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Aspalathus linearis
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Animal Studies
Aspalathus linearis upregulated IRS-1 and decreased PkB/Akt in the testis of streptozotocin-induced diabetic rats. Omolaoye 2021
Adult Male Wistar rats (n = 20 per group), fed a control or a high-fat diet for 16 weeks and treated with green leaf extract of Aspalathus linearis enriched with aspalathin at 60 mg/kg/day, for six weeks, alleviated cardiovascular risk factors of a high fat diet. 2021
Fermented Aspalathus linearis infusion increased motor activity and exploratory behavior and reduced anxiety and brain content of excitatory amino acids (aspartate and glutamate) in healthy mice. Pyrzanowska 2021
Aspalathus linearis extract supplementation (Afriplex) exhibited a cardioprotective effect against ischemia/reperfusion injury by lowering pre-ischemic heart rate, reducing infarct size, and improving heart function pre- and post-ischemia without significantly affecting biometric parameters in high fat diet-induced prediabetic rats. Smit 2020
Acute and prolonged nothofagin (from Aspalathus linearis) administration decreased systolic blood pressure and mean arterial pressure in Wistar rats. Pretreatment with N(G)-nitro-L- arginine methyl ester, methylene blue, and tetraethylammonium prevented the hypotensive effect of nothofagin. da Silva 2020
In ex vivo rat kidneys perfused with physiological saline solution, injection with nothofagin (from Aspalathus linearis and other plants) dose-dependently reduced perfusion pressure in preparations with an intact endothelium, but had no effect in those with the endothelium removed. Marques 2020
Coadministration with fermented rooibos exerted anti-contractile and pro-relaxation responses in aortic rings, increased hepatic superoxide dismutase and catalase activity, and increased intracellular NO levels in nicotine-exposed animals. Unfermented rooibos had lesser effects. Smit-Van Schalkwyk 2020
Aspalathin protected rat pancreatic ß cells in vitro against cytotoxicity and apoptosis induced by streptozotocin, hydrogen peroxide, or chronic high glucose. This effect was associated with increased translocation of NRF2 and expression of its antioxidant target genes Hmox1, Nqo-1 and Sod1. Moens 2020
In palmitate-exposed C3A liver cells and obese insulin-resistant rats, green rooibos extract showed a strong potential to ameliorate hepatic insulin resistance by improving insulin sensitivity through the regulation of PI3K/AKT, FOXO1 and AMPK-mediated pathways. Mazibuko-Mbeje 2019
Oral co-administration of aspalathin-rich green rooibos extract (Afriplex GRT™) with atorvastatin increased the Cmax and AUC0-8 of atorvastin, but had no effect on plasma levels of metformin in rats. Patel 2019
Rooibos extract, containing eriodictyol-6-C-glucoside, dose dependently increased tear and saliva volumes in mice. The effects were exerted via muscarinic acetylcholine receptor 3. Results suggest rooibos may have benefit against sicca syndrome and symptoms of dryness. Arakaki 2019
The percentage, location and type of steatosis as well as presence of inflammation and hepatocellular injury were reduced in mice subjected to a high-fat diet co-treated with Afriplex GRT™ (an aspalathin-rich green rooibos extract). Layman 2019
Administration of Afriplex GRT (an aspalathin-rich green rooibos extract) to vervet monekeys for 28 days mitigated hyperglycemia, lowered LDL cholesterol in diabetics, raised HDL cholesterol in non-diabetics, and reduced oxidative stress overall. Orlando 2019
Long-term oral administration of fermented rooibos infusion to male rats improved long-term spatial memory as tested in a Morris water maze, which as associated with increases in striatal dopamine and its metabolite 3-MT levels. Pyrzanowska 2019
In Wistar rats exposed to methanol extract of diesel exhaust particles, pre-treatment with Aspalathus linearis extract protected against cardiovascular toxicity. Lawal 2019
Rooibos treatment reduced total cholesterol levels in control rats, and co-treatment with rooibos ameliorated cardiovascular effects in isolated rat hearts exposed to antiretroviral therapy (efavirenz, emtricitabine, tenofovir). Webster 2019
Treatment with rooibos tea decreased elevated enzyme levels, improved capacity of the respiratory chain and energy production, and improved histological features in rats with CCl4-induced liver damage, presumably due to antioxidant activity and inhibition of mitochondrial lipid peroxidation. Uličná 2019
In cultured, isolated mast cells, nothofagin treatment prevented histamine and β-hexosaminidase release by reducing the influx of calcium into the cytosol in a concentration-dependent manner, and inhibited gene expression and secretion of pro-inflammatory cytokines. Kang 2018
In a mouse model of sepsis, treatment with aspalathin and nothofagin provided protection against sepsis-triggered renal injury and reduced lethality. Yang 2018
In a type 2 diabetic mouse model, treatment with a combination of aspalathin and metformin was more effective than metformin alone in ameliorating associated symptoms, including raised fasting plasma glucose levels, impaired glucose tolerance, excessive body weights, and fat content. Dludla 2018
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. Smit 2018
A systemic review and meta-analysis of current evidence found that blood glucose levels were significantly lower in diabetic rodent models treated with the phenolic compound rich in rooibos extracts, PPAG. Sasaki 2018
In rats fed a high-fat diet and exposed to 1,2-dimethyl hydrazine, treatment with orientin from rooibos suppressed colonic cell proliferation and mitigated NF-κB mediated inflammatory response. Results demonstrated an anti-proliferative and anti-inflammatory action against colorectal cancer. Thangaraj 2017
Boar semen was supplemented with four concentrations both of fermented and unfermented Aspalathus linearis extracts. Results indicated that Aspalathus linearis extract enhances sperm velocity, protects the acrosome structure, and tends to preserve the membrane integrity during semen storage. Ros-Santaella 2017
Long-term consumption of fermented rooibos herbal tea by Wistar rats significantly reduced brain edema and neuronal apoptosis, but did not attenuate BBB damage following cerebral ischemia. Akinrinmade 2017
Correction: Van der Merwe, J.D., et al. Short-Term and Sub-Chronic Dietary Exposure to Aspalathin-Enriched Green Rooibos (Aspalathus linearis) Extract Affects Rat Liver Function and Antioxidant Status. Molecules 2015, 20, 22674-22690. Van der Merwe 2016
Phenylpropenoic acid glucoside (PPAG) from Aspalathus linearis given to streptozotocin induced mice offered protection of beta cells and PPAG also protected human pancreatic islet cells against the cytotoxic action of the fatty acid palmitate. Himpe 2016
The effect of a rooibos enriched green extract (GRE), fed to male rats for 28 and 90 days showed changes in certain oxidative stress and defense related genes, possibly due to alteration in the GSH redox pathway, with possible biliary dysfunction. van der Merwe 2015
The screening of 16 herbal extracts on glucose-induced survival reaction in the nematode Caenorhabditis elegans. Administration of rooibos did not influence this reaction. Fitzenberger 2014
In LPS-exposed male Wistar rat, individual administration of red palm oil or rooibos showed anti-inflammatory effect at systemic level, while their combination exhibited an enhanced anti-inflammatory effect in the myocardial tissue. Katengua-Thamahane 2014
The effect of hyperglycemia on sperm motility, in diabetes mellitus-induced rats, treated with red palm oil (RPO), rooibos tea extract (RTE) or both was studied. The results showed no negative effects of treatment with RTE or RPO or both and even improvement on sperm motility parameters. Ayeleso 2014
Pretreatment with fermented rooibos tea extract on lipopolysaccharide-induced acute liver damage in Wistar rats showed aqueous rooibos extract possibly limited LPS-induced liver damage by affecting cytokine formation and oxidative stress. Ajuwon 2014
Evaluation of the effects of red palm oil (RPO), Rooibos tea extract (RTE) or both on STZ-induced diabetic rats and their antioxidant status showed that RET, RPO and RTE+RPO all had positive effects on the antioxidative potential of diabetic rats. Ayeleso 2014
The cardioprotective effects of an aqueous extract of fermented rooibos (FRE) on cardiomyocytes from induced diabetic rats support findings that pretreatment with FRE protects the cardiomyocytes against induced oxidative stress and ischemia. Dludla 2014
Fermented rooibos, unfermented rooibos, a rooibos-derived commercial supplement, or water was given to 40 male Wistar rats for 10 weeks. Oxidative stress was induced at week 8. Rooibos was shown to increase the antioxidant capacity of the liver with induced oxidative stress. Canda 2014
Aspalathus linearis tea ( 2% and 5%) was given to male rats for 52 days. Sperm concentration, vitality and motility were improved, Prolonged exposure could cause acrosome changes, possibly decreasing fertility, or detrimental changes to liver and kidney function. Opuwari 2014
Hypoglycemic effect of aspalathin is related to increased GLUT4 translocation to plasma membrane via AMPK activation. Aspalathin reduces the gene expression of hepatic enzymes related to glucose production and lipogenesis. These results strongly suggest that aspalathin has anti-diabetic potential. Son 2013
PPAG:Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid) (PPAG) is a major constituent in fermented rooibos infusions. This study found that PPAG increases glucose uptake in muscle cells in vitro and improved glucose tolerance in an obese-insulin resistant rat model. Muller 2013
The effects of aqueous rooibos extract and red palm oil, on induced hepatotoxicity on Wistar rats was studied. Both were able to alleviate the hepatotoxicity, alone or combined suggesting the mechanism maybe due to inhibition of lipid peroxidation, glutathione and/or antioxidants levels. Ajuwon 2013
Rooibos, Chinese green tea,and green tea supplements were given to male rats with induced oxidative stress the last 2 of 10 weeks. Sperm count, motility, catalase activity and SOD concentrations were compared. Both rooibos extract groups showed lower lipid peroxidation and reactive oxygen species. Awoniyi 2012
Fermented and unfermented rooibos, with quantified polyphenolic compounds were fed to male rats for 7 weeks. Their hearts were then studied in a heart perfusion apparatus. The results showed cardio-protective action of the aqueous rooibos by apoptosis inhibition. Pantsi 2011
The response of induced esophageal papillomas in male rats to rooibos, honeybush and Camellia sinensis teas was studied. Mean papilloma number reduction was related to the total polyphenol (TPP) and flavanol/proanthocyanidin intake, with no inhibition noted below 7 mg/100g body weight of TPP. Sissing 2011
Two groups of rats were given either Rooibos tea or water. Dextran sodium sulfate was given to induce colitis and both groups were monitored for hemoglobin, serum iron and serum superoxide dismutase. Results suggested that the Rooibos group prevented DNA damage and inflammation in vivo. Baba 2010
Aspalathin, a green rooibos tea component, may have beneficial effects on glucose homeostasis in type 2 diabetes through stimulating glucose uptake in muscle tissues and insulin secretion from pancreatic beta-cells in db/db mice. Kawano 2009
The effects of rooibos tea (Aspalathus linearis), a source of flavonoid antioxidants & compounds with phyto-oestrogenic activity, on postnatal development & egg production of aged Japanese quail was determined and showed that body weight & egg production in quail hens were positively affected. Juráni 2008
Results of a study on rats administered midazolam (MDZ) suggested that two weeks ingestion of tenryocha and rooibos tea reduced serum concentration of MDZ by the induction of intestinal CYP3A. The possible interaction between tenryocha or rooibos tea and medicines mediated by CYP3A was suggested. Matsuda 2007
Animal model studies indicate that herbal teas Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) possess potent antioxidant, immune-modulating and chemopreventive actions. No adverse effects of rooibos or honeybush consumption as tisanes have been reported. McKay 2007
The effects of rooibos tea as a source of antioxidant on prevention and treatment of oxidative stress in streptozotocin-induced diabetic rats was investigated and revealed its usefulness for prevention of diabetic vascular complications, particularly for protecting ocular membrane systems. Ulicná 2006
Effects of rooibos tea antioxidants studied for prevention and treatment of oxidative stress in streptozotocin-induced diabetic rats. Antioxidant compounds in rooibos tea partially prevents oxidative stress and are effective in both hydrophobic and hydrophylic biological systems. Ulicna 2005
Methanolic extracts of processed and unprocessed rooibos (Aspalathus linearis) was found to suppress skin tumorigenesis significantly (P<0.001). Processed rooibos exhibited 75% inhibition and the unprocessed showed 60%. Marnewick 2005
Rooibos tea and N-acetyl-L-cysteine given to CCl4-damaged rats restored liver concentrations of CoQ9H2 and alpha-tocopherol, to values comparable with healthy animals. Rooibos tea, a rich source of natural antioxidants may be a safe and effective hepatoprotector in patients with liver diseases. Kucharska 2004
Excess levels of cyclooxygenase-2 (COX-2) has been implicated in pathogenesis and progression of carcinogenesis. Methanol extracts of herbs including Aspalathus linearis inhibited (TPA)-induced COX-2 expression in human breast epithelial (MCF10A) cells and in mouse skin in vivo. Na 2004
Male Fischer rats were given unprocessed and processed rooibos, honeybush, green and black teas as a sole source of drinking fluid for 10 weeks, and sub cellular liver fractions were prepared. Both preparations of rooibos significantly (P < 0.05) reduced the activation of AFB1. Marnewick 2004
Rooibos tea showed histological regression of steatosis and cirrhosis in the liver tissue with significant inhibition of the increase of liver tissue concentrations of malondialdehyde, triacylglycerols and cholesterol. Ulicna 2003
Rooibos & honeybush teas significantly (P < 0.05) enhanced activity of cytosolic glutathione S-transferase alpha. A significant (P < 0.05) to marginal (P < 0.1) increase in activity of microsomal UDP-glucuronosyl transferase was obtained w/ unprocessed rooibos & honeybush teas, respectively. Marnewick 2003
In chinese hamster lung fibroblasts, genetically engineered for the expression of rat cytochrome P450 dependent monooxygenase 1A2 and rat sulfotransferase 1C1, rooibois strongly reduced the genotoxicity of 2-acetylaminofluorene, and either moderately or weakly reduced that of other chemicals. Edenharder 2002
Chinese hamster lung fibroblasts, genetically engineered for a specfic expression of rat cytochrome P450 were utilized to check for possible protective effects of beverages of plant origin, fruits, vegetables, and spices. Edenharder 2002
Rooibos tea found to facilitate the antigen-specific antibody production through selective augmentation of IL-2 generation in vitro & in vivo. Rooibos tea may support prophylaxis of diseases involving a severe defect in Th1 immune response such as cancer, allergy, AIDS, & other infections. Kunishiro 2001
The antihemolytic activity of Rooibos and black tea on Japanese quail erythrocytes was studied. Rooibos and black teas decreased peroxide induced hemolysis of erythrocytes incubated with each of them, but not hemolysis induced by hypotonic NaCl solution. Simon 2000
Antioxidants & scavenging agents in Rooibos tea (RT) used to investigate the effects of different concentrations of RT extract in medium on growth parameters of chick embryonic skeletal muscle cells. Inhibition effect of RT rose w/increasing concentration of the tea extract in the culture medium. Lamosova 1997
Study results suggest plant flavonoids perform as antioxidants in vivo & radioprotective effects may be attributed to their scavenging potency towards free radicals. Flavonoids contained in tea, vegetables and fruits may be important as antioxidants in the human diet. Shimoi 1996
Ad libitum administration of Rooibos Tea (RT) was begun with 3-month-old Wistar female rats and continued for 21 months. RT-administration prevented age-related accumulation of lipid peroxides in several regions of rat brain. Inanami 1995
Oncogenic transformation of mouse C3H10T1/2 cells induced by X-rays was suppressed in the presence of extract of Rooibos tea, Aspalathus linealis. Komatsu 1994
The suppressing effects of extracts of 3 kinds of green tea (GT), Po-lei tea (PT) and Rooibos tea (RT)-on the induction of chromosome aberrations in cultured CHO cells & mice were studied. Results suggests intake of tea might suppress mutagenic activity of potent mutagens in humans. Sasaki 1993
History of Record
July 2005
January 2018
LATEST UPDATES BY: Oren Rabinowitz, MSc
November 2021