scholarly journals Antihypertensive effect of aqueous polyphenol extracts of Amaranthusviridis and Telfairiaoccidentalis leaves in spontaneously hypertensive rats

2018 ◽  
Vol 1 ◽  
Author(s):  
Olayinka A. Olarewaju ◽  
Adeola M. Alashi ◽  
Rotimi E Aluko
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Antihypertensive Agents ◽  
Hypertensive Rats ◽  
Leaf Extracts ◽  
Spontaneously Hypertensive ◽  
Angiotensin I Converting Enzyme ◽  
Arterial Blood ◽  
Renin Inhibition

The antihypertensive effects of aqueous polyphenol-rich extracts of Amaranthusviridis (AV) and Telfairiaoccidentalis (TO) leaves in spontaneously hypertensive rats (SHR) were investigated. The dried vegetable leaves were extracted using 1:20 (leaves:water, w/v) ratio for 4 h at 60 °C. Results showed significantly (P < 0.05) higher polyphenol contents in TO extracts (80–88 mg gallic acid equivalents, GAE/100 mg) when compared with the AV (62–67 mg GAE/100 mg). Caffeic acid, rutin and myricetin were the main polyphenols found in the extracts. The TO extracts had significantly (P < 0.05) higher in vitro inhibition of angiotensin I-converting enzyme (ACE) activity while AV extracts had better renin inhibition. Oral administration (100 mg/kg body weight) to SHR led to significant (P < 0.05) reductions in systolic blood pressure for the AV (−39 mmHg after 8 h)and TO (−24 mmHg after 4 and 8 h).The vegetable extracts also produced significant (P < 0.05) reductions in diastolic blood pressure, mean arterial blood pressure and heart rate when compared to the untreated rats. Thus both the AV and TO leaf extracts have the potential to be used as antihypertensive agents, especially the AV, which produced persistent long-lasting effect over a 24 h period.

Solanum macrocarpon Leaf Extracts Reduced Blood Pressure and Heart Rate After Oral Administration to Spontaneously Hypertensive Rats

2019 ◽  
Vol 17 (3) ◽  
pp. 282-290 ◽  
Author(s):  
Olayinka A. Oluwagunwa ◽  
Adeola M. Alashi ◽  
Rotimi E. Aluko
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Leaf Extracts ◽  
Spontaneously Hypertensive ◽  
Vitro Analysis ◽  
Gallic Acid Equivalent ◽  
In Vitro Analysis

The aim of this work was to determine the ability of polyphenol-enriched aqueous vegetable leaf extracts to ameliorate blood pressure and heart rate dysfunctions in spontaneously hypertensive rats (SHRs). Solanum macrocarpon (SM), a common edible vegetable leaf in West Africa was cultivated using varying levels (0-80 kg/ha) of urea that was applied at planting (T1) or 2 weeks after planting (T2). In vitro analysis showed that total polyphenolic compounds varied from 489.87 ± 5.66 to 513.56 ± 1.42 mg gallic acid equivalent/g dry wt of extract. Rutin, caffeic acid and myricetin were the major polyphenols quantified in the extracts. All the extracts inhibited in vitro activities of renin and angiotensin converting enzyme to varying extents. Two extracts (SM40T1 and SM80T2) were orally administered to SHRs at 100 or 500 mg/kg body wt. Results showed that systolic blood pressure was reduced to a similar level by SM40T1 (10.8 mmHg) and SM80T2 (10.5 mmHg) for the 100 mg/kg body wt dose; the 500 mg/kg body wt dose produced similar values. Diastolic blood pressure and heart rate were also depressed by the two extracts with similar effects observed for both doses. We conclude that the leaf extracts could serve as potential ingredients to formulate antihypertensive functional foods and nutraceuticals.

scholarly journals Effects of Diabetic Hyperglycemia on Central Ang-(1-7)-Mas-R-nNOS Pathways in Spontaneously Hypertensive Rats

2016 ◽  
Vol 40 (5) ◽  
pp. 1186-1197 ◽  
Author(s):  
He Li ◽  
Xian Liu ◽  
Zhongqiao Ren ◽  
Jinxia Gu ◽  
Yingjie Lu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
Cerebral Cortex ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Systemic Injection ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Cerebrovascular Dysfunction ◽  
And Control

Background/Aims: Hypertension is a major cause of stroke, and diabetes can increase incidence of this disease. We determined the role played by central angiotensin-(1-7) [Ang-(1-7)] pathway in modulating spontaneously hypertension with diabetic hyperglycemia. Methods: Western Blot analysis and ELISA were used to determine the protein expression of Ang-(1-7) and its signal pathway Mas-R-nNOS in the cerebral cortex and hippocampus of spontaneously hypertensive rats (SHR) and control animals. In a subset of animals, diabetic hyperglycemia was induced by systemic injection of streptozotocin (STZ). We analyzed a relationship between the levels of central Ang-(1-7) and plasma brain natriuretic peptide (BNP) indicating a risk of ischemic stroke. We further examined the effects of Ang-(1-7) on arterial blood pressure. Results: Our findings demonstrated for the first time that administration of STZ 1) attenuates the levels of Ang-(1-7) in the cerebral cortex and hippocampus, which are closely linked to plasma BNP; and 2) leads to downregulation of central Ang-(1-7)-Mas-R-nNOS pathways. Notably, STZ has greater effects in SHR. Additionally, inhibition of oxidative stress can largely improve downregulation of Ang-(1-7) in diabetic SHR. Moreover, central stimulation of Ang-(1-7) pathway or a blockade of oxidative stress improves systolic blood pressure in diabetic SHR. Conclusions: The Ang-(1-7) signaling pathway is engaged in the adaptive mechanisms associated with diabetic hypertension, suggesting that enhancing Ang-(1-7)-Mas-R-nNOS system is likely to be beneficial in preventing against cardiovascular and cerebrovascular dysfunction and vulnerability related to spontaneously hypertension, particularly to diabetic hypertension.

An antihypertensive extract of erythrocytes: effects on 45Ca uptake and efflux

1986 ◽  
Vol 64 (4) ◽  
pp. 424-429
Author(s):  
G. L. Wright ◽  
G. O. Rankin ◽  
W. D. McCumbee
Keyword(s):  
Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Calcium Uptake ◽  
Slow Component ◽  
Present Report ◽  
Calcium Stores ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Washout Curves

The present report describes some aspects of the effects of a recently described antihypertensive extract of erythrocytes (AHF) on calcium uptake and efflux in rat aortae. AHF was found to be present in the erythrocytes of both spontaneously hypertensive rats and normotensive rats. Furthermore, AHF obtained from erythrocytes of SH rats was shown to be equally effective in suppressing lanthanum-resistant calcium uptake in aortae from hypertensive and normotensive rats. AHF treatment prior to incubation of aortae with 45Ca caused an apparent increase in the total 45Ca uptake. The analysis of calcium washout curves obtained for tissue in calcium-free or lanthanum-containing media indicated that AHF had no significant effect on the rate of calcium loss from the slow component of efflux, though this compartment tended to be reduced in size. This indicated that the increase in the 45Ca content of AHF-exposed aortae prior to rinsing was confined to the rapid component of efflux. The loss of calcium from the rapidly exchanging compartment was enhanced in either of the efflux media used. The results suggest that a principal action of AHF involves an increase in the lability and exchangeability of calcium stores. In addition to its effects in resting tissue, AHF abolished the increase in lanthanum-resistant calcium uptake induced in rat aortae by the addition of high K+ or norepinephrine to the incubation media. In a second part of the study, the effect of AHF on blood pressure and in vitro calcium uptake were compared with that of phosphatidylethanolamine (PEA), the probable identity of another endogenous antihypertensive (renin preinhibitor) compound earlier shown to share important functional similarities with AHF. The results reduce the likelihood that the two causal agents are identical. The AHF produced a significant (75 Torr, 1 Torr = 133.32 Pa) fall in the systolic blood pressure (SBP) of spontaneously hypertensive rats within 24 h following injection, whereas PEA had no effect on the SBP in this model. Both AHF and PEA reduced the resting in vitro uptake of "lanthanum-resistant" calcium in rat aortic segments. However, the AHF effect was significantly greater than PEA at each concentration studied.

Tubuloglomerular feedback and autoregulation in spontaneously hypertensive rats

1990 ◽  
Vol 258 (6) ◽  
pp. F1479-F1489 ◽  
Author(s):  
F. H. Daniels ◽  
W. J. Arendshorst ◽  
R. G. Roberds
Keyword(s):  
Blood Pressure ◽  
Arterial Blood Pressure ◽  
Ureteral Obstruction ◽  
Spontaneously Hypertensive Rats ◽  
Control Period ◽  
Tubuloglomerular Feedback ◽  
Hypertensive Rats ◽  
Two Phase ◽  
Spontaneously Hypertensive ◽  
Arterial Blood

Experiments were conducted in 8-wk-old spontaneously hypertensive rats to determine whether tubuloglomerular feedback is essential for the autoregulation of renal blood flow. Autoregulation curves were obtained by measuring mean renal arterial blood pressure and flow during graded aortic occlusion. Renal vascular admittance was calculated from recordings of pulsatile renal arterial blood pressure and flow during induced atrial fibrillation. After a control period, acute ureteral obstruction was used to suppress tubuloglomerular feedback, as confirmed by measuring stop-flow pressure responses to rapid perfusion of Henle's loop. Ureteral obstruction did not impair steady-state autoregulation. During both the control and obstruction periods, the admittance gain was less than 1 at frequencies below 0.2 Hz, indicating dynamic autoregulatory activity. The control admittance contained two gain shoulders and two phase maxima, suggesting the presence of two control systems with response half-times of 1 and 10 s. During ureteral obstruction, the low-frequency shoulder and maximum disappeared, indicating that the slower system was no longer active. However, the high-frequency shoulder and maximum persisted, suggesting continued activity of the faster system. Collectively, these observations indicate the existence of a rapidly acting intrarenal control mechanism, in young spontaneously hypertensive rats, that may provide efficient autoregulation without assistance from tubuloglomerular feedback.

scholarly journals Hypotensive and Bradycardic Effects of Quinovic Acid Glycosides from Aspidosperma fendleri in Spontaneously Hypertensive Rats

2015 ◽  
Vol 10 (2) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Omar Estrada ◽  
Juan M. González-Guzmán ◽  
María M. Salazar-Bookman ◽  
Alfonso Cardozo ◽  
Eva Lucena ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Arterial Blood Pressure ◽  
Mean Arterial Blood Pressure ◽  
Spontaneously Hypertensive Rats ◽  
Cardiovascular Effects ◽  
Hypertensive Rats ◽  
Triterpenoid Saponins ◽  
Spontaneously Hypertensive ◽  
Arterial Blood

The Aspidosperma genus (Apocynaceae) represents one of the largest sources of indole alkaloids widely associated with cardiovascular effects. Aspidosperma fendleri, a plant found mainly in Venezuela, has a single phytochemical report in which is revealed the presence of alkaloids in its seeds. This study explored the cardiovascular effects of an ethanolic extract of A. fendleri leaves (EEAF) in spontaneously hypertensive rats (SHR) and its potential bioactive compounds. Using bioguided fractionation, fractions and pure compounds were intravenously administered to SHR and their effects on mean arterial blood pressure (MABP) and heart rate (HR) monitored over time. EEAF induced hypotensive and bradycardic effects as shown by significant reductions in mean arterial blood pressure (MABP) and heart rate (HR), respectively. Bioactivity-guided fractionation led to the isolation of a mixture of two known isomeric triterpenoid glycosides identified by spectral evidence as quinovic acid 3- O-β-rhamnopyranoside and quinovic acid 3- O-β-fucopyranoside. This mixture of triterpenoid saponins induced reductions in MABP and HR similar to those induced by propranolol. Together, these findings indicate that the two quinovic acid glycosides are responsible for the hypotensive and bradycardic effects which suggest their potential use in cardiovascular therapy.

scholarly journals Long-Term Effect of an AqueousFraxinus excelsiorL. Seed Extract in Spontaneously Hypertensive Rats

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Noemi López-Carreras ◽  
Sandra Fernández-Vallinas ◽  
Marta Miguel ◽  
Amaya Aleixandre
Keyword(s):  
Blood Pressure ◽  
Body Weight ◽  
Spontaneously Hypertensive Rats ◽  
Seed Extract ◽  
The Body ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Arterial Blood ◽  
Plasma Antioxidant Capacity

The effect of long-term intake of different doses (20, 40, and 60 mg/kg/day) of aFraxinus excelsiorL. seed extract (FESE) on spontaneously hypertensive rats (SHR) was evaluated. Water was used as control and captopril (50 mg/kg/day) was used as positive control. Systolic blood pressure, body weight, and food and liquid intake were registered weekly in SHR. The antioxidant and vascular relaxing properties of FESE were also studied in these animals. The development of hypertension was attenuated in the groups treated with captopril or FESE. The antihypertensive effect was more accentuated in the captopril group than in the FESE groups, and it was paradoxically more accentuated in the groups treated with 20 mg/kg/day or 40 mg/kg/day of FESE than in the group treated with the highest dose of this extract. Body weight gain and food intake increased in the FESE groups. After removing the corresponding antihypertensive treatment, the arterial blood pressure and the body weight of the FESE treated animals returned to control values. In addition, FESE increased plasma antioxidant capacity and decreased plasma and liver malondialdehyde levels. Moreover, acetylcholine relaxation improved in the aorta rings from the FESE treated rats.

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