Mechanisms of the antihypertensive effects of Nigella sativa oil in L-NAME-induced hypertensive rats

OBJECTIVES: This study was conducted to determine whether the blood pressure-lowering effect of Nigella sativa might be mediated by its effects on nitric oxide, angiotensin-converting enzyme, heme oxygenase and oxidative stress markers. METHODS: Twenty-four adult male Sprague-Dawley rats were divided equally into 4 groups. One group served as the control (group 1), whereas the other three groups (groups 2-4) were administered L-NAME (25 mg/kg, intraperitoneally). Groups 3 and 4 were given oral nicardipine daily at a dose of 3 mg/kg and Nigella sativa oil at a dose of 2.5 mg/kg for 8 weeks, respectively, concomitantly with L-NAME administration. RESULTS: Nigella sativa oil prevented the increase in systolic blood pressure in the L-NAME-treated rats. The blood pressure reduction was associated with a reduction in cardiac lipid peroxidation product, NADPH oxidase, angiotensin-converting enzyme activity and plasma nitric oxide, as well as with an increase in heme oxygenase-1 activity in the heart. The effects of Nigella sativa on blood pressure, lipid peroxidation product, nicotinamide adenine dinucleotide phosphate oxidase and angiotensin-converting enzyme were similar to those of nicardipine. In contrast, L-NAME had opposite effects on lipid peroxidation, angiotensin-converting enzyme and NO. CONCLUSION: The antihypertensive effect of Nigella sativa oil appears to be mediated by a reduction in cardiac oxidative stress and angiotensin-converting enzyme activity, an increase in cardiac heme oxygenase-1 activity and a prevention of plasma nitric oxide loss. Thus, Nigella sativa oil might be beneficial for controlling hypertension

Effect of consumption of fresh and heated virgin coconut oil on the blood pressure and inflammatory biomarkers: An experimental study in Sprague Dawley rats

Background: It is a common practice to heat cooking oil and reuse it in order to cut expenses. The use of repeatedly heated cooking oil predisposes to various cardiovascular diseases. Virgin coconut oil (VCO) is reported to possess antioxidant action. Aim: The study aimed to determine the effect of heating of VCO on the blood pressure (BP) and inflammatory bio-markers. Methods: Thirty male Sprague-Dawley rats were divided into five groups and were fed with the following diet for 24 weeks: normal rat chow (control); chow + fresh VCO (FVCO); chow + VCO heated once (1HVCO); chow + VCO heated five times (5HVCO) and chow + VCO heated ten times (10HVCO). BP was measured at baseline and four weekly for 24 weeks. Blood was collected at baseline and at the end of study to measure plasma TXB2, PGI2, VCAM-1, ICAM-1 and LDH enzyme activity. Results: BP increased significantly in the 5HVCO and 10HVCO groups compared to the control and FVCO groups. The 5HVCO and 10HVCO diet caused a significant increase in the plasma TXB2 and a significant decrease in the plasma PGI2 level. The plasma levels of VCAM-1, ICAM-1 and CRP were significantly increased in the 10HVCO group. Conclusion: Repeatedly heated VCO caused an elevation in the BP. The BP elevation was associated with a significant increase in the inflammatory bio-markers (VCAM-1, ICAM-1 and CRP), TXB2 and a significant reduction in the plasma PGI2 level

The Effects of Cosmos caudatus (Ulam Raja) on the Levels of Expression of Nrf2 Target Genes in Mice Liver

Background: Cosmos caudatus (Ulam Raja) is an appetizer (ulam) eaten with rice in Malaysia. Previous studies showed that Cosmos caudatus possess high antioxidant content. Nrf2 is a transcription factor which regulates the expression of phase II enzymes and antioxidant proteins. The aim of this study is to investigate the effects of Cosmos caudatus aqueous extract (UR) on the expression of Nrf2 target genes in mice liver.Methods: ICR white mice were treated for 21 days with different doses of UR (100, 500, 1000 mg/kg) through oral gavage. Control mice were only given distilled water. After 21 days, the mice were sacrificed and their livers harvested. Total RNA was extracted, reverse transcribed and subjected to qPCR to detect Nrf2 target genes expression.Results: Administration of 100 mg/kg UR significantly increased NQO1 expression in mice liver. Administration of 500 mg/kg UR significantly increased HO-1 liver expression. Administration of 100 and 500 mg/kg UR significantly increased GSTA1 liver expression. Administration of 500 and 1000 mg/kg UR significantly increased GSTM3 liver expression, whereas GSTP and GSTM1 liver expression was significantly decreased at similar doses. Administration of all doses of UR significantly decreased the expression of GSTA3, SOD3 and GCLC in mice liver.Conclusion: UR administration mostly resulted in downregulation of Nrf2 target genes. However, conclusive evidence can only be made through the use of Nrf2 knockout mice or by performing Nrf2 nuclear translocation studies

The Effects of Cosmos caudatus (Ulam Raja) on the Levels of Expression of Nrf2 Target Genes in Mice Liver

Background: Cosmos caudatus (Ulam Raja) is an appetizer (ulam) eaten with rice in Malaysia. Previous studies showed that Cosmos caudatus possess high antioxidant content. Nrf2 is a transcription factor which regulates the expression of phase II enzymes and antioxidant proteins. The aim of this study is to investigate the effects of Cosmos caudatus aqueous extract (UR) on the expression of Nrf2 target genes in mice liver.Methods: ICR white mice were treated for 21 days with different doses of UR (100, 500, 1000 mg/kg) through oral gavage. Control mice were only given distilled water. After 21 days, the mice were sacrificed and their livers harvested. Total RNA was extracted, reverse transcribed and subjected to qPCR to detect Nrf2 target genes expression.Results: Administration of 100 mg/kg UR significantly increased NQO1 expression in mice liver. Administration of 500 mg/kg UR significantly increased HO-1 liver expression. Administration of 100 and 500 mg/kg UR significantly increased GSTA1 liver expression. Administration of 500 and 1000 mg/kg UR significantly increased GSTM3 liver expression, whereas GSTP and GSTM1 liver expression was significantly decreased at similar doses. Administration of all doses of UR significantly decreased the expression of GSTA3, SOD3 and GCLC in mice liver.Conclusion: UR administration mostly resulted in downregulation of Nrf2 target genes. However, conclusive evidence can only be made through the use of Nrf2 knockout mice or by performing Nrf2 nuclear translocation studies