Fractional composition of blood serum lipoproteins in mice and rats with Triton WR 1339-induced lipemia

Antioxidant and Hypolipidemic Activities of Cinnamic Acid Derivatives

Oxidative stress and hyperlipidemia are important factors for the initiation and progression of various cell degenerative pathological conditions, including cardiovascular and neurological diseases. A series of cinnamic acid-derived acids, such as ferulic acid, sinapic acid, 3,4-dimethoxycinnamic acid, p-coumaric acid, and (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid, were esterified or amidated with various moieties, bearing different biological activities, and evaluated. The antioxidant and radical scavenging abilities of the compounds via inhibition of rat hepatic microsomal membrane lipid peroxidation, as well as their interaction with the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), were assessed. Further, their hypolipidemic activity in vivo was tested. The majority of the obtained compounds demonstrated considerable radical scavenging and antioxidant action, with a parallel decrease in Triton-induced hyperlipidemia in rats. The (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid derivative with morpholine and 4-methylpiperidine (compounds 4 and 13, respectively) significantly decreased triglycerides and total cholesterol in the plasma of hyperlipidemic rats, with an antioxidant capacity similar to that of the antioxidant Trolox. The compounds were designed to exhibit antioxidant and hypolipidemic pharmacological actions, and this succeeded for the majority of them. Thus, such agents may be of interest in conditions and diseases implicating oxidative stress and dyslipidemia.

Onosma hispidum L. extract reverses hyperlipidemia, hypertension, and associated vascular dysfunction in rats

Onosma hispidum.L (O. hispidum) belongs to the family Boregineacea. A preliminary study and its medicinal use suggested its role in the management of hyperlipidemia. The present study aimed to assess the effect of methanolic root extract of O. hispidum in hyperlipidemia and associated vascular dysfunction. Oral administration of O. hispidum crude extract (Oh. Cr) to tyloxopol and high fat diet-induced hyperlipidemic Sprague-Dawley rats for 10 and 28 days significantly reduced total triglycerides and cholesterol (p < 0.001), compared to hyperlipidemic rats. Oh. Cr 250 mg/kg orally treated rats significantly (p < 0.001) reduced both the total body weight and atherogenic index in tylaxopol and HFD rats. In HMG-CoA assay, the inhibition of the enzyme was significant in Oh.Cr (250 mg/kg) treated group. Histopathological studies indicated that the group treated with Oh.Cr 250 mg/kg/day showed regular morphology of aortic intima, media and adventitia, and improved the endothelial damage. To investigate the vascular dysfunction, isolated rat aorta rings from all groups were pre-contracted with 1 µM phenylephrine (PE), and the effect of acetylcholine (Ach) was monitored. In the aorta isolated from Oh.Cr (50 mg/kg) treated group, Ach completely relaxed the PE-induced contraction with EC₅₀ value of 0.05 µg/mL 0.015 (0.01-0.2) compared to the hyperlipidemic control group (<30% relaxation). In atorvastatin (10 mg/kg) treated rat aorta, Ach showed 50% relaxation. The Oh.Cr extract also reduced (105.92 ± 1.14 to 66.63 ± 0.85 mmHg) mean arterial pressure in hyperlipidemic hypertensive rats. These findings suggest that extract of O. hispidum is an effective remedy for hypercholesterolemia, and hypertriglyceridemia, which acts through inhibition of HMG-CoA and improving vascular dysfunction.

Ferulic, Sinapic, 3,4-Dimethoxycinnamic Acid and Indomethacin Derivatives with Antioxidant, Anti-Inflammatory and Hypolipidemic Functionality

A series of thiomorpholine and cinnamyl alcohol derivatives, conjugated with cinnamic acid-containing moieties, such as ferulic acid, sinapic acid and 3,4-dimethoxycinnamic acid, were synthesized and tested for their antioxidant, anti-inflammatory and hypolipidemic properties. An indomethacin ester with 2,6-di-tert-butyl-4-(hydroxymethyl)phenol was also prepared for reasons of comparison. The majority of the compounds demonstrated considerable antioxidant capacity and radical scavenging activity, reaching up to levels similar to the well-known antioxidant trolox. Some of them had an increased anti-inflammatory effect on the reduction of carrageenan-induced rat paw edema (range 17-72% at 150 μmol/kg), having comparable activity to the NSAIDs (non-steroidal anti-inflammatory drugs) used as reference. They had moderate activity in soybean lipoxygenase inhibition. All the tested compounds exhibited a significant decrease in lipidemic indices in Triton-induced hyperlipidemia in rats, whilst the most active triglycerides and total cholesterol decreased by 72.5% and 76%, respectively, at 150 μmol/kg (i.p.), slightly better than that of simvastatin, a well-known hypocholesterolemic drug, but with negligible triglyceride-lowering effect. Since our designed compounds seem to exhibit multiple pharmacological activities, they may be of use in occasions involving inflammation, oxidative stress, lipidemic deregulation and degenerative conditions.

Antioxidant Serine-(NSAID) Hybrids with Anti-Inflammatory and Hypolipidemic Potency

A series of L-serine amides of antioxidant acids, such as Trolox, (E)-3-(3,5-di-tert-butyl-4-hydroxyphenyl)acrylic acid (phenolic derivative of cinnamic acid) and 3,5-di-tert-butyl-4-hydroxybenzoic acid (structurally similar to butylated hydroxytoluene), was synthesized. The hydroxy group of serine was esterified with two classical NSAIDs, ibuprofen and ketoprofen. The Trolox derivatives with ibuprofen (7) and ketoprofen (10) were the most potent inhibitors of lipid peroxidation (IC₅₀ 3.4 μΜ and 2.8 μΜ), several times more potent than the reference Trolox (IC₅₀ 25 μΜ). Most of the compounds decreased carrageenan-induced rat paw edema (37–67% at 150 μmol/kg). They were moderate inhibitors of soybean lipoxygenase, with the exception of ibuprofen derivative 8 (IC₅₀ 13 μΜ). The most active anti-inflammatory compounds exhibited a significant decrease in lipidemic indices in the plasma of Triton-induced hyperlipidemic rats, e.g., the most active compound 9 decreased triglycerides, total cholesterol and low-density lipoprotein cholesterol by 52%, 61% and 70%, respectively, at 150 μmol/kg (i.p.), similar to that of simvastatin, a well-known hypocholesterolemic drug. Since the designed compounds seem to exhibit multiple pharmacological actions, they may be of use for the development of agents against inflammatory and degenerative conditions.

Design, Synthesis and Study of Nitrogen Monoxide Donors as Potent Hypolipidaemic and Anti-Inflammatory Agents

Inflammation and oxidative stress are involved in cardiovascular diseases. Nitrogen monoxide participates in the regulation of endothelial processes. Thus, derivatives of classic nonsteroidal anti-inflammatory drugs (NSAIDs), trolox or cinnamic acids esterified with 2-(nitrooxy)ethanol were designed and studied. It was found that the nitrogen monoxide (NO) releasing activity was comparable to that of S-nitroso-N-acetylpenicillamine. The nitrooxy derivatives decreased potently lipid indices in the plasma of hyperlipidaemic rats (30–85%). All compounds presented increased anti-inflammatory activity in vivo, inhibiting carrageenan-induced rat paw oedema as high as 76%, up to six times higher than that of the parent acids. Lipoxygenase inhibitory activity was significant for most of them, although the parent molecules exerted a minor effect (IC₅₀ > 0.2 mM). Those compounds incorporating an antioxidant structure inhibited rat microsomal membrane lipid peroxidation strongly and possessed radical scavenging activity. These results indicated that the described compounds could act at different targets in multifactorial diseases, further limiting the possible adverse effects of drug combinations.

The Long Term Kinetic of Plasma Lipids and Lipoproteins in Tyloxapol Injected Rats

INTRODUCTION

The level of plasma triglyceride is balanced by the rate of secretion into and clearance from the plasma. Tyloxapol (Triton WR1339) is a nonionic detergent that inhibits lipoprotein lipase and hence clearance of triglyceride from the plasma.

AIM

To determine the kinetic of plasma lipids and lipoproteins following injection of tyloxapol over a period of two weeks.

MATERIALS AND METHODS

Fifteen male rats were starved over-night and injected intravenously with tyloxapol (400mg/kg). Blood samples were taken in three steps as, the early (1-6 hours), the middle (1-2 days) and the third (3-9 days) phase. Plasma total cholesterol and triglyceride were measured by enzymatic methods and total phospholipids were analysed as molybdenum blue. Serum lipoproteins were fractionated by electrophoresis on agarose gel (Sebia Inc).

RESULTS

The changes of plasma lipids following tyloxapol injection showed three distinctive phases. The early phase lasts at least 6 hours, and the concentrations of triglyceride, total cholesterol and phospholipids increased linearly. The rate of triglyceride secretion was 259.7 ± 8.1 mg/h.dl in this phase, which was comparable to the mean rate of 250.6 ± 37.0 mg/h.dl or 102.8 ± 15.2 mg/h.kg body in starved male rat. During the next 48 hour the lipids continued to accumulate but at a lower rate, and the levels of triglyceride, cholesterol and total phospholipids rose up to about 3200, 586 and 715 mg/dl respectively. In the last phase, the levels of plasma lipids decreased toward the basal levels after 5 days. In serum lipoprotein electrophoresis, the VLDL and LDL increased and HDL fraction disappeared simultaneously during the initial 2 hours of tyloxapol injection. The VLDL fell down toward the normal range, preceded to the reappearance of HDL during 5 days.

CONCLUSION

A single intravenous injection of tyloxapol shows three distinctive phases. In the early phase, triglyceride accumulates linearly and the rate of its increment in plasma is a good estimate of the rate of VLDL secretion from the liver.

Esters of some non-steroidal anti-inflammatory drugs with cinnamyl alcohol are potent lipoxygenase inhibitors with enhanced anti-inflammatory activity

Novel esters of non steroidal anti-inflammatory drugs, α-lipoic acid and indol-3-acetic acid with cinnamyl alcohol were synthesised by a straightforward method and at high yields (60-98%). They reduced acute inflammation more than the parent acids and are potent inhibitors of soybean lipoxygenase. Selected structures decreased plasma lipidemic indices in Triton-induced hyperlipidemia to rats. Therefore, the synthesised compounds may add to the current knowledge about agents acting against various inflammatory disorders.

Thiomorpholine Derivatives with Hypolipidemic and Antioxidant Activity

A number of thiomorpholine derivatives that are structurally similar to some substituted morpholines possessing antioxidant and hypocholesterolemic activity were synthesized. The new compounds incorporate an antioxidant moiety as the thiomorpholine N-substituent. The derivatives were found to inhibit the ferrous/ascorbate-induced lipid peroxidation of microsomal membrane lipids, with IC50 values as low as 7.5 µΜ. In addition, these compounds demonstrate hypocholesterolemic and hypolipidemic action. The most active compound (5) decreases the triglyceride, total cholesterol, and low-density lipoprotein levels in the plasma of Triton WR-1339-induced hyperlipidemic rats, by 80, 78, and 76%, respectively, at 56 mmol/kg (i.p.). They may also act as squalene synthase inhibitors. The above results indicate that the new molecules may be useful as leads for the design of novel compounds as potentially antiatherogenic factors.