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Studies of anti-inflammatory effects of Rooibos tea in rats

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Abstract

Rooibos tea is known to be caffeine free with abundant flavonoids. Aspalathin and nothofagin, the main flavonoids contained in Rooibos tea, have stronger anti-oxidative activity than other flavonoids. As oxidative stress can induce inflammation, the anti-inflammatory effects of Rooibos tea were investigated using a rat colitis model. Seven-week-old Wister rats were divided into two groups: one group given Rooibos tea, and one given water. After four weeks of breeding, serum superoxide dismutase (SOD) levels were determined using the Electron Spin Resonance analysis. Urine 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations were also determined as reflections of DNA damage using enzyme-linked immunosorbent assay. Furthermore, rats were administrated dextran sodium sulfate (DSS), which is known to induce colitis in rodents, with or without Rooibos tea to evaluate its anti-inflammatory activity. Clinical symptoms, hemoglobin, serum iron and SOD levels were compared between the groups. There were no significant differences in bodyweight gain or laboratory data between the groups. The serum SOD levels were significantly increased, and urine 8-hydroxy-2'-deoxyguanosine levels were significantly decreased in the Rooibos group compared with the controls (P < 0.05 in each). After DSS administration, the serum SOD levels were significantly higher in the Rooibos group compared to the controls (P < 0.05). As a result, a decreased hemoglobin level, observed in the control group, was prevented in the Rooibos group after the DSS challenge. Rooibos tea may prevent DNA damage and inflammation by its anti-oxidative activity in vivo. As Rooibos tea is free from caffeine, routine intake may be safe and useful in reducing oxidative stress in children.

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... C'est le cas des groupements carbonyles issus de l'oxydation des protéines dont la concentration augmente lors de l'inflammation colique induite par la consommation de DSS à 5% chez le rat (Mercier et al. 2002;Pelissier et al. 2006). L'oxydation de l'ADN se manifestant par l'augmentation du taux de 8-OH-dG dans les urines (Baba et al. 2009) ou par l'augmentation des altérations oxydatives de l'ADN mesurées par le test des comètes (Jin et al. 2008) est également augmentée lors de l'administration de DSS à 4 ou 1% chez le rat. ...
... Ces symptômes sont atténués par la consommation de resvératrol ou de wogonine(Lim 2004;Larrosa et al. 2009). Des effets similaires ont été décrits pour l'infusion de rooïbos (Aspalathus linearis) riche en flavonoïdes(Baba et al. 2009) ainsi que pour des extraits de grenade riches en ellagitanins et pour leurs principaux métabolites, les urolithines (Larrosa et al. 2010) Les effets protecteurs des polyphénols sur la prise de poids des animaux et les manifestations de l'inflammation (diarrhée et saignements rectaux) se confirment lors de l'examen histologique des côlons. b. ...
... L'ingestion de polyphénols du vin rouge permet également de limiter l'oxydation des bases puriques et pyrimidiques(Dolara et al. 2005). La mesure dans les urines du taux de 8-OHdG comme marqueur de l'oxydation de l'ADN montre également un effet protecteur lié à la consommation d'infusion de rooïbos dans le modèle DSS chez le rat(Baba et al. 2009). L'administration orale d'un extrait de Garcinia cambogia induit une diminution de l'oxydation de l'ADN dans les cellules coliques chez le rat TNBS(dos Reis et al. 2009). ...
Article
Polyphenols are micronutrients widely distributed in foods of plant origin and theirconsumption has been associated with a decreased risk of various pathologies such ascardiovascular diseases, neurodegenerative diseases and cancer. This effect of polyphenolsis sustained by their antioxidative and anti-inflammatory properties. Due to their poorabsorption in the small intestine, high amounts of polyphenols reach the colon where theycan exert such properties. Intestinal inflammation results from an interaction between gutimmunity and various environmental factors and is frequently associated with an increase ofoxidative stress. Numerous studies have shown protective effects of polyphenols in animalcolitis models. Lemon verbena (Aloysia triphylla (L'Hérit.) Britton) is a medicinal herbknown for its digestive and antispasmodic properties and is widely consumed as an infusion.Lemon verbena infusion contains large amounts of polyphenols (complex phenolic acidsand flavone glycosides) and their antioxidative properties have been shown in vitro and invivo.The aim of the present thesis was to evaluate the effects of a preventive consumptionof lemon verbena infusion at nutritional doses (40 g/l and 4 g/l) on the development of amoderate colitis in the rat. Wistar rats ingested lemon verbena infusion alone as a drink fortwo weeks and then associated with the inflammatory agent dextran sulfate sodium (DSS) at4% for 7 or 9 days. Effects of lemon verbena were evaluated on several clinical parameters(diarrhoea, rectal bleeding, body weight), inflammatory markers (colon length, histologicalscore, myeloperoxidase activity, cytokines) and oxidative stress markers (lipid peroxidation,glutathione, antioxidative enzymatic defenses). Immune cells were identified in blood andgut associated lymphoid structures using flow cytometry. Moreover, the study of polyphenolmetabolism was initiated by the analysis of urinary polyphenol metabolites in healthy andcolitis rats.During a 7 days inflammation, the preventive consumption of lemon verbenainfusion at 40 g/l and 4 g/l delays apparition of diarrhoea and rectal bleeding, limits thecolon length reduction and the decrease of body weight gain. Despite no effect onmyeloperoxidase activity, the 40 g/l infusion attenuates colonic mucosa alterations due tothe colitis. The 4 g/l infusion increases superoxide dismutase activity and reduces lipidperoxidation. Both infusions modulate immune cell populations in gut associated lymphoidstructures (mesenteric lymph nodes and Peyer patches), especially B cells and cytotoxic Tcells. Urinary excretion of lemon verbena polyphenols is low and not modified byinflammation. During a 9 days inflammation, both lemon verbena infusions limitmyeloperoxidase increase. Only the 40 g/l infusion reduces colon retraction, increasesglutathione reductase activity and reduces colonic IL-6 and TNF-α levels.Thus, we have shown that the preventive consumption of a lemon verbena infusionprovided protection against intestinal inflammation at different levels. Exploration ofvarious signalling pathways could allow better insight into the protective effects of thiscommon beverage.
... Bush tea (Athrixia phylicoides DC.), special tea (Monsonia burkeana Planch. ex Harv.), rooibos tea (Aspalathus linearis (Burm.f.) R. Dahlgren) and honeybush tea (Cyclopia intermedia E. Mey and C. subternata Vogel) are South African herbal teas all of which are known to possess anti-oxidant [1], anti-inflammatory [2] and anti-diabetic properties [3][4][5]. ...
... During inflammation, arachidonic acid is metabolised through the COX or LOX pathway [25]. Baba [2] reported the antiinflammatory properties of rooibos tea in a DSS-induced colitis rat model supplemented with rooibos tea which had increased serum superoxide dismutase compared to the control group. There was no anti-inflammatory activity shown by the methanol extract of bush tea; the activity was only observed in bush tea's essential oil [26]. ...
Article
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South Africa is home to a variety of herbal teas, such as bush tea (Athrixia phylicoides DC.), honeybush tea (Cyclopia intermedia E. Mey and C. subternata Vogel), special tea (Monsonia burkeana Planch. ex Harv.), and rooibos tea (Aspalathus linearis (Burm.f.) R. Dahlgren) that are known to possess anti-oxidant, anti-inflammatory and anti-diabetic properties. The objective of this study was to determine the in vitro anti-oxidant activity of selected tea blends using 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays, as well as to assess their anti-inflammatory properties using the 15-lipoxygenase inhibitory assay. Furthermore, the study measured glucose utilisation in C2C12 myotubes. Lastly, 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to test the safety of the tea extracts on Vero cells (African green monkey kidney cell line). Special tea and its blend with bush tea exhibited potent anti-oxidant and anti-inflammatory activity. The blending of bush tea with special tea at different ratios resulted in increased anti-oxidant activity. Although special tea had a level of cell toxicity, its toxicity was lowered during blending. All of the tea samples showed anti-diabetic effects, although with less potency as compared to insulin. The current investigation supports the use of blended herbal teas, and the positive anti-inflammatory effect of special tea warrants further research.
... 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. ...
Article
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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.
... Active oxygen and free radicals can induce inflammation. Vitamin C and E, flavonoids and enzymes such as catalase, glutathione peroxidase (GPx), and serum superoxide dismutase (SOD) are known antioxidants 25 . An in vivo study investigated the anti-inflammatory effects of Aspalathus linearis (rooibos) tea using a rat colitis model. ...
... Levels of SOD of the Aspalathus lineari s(rooibos) group were significantly increased (P<0.05) compared with the controls whilst urine 8-OHdG levels were significantly decreased (P<0.05) in the Aspalathus linearis (rooibos) group compared with the controls. The antioxidant activity of Aspalathus linearis (rooibos) tea were proposed as the mechanism preventing DNA damage and inflammation in vivo 25 . Aspalathus linearis (rooibos) was included in an anti-inflammatory study using LPS-stimulated macrophage model. ...
Article
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African plants have been used for medicinal purposes for many centuries. Many of these African medicinal plants are assumed to be safe but have yet to be scientifically validated. Aspalathus linearis (rooibos) is a commercialised South African tea recognised for its phytopharmaceutical potential. Aspalathus linearis (rooibos) has been gaining popularity globally for its health benefits and accepted as a nutraceutical due to the growing evidence of its efficacy. The bioactive constituents found in Aspalathus linearis (rooibos) have been reported to exert both anti-inflammatory and antioxidant activity however a few in vitro studies has suggested otherwise. Aspalathus linearis (rooibos) has shown to modify the actions of the immune system by influencing the regulation of messenger molecules like cytokines and nitric oxide however most of these studies have been conducted in vitro with a very few studies reaching in vivo application. Divergent in vitro cell models has shown to produce varying results regarding cytokine and nitric oxide NO activity of Aspalathus linearis (rooibos). This review highlights recent studies on the (NO) and cytokine activities of Aspalathus linearis (rooibos) both in vitro and in vivo. Most studies report on its anti-inflammatory and antioxidant activity however a few in vitro studies suggests opposite effects which should be considered for prolonged use especially when prescribed in a supplementation form. Many studies have looked at aspects of safety and toxicity of Aspalathus linearis (rooibos) however no complete toxicological studies have been done as yet.International Journal of Human and Health Sciences Vol. 03 No. 03 July’19. Page: 150-157
... In comparison to other teas, rooibos has been shown to exert higher antioxidant effects than black and oolong teas, and comparable effects to green tea (Von Gadow, Joubert, & Hansmann, 1997). In vivo studies have shown that rooibos potentially reduces prolonged stress (Schloms et al., 2014), and exerts potent anti-inflammatory (Baba et al., 2009) and chemoprotective effects (Marnewick et al., 2009). A recent study in rats showed that aspalathin-enriched green rooibos extract could https://doi.org/10.1016/j.jff.2019.103616 ...
... Rooibos (Aspalathus linearis) is a popular South African herbal tea known for its naturally sweet taste and numerous health benefits (Baba et al., 2009;Marnewick et al., 2009;Mazibuko-Mbeje et al., 2019;Schloms et al., 2014). In vitro studies have shown that aqueous rooibos extract has the potential to increase osteoblast activity (Nash & Ward, 2016) and inhibit osteoclast formation and activity (Moosa et al., 2018). ...
Article
Bone remodelling in a healthy body is in constant balance, maintaining an adaptive and robust skeletal system. In osteoporosis this balance is disrupted with the rates of osteoclastic bone resorption exceeding osteoblastic bone formation, resulting in lower bone mineral density. Rooibos tea, is a popular South African drink made from Aspalathus linearis leaves grown in the Western Cape. This tea is rich in phenolic compounds which have been widely investigated in recent years as a potential treatment for many ailments. In this study, aspalathin, a phenolic compound found exclusively in rooibos, increases osteoblast formation and function including increased osteoblast marker expression and mineralisation. In addition, aspalathin decreased differentiation and function of osteoclasts as well as reducing osteoclast formation in an osteoclast/osteoblast co-culture model. These results illustrate bone-protective effects of aspalathin in vitro through the reduction of osteoclast activity and promotion of osteoblast activity, with potential applications in the maintenance of bone density.
... Activated Nrf2 causes it to dissociate from Keap1 and migrate into the nucleus where it binds ARE and cause increased expression of cytoprotective genes and phase II detoxifying enzymes to eliminate ROS. Keys: ARE-antioxidant response element; CAT-catalase; Gpx-glutathione peroxidase; GSH-glutathione; Keap1-Kelch-like ECH-associated protein 1; Nox-NADPH oxidase; O 2 •− superoxide ion; Nrf2-nuclear factor (erythroid-derived 2)-like 2; ROS-reactive oxygen species antioxidant capacity [18,[84][85][86][87][88][89], rooibos has been shown to inhibit adipogenesis in vitro [90], reverse palmitate-induced insulin resistance in 3T3-L1 adipocytes [91] and prevent inflammation in vivo [92][93][94]. An aspalathin-enriched green rooibos extract, containing 18.4% aspalathin has demonstrated an even higher hypoglycemic potential through its inhibitory effect of alpha-glucosidase and suppressing fasting plasma glucose levels in animal models [91,95]. ...
... Prevented vascular-induced inflammation by enhancing nitric oxide production [86,92,93] Aqueous extract of fermented rooibos on non-diabetic rats Acted as a bronchodilator, antispasmodic and blood pressure lowering effects [97] Fermented rooibos tea in healthy human subjects ...
Article
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Diabetic patients are at an increased risk of developing heart failure when compared to their non-diabetic counter parts. Accumulative evidence suggests chronic hyperglycemia to be central in the development of myocardial infarction in these patients. At present, there are limited therapies aimed at specifically protecting the diabetic heart at risk from hyperglycemia-induced injury. Oxidative stress, through over production of free radical species, has been hypothesized to alter mitochondrial function and abnormally augment the activity of the NADPH oxidase enzyme system resulting in accelerated myocardial injury within a diabetic state. This has led to a dramatic increase in the exploration of plant-derived materials known to possess antioxidative properties. Several edible plants contain various natural constituents, including polyphenols that may counteract oxidative-induced tissue damage through their modulatory effects of intracellular signaling pathways. Rooibos, an indigenous South African plant, well-known for its use as herbal tea, is increasingly studied for its metabolic benefits. Prospective studies linking diet rich in polyphenols from rooibos to reduced diabetes associated cardiovascular complications have not been extensively assessed. Aspalathin, a flavonoid, and phenylpyruvic acid-2-O-β-D-glucoside, a phenolic precursor, are some of the major compounds found in rooibos that can ameliorate hyperglycemia-induced cardiomyocyte damage in vitro. While the latter has demonstrated potential to protect against cell apoptosis, the proposed mechanism of action of aspalathin is linked to its capacity to enhance the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression, an intracellular antioxidant response element. Thus, here we review literature on the potential cardioprotective properties of flavonoids and a phenylpropenoic acid found in rooibos against diabetes-induced oxidative injury.
... Rooibos (Aspalathus linearis) tea is a caffeine-free herbal tea that originated from South Africa that is now consumed worldwide. Rooibos tea is rich with dihydrochalcones, aspalathin, nothofagin, and quercetin, traditionally being used for its therapeutic properties due to antioxidant, anti-mutagenic, anti-carcinogenic, anti-inflammatory, anti-viral, and anti-diabetic activities [11][12][13][14]. In traditional processing, the green needle-like leaves and stems are shredded into 3-4 mm length and then left to ferment for 8-24 h before sun-drying in order to produce a red color, a shade called Rooibos [15]. ...
... Rooibos tea has also been shown to increase IL-2 and inhibit IL-4 production in ovalbumin-induced splenocytes, thereby indicating the potential efficacy in mitigating diseases such as cancer, allergy, acquired immune deficiency syndromes (AIDS), and other kinds of infection [42]. Rooibos tea has also been shown to have cardio-protective properties through improving the aortic output recovery in the hearts of rats, which was related to its unique flavonol content [43], while also preventing dextran sodium sulfate-induced DNA damage and inflammation in rats through its antioxidant activity [13]. ...
Article
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Background: Indigenous or traditional aqueous plant extracts are commonly used by nearly 80% of the world’s population for primary health needs. Accordingly, teas such as Camellia sinensis and herbal teas were characterized for their phytochemical content and potential to offer specific bioactivities that could benefit human health by mitigating oxidative stress and inflammation. Methods: In the present study, we compared the phytochemical profiles, antioxidant, and antiinflammatory activities of four Camellia sinensis teas, including white, green, oolong, black, and two herbal teas such as Rooibos and Yerba mate, which are produced and consumed by different populations worldwide. We also studied the impact of the Rooibos tea on the production of inflammatory mediators, including nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and different cytokines in Raw 264.7 cells, both with or without interferon γ (IFN-γ) and lipopolysaccharide (LPS) stimulation. Results: White tea had the highest total phenolic content (TPC) and antioxidant activity among the six teas that were examined. In contrast, Rooibos tea had the lowest TPC, antioxidant, and antiinflammatory activities. Yerba mate tea exhibited the greatest potential to inhibit NO production in IFN-γ and LPS-induced Raw 264.7 cells. The anti-inflammatory activity of teas was discovered to be correlated with antioxidant activity and phytochemical composition. Among the six teas examined, only Rooibos tea was found to induce NO in unstimulated Raw 264.7 cells. Under basal conditions, Rooibos tea induced interleukin-1α (IL-1α), IL-1β, IL-6, IL-10, granulocyte-colony stimulating factor (G-CSF), granulocyte macrophage colony-stimulating factor (GM-CSF), tumor necrosis factor-alpha (TNF-α), iNOS, and COX-2 production. However, Rooibos tea also demonstrated a dose-dependent inhibition of IL-6, IL-10, iNOS, and COX-2 expression in stimulated Raw 264.7 cells. Although a high concentration of Rooibos tea was effective in inhibiting induced IL-1α, G-CSF, and GM-CSF, lower concentrations also up-regulated the expression of these cytokines. No inhibitory effects of Rooibos tea examined were discovered with the mitigation of IL-1β and TNF-α. Conclusions: Rooibos tea possesses dual functions on inflammation, either by promoting an inflammatory response to cytokine induction or alternatively inhibiting inflammation during tissue injury or a pathogen infection via a mechanism involving the inhibition of pro-inflammatory cytokines and mediators such as iNOS and COX-2. The potential of Rooibos tea to induce NO production is also noteworthy in mitigating disease states including hypertension and cardiovascular diseases.
... The potential of rooibos to enhance antioxidant defences, including SOD and CAT activity, has previously been demonstrated in rat brain extracts in an immobilisation stress model, 46 while SOD levels were significantly higher in RUF-treated animals in a rat colitis model. 47 These actions have been attributed to the flavonoid content in rooibos 46 and the potential ability of rooibos to reduce DNA damage caused by oxidative reactions. 47 Epidemiological evidence suggests that dietary-derived antioxidants have the potential for disease prevention, 48 and it has been shown that dietary polyphenols can increase endothelium-dependent NO generation by modulating cellular sensors for oxidative stress. ...
... 47 These actions have been attributed to the flavonoid content in rooibos 46 and the potential ability of rooibos to reduce DNA damage caused by oxidative reactions. 47 Epidemiological evidence suggests that dietary-derived antioxidants have the potential for disease prevention, 48 and it has been shown that dietary polyphenols can increase endothelium-dependent NO generation by modulating cellular sensors for oxidative stress. NO is capable of reacting with O 2 •-to form peroxynitrite, which can lead to the nuclear accumulation of nuclear factor erythroid 2-related factor (Nrf2). ...
Article
Background: Rooibos (Aspalathus linearis) is an indigenous South African plant, traditionally used by the local population as a remedy against several ailments. More recently, rooibos was shown to exhibit potent antioxidant properties, attributed to its polyphenols. We assessed whether treatment with fermented rooibos (RF), unfermented rooibos (RUF) and melatonin (Mel), a well-documented antioxidant included for comparison, could counter the harmful vascular and pro-oxidant effects of nicotine. Methods: Vascular function, antioxidant enzyme activity and lipid peroxidation were assessed in male adult rats treated with nicotine (5 mg/kg body weight/day) and 2% RF, 2% RUF or 4% Mel co-administration. Nitric oxide (NO) production and cell viability were measured in nicotine-exposed rat aortic endothelial cells (AECs) pre-treated with RF (0.015 mg/ml). Results: Vascular studies showed that co-administration with RF or Mel exerted anti-contractile and pro-relaxation responses in aortic rings, and increased hepatic superoxide dismutase and catalase activity in nicotine-exposed animals. Co-treatment with Mel additionally decreased lipid peroxidation in nicotine-exposed rats. RUF exerted anti-contractile responses in aortic rings of nicotine-treated animals, while in nicotine-exposed AECs, RF pre-treatment increased intracellular NO levels. Conclusions: For the first time, we have shown that rooibos co-treatment exerted beneficial vascular effects in nicotine-exposed rats, and that this was associated with increased antioxidant enzyme activity.
... Although literature on its classification and rising economic value emerged as early as the 1960′s [29,95], only the past three decades have seen the rapid development in data supporting the therapeutic value of rooibos. Apparently, because of its strong antioxidant and antiinflammatory properties [96][97][98][99][100][101], biological activities attributed to rooibos extend to ameliorating metabolic complications affecting the major body tissues such as the liver, pancreas, skeletal and heart muscles [102][103][104][105]. Most recently, a systematic review and meta-analysis supports published evidence showing that rooibos can be beneficial in lowering blood glucose levels in a diabetic state [106]. ...
... Although experimental data on the comparative effects of different rooibos extracts is limited, both unfermented and fermented rooibos containing isoorientin displayed robust properties to prevent metabolic disease linked complications on skeletal muscle cells [104]. Mostly because of relatively high levels of antioxidants [48,98,111,112], some metabolic properties attributed to these extracts include antidiabetic [106,113], anti-inflammatory and oxidative stress ameliorative effects [97,114], in addition to cardioprotective activity [103,115,116]. Besides intracellular enhancements of antioxidants and promotion of glucose uptake, co-ordinated activation of AMPK and regulation of cellular substrate metabolism are some of the mechanisms that partially explain the therapeutic potential of Aspalathus linearis [7,117,118]. ...
Article
Isoorientin is a natural C-glucosyl flavone that is generating a lot of interest due to its multiple pharmacological activities. Increasingly experimental data have shown that the robust antioxidant and anti-inflammatory properties of isoorientin remain important in ameliorating a number of metabolic complications. In fact, plants rich in isoorientin have demonstrated strong ameliorative properties against complications such as hyperglycemia, hyperlipidemia, and insulin resistance. However, while such evidence is accumulating, it has not been reviewed to better inform on the therapeutic potential of this flavone in improving human health. This review examines and extrapolates available literature on the beneficial or detrimental effects associated with the use of isoorientin in mitigating metabolic diseases, with a specific focus on diabetes, obesity, and insulin resistance, including associated complications. The discussion includes effective doses in various experimental settings and proposed molecular mechanisms by which isoorientin may exert its therapeutic effects. In addition, the protective effects of extracts of a number of isoorientin-rich plants against metabolic complications will be highlighted.
... Forty-nine laboratory/mechanistic studies were identified and published over the last two decades. Of these, eleven focused on aspects of oxidative stress and antioxidant activity [10,12,[27][28][29][30][31][32][33][34][35]. Four studies observed improvements in dimensions of sperm function [36][37][38][39]. ...
... black, green and oolong tea) could be regarded as a 'general health' tea, potentially providing an array of benefits to human health and wellbeing [56] Rooibos tea is naturally slightly sweet [16] thus does not require the addition of extra sugar or artificial sweeteners. It is also caffeine free with a favourable phenolic composition [9,10]. (Table 2) Ulicná O-et al. (2006) [49] Streptozotocininduced diabetic rats Aqueous and alkaline extracts of Rooibos tea Antidiabetic potential Antioxidant compounds in rooibos tea partially prevent oxidative stress and they are effective in both hydrophobic and hydrophilic biological systems. ...
Article
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An expanse of research has investigated the effects of black and green teas in relation to aspects of health. Rooibos tea, also known as Red bush is derived from the South African Cape fynbos plant, Aspalathus linearis, and is caffeine free, naturally sweet and abundant in polyphenols. Evidence related to the health aspects of drinking Rooibos tea is advancing, but does not appear to have been collated. Therefore, we aimed to examine the health effects of Rooibos tea through a systematic review of the literature. A PUBMED search was undertaken (2000 up to June 2020) for human and laboratory studies investigating the efficacy of Rooibos in relation to health. Seven human studies and 49 laboratory studies were identified. Overall Rooibos tea consumption seems to benefit the lipid and redox profiles of those at risk of cardiovascular disease. It also appears to possess other promising ‘general’ effects on glycaemic control, bone, liver, cognitive and respiratory health. Ongoing research using standardised interventions is now needed to help formulate congruent conclusions that are relevant to public health.
... Beverage consumption, in particular of tea, makes a large contribution to daily polyphenolic intake (Manach et al. 2004) and dietary TAC (Louwrens, Rautenbach & Venter 2009). Rooibos herbal tea is an excellent source of polyphenolic flavonoids (Baba et al. 2009). Consuming a cup of rooibos herbal tea prepared for optimal polyphenol extraction could therefore make a notable contribution to daily dietary polyphenolic content and TAC. ...
... The intake of tea can make an important contribution to the water or fluid intake, as well as fluoride intake, of an individual and should be encouraged. Rooibos herbal tea as a beverage is mostly made up of water and additionally provides protective effects against disease occurrence, in particular those associated with oxidative stress (Baba et al. 2009), which is ascribed to the phenolic constituents it contains (Van Heerden et al. 2003). The rooibos industry should strive to increase the consumption of rooibos by its consumers and inform them that a longer steeping time provides for a more optimal cup in terms of the total polyphenol content and the TAC. ...
Article
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Background: Rooibos types and forms and how prepared and flavoured influence the total polyphenol content and total antioxidant capacity (TAC). Aim: To denote an optimal rooibos cup as having the highest total polyphenol content and TAC, considering the different types, forms, preparation methods and flavourings and amounts (Phase 1), and determine the demographic, lifestyle and rooibos consumption characteristics of adult rooibos consumers, and the association of these characteristics with drinking the optimal cup (Phase 2). Setting: Assays: Oxidative Stress Research Centre, Cape Peninsula University of Technology; Consumer survey: George area, South Africa. Method: Phase 1 entailed determining the total polyphenol content (Folin–Ciocalteau method) and TAC (Trolox equivalent antioxidant capacity and ferric-reducing antioxidant power assay) of the prepared rooibos samples. For Phase 2, a developed, pilot tested questionnaire was used to profile adult rooibos consumers. Results: Phase 1: the following samples delivered higher total polyphenol content and TAC: green (type), green leaves and powdered extract (forms), and sample steeped for 10 min or longer (preparation method). The identified optimal cup was sample steeped for 10 min or longer. Phase 2: a total of 308 respondents completed the questionnaire. Few consumed more than one rooibos cup per day (25.3%; n = 78) and the optimal cup (15.9%; n = 49). These latter respondents comprised those who steeped rooibos in a teapot (not a cup or mug) (p < 0.05). Conclusions: The optimal cup was identified as sample steeped for 10 min or longer. The rooibos consumers did not consume it sufficiently, nor steeped it long enough.
... TF-2 may be useful as therapy for cancer and inflammatory-related diseases Gosslau et al., 2011 Yerba mate extract TNF-a, IL-6, iNOS, NF-kB Male Swiss mice were introduced to either standard or high-fat diets for 16 weeks. After the first 8 weeks on a high-fat diet, the animals received an aqueous extract of roasted yerba mate extract (1.0 mg/kg), for 8 weeks Baba et al., 2009 This table presents a summary of the results of studies considering the effects of tea or tea components on markers of inflammation using different animal models. The targeted molecules, models used, and doses of exposure are presented. ...
... Tea and Inflammation herbal tea rooibos (Aspalathus linearis) has been shown to have anti-inflammatory properties in a rat colitis model (Baba et al., 2009). ...
Chapter
Scientific evidence from preclinical and clinical studies suggests that chronic inflammation may lead to cardiovascular disease, diabetes, metabolic syndrome, among other devastating diseases. Several studies have concluded that bioactive compounds present in tea, such as catechins and theaflavins, may reduce the risk of inflammation, and therefore various related chronic diseases, including cancer. Dietary intake of green tea and some herbal teas may regulate pro-inflammatory cytokine activity in inflammatory-related diseases. Green tea extracts may also reduce inflammation in addition to oxidative and metabolic stress. Major advances have been made to understand the role of tea and its compounds in the molecular events leading to inflammation reduction and health promotion; however, the evidence is not conclusive. Possible mechanisms of action may explain the cancer-preventing aspects of tea components, specifically related to its anti-inflammatory effects. Tea polyphenols inhibit nuclear translocation of NF-κB subunits which prevent the transcription of inflammatory genes – resulting in reduced inflammation. Human interventional studies with well-characterized tea products are needed.
... It's flavonoids are unique in that it contains the C-C linked dihydrochalcone glucoside, aspalathin which is oxidized to the flavanones dihydro-iso-orientin and dihydro-orientin during fermentation, the cyclic dihydrochalcone, aspalalinin, the rare 3-dehydroxy dihydrochalcone glucoside, nothofagin, the C-glycosyl flavones orientin, isoorientin, vitexin, isovitexin, and the flavones hemiphlorin and chrysoeriol, luteolin and luteolin-7-O-glucoside and flavonols quercetin and its O-linked glycosides quercetin-3robinobioside, hyperoside, isoquercitrin and rutin [23][24][25]. The health effects of rooibos have been proposed to be mostly attributed to the unique polyphenolic composition and its related antioxidant activities [26][27][28][29][30]. Animal and recent human studies have shown that consumption of rooibos or its phenolic components had positive effects on cardiovascular health and inflammation [31][32][33][34][35][36][37][38]. Studies have shown that rooibos may have potential preventive and therapeutic effects against vascular complications in diabetic rats [39]. ...
... Studies have shown that rooibos may have potential preventive and therapeutic effects against vascular complications in diabetic rats [39]. Aspalathin, the main and unique polyphenol in rooibos, has been shown to positively modulate glucose homeostasis in type 2 diabetes [30], while the antioxidant activity of rooibos has also been linked to its potential antiinflammatory and DNA protective effects in a rat colitis model [33]. ...
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Red palm oil (RPO) and rooibos have been shown to exhibit cardioprotective properties. RPO is rich in essential fatty acids and fat soluble antioxidants while rooibos contains polyphenolic compounds with a unique composition of flavonoids. They exert their biological effects in different cellular compartments. Therefore the combination of these two natural food compounds has the potential to enhance the spectrum of available dietary antioxidants in different cellular compartments, which could result in an enhanced protection against certain pathological conditions such as inflammation. Male Wistar rats weighing 150-200 g were supplemented with RPO, rooibos or their combination for 28 days. The Langendorff system and the lipoposaccharide (LPS)-induced inflammatory model were used to establish if RPO and rooibos, when supplemented alone or in combination, will reverse the negative effects of LPS on cardiac function at baseline. The effect of dietary intervention was also investigated on modulation of pro-inflammatory and anti-inflammatory cytokines in plasma and myocardial tissue. The LPS resulted in induction of systemic inflammation as evidenced by increased levels of IL-1β in plasma of LPS-treated rats compared to their non-treated control counterparts. Dietary supplementation and LPS treatment did not have an effect on baseline cardiac functional parameters. However, the elevation of IL-1β levels in plasma of LPS-induced rats consuming either RPO or rooibos alone were paralleled with increased levels of the anti-inflammatory cytokine, IL-10. The combination of rooibos and RPO was associated with enhanced endogenous production of myocardial IL-10 in LPS-induced rats. The results of this study indicate that RPO and rooibos when supplemented individually showed anti-inflammatory effect at systemic level while their combination exhibited an enhanced anti-inflammatory effect in the myocardial tissue. Therefore, the findings in the current study argue that the combination of these two natural food substances could be beneficial in clinically relevant conditions where inflammation plays a role.
... Based on this a multicentre, randomised controlled trial of tocilizumab (IL-6 receptor blockade, licensed for cytokine release syndrome), has been approved in patients with COVID-19 pneumonia and elevated IL-6 in China (ChiCTR2000029765) (Mehta et al., 2020, McGonagle et al., 2020. When considering Rooibos in experimental models of disease and elevated levels of inflammation, encouraging results regarding the attenuation of circulating cytokine levels and reduced inflammatory responses have been reported by a number of authors (Baba et al., 2009, Smith and Swart, 2016, Katengua-Thamahane et al., 2014, Lee and Bae, 2015, Ku et al., 2015. ...
... Rooibos exerts antioxidant activities in vivo and in vitro by scavenging free radicals, inhibiting ROS formation and/or supporting endogenous antioxidant defence systems. In an early study into the non-enzymatic antioxidant effects, normally healthy rats supplemented with Rooibos herbal tea (at a concentration customarily consumed by humans) showed increased redox status (reduced to oxidised ratio) of the endogenous antioxidant, glutathione, (increased GSH: GSSG ratio) in livers (Marnewick et al., 2003) and increased the activity of certain antioxidant enzymes (Baba et al., 2009, Hong et al., 2014. Furthermore, Rooibos was shown to scavenge the physiologically relevant reactive oxygen species, superoxide radical anion (O 2− ) and hydroxyl radical (OH), thoroughly reviewed in (Joubert et al., 2008, Ajuwon et al., 2015. ...
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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.
... This is particularly significant when considering that in comparison, black (Camilla sinensis) tea decreased the liver oxygen radical absorbance capacity (ORAC) in the same study, suggesting a relative depletion of endogenous antioxidant systems. Several subsequent studies confirmed the antioxidant effect of Rooibos in ethnopharmacological studies, 9 as well as in in vitro studies, [10][11][12] animal studies [13][14][15][16][17][18] and in a human model. 19 Most notable was the latter study by Marnewick and colleagues, which was the first to provide clinical proof that daily Rooibos consumption has a beneficial role in the context of CVD prevention. ...
Article
Increasing consumer bias toward natural products and the considerable wealth of indigenous knowledge has precipitated an upturn in market-driven research into potentially beneficial medicinal plants. In this context, Aspalathus linearis (Rooibos) has been identified to be a promising candidate which may impact cardiovascular disease (CVD), which is one of the most widely studied chronic diseases of modern times. Despite these efforts, ischemic heart disease remains the number one cause of mortality globally. Apart from genetic predisposition and other aetiological mechanisms specific to particular types of CVD, co-factors from interlinked systems contribute significantly to disease development and the severity of its clinical manifestation. The bioactivity of Rooibos is directed towards multiple therapeutic targets. Experimental data to date include antioxidant, anti-inflammatory and anti-diabetic effects, as well as modulatory effects in terms of the immune system, adrenal steroidogenesis and lipid metabolism. This review integrates relevant literature on the therapeutic potential of Rooibos in the context of CVD, which is currently the most common of non-communicable diseases. The therapeutic value of whole plant extracts versus isolated active ingredients are addressed, together with the potential for overdose or herb–drug interaction. The body of research undertaken to date clearly underlines the benefits of Rooibos as both preventative and complementary therapeutic functional food in the context of CVD.
... Although there are numerous reports mentioning the use of rooibos in the treatment of skin ailments including wounds, no direct scientific evidence exists demonstrating the efficacy and safety of rooibos as a therapeutic strategy in the management of chronic wounds such as diabetic and pressure wounds. Since inflammation and oxidative stress are implicated in the pathogenesis of chronic wounds, it may be argued that the several publications attributing such activities to rooibos provides some support for potential wound healing activity, however, the majority of these in vivo studies evaluate the pharmacological properties from the perspective of an herbal tea and not as a dermally applied preparation [6,7]. ...
Article
The process of wound healing constitutes an ordered sequence of events that provides numerous opportunities for therapeutic intervention to improve wound repair. Rooibos, Aspalathus linearis, is a popular ingredient in skin care products, however, little scientific data exists exploring its therapeutic potential. In the present study, we evaluated the effects of fermented and aspalathin-enriched green rooibos in various in vitro models representative of dermal wound healing. Treatment of RAW 264.7 macrophages with fermented rooibos resulted in increased nitric oxide production as well as increased levels of cellular inducible nitric oxide synthase and cyclooxygenase-2, which are typical markers for classically activated macrophages. In contrast, the green extract was devoid of such activity. Using glycated gelatin as a model to mimic diabetic wounds, only the green extract showed potential to reduce cyclooxygenase-2 levels. Considering the role of reactive oxygen species in wound healing, the effects of rooibos on oxidative stress and cell death in human dermal fibroblasts was evaluated. Both fermented and green rooibos decreased cellular reactive oxygen species and attenuated apoptotic/necrotic cell death. Our findings highlight several properties that support the therapeutic potential of rooibos, and demonstrate that green and fermented rooibos present distinctly different properties with regards to their application in wound healing. The proinflammatory nature of fermented rooibos may have therapeutic value for wounds characterised with a delayed initial inflammatory phase, such as early diabetic wounds. The green extract is more suited to wounds burdened with excessive inflammation as it attenuated cyclooxygenase-2 levels and effectively protected fibroblasts against oxidative stress.
... Also, rooibos upregulated sod-3, an enzyme that eliminates ROS, leading to an increase in stress resistance. Similarly, rats treated with rooibos tea, had upregulated serum SOD (superoxide dismutatase) levels (Baba et al., 2009). Chen et al. (2013) investigated the protective properties of aspalathin, GRE and FRE in C.elegans -an invertebrate organism used for investigating hyperglycemic conditions, ageing and longevity through simulation of a high glucose environment (Schlotterer et al., 2009). ...
Article
Rooibos, an indigenous South African plant ingested as herbal tea, is well known for its antioxidant effects. This in vitro study investigated aspalathin (C21H24O11), a dihydrochalcone unique to rooibos, for hypoglycemic effects in the context of age- and obesity-induced insulin resistance and the mechanisms involved. Male Wistar rats were allocated into three groups: 16 – 30 weeks feeding with either standard rat chow or a high-caloric diet, or 6 – 10 weeks feeding with standard rat chow. Ventricular cardiomyocytes were isolated by collagenase perfusion digestion, and glucose uptake was determined by 2-[3H]-deoxyglucose accumulation. Viability was tested by trypan blue exclusion or propidium iodide staining. The high-caloric diet significantly increased body weight gain (508.5 ± 50.0 vs. 417.3 ± 40.0 g), visceral adiposity (42.30 ± 10.1 vs. 21.75 ± 7.0 g), and fasting blood glucose (5.7 ± 0.4 vs. 4.7 ± 0.1 mM). Aspalathin (10 µM for 90 min) induced 2-[3H]-deoxyglucose uptake in young cardiomyocytes (37.2 ± 13.9 vs. 25.7 ± 2.5 pmol 2-[3H]-deoxyglucose/mg protein) and enhanced insulin-mediated 2-[3H]-deoxyglucose uptake in control cells (32.4 ± 6.4 vs. 23.5 ± 10.0 pmol 2-[3H]-deoxyglucose/mg protein), but failed to induce 2-[3H]-deoxyglucose uptake in high-caloric diet cells. Aspalathin induced glucose uptake in insulin-sensitive cardiomyocytes from young and aged rats, but not in high-caloric diet animals and enhanced the actions of insulin through a PI3K-dependent mechanism, resulting in an additive response.
... It has been shown to have antidiabetic and hypoglycaemic effects (Jin et al., 2013;Kamakura et al., 2015;Van Der Merwe et al., 2015;Mahmood et al., 2016), antioxidant (Canda et al., 2014) as well as anti-HIV effects in vitro (Nakano et al., 1997). In addition, rooibos also has demonstrated antiinflammatory effects (Baba et al., 2009), it has been shown to reduce colitis and modulate immune function in vitro (Hendricks and Pool, 2010) as well as in vivo where it has been shown to promote antigen-specific antibody production through augmentation of interleukin-2 production (Kunishiro et al., 2001). The bronchodilatory effects of rooibos have been attributed to the phytochemical chrysoeriol which also has antispasmodic, antiviral and antimicrobial effects (Khan and Gilani, 2006). ...
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Aspalathus linearis (rooibos) is a plant which grows in a limited habitat in South Africa. The plant is mainly renowned for the beverage (herbal tea) which is made from its aerial parts. The popularity of the herbal tea is not confined to South Africa as significant amounts of the tea are exported to many countries worldwide. Rooibos reportedly has several health benefits which have been attributed to its constituent phytochemicals. One of the major phytochemicals in rooibos is aspalathin. Aspalathin makes up between 4-12% of the plant. Aspalathin is a dihydrochalcone glycoside which has thus far only been isolated from Aspalathus linearis. Aspalathin has been shown to possess biological activity which imparts it with multiple health beneficial effects. This mini review highlights the recent findings on the biological properties of aspalathin. These include antioxidant, antidiabetic, cardioprotective, antihypertensive and antimutagenic effects. Given its multiplicity of biological effects, aspalathin is a natural phytochemical which has potential to be incorporated into current medical therapeutic regimes in light of recent preferences for the use of natural medicines.
... Rooibos Tea and Inflammatory Bowel Disease A Japanese study by Baba, et al. (2009) showed that Rooibos could reduce inflammation in rats with colitis (open sores in the colon) via increased antioxidant activity with a consequent reduction in damage to DNA caused by oxidation. These researchers recommend Rooibos as a safe and useful way to reduce oxidative stress. ...
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... Therefore, ASP, as a dietary supplement, through its beneficial effect on glycemia and associated oxidative stress may protect the diabetic heart. A systematic review of literature led us to believe that a combination of ASP with MET may have an additive effect on glycemia, reduce oxidative stress, and lower the risk for DICM [22][23][24][25][26][27][28]. The aim of our study was to investigate the ameliorative effect of ASP as a monotherapy or in combination with MET on oxidative stress and FAO in H9c2 cardiac muscle cells exposed to a high glucose (HG) concentration. ...
Article
Scope: Energy deprivation in the myocardium is associated with impaired heart function. This study aim to investigate if aspalathin can ameliorate hyperglycemic-induced shift in substrate preference and protect the myocardium against cell apoptosis. Methods and results: H9c2 cells were exposed to, either normal (5.5 mM) or high (33 mM) glucose concentrations for 48 hours. Thereafter, cells exposed to 33 mM glucose were treated with metformin (1 μM) or aspalathin (1 μM), as well as a combination of metformin and aspalathin for 6 hours. In vitro studies revealed that aspalathin improved glucose metabolism by decreasing fatty acid uptake and subsequent β-oxidation through the decreased expression of pAMPK (Thr(172) ) and CPT1, while increasing ACC and GLUT4 expression. Aspalathin inhibited high glucose-induced loss of membrane potential in H9c2 cells as observed by an increase in JC-1 ratio (orange\red fluorescence) and decreased apoptosis by reducing intracellular ROS and DNA nick formation, while increasing glutathione, superoxide dismutase, UCP2 and Bcl-2\Bax ratio. Conclusion: Our study provides evidence that aspalathin increases glucose oxidation and modulates fatty acid utilization producing a favorable substrate shift in H9c2 cardiomyocytes exposed to high glucose. Such a favorable shift will be of importance in the protection of cardiomyocytes in the diabetic heart. This article is protected by copyright. All rights reserved.
... Scientific studies reporting on the possible anti-inflammatory effects of rooibos and/or its flavonoids are sparse. A study in Japan reported that unfermented rooibos extract (1.6%, w/v) administration as the only source of drinking fluid for 8 weeks reduced inflammation in dextran sodium sulphate (DSS)-induced colitis rats via an increased antioxidant activity [275]. ...
... It tones the uterus and pelvic muscles, but does not stimulate contractions, so it won't induce labour or miscarriage.  Astragalus tea is known to cure HIV and AIDS [10].  Ginger tea is also good for nausea of any kind, from morning sickness to motion sickness and anything in between. ...
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Herbal tea is essentially an herbal mixture made from leaves, seeds and/ or roots of various plants. As per popular misconception, they are not derived from the usual tea plants, but rather from what are called as ‘tisanes’. There are several kinds of tisanes (herbal teas) that have been used for their medicinal properties. Some of them being consumed for its energizing properties to help induce relaxation, to curb stomach or digestive problems and also strengthen the immune system. Some of the popular herbal teas are Black tea, Green tea, Chamomile tea, Ginger tea, Ginseng tea, Peppermint tea, Cinnamon tea etc. Some of these herbal teas possess extremely strong medicinal benefits such as, Astragalus tea, a Chinese native herb that is used for its anti-inflammatory and anti-bacterial properties; which in many cases helps people living with HIV and AIDS. Demonstrating very few demerits, researchers continue to examine and vouch for the health benefits of drinking herbal teas.
... 60 In addition, daily intake of fermented rooibos and green rooibos resulted in an increase in superoxide dismutase and catalase activities in Wistar rats injected with t-butyl hydroperoxide. 61 Similar results were reported by Baba et al. 62 after providing rooibos tea to 7-week-old Wistar rats. A literature search showed that in vivo studies are still limited as compared to in vitro studies; perhaps due to increased financial and human resources involved in human and animal studies. ...
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Tea is one of the most widely consumed non-alcoholic beverages in the world next to water. It is classified as Camellia sinensis and non-Camellia sinensis (herbal teas). The common bioactive compounds found mainly in green teas are flavan-3-ols (catechins) (also called flavanols), proanthocyanidins (tannins) and flavonols. Black tea contains theaflavins and thearubigins and white tea contains L-theanine and gamma-aminobutyric acid (GABA), while herbal teas contain diverse polyphenols. Phytochemicals in tea exhibit anti-microbial, anti-diabetic and anti-cancer activities that are perceived to be helpful in managing chronic diseases linked to lifestyle. Many of these phytochemicals are reported to be biologically active when combined. Knowledge of the synergistic interactions of tea with other teas or herbs in terms of biological activities will be of benefit for therapeutic enhancement. There is evidence that various types of teas act synergistically in exhibiting health benefits to humans, improving consumer acceptance and economic value. Similar observations have been made when teas and herbs or medicinal drugs were combined. The aim of this review is to highlight potential beneficial synergies between combinations of different types of teas, tea and herbs, and tea and medicinal drugs.
... Although Apigenin is not present in R f it supports our hypothesis that excess AO's have a generic effect on suppressing cellular proliferation. Rooibos is known to possess an abundance of flavonoids, Aspalathin being the main flavonoid having stronger AO activities than other flavonoids [36]. Although we used a much lower R f concentration range (0.0625-1%), our findings were also in alignment with research conducted by Lamosŏvá et al., (1997) [3] who reported on the use of concentrations of 2-100% of a Rooibos extract, which resulted in the inhibition of cellular proliferation in primary cultures of chick skeletal cells [3]. ...
Article
Oxidative stress in the brain microvasculature is a common characteristic in models of cerebrovascular disease. Considering the effects of reactive oxygen species activity in vascular-derived insults, it is naturally prudent to hypothesize those interventions inhibiting reactive oxygen species activity, such as antioxidant supplementation, may be beneficial for cerebrovascular disease. Hyper doses of antioxidant supplements, and foods with high antioxidant concentrations, are commonly used as an ongoing remedial and 'over-the-counter' treatments for most seasonal ailments. For the first time, this study reports the adverse effects of excess antioxidants on angiogenic properties of the blood-brain barrier (BBB) which have clinical implications. A medicinal tea, known as Rooibos, commonly used in South Africa and marketed globally, for its prominent antioxidant profile, demonstrated its effects on brain endothelial cellular proliferation, toxicology, mitochondrial activity and permeability. Mouse brain endothelial cells were seeded at cell densities ranging from 103-106 cells/ml and were incubated at pre-determined time intervals of 24 to 120 hours. Daily exposure of a selected concentration range of fermented Rooibos tea caused dose-related decreases in cellular proliferation, and unequivocally decreased permeability across our in vitro BBB model. Despite the negative effects on cellular proliferation, no toxicity was observed for all selected fermented Rooibos concentrations. Our data conclusively shows that the use of excess antioxidants perturbs BBB functionality and angiogenic properties, adversely implicating the homeostatic regulation of the brain microenvironment, while suppression in cellular proliferation impacts both the maintenance and repair function of brain capillaries. Our study indicates that excess antioxidants will lead to an impaired response to mechanical-induced injury and pathogenic infection of the BBB, compromising patient recovery.
... This is particularly significant when considering that in comparison, black (Camilla sinensis) tea decreased the liver oxygen radical absorbance capacity (ORAC) in the same study, suggesting a relative depletion of endogenous antioxidant systems. Several subsequent studies confirmed the antioxidant effect of Rooibos in ethnopharmacological studies, 9 as well as in in vitro studies, [10][11][12] animal studies [13][14][15][16][17][18] and in a human model. 19 Most notable was the latter study by Marnewick and colleagues, which was the first to provide clinical proof that daily Rooibos consumption has a beneficial role in the context of CVD prevention. ...
... The aforementioned flavonoid compounds in Rooibos, stable in the processing of Rooibos, may act in concert, contributing to beneficial effects reported in in vivo and in vitro studies. These benefits, whether by fermented or unfermented Rooibos consumption, include (a) hypoglycaemic effects: enhanced glucose uptake and glucose tolerance, increased GLUT4 levels; (b) cardio-protective effects: decreased serum cholesterol, triglycerides, free fatty acids and LDL cholesterol levels as well as increased HDL cholesterol; (c) oxidative stress reduction: increased GSH levels and GSH/GSSG ratios; and (d) steroidogenic effects: decreased glucocorticoid levels, increased cortisol:cortisone ratios and 11βHSD1 inhibition (Baba et al., 2009;Beltran-Debon et al., 2011;Dludla et al., 2014;Hong, Lee, & Kim, 2014;Marnewick et al., 2011;Mazibuko et al., 2013;Son et al., 2013). These bioactivities of Rooibos, its high polyphenol content, and our added findings of immunomodulatory properties further add to its attributes of Rooibos as a value added product in nutraceutical markets. ...
... Its leaves and stems are fermented, and their aqueous infusion is consumed as "rooibos tea," which is red-colored and caffeine-free, and has a low tannin content (Morton, 1983). Rooibos tea contains various flavonoids (Krafczyk and Glomb, 2008) and has been reported to show antioxidant (Fukasawa et al., 2009, antiinflammatory (Baba et al., 2009), and anti-mutagenic (Snijman et al., 2007) effects. ...
Article
To evaluate the suppressive effects of green rooibos (Aspalathus linearis) unfermented tea on postprandial hyperglycemia, we orally administered four carbohydrates with or without green rooibos extract (GRE) and its major flavonoid aspalathin (Asp). GRE significantly suppressed the elevation of blood glucose levels after glucose, maltose, and starch intake. Asp also lowered the levels for all four carbohydrates. To clarify the mechanism underlying these results, we performed an intraperitoneal glucose tolerance test (IPGTT) and measured the ability of GRE and Asp to inhibit the activities of carbohydrate-hydrolyzing enzymes in vitro. In IPGTT, GRE and Asp did not show suppressive effects on blood glucose, while they dose-dependently inhibited the activities of α-glucosidase and α-amylase in vitro. These results showed that GRE and Asp suppress the elevation of blood glucose levels. It was indicated that these effects may result from the suppression of glucose absorption and the inhibition of carbohydrate-hydrolyzing enzyme activities by GRE and Asp.
... Isolation and Structure Elucidation. Phytochemical investigation of the MeOH extract of A. linearis mixed parts comprising leaves and stems resulted in the isolation and characterization of 11 flavonoid glycosides including two dihydrochalcone derivatives, aspalathin 25 (1) and nothofagin 26 (2); four flavone derivatives, thermopsoside 27 (3), isoorientin 28 (4), vitexin 29 (5) and isovitexin 29 (6); three flavonol derivatives, isoquercitrin 30 (7), rutin 31 (8), and bioquercetin 32 (9); one flavanone derivative, (R/S)-eriodictyol-6-C-β-Dglucopyranoside 12 (10); and one phenylpropanoid derivative, syringin 33 (11) (Figure 1). Structure elucidation was mainly achieved by spectroscopic data analysis including 1D and 2D NMR ( 1 H, 13 ...
Article
Rooibos tea (Aspalathus linearis) is a well-known South African herbal tea enjoyed worldwide. Limited reports indicate the potential of rooibos tea to alter the activity of certain cytochrome P450 (CYP450) isozymes. In this study, the phytochemical investigation of MeOH extract of A. linearis (leaves and stems) resulted in the isolation and characterization of 11 phenolic compounds. The MeOH extract exhibited significant inhibition of the major human CYP450 isozymes (CYP3A4, CYP1A2, CYP2D6, CYP2C9, and CYP2C19). The strongest inhibition was observed by the extract for CYP3A4 (IC 50 1.7 ± 0.1 μg/mL) followed by CYP2C19 (IC 50 4.0 ± 0.3 μg/mL). Among the tested phytochemicals, the most potent inhibitors were isovitexin on CYP3A4 (IC 50 3.4 ± 0.2 μM), vitexin on CYP2C9 (IC 50 8.0 ± 0.2 μM), and thermopsoside on CYP2C19 (IC 50 9.5 ± 0.2 μM). The two major, structurally related compounds aspalathin and nothofagin exhibited a moderate pregnane-X receptor (PXR) activation, which was associated with increased mRNA expression of CYP3A4 and CYP1A2, respectively. These results indicate that a high intake of nutraceuticals containing rooibos extracts may pose a risk of herb−drug interactions when consumed concomitantly with clinical drugs that are substrates of CYP enzymes.
... Similar to the findings of previous studies, our results showed that rooibos did not alter body weight or fluid consumption. [33][34][35][36] Furthermore, ART alone had no effect on body weight, also similar to previous findings in humans. 37 Consequently, it was not unexpected, that the combination of ART and rooibos also had no effect on body weight. ...
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HIV-infected populations receiving antiretroviral therapy (ART) have an increased risk of cardiovascular disease. The beneficial cardiovascular effects of rooibos are well described; however, it is unknown whether rooibos ameliorates harmful ART-induced cardiovascular side effects. We investigated the cardiometabolic effects of rooibos co-treatment in rats receiving ART (efavirenz, emtricitabine, tenofovir) for nine weeks. Rooibos treatment reduced total cholesterol levels; however, triglyceride, phospholipid and thiobarbituric acid-reactive substance levels were unaffected by ART, rooibos or combination treatment. In isolated hearts exposed to ischae-mia-reperfusion injury, ART resulted in increased infarct sizes compared to controls, which was not observed when co-treated with rooibos. Vascular studies showed reduced aortic relaxation with ART, and improved relaxation when co-treated with rooibos. In conclusion, we show that rooi-bos treatment reduced total cholesterol levels in control rats, and that rooibos co-treatment ameliorated the harmful ART-induced cardiovascular effects. These findings are novel and warrant further studies into underlying mechanisms and clinical relevance.
... Consequently, the potent in vitro antioxidant capabilities of aspalathin makes it an attractive molecule for therapy (Pereira, 2017). In addition, rooibos has anti-ageing, anticaries, hepatoprotective, nephroprotective, immunomodulating, antimicrobial, antispasmodic, antieczema activities, and may prevent DNA damage and inflammation in vivo (Baba et al., 2009;De Mejia et al., 2013;Morton, 1983;Yang et al., 2018). It has great potential of being included in the current medical therapeutic regime, especially with the global increase and preference for natural remedies to maintain and promote general well-being (Erlwanger and Ibrahim, 2017;Kreuz et al., 2008;Persson, 2013). ...
... Hence, green rooibos is a better option for targeted isolation of aspalathin and polyphenolic compounds reported as active ingredients for cosmeceutical products [16,17]. Extracts prepared from green rooibos possess potent antioxidant, anti-inflammatory and anti-tumour properties [18][19][20][21] with evidence supporting its photoprotective effects in the skin [12,20,22]. These effects are strongly linked to its unique phytochemical composition and bioactive compounds [23]. ...
Article
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Skin cells suffer continuous damage from chronic exposure to ultraviolet light (UV) that may result in UV-induced oxidative stress and skin thinning. This has necessitated the formulation of cosmeceutical products rich in natural antioxidants and free radical scavengers. Aspalathus linearis (rooibos) is an endemic South African fynbos plant growing naturally in the Western Cape region. The plant is rich in phenolics and other bioactives with a wide spectrum of health benefits. The chemical study of an acetonic extract of green A. linearis afforded a novel compound named linearthin (1) and two known dihydrochalcones, aspalathin (2) and nothofagin (3). The chemical structure of the novel compound was elucidated based on spectroscopic data analysis. The bio-evaluation of the isolated chalcones in vitro for protection against UVB-induced oxidative stress were systematically assessed by examining cell viability, metabolic activity, apoptosis, and cytotoxicity using HaCaT and SK-MEL-1 skin cells models. It was observed that pre-treatment with tested samples for 4- and 24 h at low concentrations were sufficient to protect skin cells from UVB-induced damage in vitro as evidenced by higher cell viability and improved metabolic activity in both keratinocytes (HaCaT) and melanocytes (SK-MEL-1). The results further show that the pre-treatment regimen employed by this study involved some degree of cellular adaptation as evidenced by higher levels of reduced glutathione with a concomitant decrease in lipid peroxidation and lowered caspase 3 activity. Furthermore, compound 1 was most cytoprotective against UVB irradiation of HaCaT cell line (over 24 h) with an IC50 of 282 µg/mL and SK-MEL-1 cell line with IC50 values of 248.3 and 142.6 µg/mL over 4 and 24 h, respectively. On the other hand, HaCaT cells exposed to 2 over 4 h before UVB irradiation showed the highest degree of cytoprotection with an IC50 of 398.9 µg/mL among the four studied samples. These results show that linearthin (1) and the two glycoside dihydrochalcone of A. linearis have the potential to be further developed as antioxidant cosmeceutical ingredients that may protect skin against UVB-induced damage.
... Działanie przeciwzapalne powiązano z właściwościami antyoksydacyjnymi czerwonokrzewu. Autorzy tego badania sugerują zastosowanie czerwonokrzewu w charakterze nutraceutyku wspomagającego leczenie zapalnych chorób jelit [32]. ...
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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.
... These symptoms are alleviated by administration of Bixa orellana extract or loperamide. The extract via flavonoids (Baba et al. 2009) would inhibit intestinal inflammation, thus promoting iron absorption and stimulation of hematopoiesis. ...
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Ulcerative colitis is one of the inflammatory bowel diseases that is increasing in incidence worldwide. The objective of this work was to evaluate the activities of the hydroethanolic extract of the leaves of Bixa orellana on colitis in rats. Thirty-six rats were anesthetized with ether after 18 hours of fasting and ulcerative colitis was induced by intrarectal administration of 1 mL of acetic acid (5%) in all animals except the normal control group which received instead distilled water (1 mL). 48 hours after induction, the normal control and the negative control received distilled water (10 mL/kg), the positive control received loperamide (5 mg/kg) and three test groups received hydroethanolic extract Bixa orellana leaves at 100, 200 and 400 mg/kg per day for seven days. Administration of the extract significantly (P <0.01) reduced the number of diarrheal stools, nitric oxide and malonedialdheide levels, anemia and the number of colon lesions. The extract significantly (P <0.01) improved body weight loss as well as antioxidant parameters (superoxide dismutase, catalase, gluthation). These results would justify the use of Bixa orellana in the treatment of inflammatory bowel disease.
... These unique actions of rooibos and melatonin may have provided enough protection on MSCs/osteoblasts to produce the clinical actions observed for rooibos on decreasing CTX levels since melatonin-mediated increases in osteoblastogenesis are associated with decreases in osteoclastogenesis (22). Rooibos tea, rich in polyphenols, possesses strong antiinflammatory and antioxidant effects (33,67). Although rooibos did not impact on cortisol or CRP levels and no correlations were found between these markers of inflammation on any endpoints measured (Table S2), perhaps these properties of rooibos increased the synthesis and secretion of melatonin, which is also a strong free radical scavenger and inducer of antioxidant enzymes (68). ...
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The purpose of the OsTea translational study was to assess the efficacy of teas (tulsi, rooibos, oolong) compared to placebo (coriander) on markers of bone health and quality of life (QOL) in those with osteopenia and on human mesenchymal stem cell (hMSC) differentiation into osteoblasts to identify potential mechanisms of action. Following consumption of tea (3 times/day; 90 days), participants collected a urine sample during the night (10pm-6am) and filled in questionnaires before and after the study. Rooibos consumption demonstrated a significant decrease in urinary CTX levels vs placebo; trended towards increases in nocturnal melatonin levels (p=0.06); significantly decreased serotonin-producing microbes in the gut; and demonstrated trends towards improvements (p=0.09) in QUALIOST emotional parameters. Tulsi consumption primarily affected subjective measures, such as significantly improved scores for PSS, STAI-trait anxiety, and osteoporosis/osteopenia-related parameters in the QUALIOST. To further identify potential mechanisms underlying these actions of rooibos on CTX and melatonin (urinary and gut), rooibos and melatonin effects on human osteoblastogenesis were carried out for 21 days under oxidative stress conditions to mimic osteopenia. Although both rooibos and melatonin protected against oxidative stress-induced loss of osteoblasts in vitro, their underlying mechanisms were different. Melatonin, like tulsi and oolong, demonstrated the greatest protection against oxidative stress at days 10-11 of exposure, which was due to effects on hMSC viability and through melatonin receptors. Rooibos, on the other hand, demonstrated protection at days 10-11 and 20-21, which was through signaling mechanisms involved in differentiation processes and not on cell viability. These findings suggest that the clinical actions of rooibos on decreasing CTX levels in a population with osteopenia may be through a cooperative effort between melatonin and rooibos by protecting hMSC viability against oxidative stress-induced loss and by promoting osteoblast differentiation, respectively. This study also supports the use of tulsi for improving quality of life in a population susceptible to osteoporosis.
... The anti-inflammatory effect of ARRE was observed in a dextran sodium sulfate (DSS)-induced rat colitis model (Baba et al. 2009). In the study, seven week old Wistar rats were divided into two groups: water and ARRE. ...
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Aspalathin (2′,3,4,4′,6′-pentahydroxy-3′-C-β-D-glucopyranosyldihydrochalcone) is a natural C-linked glucosyl dihydrochalcone present in Aspalathus linearis (Burm.f.) R.Dahlgren (rooibos), a South African endemic plant, popularly consumed globally as a herbal tea. Aspalathin is reported to possess potent anti-oxidant properties that are believed to be responsible for the health benefits of rooibos. Other pharmacological properties ascribed to the molecule include antidiabetic, antimutagenic, anti-inflammatory, antithrombotic, and xanthine oxidase inhibitory activities. The role of aspalathin in limiting the progression of metabolic disorders and preventing diabetes-induced cardiovascular complications has been reported. The aforementioned potential health benefits of aspalathin have rendered it a popular natural ingredient that is incorporated in various nutraceutical and cosmeceutical products for protection against different conditions. Percutaneous permeation studies revealed some degree of absorption through the skin, supporting its use in cosmetic preparations. To perform an in-depth assessment of the scientific literature available on aspalathin, a bibliometric analysis was carried out on publications for the period 1965–2020, using the Scopus database. A total of 140 articles were retrieved, indicating that South African authors are major contributors to aspalathin research. The most common areas of investigation were identified as anti-oxidation, chemistry/chemical profiling, antidiabetic and anti-inflammatory activities. A comprehensive literature search showed that there are currently only two available reviews on aspalathin. Hence, the present review aims to explore the history and fill gaps with regards to collating aspects of the synthesis, quality control, metabolism and various biological activities of the molecule.
... Consequently, the potent in vitro antioxidant capabilities of aspalathin makes it an attractive molecule for therapy (Pereira, 2017). In addition, rooibos has anti-ageing, anticaries, hepatoprotective, nephroprotective, immunomodulating, antimicrobial, antispasmodic, antieczema activities, and may prevent DNA damage and inflammation in vivo (Baba et al., 2009;De Mejia et al., 2013;Morton, 1983;Yang et al., 2018). It has great potential of being included in the current medical therapeutic regime, especially with the global increase and preference for natural remedies to maintain and promote general well-being (Erlwanger and Ibrahim, 2017;Kreuz et al., 2008;Persson, 2013). ...
Article
Edited by J Van Staden A B S T R A C T This bibliometric assessment aimed to gain insight into the publication landscape over a 25-year period on one of South Africa's most coveted indigenous plants, Aspalathus linearis, known in commerce as rooibos tea. Despite the growing global market, and acceptance as a refreshing and health-promoting tea, scientific publications on rooibos, have not been subjected to scientometric analyses. A total of 421 relevant documents spanning the period 1994-2018 as indexed in the Scopus database were considered using VOSviewer. The global publication contribution on rooibos tea shows an average annual growth rate of 27.2%, and citation impact averaged 30 per publication. South African authors dominated the research landscape, contributing to approximately 60% of the total publication output. Prominent research themes include oxidative stress and inflammatory process mitigation using rooibos tea extracts, agronomy and fair trade in the rooibos tea industry, metabolic syndrome research, antioxidant activity, toxicity, quality control of rooibos tea and formulated products. More recently, a research focus has developed around bioavailability evaluation of rooibos tea components, green synthesis and nanoparticle formulations with the aim of improving the efficacy and potency of rooibos tea in the treatment of Type 2 Diabetes. We propose that research attention should be devoted to the mechanistic action of rooibos metabolites in mitigation of infectious diseases, diabetes, cardiovascular diseases and obesity which will inevitably lay the foundation for clinical studies to proceed.
... Studies have reported on the in vivo and invitro antioxidant (11) , anti-inflammatory properties (12 ) as well as the modulation of oxidative stress by Rooibos (5) . Galectin-3 is a new biomarker indicator of CVD; it is a member of a family of proteins comprising soluble β_galactoside-binding lectin that appears to be a direct mediator of pro-fibrotic pathways and is a potential marker of adverse cardiac remodeling (13) . ...
... Rooibos contains strong antioxidative substances; in particular aspalathin has higher antioxidative abilities in comparison with other contents [32]. Despite many studies on rooibos and properties of its flavonoids, for example, protective effects against DNA damage [33], inflammation [34], cancer promotion [35], and hyperlipidemia [36], few studies have been attempted to elucidate their anti-diabetic effect. Kawano et al. have reported that aspalathin itself possesses a potential to promote glucose uptake in L6 myotubes and to suppress rises in fasting blood glucose levels and to improve glucose intolerance in T2D model db/db mice that lack leptin receptor [37]. ...
... These often include the use of extracts containing complex mixtures of bioactive phenolic compounds (Kang et al., 2012;Haddad et al., 2015;Oh, 2015;Shay et al., 2015). Aspalathus linearis, better known as rooibos, an indigenous South African fynbos legume shown to offer several health benefits, such as antiinflammatory (Baba et al., 2009), anti-obesity (Sanderson et al., 2014), and more importantly, anti-diabetic effects. The role of aspalathin as a major bioactive C-glucosyl dihydrochalcone in rooibos extracts was reviewed by Johnson et al. (2018). ...
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An aspalathin-rich green rooibos extract (Afriplex GRT™) has demonstrated anti-diabetic and hypolipidemic properties, while also moderately inhibiting CYP3A4 activity, suggesting a potential for herb–drug interaction. The present study, therefore, evaluated the effects of orally administered GRT on the pharmacokinetics of atorvastatin and metformin in Wistar rats. Wistar rats were orally treated with GRT (50 mg/kg BW), atorvastatin (40 mg/kg BW) or metformin (150 mg/kg BW) alone or 50 mg/kg BW GRT in combination with 40 mg/kg BW atorvastatin or 150 mg/kg BW metformin. Blood samples were collected at 0, 10, and 30 min and 1, 2, 4, 6, and 8 h and plasma samples obtained for Liquid chromatography-mass spectrometry (LC-MS/MS) analyses. Non-compartment and two-compartment pharmacokinetic parameters of atorvastatin and metformin in the presence or absence of GRT were determined by PKSolver version 2.0 software. Membrane transporter proteins, ATP-binding cassette sub-family C member 2 (Abcc2), solute carrier organic anion transporter family, member 1b2 (Slco1b2), ATP-binding cassette, sub-family B (MDR/TAP), member 1A (Abcb1a), and organic cation transporter 1 (Oct1) mRNA expression were determined using real-time PCR expression data normalized to β-actin and hypoxanthine-guanine phosphoribosyltransferase (HPRT), respectively. Co-administration of GRT with atorvastatin substantially increased the maximum plasma concentration (Cmax) and area of the plasma concentration–time curve (AUC0-8) of atorvastatin by 5.8-fold (p = 0.03) and 5.9-fold (p = 0.02), respectively. GRT had no effect on the plasma levels of metformin. GRT increased Abcc2 expression and metformin downregulated Abcb1a expression while the combination of GRT with atorvastatin or metformin did not significantly alter the expression of Slco1b1 or Oct1 did not significantly alter the expression of Sclo1b2 or Oct1. Co-administration of GRT with atorvastatin in rats may lead to higher plasma concentrations and, therefore, to an increase of the exposure to atorvastatin.
... Although Apigenin is not present in R f it supports our hypothesis that excess AO's have a generic effect on suppressing cellular proliferation. Rooibos is known to possess an abundance of flavonoids, Aspalathin being the main flavonoid having stronger AO activities than other flavonoids [36]. Although we used a much lower R f concentration range (0.0625-1%), our findings were also in alignment with research conducted by Lamosŏvá et al., (1997) [3] who reported on the use of concentrations of 2-100% of a Rooibos extract, which resulted in the inhibition of cellular proliferation in primary cultures of chick skeletal cells [3]. ...
Article
Oxidative stress in the brain microvasculature is a common characteristic in models of cere-brovascular disease. Considering the effects of reactive oxygen species activity in vascular-derived insults , it is naturally prudent to hypothesize those interventions inhibiting reactive oxygen species activity, such as antioxidant supplementation, may be beneficial for cerebrovascular disease. Hyper doses of anti-oxidant supplements, and foods with high antioxidant concentrations, are commonly used as an ongoing remedial and 'over-the-counter' treatments for most seasonal ailments. For the first time, this study reports the adverse effects of excess antioxidants on angiogenic properties of the blood-brain barrier (BBB) which have clinical implications. A medicinal tea, known as Rooibos, commonly used in South Africa and marketed globally, for its prominent antioxidant profile, demonstrated its effects on brain endothelial cellular proliferation, toxicology, mitochondrial activity and permeability. Mouse brain endothelial cells were seeded at cell densities ranging from 10 3-10 6 cells/ml and were incubated at predetermined time intervals of 24 to120 hours. Daily exposure of a selected concentration range of fermented Rooibos tea caused dose-related decreases in cellular proliferation, and unequivocally decreased permeability across our in vitro BBB model. Despite the negative effects on cellular proliferation, no toxicity was observed for all selected fermented Rooibos concentrations. Our data conclusively shows that the use of excess antioxidants perturbs BBB functionality and angiogenic properties, adversely implicating the homeostatic regulation of the brain microenvironment, while suppression in cellular proliferation impacts both the maintenance and repair function of brain capillaries. Our study indicates that excess antioxidants will lead to an impaired response to mechanical-induced injury and pathogenic infection of the BBB, compromising patient recovery.
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Rooibos extract, due to its glucose and lipid lowering effects, has potential as a nutraceutical for improvement of metabolic dysfunction. Potential herb-drug interactions as a result of the use of natural products are of increasing concern. Cytochrome P450 enzymes, CYP2C8, CYP2C9, and CYP3A4, are important in the metabolism of hypoglycemic drugs, such as thiazolidinediones (TZDs) and sulfonylureas, and hypocholesterolemic drugs, such as atorvastatin. This study investigated the effects of rooibos extracts, prepared from "unfermented" and "fermented" rooibos plant material and two of the major bioactive compounds, Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid (PPAG) and aspalathin (ASP), on Vivid® recombinant CYP450 enzymes. Unfermented (GRT) and fermented (FRE) rooibos extracts inhibited the activity of CYP2C8 (7.69 ± 8.85 μg/mL and 8.93 ± 8.88 μg/mL, respectively) and CYP3A4 (31.33 ± 4.69 μg/mL and 51.44 ± 4.31 μg/mL, respectively) based on their respective IC50 concentrations. Both extracts dose- and time-dependently inhibited CYP2C8 activity, but only time-dependently inhibited CYP2C9. CYP3A4 showed concentration-dependent inhibition by ASP, GRT, and FRE at 25, 50, and 100 μg/mL concentrations. ASP, GRT, and FRE time-dependently inhibited CYP3A4 activity with GRT and FRE showing a more potent time-dependent inhibition, comparable to erythromycin. These findings suggest that herb-drug interactions may occur when nutraceuticals containing rooibos extracts are co-administered with hypoglycemic drugs such as TZDs, sulfonylureas, and dyslipidemic drug, atorvastatin.
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The antidiabetic potential of Aspalathus linearis has been investigated for over a decade, however, its characterisation remains incomplete with results scattered across numerous journals making the information difficult to compare and integrate. To explore whether any potential antidiabetic mechanisms for A. linearis have been neglected and to compare the suitability of extracts of green and “fermented” A. linearis as potential antidiabetic treatment strategies, this study utilised a comprehensive in vitro antidiabetic target-directed screening platform in combination with high content screening and analysis/ cellomics. The antidiabetic screening platform consisted of 20 different screening assays that incorporated 5 well-characterised antidiabetic targets i.e. the intestine, liver, skeletal muscle, adipose tissue/ obesity and pancreatic β-cells. Both the green and fermented extracts of A. linearis demonstrated very broad antidiabetic mechanisms as they revealed several promising activities that could be useful in combatting insulin resistance, inflammation, oxidative stress, protein glycation as well as pancreatic β-cell dysfunction and death - with a strong tendency to attenuate postprandial hyperglycaemia and the subsequent metabolic dysfunction which arises as a result of poor glycaemic control. The green extract was more successful at combatting oxidative stress in INS-1 pancreatic β-cells and enhancing intracellular calcium levels in the absence of glucose. Conversely, the fermented extract demonstrated a greater ability to inhibit α-glucosidase activity as well as palmitic acid-induced free fatty acid accumulation in C3A hepatocytes and differentiated L6 myotubes, however, further studies are required to clarify the potentially toxic and pro-inflammatory nature of the fermented extract.
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The emergence of the novel coronavirus (SARS-CoV-2) that emanated from Wuhan in China in 2019 has become a global concern. The current situation warrants ethnomedicinal drug discovery and development for delivery of phytomedicines with potential for the treatment of COVID-19. The aim of this review is to provide a detailed evaluation of available information on plant species used in African traditional medicines with antiviral, anti-inflammatory, immunomodulatory, and COVID-19 symptoms relieving effects. Literature from scientific databases such as Scopus, PubMed, Google scholar, African Journals OnLine (AJOL), Science Direct, and Web of Science were used for this review. A total of 35 of the 38 reviewed plants demonstrated a wide range of antiviral activities. Bryophyllum pinnatum, Aframomum melegueta, Garcinia kola, Sphenocentrum jollyanum, Adansonia digitata, Sutherlandia frutescens, Hibiscus sabdariffa, Moringa oleifera, and Nigella sativa possess a combination of antiviral, immunomodulatory, anti-inflammatory, and COVID-19 symptoms relieving activities. Nine, 13, and 10 of the plants representing 23.7%, 34.2%, and 26.3% of the plants studied had antiviral activity with 3 other activities, antiviral activity with 2 other activities, and antiviral with one pharmacological activity alone, respectively. The plants studied were reported to be relatively safe at the subchronic toxicity level, except for 2. The study provides baseline information on the pharmacological activities , toxicity, and chemical components of 9 African medicinal plants with antiviral, immunomodulatory, anti-inflammatory, and symptoms relieving activities, thereby making the plants candidates for further investigation for effectiveness against COVID-19.
Chapter
Aspalathus linearis (Brum.f) R.Dahlgren (Fabaceae), commonly referred to as ‘rooibos tea’, is native to South Africa and restricted to a relatively small region in the Western Cape Province. Rooibos tea is mostly enjoyed as a beverage and also used medicinally to improve appetite, reduce nervous tension and alleviate indigestion, heartburn, nausea and dermatological problems. Commercially, it is used as an ingredient of cosmetics, food, flavour and weight-loss products. Fermented and non-fermented rooibos are hailed for their anti-oxidant, anti-inflammatory, anticancer, antidiabetic and antimicrobial properties. Quality control protocols for A. linearis, based on chromatographic profiling of non-volatile fractions, were developed using semi-automated high-performance thin-layer chromatography (HPTLC) and ultra-performance liquid chromatography, coupled to mass spectrometry and photodiode array detection (UPLC-MS-PDA). Five fermented and unfermented (5) A. linearis specimens were obtained from commercial sites and the aerial parts extracted with methanol to obtain the non-volatile fractions. The extracts were profiled using HPTLC and UPLC-MS-PDA methods. The HPTLC fingerprints of the methanol extracts viewed under 366 nm radiation after derivatisation, revealed aspalathin, rutin, vitexin and orientin in all the samples. The presence of these marker compounds was confirmed by UPLC-MS-PDA and additional peaks for iso-orientin, isovitexin, hyperoside, isoquercitin, luteolin-7-glucoside, luteolin and chrysoerioal were also identified.
Chapter
The South African fynbos plant, Aspalathus linearis (Brum.f) Dahlg. (Fabaceae, Tribe Crotalarieae), is traditionally used as a herbal tisane referred to as rooibos or redbush. This plant has claimed medicinal properties based mostly on anecdotal evidence. Rooibos is naturally caffeine free and contains a unique blend of polyphenolic compounds. Based on its in vitro antioxidant potential, a few studies also suggest modulation of oxidative stress/damage by rooibos extracts in experimental animals. More recent studies have examined the bioactivity of rooibos in humans. Together, these factors have contributed to the popularity of this herbal tea as a health beverage, both locally and internationally. This chapter focuses on the in vitro antioxidant activity of rooibos and discusses recent animal and human studies.
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Rooibos is a herbal tea which is known to contain a high amount of polyphenols. The lipid profiles, antioxidant status and liver histopathology in male rats fed with aqueous rooibos extract at different concentrations were studied. The rats were randomly divided into groups (A-D). Group A was the control group which received tap water only while groups B, C and D received 2, 4 and 6% aqueous rooibos extracts respectively orally for 7 weeks. The results showed no significant differences in the plasma and liver ferric reducing antioxidant powers (FRAP) in all the rooibos extracts fed groups. There were no significant (p>0.05) decreases in total cholesterol, triglycerides, low density lipoprotein cholesterol and high density lipoprotein cholesterol levels in all the rooibos extracts fed groups. Liver catalase activity significantly (p<0.05) increased in all of the rooibos extracts fed groups. There were no significant differences in glutafhione peroxidase activities in the red blood cells and liver of rooibos extracts fed groups. Superoxide dismutase activities did not show any significant (p>0.05) difference in both the red blood cells and liver of rooibos extracts fed groups. There was a significant increase in glutafhione levels at 4 and 6% rooibos extracts when compared with the control group. Total protein, albumin and globulin levels were not significantly (p>0.05) different in all the groups. Histopafhological evaluations revealed no adverse effects in the structure of the liver in the rats. In conclusion, intake of rooibos did not have significant effects on lipid profiles while it contributed to the improvement of the body antioxidant system.
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Objectives: Rooibos tea, a very popular everyday beverage made of Aspalathus linearis plant material and containing multiple polyphenolic compounds, reveals an expectation to positively affect various processes observed in the pathogenesis of neurodegenerative diseases as in the case of consumption of other polyphenol-abundant food products. Methods: This review is based on available data from pre-clinical in vitro and in vivo studies and presents a broad report on the pharmacological activity of the A. linearis extracts relevant for neurodegenerative diseases. Results: Flavonoids present in herbal infusions are absorbed from gastro-intestinal tract and may affect the central nervous system. The experimental investigations yield the results indicating to supporting role of A. linearis in the prevention of neurodegeneration, primarily owing to anti-oxidative and anti-inflammatory properties, anti-hyperglycaemic and anti-hyperlipidaemic effects as well as favourable impact on neurotransmission with following cognitive and behavioural after-math. Discussion: The multiple pharmacological activities and safety of Aspalathus linearis extracts are commented in the manuscript. The continuous rooibos tea consumption seems to be safe (despite anecdotal liver irritation); however, there is a risk of herbal-drug interactions.
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The purpose of this study was to assess the effects of dietary fish oil (FO) and rooibos supplementation on semen quality, fatty acids composition and reproductive performance of aged male broiler breeders. Seventy‐two 47‐week‐old Ross broiler breeder roosters were randomly assigned to a 2 × 3 factorial arrangements to include two FO concentrations (0% and 2%) and 3 rooibos concentrations (0%, 1.5% and 3%) for 13 weeks consecutive. The different diets affected semen parameters significantly (p < 0.05), except for the semen concentration and abnormality of the sperm. The sperm of the FO and 3% rooibos‐treated group showed better motility and viability when compared to the other groups (p < 0.05). The susceptibility of semen to lipid peroxidation was increased in roosters fed the rooibos‐free diets (p < 0.05), but it was reduced (p < 0.05) when the diet was supplemented with 1.5% and 3% rooibos. In addition, at 64 weeks, the highest concentration of testosterone was observed in the roosters fed a diet that included 2% FO and 3% rooibos (p < 0.05); however, the difference in testosterone levels between Week 52 and Week 64 was not significant (p > 0.05). The fertility rate of collected eggs from the FO and 3% rooibos group was higher (p < 0.05) than that of the other groups at the end of the experiment. In conclusion, dietary inclusion of FO along with rooibos improved seminal quality and reproduction performance in aged roosters.
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ScopeSeveral epidemiological studies have shown that tea consumption is associated with higher bone mineral density in women. Flavonoids in tea are recognized as potential estrogen mimics and may positively influence bone metabolism in estrogen-deficient women. Luteolin and orientin, flavonoids from rooibos tea, are of particular interest as rooibos tea contains no caffeine that can be detrimental to bone health. This study analyzed changes in mineral content when luteolin or orientin was added to a human osteoblast cell line and the potential mechanisms involved. Measurements included alkaline phosphatase (ALP) activity, cell mitochondrial activity, toxicity, and changes in regulatory proteins involved in osteoblast metabolism.Methods and resultsMineral was significantly elevated in Saos2 cells treated with orientin (0.1-1.0 μM, 15-100 μM) or luteolin (5.0 μM) and was associated with increased ALP and mitochondrial activity, as determined by the production of p-nitrophenol and the reduction of 2-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, respectively. Greater mineral content was also associated with lower toxicity as determined by lactate dehydrogenase activity and lower expression of TNF-α, IL-6, sclerostin, osteopontin, and osteoprotegerin.Conclusion Orientin and luteolin, flavonoids in rooibos tea, enhance mineral content in Saos2 cells. These findings provide guidance for doses to be studied in well-established animal models.
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Free radical scavenging activities of water-soluble extracts from some natural sources, health foods, and antioxidant substances were measured using the JES-FR30 JEOL spectrometer. The objective was to develop a standardized method whereby comparison could be made between the radical scavenging activities of complex mixtures. Scavenging of hydroxyl radical was determined using DMPO. Activity was calibrated using a standard material, L-ascorbic acid 2-[3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H -1- benzopyran-6yl-hydrogen phosphate] potassium salt (EPC-K1), an analog of vitamin C and vitamin E which is water soluble and stable at room temperature. The order of greatest hydroxyl radical scavenging activity was green tea extract, pine bark extract (Pycnogenol), Ginkgo Biloba extract (EGb 761), a flavonoid blend of several fruit and vegetable extracts (GNLD), and Bio-Normalizer (Sun-O Corp). Activity was determined after treatment of samples with ascorbic acid oxidase. This treatment revealed the presence of ascorbate in some natural extracts and commercial preparations. The pine bark extract was the most heat resistant and had ascorbate-like activity in the preparations. Scavenging of superoxide anion was determined using the spin trap, 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), and analyzed by comparison with a standard curve made with superoxide dismutase. Comparison of the water solubilized components of natural source antioxidants showed that filtrates fractionated using centrifuge type Millipore filter tubes (M.W. < 100,000; M.W. < 10,000) also had almost the same SOD-like activity. Samples were also treated with ascorbate oxidase or by heating (100 degrees C for 10 min). The order of activity, from greatest to least, was Ginkgo biloba extract EGb 761, pycnogenol, beta-catechin, tea and BioNormalizer.
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Hepatoprotective properties of rooibos tea (Aspalathus linearis) were investigated in a rat model of liver injury induced by carbon tetrachloride (CCl(4)). Rooibos tea, like N-acetyl-L-cysteine which was used for the comparison, showed histological regression of steatosis and cirrhosis in the liver tissue with a significant inhibition of the increase of liver tissue concentrations of malondialdehyde, triacylglycerols and cholesterol. Simultaneously, rooibos tea significantly suppressed mainly the increase in plasma activities of aminotransferases (ALT, AST), alkaline phosphatase and billirubin concentrations, which are considered as markers of liver functional state. The antifibrotic effect in the experimental model of hepatic cirrhosis of rats suggests the use of rooibos tea as a plant hepatoprotector in the diet of patients with hepatopathies.
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Acute and chronic experimental ulcerative colitis models were produced in mice by providing them with drinking water containing synthetic dextran sulfate sodium. Mice that developed acute colitis showed signs of diarrhea, gross rectal bleeding, and weight loss within 6–10 days after ingesting 3%–10% dextran sulfate sodium. On postmortem examination, multiple erosions and inflammatory changes including crypt abscesses were found on the left side of the large intestine. Mice that developed chronic colitis showed signs of erosions, prominent regenerations of the colonic mucosa including dysplasia, shortening of the large intestine, and frequent formation of lymphoid follicles after 5 administration cycles, where each cycle was composed of 7 days' consumption of drinking water containing 5% dextran sulfate sodium followed by 10 days' consumption of distilled water. The population of intestinal microflora, Bacteroides distasonis and Clostridium spp., increased significantly in mice with acute and chronic ulcerative colitis. Further, morphological studies suggest that the administered dextran sulfate sodium was partially phagocytized by macrophages in the colonic mucosa.
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Oncogenic transformation of mouse cells induced by X-rays was suppressed in the presence of extract of Rooibos tea, Aspalathus linealis. Transformation was reduced with increased concentration of the extract, so that at an extract concentration of 10%, transformation incidence was similar to the spontaneous level. Suppression was also dependent on treatment time with the extract and was maximal when present during the entire incubation period. In contrast, green tea extract at an equitoxic concentration showed no detectable effect on transformation incidence.
Article
Rooibos tea (Aspalathus linearis , formerlyA. Contaminatus ), is a leguminous shrub with needlelike leaves native to mountain slopes of western Cape Province, South Africa. Its beverage use by the Hottentots was first reported by the botanist Carl Thunberg in 1772. About 1900, it began to be marketed and then domesticated on a small scale. Seed selection and improved cultivation and processing started in the 1920s. Important advances were made in 1930. Demand for the product jumped during World War II because of the shortage of Oriental tea, then declined. The industry was stabilized in 1954 and continued to expand, with exports to Australia, New Zealand, Europe, the United Kingdom, Canada and, to a very limited extent, the United States. A fungus disease, then drought, followed by floods temporarily reduced the supply in 1980. The tea is gaining recognition for its freedom from caffeine, low tannin and high ascorbic acid content.It contains the antispasmodic principle, quercetin, and is said to have enoughfluoride to inhibit caries. Consumer tests indicate that rooibos tea may be an acceptable alternative to tea, coffee, cocoa and high-caffeine soft drinks.
Article
A study was carried out to determine if rooibos tea (Aspalathus linearis) has a deleterious effect on iron absorption similar to that of ordinary tea (Camellia sinensis). Three groups of volunteers, each consisting of 10 healthy young men comparable with regard to iron status and body dimensions, were studied. After ingestion of 1 muCi 59Fe and 16 mg of elemental iron, group A drank rooibos tea, group B ordinary tea and group C boiled water. Iron absorption was measured 14 days later with a whole body counter. Mean iron absorption after ingestion of rooibos tea, ordinary tea, and water was 7,25%, 1,70% and 9,34% respectively. In contrast to ordinary tea (P less than 0,0001), rooibos tea did not affect iron absorption significantly. The ascorbic acid content of rooibos tea varies between 121,8 and 154,9 mumol/l, depending on the method of preparation. Rooibos tea contains small amounts of iron, magnesium, phosphorus, sodium, chloride and potassium. These findings have practical nutritional and therapeutic implications.
Article
Polysaccharide that has been extracted with 1% sodium carbonate from Rooibos leaves (Aspalathus linearis) showed strong anti-HIV activity. Du-Zhong leaves also showed anti-HIV activity, although lower than the extract of Aspalathus linearis, but Japanese tea leaves and a hot water extract of Aspalathus linearis did not. The anti-HIV activity of the alkaline extract from Aspalathus linearis was recovered mainly in the 25-75% ethanol-precipitated fraction. The polysaccharide almost completely inhibited the binding of HIV-1 to MT-4 cells. It is inferred from these results that the polysaccharide from Aspalathus linearis is involved in the mechanism for virus binding to T cells.
Article
The active substances, acid polysaccharides, were extracted with 1% sodium hydroxide from the leaves of rooibos tea (Aspalathus linearis), Du Zhong Cha (Eucommia ulmoides Oliv.) and Japanese tea leaves (Camellia sinensis var. sinensis). The alkaline extracts of Rooibos tea and Du-Zhong tea leaves, but not Japanese tea leaves suppressed the HIV-induced cytopathicity using HIV (HTLV-III) infected MT-4 cells, having extremely low cytotoxicity: Its 50% effective concentration (EC50) was 12-67 micrograms/mL, white 50% cytotoxic concentration (CC50) was higher than 1.0 mg/mL. The active substances were purified with ethanol precipitation. The substances were composed of 27% of reducing sugar, 46% of neutral sugars and 22% of uronic acid. A LD50 of the alkaline extracts from rooibos tea was higher than 1.2 g/kg body weight. Acid degradated substances composed of disaccharides and trisaccharides, were also suppressed the HIV-induced cytopathicity. From these results, it is probable that acid polysaccharides from rooibos tea were extremely safe, and that HIV infection may be suppressed by daily intake of the alkaline extracts of rooibos tea and Du-Zhong tea.
Article
Although a dextran sodium sulfate (DSS)-induced colitis is commonly used as an ulcerative colitis (UC) model in adult rodents, there are no studies using this model in young animals. We examined differences in the severity of DSS-induced colitis as a function of the concentration of DSS administered and sought to establish a DSS-induced colitis model in young rats. We administrated different concentrations of DSS solution (2%, 3%, and 4%) to 4-week-old weanling rats and compared their clinical findings, colonic histologic findings, mucosal leukotriene B4 (LTB4) production, and mucosal blood flow with control weanling rats and 8-week-old adult rats given 4% DSS for induced colitis. Clinical symptoms, such as diarrhea and rectal bleeding, histologic findings, and disturbance of mucosal microcirculation in weanling rats given 4% DSS were significantly more severe than those in adult rats given the same treatment. Three of 10 rats given 2% DSS had no bloody stool and 2 of 10 rats given 4% DSS died during the experimental periods. Clinical symptoms, hemoglobin levels, histologic damage scores, mucosal LTB4 production, and mucosal blood flow became more severely deranged as the concentration of DSS increased from 2% to 4%. These findings suggest that we can adjust disease severity in UC model for young children by giving different concentrations of DSS to weanling rats.
Article
We developed a strategy for determination and quantification of glycosyl flavonoids using liquid chromatography-triple quadrupole mass spectrometry with neutral loss scan at 15 and 30eV collision energy in the positive ion mode. The fragmentation patterns of glycosyl flavonoids at 15 and 30eV showed that fragmentation of sugar moiety depended on the type of glycosidic bond to aglycone, the site of C-glycosylation, and the type of aglycone. C-Glycosyl dihydrochalcones especially stood out because they produced [M+H-162](+) even at 15eV such as O-glycoside in spite of C-glycoside. C-Glycosides were classified according to (i) the intensity ratio A of [M+H-150](+) to [M+H-120](+) at 30eV and (ii) the intensity ratio B of [M+H-120](+) at 15eV to one at 30eV. The 8-C-glycosides were A<1 and B<1, the 6-C-glycosides were A>1 and B<1, and the C-glycosyl dihydrochalcones were A>1 and B>1. Therefore, the intensity ratios of the neutral loss scan of 120 and 150Da at 30eV and those of 120, 162, and 308Da at 15eV allowed sequential distinction among these three types of C-glycosides as well as between O- and C-glycosides. Our method was applied for analysis of Rooibos tea, and the identified glycosides could be quantified specifically by the selected reaction monitoring method.
Frontiers of mucosal immunology
  • Takizawa
Dextran sulfate sodium (DSS) colitis in rats
  • Gaudio