Satirah Zainalabidin

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes

OBJECTIVES: The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes. METHODS: Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days. RESULTS: The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained. CONCLUSION: The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients.

Aortic remodelling in chronic nicotine-administered rat.

Vascular remodelling is an adaptive mechanism, which counteracts pressure changes in blood circulation. Nicotine content in cigarette increases the risk of hypertension. The exact relationship between nicotine and vascular remodelling still remain unknown. Current study was aimed to determine the effect of clinically relevant dosage of nicotine (equivalent to light smoker) on aortic reactivity, oxidative stress markers and histomorphological changes. Twelve age-matched male Sprague-Dawley rats were randomly divided into two groups, i.e.: normal saline as control or 0.6 mg/kg nicotine for 28 days (i.p., n=6 per group). On day-29, the rats were sacrificed and the thoracic aorta was dissected immediately for further studies. Mean arterial pressure (MAP) and pulse pressure (PP) of nicotine-treated vs. control were significantly increased (p<0.05). Nicotine-treated group showed significant (p<0.05) increase tunica media thickness, and decrease in lumen diameter, suggesting vascular remodelling which lead to prior hypertension state. The phenylephrine (PE)-induced contractile response in nicotine group was significantly higher than control group (ED50=1.44×105 M vs. 4.9×106 M) (p<0.05~0.001). However, nicotine-treated rat showed significantly lower endothelium-dependent relaxation response to acetylcholine (ACh) than in control group (ED50=6.17×107 M vs. 2.82×107 M) (p<0.05), indicating loss of primary vascular function. Malondialdehyde (MDA), a lipid peroxidation marker was significantly higher in nicotine group. Superoxide dismutase (SOD) enzymatic activity and glutathione (GSH) were all reduced in nicotine group (p<0.05) vs. control, suggesting nicotine induces oxidative imbalance. In short, chronic nicotine administration impaired aortic reactivity, probably via redox imbalance and vascular remodelling mechanism.

Lactobacillus casei strain C1 attenuates vascular changes in spontaneously hypertensive rats

Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.

Roselle supplementation prevents nicotine-induced vascular endothelial dysfunction and remodelling in rats

Vascular endothelial dysfunction (VED) plays an important role in the initiation of cardiovascular diseases. Roselle, enriched with antioxidants, demonstrates high potential in alleviating hypertension. This study was undertaken to investigate the effects of roselle supplementation of VED and remodelling in a rodent model with prolonged nicotine administration. Male Sprague-Dawley rats (n = 6 per group) were administered with 0.6 mg/kg nicotine for 28 days to induce VED. The rats were given either aqueous roselle (100 mg/kg) or normal saline orally 30 min prior to nicotine injection daily. One additional group of rats served as control. Thoracic aorta was isolated from rats to measure vascular reactivity, vascular remodelling and oxidative stress. Roselle significantly lowered aortic sensitivity to phenylephrine-induced vasoconstriction (Endo-(+) Cmax = 234.5 ± 3.9%, Endo-(-) Cmax = 247.6 ± 5.2%) compared with untreated nicotine group (Endo-(+) Cmax = 264.5 ± 6.9%, Endo-(-) Cmax = 276.5 ± 6.8%). Roselle also improved aortic response to endothelium-dependent vasodilator, acetylcholine (Endo-(+) Rmax = 73.2 ± 2.1%, Endo-(-) Rmax = 26.2 ± 0.8%) compared to nicotine group (Endo-(+) Rmax = 57.8 ± 1.7%, Endo-(-) Rmax = 20.9 ± 0.8%). In addition, roselle prevented an increase in intimal media thickness and elastic lamellae proliferation to preserve vascular architecture. Moreover, we also observed a significantly lowered degree of oxidative stress in parallel with increased antioxidant enzymes in aortic tissues of the roselle-treated group. This study demonstrated that roselle prevents VED and remodelling, and as such it has high nutraceutical value as supplement to prevent cardiovascular diseases.

Roselle is cardioprotective in diet-induced obesity rat model with myocardial infarction

Aims: Obesity increase the risks of hypertension and myocardial infarction (MI) mediated by oxidative stress. This study was undertaken to investigate the actions of roselle aqueous extract (R) on cardiotoxicity in obese (OB) rats and thereon OB rats subjected to MI. Main methods: Male Sprague‐Dawley rats were fed with either normal diet or high‐fat diet for 8 weeks. Firstly, OB rats were divided into (1) OB and (2) OB + R (100 mg/kg, p.o, 28 days). Then, OB rats were subjected to MI (ISO, 85 mg/kg, s.c, 2 days) and divided into three groups: (1) OB + MI, (2) OB + MI + R and (3) OB + MI + enalapril for another 4 weeks. Key findings: Roselle ameliorated OB and OB + MIs cardiac systolic dysfunction and reduced cardiac hypertrophy and fibrosis. The increased oxidative markers and decreased antioxidant enzymes in OB and OB + MI groups were all attenuated by roselle. Significance: These observations indicate the protective effect of roselle on cardiac dysfunction in OB and OB + MI rats, which suggest its potential to be developed as a nutraceutical product for obese and obese patients with MI in the future.

Roselle (Hibiscus sabdiriffa) polyphenol-rich extract prevents testicular damage of diabetic rats

© 2018 Siti Balkis Budin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License -NonCommercialShareAlikeUnported License (http://creativecommons.org/licenses/by-nc-sa/3.0/). *Corresponding Author Siti Balkis Budin, Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia. E-mail: balkis @ ukm.edu.my Roselle (Hibiscus sabdiriffa) Polyphenol-Rich Extract Prevents Testicular Damage of Diabetic Rats

Hibiscus sabdariffa Linn. improves the aortic damage in diabetic rats by acting as antioxidant

© 2018 Satirah Zainalabidin et al. This is an open access article distributed under the terms of the Creative Commons Attribution License -NonCommercialShareAlikeUnported License (http://creativecommons.org/licenses/by-nc-sa/3.0/). *Corresponding Author Siti Balkis Budin, Biomedical Science Programme, School of Diagnostic and Applied Health Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia. E-mail: balkis @ ukm.edu.my Hibiscus sabdariffa Linn. improves the aortic damage in diabetic rats by acting as antioxidant

Hibiscus sabdariffa (Roselle) Polyphenol-rich Extract Averts Cardiac Functional and Structural Abnormalities in Type 1 Diabetic Rats

Diabetes mellitus is often associated with cardiac functional and structural alteration, an initial event leading to cardiovascular complications. Roselle (Hibiscus sabdariffa) has been widely proven as an antioxidant and recently has incited research interest for its potential in treating cardiovascular disease. Therefore, this study aimed to determine the cardioprotective effects of H. sabdariffa (roselle) polyphenol-rich extract (HPE) in type-1-induced diabetic rats. Twenty-four male Sprague-Dawley rats were randomized into 4 groups (n = 6/group): nondiabetic, diabetic alone (DM), diabetic supplemented with HPE (DM+HPE), and diabetic supplemented with metformin. Type-1 diabetes was induced with streptozotocin (55 mg/kg intraperitoneally). Rats were forced-fed with HPE (100 mg/kg) and metformin (150 mg/kg) daily for 8 weeks. Results showed that HPE supplementation improved hyperglycemia and dyslipidemia significantly (p < 0.05) in the DM+HPE compared with the DM group. HPE supplementation attenuated cardiac oxidative damage in the DM group, indicated by low malondialdehyde and advanced oxidation protein product. As for the antioxidant status, HPE significantly (p < 0.05) increased glutathione level, as well as catalase and superoxide dismutase 1 and 2 activities. These findings correlate with cardiac function, whereby left ventricle developed pressure in DM+HPE (79.13 ± 3.08 mm Hg) was higher significantly compared with DM (45.84 ± 1.65 mm Hg). Coronary flow of DM+HPE (17.43 ± 0.62 mL/min) was also greater compared with DM (13.02 ± 0.6 mL/min), showing that HPE supplementation improved cardiac contractility and relaxation rate significantly (p < 0.05). Histological analysis showed a marked decrease in cardiomyocyte hypertrophy and fibrosis in DM+HPE compared with the DM group. Ultrastructural changes and impairment of mitochondria induced by diabetes were minimized by HPE supplementation. Collectively, these findings suggest that HPE is a potential cardioprotective agent in a diabetic setting through its hypoglycemic, anti-hyperlipidemia, and antioxidant properties.

The vasorelaxant effect of Canarium odontophyllum Miq. (Dabai) extract in rat thoracic aorta

Abstract Canarium odontophyllum (CO) (Miq.) (Burseraceae) has been traditionally consumed for its antioxidant benefit in maintaining longetivity. However, there is no report concerning its pharmacological activity on blood vessels. This study was aimed to investigate the effects of CO aqueous leaf extract on isolated aortic rings. Methods Isolated thoracic aortic rings were suspended in a tissue bath and placed between 2 tungsten wires and connected to an isometric force transducer. The tension changes were recorded to a data acquisition system. Results The leaf aqueous extract (3–15mg/ml) induced relaxation in endothelium-intact and endothelium-denuded aortic rings precontracted with PE. Incubation with nitric oxide enzyme inhibitor L-NAME, however, did not alter the CO-induced vasorelaxant on endothelium-intact aortic ring. The vasorelaxant effect of CO was endothelium-independent as it reduced the contraction induced by extracellular Ca2+ in endothelium-denuded aortic ring precontracted by PE and KCl in Ca2+-free Krebs solution. However, CO did not inhibit the release of intracellular Ca2+ from sarcoplasmic reticulum. Conclusion This study suggests that the vasorelaxant effect of aqueous extract from CO leaves was endothelium-independent and was possibly mediated through the blockade of voltage-dependent calcium channel and receptor-operated calcium channel.

Low-dose nicotine exposure induced the oxidative damage of reproductive organs and altered the sperm characteristics of adolescent male rats

Background Nicotine is a major toxic and hazardous component of cigarette smoke, and it has been widely used in nicotine replacement therapy (NRT). This study was aimed to investigate the effects of chronic low-dose nicotine on sperm characteristics and reproductive organ integrity in adolescent male Sprague-Dawley rats. Methods Twelve rats were equally divided into two groups. Group I received normal saline, and group II received 0.6 mg/kg body weight nicotine intraperitoneally for 28 consecutive days. At the end of the experimental period, sperm was collected for sperm characteristic evaluation, and the testes and prostate were isolated for biochemical and morphological analysis. The effects of nicotine on the body and reproductive organ weights of the animals were evaluated. Results Chronic nicotine treatment significantly (P < 0.05) altered the sperm count, motility, viability, and morphology, and remarkably increased the malondialdehyde (P < 0.001) and advanced oxidation protein product (P < 0.05) levels in the testes and prostate of nicotine-treated group compared to control group. Moreover, nicotine caused a significant decrease (P < 0.05) in the superoxide dismutase activity of the testes. No significant differences were observed in the reduced glutathione level in both of the testes and prostate of nicotine group compared with control group. Nicotine also induced histopathological alteration in the testes. Conclusion A low-dose nicotine exposure at 0.6 mg/kg caused detrimental effects on sperm characteristics and induced oxidative stress in the testes and prostate.