Effects of citrus leaf extract on aortic vascular reactivity in hypertensive rats fed repeatedly heated vegetable oil

2019 ◽  
Vol 44 (4) ◽  
pp. 373-380
Author(s):  
Hawa Nordin Siti ◽  
Yusof Kamisah ◽  
Suhaila Mohamed ◽  
Kamsiah Jaarin

The prolonged intake of diet containing repeatedly heated vegetable oil can cause hypertension in the long run. In this study, the effects of citrus leaf extract (CLE) supplementation on vascular reactivity, plasma nitrite, and aortic structure in hypertensive rats that consumed were investigated by the consumption of repeatedly heated vegetable oil. Male Sprague Dawley rats (n = 56) were divided into 7 groups corresponding to the respective diets. For 16 weeks, 1 group was given standard rat chow (control) while other groups were given diets containing 15% w/w of palm oil, fresh palm oil (FPO), palm oil heated 5 times (5HPO), and palm oil heated 10 times (10HPO), with or without the incorporation of 0.15% w/w CLE (FPO+CLE, 5HPO+CLE, or 10HPO+CLE). Plasma nitrite levels were measured before and at 16 weeks of treatment. After 16 weeks, the rats were sacrificed and aortae were harvested for measuring vascular reactivity and for microscopic study. CLE supplementation had significantly reduced the loss of plasma nitrite and attenuated the vasoconstriction response to phenylephrine in the 5HPO group but not in the 10HPO group. However, CLE had no significant effect on the vasorelaxation response to acetylcholine and sodium nitroprusside. The elastic lamellae of tunica media in 5HPO, 10HPO, and 10HPO+CLE groups appeared disorganised and disrupted. Obtained findings suggested that CLE was able to enhance nitric oxide bioavailability that might dampen the vasoconstriction effect of phenylephrine.

2017 ◽  
Vol 87 ◽  
pp. 451-460 ◽  
Author(s):  
Hawa Nordin Siti ◽  
Yusof Kamisah ◽  
Mohd Ishak Nur Iliyani ◽  
Suhaila Mohamed ◽  
Kamsiah Jaarin

Author(s):  
Davie Rexon Kamadyaapa ◽  
Mavuto Masopera Gondwe ◽  
Mathulo Shauli ◽  
Constance Sewani Rusike ◽  
Jehu Iputo

Objective: The study was carried out to investigate the antidiarrheal activity of ethanolic leaf extract of Eriobotrya japonica (EEJ) using various models of experimental diarrhea.Methods: Antidiarrheal property of EEJ at 100, 200, and 400 mg/kg/bwt was evaluated using castor oil-induced diarrhea, castor oil-induced enteropooling, and gastrointestinal propulsive models of experimental diarrhea in Sprague Dawley rats of both sexes, weighing 200–250 g. Cytotoxicity test of EEJ was performed using brine shrimp bioassay.Results: Toxicity assay of EEJ showed a lethal concentration value of 1225 μg/ml suggesting non-toxicity. EEJ significantly (p<0.05) and dose-dependently (100, 200 and 400 mg/kg/bwt) inhibited castor oil-induced diarrhea by 38.1%, 76.19%, and 100%, respectively, and enteropooling by 28%, 56%, and 88%, respectively, compared with control. Pre-treatment with yohimbine, α2-adrenoceptor blocker significantly reversed the protective effect of EEJ (400 mg/kg) against castor oil-induced diarrhea and against castor oil-induced enteropooling, suggesting the involvement of α2-adrenoceptors in antidiarrheal property of EEJ. Furthermore, EEJ significantly (p<0.05) and dosedependently (100, 200, and 400 mg/Kg/bwt) inhibited gastrointestinal motility by 28%, 62%, and 83.92%, respectively.Conclusion: The study has demonstrated the antidiarrheal potential of ethanolic leaf extract of EEJ, which may be attributable to its dual antisecretory and antimotility activities probably through activation of the sympathetic α2-adrenergic pathway.


1981 ◽  
Vol 15 (4) ◽  
pp. 339-342 ◽  
Author(s):  
P. Carthew ◽  
R. P. Slinger

In a natural outbreak of sialodacryoadenitis virus it was observed that the incidence of clinical signs in spontaneous-hypertensive rats was 100%, and that these signs were of a severity not observed before in other strains of rats. Rats free of the virus were introduced so that the progress of the disease could be studied under natural conditions of spontaneous spread from the enzootically-affected breeding colony. The pathogenesis of the infection in these Sprague-Dawley rats has been recorded over a period of 10 days after their introduction to the colony, and the results of extensive serological screening have shown that the antibody response of the spontaneous-hypertensive rats to the virus is lower than in other strains of rat.


2018 ◽  
Vol 52 (6) ◽  
Author(s):  
Maria Concepcion C. Sison ◽  
Lynn Crisanta R. Panganiban ◽  
Daisy Mae A. Bagaoisan ◽  
Nelia P. Cortes-Maramba

Objective. To To evaluate potential effects of the aqueous extract of Quassia amara L. leaves on the cardiovascular and respiratory systems of adult male Sprague- Dawley rats. Methods. The cardiovascular and respiratory effects of the Quassia amara L. leaf extract on adult male SpragueDawley rats were assessed using non-invasive blood pressure (NIBP) determination and head-out plethysmography, respectively, in a randomized, parallel group study. Mean observations of blood pressure and heart rate were recorded at different time periods after dosing. Respiratory flow and irritation effects were evaluated using mean observations of respiratory rate (RR), tidal volume (TV), mid-expiratory flow rate (EF50), time of inspiration (TI) and expiration (TE), and time of break (TB) and pause (TP). Results. There were no significant differences among the control and the treatment groups in SBP, DBP and HR parameters. The extract showed statistically significant effect on mean RR by time period (F=2.45, p=0.0234), trends over time of TV among the dose groups (F=2.00, p=0.0202), and EF50 among dose groups ((F=3.11, p=0.0422). However, these did not correlate with the changes in the time of break (TB) and time of pause (TP) which are more sensitive and specific tests for respiratory irritation. Conclusion. Aqueous leaf extract of Quassia appeared to have no significant effects on SBP, DPB, Pulse pressure, and HR. There are no conclusive dose-related respiratory flow or pulmonary irritation effects.


2007 ◽  
Vol 292 (6) ◽  
pp. H2737-H2744 ◽  
Author(s):  
Masahito Kajiya ◽  
Masanori Hirota ◽  
Yousuke Inai ◽  
Takahiko Kiyooka ◽  
Taro Morimoto ◽  
...  

Pulmonary hypertension (PH) causes right ventricular (RV) hypertrophy and, according to the extent of pressure overload, eventual heart failure. We tested the hypothesis that the mechanical stress in PH-RV impairs the vasoreactivity of the RV coronary microvessels of different sizes with increased superoxide levels. Five-week-old male Sprague-Dawley rats were injected with monocrotaline ( n = 126) to induce PH or with saline as controls ( n = 114). After 3 wk, coronary arterioles (diameter = 30–100 μm) and small arteries (diameter = 100–200 μm) in the RV were visualized using intravital videomicroscopy. We evaluated ACh-induced vasodilation alone, in the presence of Nω-nitro-l-arginine methyl ester (l-NAME), in the presence of tetraethylammonium (TEA) or catalase with or without l-NAME, and in the presence of SOD. The degree of suppression in vasodilation by l-NAME and TEA was used as indexes of the contributions of endothelial nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF), respectively. In PH rats, ACh-induced vasodilation was significantly attenuated in both arterioles and small aretries, especially in arterioles. This decreased vasodilation was largely attributable to reduced NO-mediated vasoreactivity, whereas the EDHF-mediated vasodilation was relatively robust. The suppressive effect on arteriolar vasodilation by catalase was similar to TEA in both groups. Superoxide, as measured by lucigenin chemiluminescence, was significantly elevated in the RV tissues in PH. SOD significantly ameliorated the impairment of ACh-induced vasodilation in PH. Robust EDHF function will play a protective role in preserving coronary microvascular homeostasis in the event of NO dysfunction with increased superoxide levels.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Arnold Donkor Forkuo ◽  
Kwesi Boadu Mensah ◽  
Elvis Ofori Ameyaw ◽  
Aaron Opoku Antwi ◽  
Nana Kofi Kusi-Boadum ◽  
...  

Background. The increasing mortality and morbidity of malaria in Africa coupled with the recent reports of antimalarial drug resistance reinforces the need for novel antimalarial agents from natural plant products with folkloric use for the disease. Murraya exotica (L.) (Rutaceae) is widely used as an ornamental plant used indigenously to treat fever, cough, and infectious wounds and eliminate pain from injury and trauma. This study was conducted to evaluate extracts of the leaves of Murraya exotica (L.) (Rutaceae) for its safety and antipyretic and antimalarial activity in rodent models. Method. In this study, the Peters 4-day suppressive and curative test in Plasmodium berghei-infected mice was used to demonstrate the antiplasmodial activity of the methanolic leaf extract of Murraya exotica (L.) (MEE). The study also evaluated the subacute toxicity study and the antipyretic activity of MEE on baker’s yeast-induced hyperthermia in rodent models. Results. Murraya exotica (L.) extract demonstrated curative antimalarial activity, with a percentage suppression of 45.84, 64.32±0.33, 56.74±2.16, and 64.61±0.67 at doses of 50, 100, 300, and 600 mg/kg, respectively. In the Peters 4-day suppressive test, MEE at dose 600 mg/kg had the highest chemosuppression (76.02±1.38%) compared with artesunate (2 mg/kg, p.o.) (82.56±0.97%). Subacute oral toxicity studies in Sprague-Dawley rats documented no deaths, with no significant changes in clinical signs, organ weights, and hematological and biochemical parameters. The LD50 of MEE was estimated to be above 1000 mg/kg in Sprague-Dawley rats. All doses of MEE and paracetamol reduced pyrexia in 1 h and 2 h after their administration. The percentage reduction of rectal temperature (TR) for the positive control (paracetamol, 150 mg/kg, p.o.) was 44.36% while the Murraya exotica extract at doses 50 mg/kg, 100 mg/kg, 300 mg/kg, and 600 mg/kg recorded 67.74%, 40.78%, 66.42%, and 59.42%, respectively. Murraya exotica at dose 100 mg/kg exhibited significant reduction (p<0.05) in baker’s yeast-induced pyrexia. Conclusions. The findings in this study show the antipyretic, curative, and suppressive antiplasmodial activity as well as the safety of the methanolic leaf extract of Murraya exotica (L.) supporting its traditional use for malaria and fever.


2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Khuzaidatul Azidah Ahmad Nazri ◽  
Norsyahida Mohd Fauzi ◽  
Fhataheya Buang ◽  
Qodriyah Haji Mohd Saad ◽  
Khairana Husain ◽  
...  

Gynura procumbens (Lour.) Merr. (GP) has been reported in previous studies to possess antihyperlipidaemic, antioxidative, and cardioprotective properties. This study was aimed to determine the effect of standardised 80% ethanol extract of GP on lipid profiles and oxidative status of hypercholesterolemic rats. Postmenopausal (PM) Sprague-Dawley rats were ovariectomised and fed with 2% cholesterol diet fortified with five times heated palm oil to develop hyperlipidaemia status. Two doses of the extract (250 and 500 mg/kg) and atorvastatin (10 mg/kg) were administered once daily via oral gavage for 24 weeks. Systolic blood pressure (SBP) was increased during the first month in the postmenopausal group and decreased with GP supplementation. Lipid droplets accumulation was shown at the tunica media (TM) area of the aorta in the postmenopausal group and reduced with GP supplementation. Total cholesterol (TC), total triglycerides (TG), low-density lipoprotein (LDL), and malondialdehyde (MDA) levels increased (p<0.05) at 3 and 6 months in the postmenopausal group and were reduced with GP supplementation. GP also increased high-density lipoprotein (HDL) level in the postmenopausal group. Superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were reduced in the postmenopausal group compared to control in the sham group but increased (p<0.05) with GP supplementation. The results showed that the higher dose of GP (500 mg/kg) gave better effect. GP has the ability to reduce oxidative stress and prevent membrane cell damage through antioxidant enzyme activity modification and lipid profile changes in postmenopausal rats related to atherosclerosis.


1991 ◽  
Vol 260 (2) ◽  
pp. H453-H458 ◽  
Author(s):  
J. N. Stallone ◽  
J. T. Crofton ◽  
L. Share

Previously, we reported that, in the rat, pressor responsiveness to vasopressin (VP) is higher in males than in females during most phases of the estrous cycle. To explore the role of the vasculature in this phenomenon, we examined vascular reactivity to VP in thoracic aortas of male rats and female rats during each phase of the estrous cycle. Aortic rings were prepared from age-matched male and female Sprague-Dawley rats and mounted for isometric tension recording. Maximal response of female aortas to VP (4,246 +/- 163 mg/mg ring dry wt) was more than twice (P less than 0.001) that of male aortas (1,877 +/- 215 mg/mg ring wt). Sensitivity of female aortas to VP was substantially higher (P less than 0.001) than that of male aortas (EC50: 10.9 +/- 0.7 vs. 19.0 +/- 1.6 nM, respectively). Maximal rate of tension development (dT/dtmax) during contraction with VP was nearly twofold higher (P less than 0.01) in female aortas (536 +/- 23 mg/min) than in male aortas (300 +/- 19 mg/min). Maximal response, sensitivity, and dT/dtmax of female aortas did not vary significantly during the estrous cycle. Maximal response of female aortas to phenylephrine (PE; 1,251 +/- 93 mg/mg ring wt) was half that (P less than 0.001) of male aortas (2,546 +/- 194 mg/mg ring wt); sensitivity to PE did not differ significantly (EC50: 0.33 +/- 0.02 vs. 0.38 +/- 0.06 microM, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)


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