3, R3,R4=H, R5=C6H5 (compound 2) or R1=H, R213 R3=(CH2)4, R4=H, R5=C6H5 (compound 3) or R1=CH2CH2CH3, R2xe2x80x94R3=(CH2)4, R4=H, R5=C6H5 (compound 4) or R1=CH2CH2CH2ONO2 R2xe2x80x94R3=(CH2)4, R4=H, R5=C6H5 (compound 5) or R1=H, R2=CH3, R3xe2x80x94R4=(CH2)4, R5=C6H5 (compound 6) or R1=CH2CH2CH3, R2=CH3, R3xe2x80x94R4=(CH2)4, R5=C6H5 (compound 7) or R1=CH2CH2CH2ONO2, R2=CH3, R3xe2x80x94R4=(CH2)4, R5=C6H5 (compound 8) or R1=CH2CH2CH2ONO2, R2=CH3, R3, R4=H, R5=H (compound 9) or R1=H, R2=p-NO2xe2x80x94C6H4xe2x80x94CH2CH2, R3, R4=H, R5=C6H5 (compound 10).
It is well known that the pathogenesis of atheromatosis is related with a lot of factors, the most important of them are:
oxidative modification of the low density lipoproteins (LDL)
increased levels of cholesterol and LDL-cholesterol in blood
increased levels of triglycerides in blood
decreased levels of HDL-cholesterol in blood
thrombogenesis, endothelial injury and haemodynamic factors.
Especially, the oxidative modification of LDL appears to be the most risk atherogenic process, which induces inflammatory and apoptotic mechanisms and finally the formation of foam cells and fatty streaks.
At this field of research, the most of the synthetic compounds posses hypocholesterolemic or hypolipidemic or antioxidant activity. Their are no reports about compounds able to decrease total cholesterol, triglycerides and LDL-cholesterol in blood in combination with antioxidant activity.
Considering the above we think that it would be interesting to design, synthesise and evaluate compounds with hypocholesterolemic, hypolipidemic and antioxidand activity.
The novel derivatives we are reporting are able to decrease total cholesterol levels in plasma significantly. Also, the novel derivatives are able to decrease triglycerides and LDL-cholesterol levels in plasma.
The novel derivatives, except their hypolipidemic activity posses also potent antioxidant activity. We think that the combination of the hypolipidemic and the antioxidant activity is necessary for the prevention and treatment of ahteromatosis more effectively.
The present invention relates to the synthesis and the evaluation of antioxidant, hypocholesterolemic and hypolipidemic activity of novel morpholine derivatives of the general structure (I).
Synthesis
The 2-hydroxy-morpholine derivatives 3, 6 and 10 are synthesised by the reaction of the appropriate aminoalcohol (22 mmol) and the 2-bromo4-phenylacetophenone or the 2-bromoacetophenone (10 mmol) in ether and acetone for 15 hours at room temperature. After washing with saturated solution of sodium chloride, drying with potassium carbonate, evaporation in vacuo and neutralisation with hydrochloric acid 10% in ether, the 2-hydroxy derivatives are obtained and recrystalised from acetone and ether.
The 2-alkoxy derivatives 1, 4 and 7 are synthesised by the reaction of the respective 2-hydroxy derivative with the appropriate alcohol, in acid medium and reflux.
Compounds 2, 5, 8 and 9 are synthesised by the reaction of the respective 2-hydroxy derivative with the 3-bromopropanol in acidic medium and reflux. The 2-(3-bromopropoxy) derivatives then react with silver nitrate in acetonitrile and reflux. 
Evaluation of the Antioxidant Activity
[Method]
The evaluation of the antioxidant activity of the novel compounds was performed in vitro by peroxidation of rat hepatic microsomal membrane lipids. Lipid peroxidation was induced by the Fe2+/ascorbic acid system. Rat hepatic microsomes were heat-inactivated (90xc2x0 C. for 90 s). A fresh solution of ascorbic acid (0.2 mM) in Tris-HCl buffer (pH 7.4) and the tested compounds, dissolved in DMSO to give final concentrations of 1 mM to 0.1 mM, were added to microsomes Equal amount of buffer was added to the control samples. The reaction was initiated by addition of FeSO4 (10 xcexcM). The mixture was incubated at 37xc2x0 C. for 45 min. Aliquots were taken at various time intervals and lipid peroxidation was assessed by spectrophotometric determination of the 2-thiobarbituric acid reactive material at 535 nm.
[Results]
All tested compounds inhibited lipid peroxidation 100% at 1 mM and this action is maintained even at 0.1 mM.
Evaluation of the Hypolipidemic Activity
[Method]
The hypocholesterolemic and hypolipidemic activity of the synthesised compounds was performed by the inhibition of the hyperlipidemia induced by the Triton WR 1339 in rats. Triton WR 1339 as an intraperitoneal (i.p.) injection acts due to induction of HMG-CoA reductase. Using male Fischer rats (230-280 g) in group of five (test group), we injected a solution of 200 mg/Kg Triton WR 1339 i.p. and the same time 28 to 56 xcexcmol/Kg of the tested compounds and probucol (as reference), suspended in aqueous solution was injected i.p. Control group was treated i.p. with Triton WR 1339 and 10 ml/Kg of the vehicle of the tested compounds i.p. After 24 hours, blood was taken from the celiac aorta and collected to heparinised tubes. Blood was centrifuged for 15 minutes at 3000 rpm and plasma was selected for the determination of total cholesterol (TC), LDL cholesterol (LDL-C) and triglycerides (TG) using commercial kits.
[Results]
Our results indicate that the tested compound decrease total cholesterol levels in plasma even by 54%, triglyceride levels even by 49% and LDL-cholesterol level even by 51% and all compounds were more potent than probucol (table 1).
The above results indicate that the novel compounds posses antioxidant and potent hypolipidemic and hypocholesterolemic action. This combination of antioxidant and hypolipidemic properties may be useful against atheromatosis.