The present study aimed to investigate the cardioprotective effect of hydroxytyrosol (HT) against isoproterenol-induced myocardial infarction in rats. Male rats were randomly divided into four groups, control, isoproterenol (Isop) and pretreated animals with HT in two different doses (2 and 5 mg/kg) orally for 7 days and intoxicated with isoproterenol (Isop + HT1) and (Isop + HT2) groups. Myocardial infarction in rats was induced subcutaneously by isoproterenol (100 mg/kg, s.c.) at an interval of 24 h on 6th and 7th day. On 8th day, electrocardiographic (ECG) pattern, gravimetric and biochemical parameters were assessed. Isoproterenol exhibited changes in ECG pattern, including significant ST-segment elevation and increase in the serum troponin-T level by 317 % as compared to control rats. Moreover, cardiac injury markers (creatine kinase-MB, lactate dehydrogenase, alanine aminotransferase) underwent a notable rise in serum of infarcted animals. Else, a disturbance in lipids profile and significant increase in lipase and angiotensin-converting enzyme (ACE) activities and heart weight ratio were observed in isoproterenol group. However, pre- and co-treatment with HT (2 and 5 mg/kg) improved the myocardium injury, restored the hemodynamic function and inhibited the ACE activity that prevent cardiac hypertrophy and remodeling. Overall, these findings demonstrated that HT exerted a potent cardioprotective effect against isoproterenol-induced myocardial infarction.

The present study investigated the effect of treating diabetic rats with eugenol (EG). In vitro enzyme activity was measured in the presence of eugenol, and it was found to inhibit pancreatic α-amylase (IC(50) = 62.53 µg/mL) and lipase (IC(50) = 72.34 µg/mL) as well as angiotensin converting enzyme (ACE) activity (IC50 = 130.67 µg/mL). In vivo, EG reduced the activity of amylase in serum, pancreas and intestine also the peak level of glucose by 60% compared to diabetic rats. Furthermore, eugenol similar to acarbose reduced serum glycosylated hemoglobin (HbA1c), lipase and ACE levels. In addition, treatments with EG showed notable decrease in serum total-cholesterol, triglycerides and low density lipoprotein-cholesterol levels with an increase of high density lipoprotein-cholesterol. Overall, EG significantly reverted back to near normal the values of the biochemical biomarkers such as transaminases (AST&ALT), alkaline phosphatase (ALP), creatine phosphokinase (CPK) and gamma-glutamyl transpeptidase (GGT) activities, total-bilirubin, creatinine, urea and uric acid rates.

This study aimed to evaluate the antithrombotic, anti-inflammatory and anti-cardiac remodeling properties of eugenol in isoproterenol-induced myocardial infarction in rats. Male Wistar rats were randomly divided into four groups, control, iso [100 mg/kg body weight was injected subcutaneously into rats at an interval of 24 h for 2 days (6th and 7th day) to induce MI] and pretreated animals with clopidogrel (0.2 mg/kg) and eugenol (50 mg/kg) orally for 7 days and intoxicated with isoproterenol (Iso + Clop) and (Iso + EG) groups. Isoproterenol-induced myocardial infarcted rats showed notable changes in the ECG pattern, increase in heart weight index, deterioration in the hemodynamic function and rise in plasma level of troponin-T, CK-MB and LDH and ALT by 316, 74, 172 and 45 %, respectively, with histological myocardium necrosis and cells inflammatory infiltration. In addition, significant increases in plasma levels of inflammatory biomarkers such as fibrinogen, α1, α2, β1, β2 and γ globulins with decrease level of albumin were observed in infarcted rats as compared to normal ones. Else, the angiotensin-converting enzyme (ACE) activity in plasma, kidney and heart of the isoproterenol-induced rats was significantly increased by 34, 47 and 93 %, respectively, as compared to normal group. However, the administration of eugenol induced a clear improvement in cardiac biomarkers injury, reduced inflammatory mediators proteins, increased heart activities of superoxide dismutase and glutathione peroxidase with reduce in thiobarbituric acid-reactive substances content and inhibition of ventricular remodeling process through inhibition of ACE activity. Overall, eugenol evidences high preventive effects from cardiac remodeling process.

Obesity is a serious health problem that increased risk for many complications, including diabetes and cardiovascular disease. The results showed EZA, which found rich in flavonoids and phenolic compounds, exhibited an inhibitory activity on pancreatic lipase in vitro with IC50 of 91.07 μg/mL. In vivo administration of this extract to HFD-rats lowered body weight and serum leptin level; and inhibited lipase activity of obese rats by 37% leading to notable decrease of T-Ch, TGs and LDL-c levels accompanied with an increase in HDL-c concentration in serum and liver of EZA treated HFD-rats. Moreover, the findings revealed that EZA helped to protect liver tissue from the appearance of fatty cysts. Interestingly, supplementation of EZA modulated key enzyme related to hypertension such as ACE by 36% in serum of HFD animals and improve some of serum electrolytes such as Na+, K+, Cl−, Ca2+ and Mg2+. Moreover, EZA significantly protected the liver-kidney function by reverted back near to normal the values of the liver-kidney dysfunction indices AST&ALT, ALP, CPK and GGT activities, decreased T-Bili, creat, urea and uric acid rates. In conclusion, these results showed a strong antihypelipidemic effect of EZA which can delay the occurrence of dislipidemia and hypertension.

The present study was designed to evaluate the cardioprotective effect of Tunisian flaxseed oil (Linum usitatissimum) against isoproterenol-induced myocardial infarction in rats by studying hypertensive and cardiac damage markers especially electrocardiographic changes and troponin T serum level. In vitro, the extracted oil showed an important inhibition of angiotensin converting enzyme (ACE) with an IC50 = 85.96 μg/ml. According to chemical analysis, this extract is composed essentially of alpha linolenic acid (ALA), an n-3 polyunsaturated fatty acid (58.59 %). Male rats were randomly divided into three groups, namely control (C), isoproterenol (ISO), and isoproterenol-treated group with flaxseed oil (FO + ISO). Isoproterenol injection showed changes in ECG pattern, including ST-segment elevation (diagnostic of myocardial infarction), increase in the serum levels of Troponin T and cardiac injury markers (creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), alkaline phosphatase (ALP), aspartate transaminase (AST), and alanine transaminase (ALT)). However, Linum oil pre-co-treatment prevented almost all the parameters isoproterenol-induced myocardial infarction in rats. Results of the present study proved that flaxseed oil has a significant effect by heart protection against isoproterenol-induced myocardial infarction through beneficial effect of the important fraction of ALA.