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Effects of green tea, black tea and Rooibos tea on angiotensin-converting enzyme and nitric oxide in healthy volunteers

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Tea has been reported to reduce cardiovascular mortality, but the underlying mechanisms are largely unknown. The aim of the current project was to investigate the effect of green tea (Japanese Sencha), black tea (Indian Assam B.O.P.) and Rooibos tea (South Africa) on angiotensin-converting enzyme (ACE) and nitric oxide (NO). Seventeen healthy volunteers received a single oral dose of 400 ml green tea, black tea or Rooibos tea in a randomized, three-phase, crossover study. ACE activity and NO concentration were measured (at 0, 30, 60 and 180 min) in all phases. ACE activity was analysed by means of a commercial radioenzymatic assay. Nitrite was analysed as a marker of NO concentration. In addition, ACE genotype was determined using a PCR method. Oral intake of a single dose of Rooibos tea significantly inhibited ACE activity after 30 min (P < 0.01) and after 60 min (P < 0.05). A significant inhibition of ACE activity was seen with green tea for the ACE II genotype 30 min after intake of the tea (P < 0.05) and for the ACE ID genotype 60 min after intake (P < 0.05). A significant inhibition of ACE activity was also seen with Rooibos tea for the ACE II genotype 60 min after intake (P < 0.05). No significant effect on NO concentration was seen. These results suggest that green tea and Rooibos tea may have cardiovascular effects through inhibition of ACE activity.
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... Rooibos may help mitigate some of these adverse effects of Ang II based on its ability to significantly inhibit ACE with maximum inhibition at 30-60 min (min) and persisting for about 60 min after participants consumed an acute dose of fermented rooibos (Persson et al., 2010, Persson, 2012, Persson et al., 2006. According to the kinetic study, Rooibos probably inhibits ACE activity using a mixed inhibitor mechanism. ...
... Another indirect method to increase adiponectin levels has been shown to include the use of ACEinhibitors (Messina et al., 2020b). Previously we have discussed the ability of Rooibos to inhibit ACE after 30-60 min of consuming 500 mL of traditional Rooibos by the study participants (Persson et al., 2010). ...
... When considering the experimental data related to potential sideeffects, the intricacy of the topic and the need for individualized characterization in this context becomes apparent. However, it is possible that Rooibos may recompense due to its specific beneficial bioactivities based on in vivo studies (Kawano et al., 2009, Ayeleso et al., 2014 and clinical trials , Persson et al., 2010. Rooibos was shown not to compromise the organism's ability to respond to disease conditions and suggests Rooibos to be a potential low-risk, dietary supplementation, and supportive strategy for everyone during this pandemic and perhaps more so for those with identified comorbidities. ...
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This article presents the potential health benefits of Rooibos to be considered a support during the COVID-19 pandemic. The recent pandemic of COVID-19 has led to severe morbidity and mortality. The highly infectious SARS-CoV-2 is known to prime a cytokine storm in patients and progression to acute lung injury/acute respiratory distress syndrome. Based on clinical features, the pathology of acute respiratory disorder induced by SARS-CoV-2 suggests that excessive inflammation, oxidative stress, and dysregulation of the renin angiotensin system are likely contributors to the COVID-19 disease. Rooibos, a well-known herbal tea, consumed for centuries, has displayed potent anti-inflammatory, antioxidant, redox modulating, anti-diabetic, anti-cancer, cardiometabolic support and organoprotective potential. This article describes how Rooibos can potentially play a supportive role by modulating the risk of some of the comorbidities associated with COVID-19 in order to promote general health during infections.
... 4,5 Obesity is also associated with the development of endothelial dysfunction 6 and oxidative stress. 7 Rooibos (Aspalathus linearis), a leguminous shrub indigenous to the Cederberg Mountains of the Western Cape in South Africa, has numerous health-promoting properties, such as anti-hypertensive, 8 antidiabetic, 9,10 anti-hyperglycaemic, [9][10][11][12] antiinflammatory, 13 antioxidant, 14 anti-cancer 15 and anti-obesity effects. 16 This is mainly attributed to its polyphenolic composition, particularly aspalathin, a unique major active flavonoid compound, and nothofagin, a 3-dehydroxydihydrochalcone glucoside. ...
... 5 Leptin and angiotensinogen serve as examples of pro-inflammatory adipokines, which contribute to the dysregulation in adipocyte metabolism. A number of studies have shown the ameliorative effects of unfermented rooibos against the above obesity-induced CVD risk factors, 8,9,[11][12][13][16][17][18] resulting from adipocyte hypertrophy. Fermented rooibos has been shown to inhibit adipogenesis and intracellular lipid accumulation, and it attenuates leptin secretion. ...
... The anti-hypertensive effects of unfermented rooibos have previously been documented. 8,42,43 Effects on the expression and phosphorylation state of the main proteins involved in the activation of eNOS were affected by the ingestion of GRT observed in this study. This could be one of the mechanisms that potentially contributed to the reduction in blood pressure, as observed in the HFD animals treated with the GRT extract. ...
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Purpose: Obesity is associated with the development of risk factors for cardiovascular disease (CVD) and polyphenols have been shown to possess ameliorative effects against obesity-induced CVD risk factors. Rooibos (Aspalathus linearis) is rich in polyphenols, therefore we investigated the cardioprotective effects of aspalathin-rich green rooibos (GRT) on obesity-induced CVD risk factors in obese Wistar rats. Methods: Adult male Wistar rats (n = 20 per group) were fed a control or a high-fat diet (HFD) for 16 weeks and treated with GRT (60 mg/kg/day) for six weeks. Blood pressure was monitored throughout. Vascular reactivity was measured and Western blots of cell-signalling proteins (eNOS, AMPK and PKB) were performed in aortic tissues. Effects on oxidative stress were determined by measuring antioxidant enzyme activity and thiobarbituric reactive substance (TBARS) levels in the liver. Results: HFD animals had (1) increased blood pressure, (2) impaired vasodilation, (3) attenuated PKB and AMPK expression, (4) decreased antioxidant enzyme activity, (5) increased malondialdehyde (MDA) levels, and (6) increased phosphorylated eNOS levels. Treatment with GRT extract significantly alleviated these obesity-induced CVD risk factors. Conclusions: Supplementation with GRT extract alleviated cardiovascular risk factors in the HFD animals, suggesting a therapeutic potential for GRT in obesity-induced cardiovascular risk.
... In a clinical study conducted by Marnewick and colleagues, it was evident that regular consumption of six cups of rooibos tea can markedly improve the lipid profile as well as redox status in individuals at increased risk of CVD [161]. Interestingly, other clinical studies have indicated that consumption of rooibos tea indeed displays some potential to improve cardiovascular outcomes in patients at risk of CVD [162,163]. However, there is limited studies reporting on its effect on inflammatory markers in a clinical setting. ...
... Interestingly, available clinical data suggests that plant based-food and medicinal plants containing relatively high levels of rutin, such as Fagopyrum tataricum [115], Crataegus spp. [125], Coffea arabica [134], Schisandra chinensis [147], and rooibos [162,163], can reduce blood pressure and cholesterol levels, in part by reducing oxidative stress and mediators of inflammation such as MPO, lipid-laden macrophages and NF-κB signaling activity (Fig. 4). While the potential therapeutic benefits of rutin or its enriched plants are acknowledged, available evidence still suggests that additional studies are still required to clarify its bioavailability profile. ...
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Chronic inflammation remains an essential complication in the pathogenesis and aggravation of metabolic diseases. There is a growing interest in the use of medicinal plants or food-derived bioactive compounds for their antioxidant and anti-inflammatory properties to improve metabolic function. For example, rutin, a flavonol derivative of quercetin that is found in several medicinal plants and food sources has displayed therapeutic benefits against diverse metabolic diseases. Here, we searched the major electronic databases such as PubMed/MEDLINE, Scopus and Google Scholar to systematically extract and critically discuss evidence reporting on the impact of rutin against metabolic diseases by attenuating inflammation. In fact, available preclinical evidence suggests that rutin, through its strong antioxidant properties, can effectively ameliorate inflammation by reducing the levels of pro-inflammatory markers such as tumor necrosis factor-α, interleukin (IL)-6, cyclooxygenase-2, IL-1β, as well as blocking nuclear factor kappa B (NF-κB)/ mitogen-activated protein kinase (MAPK) activation to improve metabolic function. Notably, although clinical data on the impact of rutin on inflammation is limited, food-derived sources rich in this flavonol such as Fagopyrum tataricum, Coffea arabica and Aspalathus linearis (rooibos) have shown promise in improving metabolic function, in part by reducing markers of oxidative stress and inflammation. However, additional studies are still required to confirm the therapeutic properties of rutin in a clinical setting, including the enhancement of it low bioavailability profile.
... Previous studies have demonstrated that green tea and its bioactive compound, EGCG, can inhibit ACE activity in endothelial cells [8]. GT was also shown to cause the inhibition of ACE activity in healthy humans [9]. However, little is known on whether green tea can inhibit ACE activity in hypertensive rats. ...
... For example, green tea extract and its active components including (-)-epicatechin, (-)-epigallocatechin, (-)epicatechingallate and (-)-epigallocatechingallate reduced ACE activity in human endothelial cells in a dose dependent manner after 10 min of treatment [8]. Moreover, green tea reduces the ACE activity in healthy human blood after consumption of tea infusion (10 mg in 400 ml) at 30 min, 1 and 3 h [9]. ...
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Purpose: To investigate the blood pressure-lowering effect of green tea (GT) extract alone and in combination with an angiotensin converting enzyme (ACE) inhibitor, perindopril, on rats. Methods: The study consisted of four groups of five spontaneously hypertensive rats (SHR): negative control (2 % tragacanth mucilage), positive control group (perindopril, 0.36 mg/kg/day) and two treatment groups (green tea, 25 mg/kg/day; and combined green tea/perindopril). The treatments were given orally for 14 days. Systolic blood pressure was measured before and after treatment using the tail cuff technique. Angiotensin converting enzyme activity in the lung homogenate of the hypertensive rats was determined spectrophotometrically. Results: Green tea extract significantly reduced the rats’ systolic blood pressure (p < 0.05) but did not inhibit the angiotensin-converting enzyme. The combination of green tea extract with perindopril also caused a significant decline in blood pressure (p < 0.001). However, the green tea extract attenuated the inhibition of the angiotensin-converting enzyme activity by perindopril. Conclusion: Green tea extract produces anti-hypertensive activity in rats, but its mechanism of action is not via inhibition of angiotensin-converting enzyme. The interaction of GT extract with perindopril results in a reduction of ACE inhibitory activity.
... As green tea contains epigallocatechin gallate, its consumption can lead to the release of nitric oxide and prostaglandins and thus cause vasodilation. The catechins available in green tea have also been reported to reduce systolic blood pressure [98,99]. Garlic: The plant with the scientific name of Allium sativum has significant antioxidant capacity and includes disulfide, propyl sulfide, allyl propyl disulfide compounds, as well as allicin. ...
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Although the people's knowledge about cardiovascular diseases (CVDs) has increased, these diseases are still among the main causes of mortality in industrialized and developing countries and communities. For controlling and treating CVDs, both pharmaceutical and non-pharmaceutical methods can be helpful. The high global prevalence of CVDs and associated serious effects on the body organs made them a major health problem in all societies. Concerns about the side effects of synthetic drugs lead to their improper usage and rejection by patients and subsequently a disrupted disease management process. For this reason, today, a new approach is emerging toward medicinal plants, and in fact, they are subjected to extensive research these days. The aim of this review was to introduce medicinal plants and present their action mechanisms, which have been effective in the treatment of CVDs. A literature search was conducted to recruit the articles published in various databases. We also reviewed reference textbooks to elaborate on the mechanisms of action of various plants in the treatment of cardiac diseases and investigate the involved molecular mediators and pathways. Studies have shown that herbal medicines through various mechanisms such as lowering blood pressure, resolving diabetes, improving atherosclerosis, reducing blood fats, inducing nitric oxide, blocking calcium channels, and suppressing the renin-angiotensin pathway can help improve CVDs.
... On the same note, certain in vitro studies reported that some antioxidants present in tea, such as quercetin and luteolin, have anticancer and antitumor effects (Lee et al., 2002;Mouria et al., 2002), but no clinical studies have been reported thus far. Moreover, there are clinical studies conducted on the overall cardiovascular and health-promoting potentials of rooibos, whereby it was reported that drinking rooibos tea may have beneficial effects on blood pressure by inhibiting angiotensin-converting enzyme (ACE), and also reducing blood cholesterol levels (Persson, Persson, Hägg, & Andersson, 2010); (Marnewick et al., 2011). The bronchodilatory, antispasmodic, and blood pressure lowering effects of rooibos were also reported in rat studies and mechanistically investigated to decode their heart health potentials (Khan & Gilani, 2006). ...
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Functional foods contain health-promoting ingredients, which make them beneficial to humans and potentially help in disease prevention or treatment. The demand for functional foods is growing not just in the developed regions, but also in the developing regions of the world such as in Africa due to heightened consumer awareness on the role of foods in human health. African functional foods are foods of African origin that possess various characteristics like prebiotic, probiotic, satiety, immune modulation, stress-reduction, improved memory, and cardiovascular benefits. Traditionally fermented functional foods prepared from cereals like maize, millet, or sorghum abound in many African countries. Traditional fermentation, often spontaneous, utilizes a mixed culture of microorganisms mostly belonging to the lactic acid bacteria and yeast groups. The present review corroborated these pieces of information into the famous African functional foods and beverages, their sources, and quality attributes. Furthermore, functional foods were explained in very clear terms while evaluating the relationship between functional foods and African consumer's health benefits. The study peaked at future work and further considerations on the potential of common functional foods from Africa, which are cheap and readily available to the people. ARTICLE HISTORY
... Nie odnotowano istotnego statystycznie wpływu naparów na stężenie NO. Wyniki badania sugerują, że napary z czerwonokrzewu (oraz zielonej herbaty) regulują w korzystny sposób wartości ciśnienia tętniczego [54]. Istotny wpływ na rozwój zespołu metabolicznego i powikłań naczyniowych mają także zaburzenia gospodarki węglowodanowej, stres oksydacyjny i procesy zapalne opisane w poprzednich rozdziałach. ...
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Aspalathus linearis (Burman f.) R. Dahlgren is a shrub of the Fabaceae family, growing endemically in southern Africa. Aspalathus linearis has transformed from a wild plant to a cultivated crop. Now it is commercially available as fermented (red) rooibos and the less common unfermented (green) rooibos. This article aimed to review the literature on the redbush with a focus on its health-promoting properties. Numerous laboratory investigations of extracts and infusions of A. linearis have shown that rooibos is a rich source of biologically active compounds, especially polyphenols. The active compounds present in redbush infusions and extracts include flavonoids, phenolic acids, and minute amounts of procyanidins, coumarins, lignans, phenylethanoids, and phenylpropanoids. The characteristic active compounds of rooibos are the C-glucosyl dihydrochalcone - aspalathin and notofagin. An important active compound found in the infusion is also PPAG (Z-2-(beta-D-glucopyranosyloxy)-3-phenylpropenoic acid), which significantly determines the sensory quality of the infusion and its hypoglycaemic properties. Rooibos is also a source of minerals. Studies in both experimental models and healthy volunteers have confirmed the multiple effects of the redbush. The antioxidant properties of A. linearis were especially well studied. The greater antioxidant activity has been reported for aspalathin-rich green rooibos. The consumption of redbush infusions has been reported to have beneficial effects on the parameters like total plasma antioxidant capacity, lipid peroxidation index, and blood glutathione levels. Rooibos has also been shown to alleviate the inflammatory process induced by lipopolysaccharides or that associated with colitis. This is underlined by reduced expression of pro-inflammatory factors, as well as antioxidant properties. Redbush may be used in supporting the treatment of glucose and lipid metabolism disorders, endocrine disorders, and metabolic syndrome. It has been proven to stimulate pancreatic cells to secrete insulin, regulate the expression of genes responsible for glucose metabolism, and affect the amount of glucose transporter protein type 4 (GLUT-4). Other health properties of rooibos may include antimutagenic and hepatoprotective properties and acceleration of skin healing. The bioavailability of redbush flavonoids and the interaction of rooibos ingredients with drugs were also investigated. Studying the mechanism of absorption of flavonoids contained in the redbush and their interactions with drugs will allow determining the appropriate dosage of the extracts. Precise recognition of the chemical composition and health-promoting properties of the redbush will enable its utilization as pharmacotherapy support.
... According to a study conducted by Takahashi et al. (2015), soybean (Persson et al., 2010) and also might cover the cardiovascular symptoms of COVID-19, which needs further evaluation. ...
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The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first occurred in China in December 2019 and subsequently spread all over the world with cardiovascular, renal, and pulmonary symptoms. Therefore, recognizing and treating the cardiovascular sign and symptoms that caused by coronavirus disease 2019 (COVID-19) can be effective in reducing patient mortality. To control the COVID-19-related cardiovascular symptoms, natural products are considered one of the promising choices as complementary medicine. Scientists are struggling to discover new antiviral agents specific to this virus. In this review, the natural products for management of cardiovascular symptoms of COVID-19 are categorized into three groups: (a) natural products with an impact on angiotensin II type 1 receptor; (b) natural products that inhibit angiotensin-converting enzyme activity; and (c) natural products that mimic adenosine activity. All these natural products should undergo clinical investigations to test their efficacy, safety, and toxicity in the treatment of cardiovascular symptoms of COVID-19. This article summarizes agents with potential efficacy against COVID-19-related cardiovascular symptoms.
Chapter
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Factors involved in the pathogenesis of atherosclerosis, thrombosis and vasoconstriction contribute to the development of coronary heart disease. In a study comparing patients after myocardial infarction with controls, we have explored a possible association between coronary heart disease and a variation found in the gene encoding angiotensin-converting enzyme (ACE). The polymorphism ACE/ID is strongly associated with the level of circulating enzyme. This enzyme plays a key role in the production of angiotensin II and in the catabolism of bradykinin, two peptides involved in the modulation of vascular tone and in the proliferation of smooth muscle cells. Here we report that the DD genotype, which is associated with higher levels of circulating ACE than the ID and II genotypes, is significantly more frequent in patients with myocardial infarction (n = 610) than in controls (n = 733) (P = 0.007), especially among subjects with low body-mass index and low plasma levels of ApoB (P < 0.0001). The ACE/ID polymorphism seems to be a potent risk factor of coronary heart disease in subjects formerly considered to be at low risk according to common criteria.
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