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Fact Sheet on Rooibos Tea

Authors:
  • Cancer Association of South Africa
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 1
Cancer Association of
South Africa (CANSA)
Fact Sheet
on
Rooibos Tea
Introduction
Rooibos meaning ‘red bush’ with the scientific
name of Aspalathus linearis is a broom-like
member of the legume family of plants growing
in South Africa’s fynbos.
[Picture Credit: Rooibos Tea Plantation]
The generic name of
the Rooibos tea
plant comes from the
plant Calicotome
villosa, aspalathos in
Greek. This plant has very similar growth and flowers to the
Rooibos plant. The specific name linearis comes from the plant's
linear growing structure and needle-like leaves. The leaves are
used to make a tea called Rooibos, bush tea (esp. Southern
Africa), or simply rooibos. The product has been popular in
Southern Africa for generations and is now consumed in many
countries. It is sometimes spelled rooibosch in accordance with
the old Dutch etymology.
(Wikipedia).
[Picture Credit: Rooibos Tea Plant]
While it is steadily gaining popularity, delicious and nutritious
Rooibos tea is still relatively unknown to many tea drinkers worldwide. Because Rooibos tea
is healthy and contains very little tannin and no caffeine, it is making a real name for itself
and should have a long future in the global tea market.
(Life is Beautiful).
Varieties of Rooibos Tea
Rooibos is not technically a proper tea, because it is not derived from the Camellia sinensis
plant. Rooibos, however, is not usually referred to as a tisane (herbal infusion). The
Rooibos leaf comes from the plant, a member of the legume family of plants. The Rooibos
bush is a small and shrubby bush, with thin needle-like leaves. The bush only grows
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 2
between ½ to 1 meter tall. On the bush, the leaves are green, but once processed they turn
a deep red from the oxidization of the Rooibos leaves.
Rooibos is available in the market in several forms. Typically, one will get the red leaved
Rooibos either in it’s plain, unflavoured form, or in a flavoured or blended form. Rooibos is
now becoming more widely available in its ‘green’ form as well as Green Rooibos. Even
more recently sees Green Rooibos being flavoured and blended like the typical Red
Rooibos. The difference between the two is that the Green Rooibos is the un-oxidized form
of the Rooibos bush (Teafrog.wordpress.com).
Which is Better: Red or Green Rooibos Tea?
It is known that Green Rooibos tea has higher levels of antioxidants than traditional Rooibos,
but recent studies are proving that both kinds of Rooibos protect against a range of diseases
including cancer and that drinking Green Rooibos is not necessarily better.
“People should drink the kind of Rooibos they enjoy most, since we now know that Rooibos
with a higher antioxidant content does not always provide the best benefits”, recommends
Professor Jeanine Marnewick, manager of the Oxidative Stress Research Centre in the
Faculty of Health and Wellness Sciences at Cape Peninsula University of Technology.
Professor Marnewick, who has been actively involved in Rooibos research over the last
fifteen years, explains that it is not only the level of antioxidants, but also the specific
combination of bio-active compounds in rooibos that are important.
“The health benefits from drinking Rooibos tea will also be different for every person
depending on that person’s overall health status”, she adds.
(SA Rooibos Council).
Health Benefits of Rooibos Tea
Evidence of the health benefits of Rooibos Tea is growing by the day. Health benefits,
especially the ones associated with drinking of Rooibos tea, are most significant. Rooibos
tea contains extremely high levels of antioxidants, powerful substances that fight free
radicals in the bloodstream and keep bodies healthy and strong.
Reduction of insomnia, tension headaches and irritability are well known benefits associated
with Rooibos tea. As a tea with no caffeine, Rooibos drinkers have found that enjoying a
‘cuppa’ before bed helps to relax them and relieves tension, allowing for a great night of
sleep. By helping to normalise tea drinkers’ sleeping habits, Rooibos often reduces
headaches and irritability. Although only supported by anecdotal evidence, relief from colic
and stomach cramps in babies is a well-known benefit fully accepted by the South African
public at large.
Research (not sponsored by CANSA) showed that six cups of Rooibos tea per day
increased glutathione by 100%. Rooibos tea, unique to South Africa, is consumed by
millions every day and could be playing an important role in preventing cancer.
The most important connection found with cancer was the observation that rats given
Rooibos tea as the only source of liquid showed a 500% increase in the master antioxidant,
glutathione in the liver. Made within the body, glutathione cannot be taken as a supplement
as it is destroyed in the gut. There is ample evidence that glutathione fights cancer by
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 3
neutralising carcinogens. For instance, glutathione can bind to the carcinogen aflatoxin,
neutralise it so that it cannot bind to DNA and then facilitate the excretion of the glutathione-
aflatoxin complex.
(Life is Beautiful).
Rooibos Tea and Cancer
The ability of South African herbal teas (Rooibos and
Honeybush extracts) to act as chemopreventors in
skin cancer was highlighted by a South African
research team (Marnewick, et al.) using an animal
model. They showed that topical (external) application
of tea fractions significantly suppressed tumour growth
in mice with skin cancer, when using processed and
unprocessed tea. [Picture Credit: Rooibos Tea]
South African researchers (Van der Merwe, et al.) collaborated to compare the potential of
different kinds of tea (Rooibos, Honeybush, black oolong and green tea) to suppress
mutations, and thereby prevent cancer. Their results confirmed that the phenolic compounds
in herbal tea extracts have a strong anti-mutagenic effect (in vitro study using cell lines). In
vitro’ means taking place in a test tube.
Rooibos Tea and Stress
Scientists at Stellenbosch University are shedding new light on the long-held belief that a
cup of Rooibos helps us to relax and cope better with the stresses of daily life. A research
team at the University’s biochemistry department, led by Professor Amanda Swart, has
produced scientific evidence that Rooibos tea lowers the production of cortisol by the human
body’s adrenal glands. Cortisol is the so-called stress hormone. Lowering cortisol levels
also lowers the effect of the body’s stress response.
They were also able to pinpoint two rare components in Rooibos the two flavonoids called
aspalathin and nothofagin that contribute to this stress-lowering effect. Aspalathin has not
been found in any other plant material, while nothofagin has a very limited distribution in
nature.
(Stellenbosch University; Hong, Lee & Kim).
Rooibos Tea and Hypertension
Rooibos tea has been shown to alleviate hypertension in some cases. The identities of the
compounds in rooibos tea that are attributed to this reduction are unclear. However, a study
in the December 2006 edition of European Journal of Nutrition presents the blood pressure
lowering capabilities of rooibos tea extract. In addition to lowering blood pressure, rooibos
tea was shown to reduce the activity of angiotensin converting enzyme in the May 2010
issue of the journal Public Health Nutrition. These results suggest that rooibos tea is good for
overall cardiovascular health (Hypertension).
Researchers in Pakistan (Khan & Gilani) found that chrysoeriol (a bioactive components of
Rooibos, but usually only present at low levels) acted effectively as a bronchodilator, with an
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 4
associated effect on lowering blood pressure and relieving spasms. Aorta, trachea and other
tissue from rabbits and guinea-pigs were used to illustrate this effect. Chrysoeriol is known
for its antioxidant, anti-inflammatory, antitumour, antimicrobial, antiviral and free radical
scavenging abilities.
Rooibos Tea and Cardiovascular Disease
A study by Dludla, et al. provided evidence that an aqueous extract of fermented rooibos tea
protects cardiomyocytes (the cells that constitute hear muscle), derived from diabetic rats,
against experimentally induced oxidative stress and ischaemia (shortage of oxygen).
In a study by Pantsi, et al. the cardio-protective properties of aqueous rooibos extracts was
clearly demonstrated via the inhibition of apoptosis (cell death) which can be related to the
flavonol content of this unique South African herbal tea.
Swedish researchers found that Rooibos tea could help to promote heart health in humans.
They found that 30 and 60 minutes after drinking 400 ml of Rooibos, the activity of a specific
enzyme (called angiotensin-converting enzyme, or ACE) is significantly inhibited. This
enzyme is believed to be involved in the development of cardiovascular disease, and
therefore ACE inhibitors are used to treat hypertension and heart disease. The research
team could not demonstrate the same effect with green tea and black tea in the group of 17
healthy volunteers who participated in the study. (Persson, et al.).
Rooibos Tea and Cancer, Allergy, Aids and Other Infections
The findings of a study by Kunishiro, Tai & Yamamoto, suggested that Rooibos tea extract
may facilitate the antigen-specific antibody production through selective augmentation of IL-2
generation both in vitro (taking place in a test tube) and in vivo (taking place in a living
organism). Collectively, Rooibos tea intake may be of value in prophylaxis of the diseases
involving a severe defect in Th1 immune response such as cancer, allergy, AIDS, and other
infections.
Rooibos Tea and Diabetes Mellitus Type II
A study by Kawano, et al. suggested that aspalathin in Rooibos tea had beneficial effects on
glucose homeostasis (stabilisation) in type 2 diabetes through stimulating glucose uptake in
muscle tissues and insulin secretion from pancreatic beta-cells.
A study by Uličná, et al. in the Slovak Republic
(2006) found that Rooibos provides effective
protection against oxidative stress in diabetic rats.
These scientists recommend the use of Rooibos for
the prevention and therapy of diabetic vascular
(blood vessel) complications, especially to protect
ocular (eye) membrane systems against
peroxidation (a well-defined mechanism of cellular
damage in both animals and plants that occurs in
vivo during aging and in certain disease states).
[Picture Credit: Rooibos Tea Bags]
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 5
Rooibos Tea and Human Immune Deficiency Virus (HIV)
In their study Nakano, Nakashima & Itoh (1997) showed that 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.
Rooibos Tea and Abdominal Spasm and Diarrhoea
Rooibos tea has been widely used for abdominal spasm
and diarrhoea for many years. It possesses a
combination of dominant K(ATP) channel activation and
weak Ca(++) antagonist mechanisms and hence justifies
its use in hyperactive gastrointestinal disorders.
(Gilani, et al.).
[Picture Credit: Rooibos Tea 2]
Rooibos Tea and Obesity
Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including
flavonoids, considered to be largely responsible for its health promoting effects, including
combatting obesity. The data from a study by Sanderson, et al. showed that hot water
soluble solids from fermented rooibos inhibited adipogenesis (formation of fat or fatty tissue)
and affect adipocyte metabolism, suggesting its potential in preventing obesity.
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.
Rooibos Tea and Immune Function
Research teams in Japan (Ichiyama, et al.) demonstrated that the active ingredients in a
water-soluble fraction of Rooibos restored immune function in immune-suppressed rats.
These results hold significant potential for future research into the immune-boosting
properties of Rooibos that could potentially benefit people living with HIV/AIDS.
Rooibos Tea and Ageing
Researchers (Juráni, et al.) from the Slovak Republic
were able to demonstrate the anti-ageing effect of
Rooibos in Japanese quails. The birds were given
Rooibos to drink and had ground Rooibos added to
their food. The hens on the Rooibos diet laid more
eggs and kept on laying eggs as they were getting
older, compared to quail hens on a standard diet.
[Picture Credit: Rooibos Tea 3]
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 6
Medical Disclaimer
This Fact Sheet is intended to provide general information only and, as such, should not be
considered as a substitute for advice, medically or otherwise, covering any specific situation.
Users should seek appropriate advice before taking or refraining from taking any action in
reliance on any information contained in this Fact Sheet. So far as permissible by law, the
Cancer Association of South Africa (CANSA) does not accept any liability to any person (or
his/her dependants/estate/heirs) relating to the use of any information contained in this Fact
Sheet.
Whilst CANSA has taken every precaution in compiling this Fact Sheet, neither it, nor any
contributor(s) to this Fact Sheet can be held responsible for any action (or the lack thereof)
taken by any person or organisation wherever they shall be based, as a result, direct or
otherwise, of information contained in, or accessed through, this Fact Sheet.
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 7
Sources and References
Baba, H., Ohtsuka, Y., Haruna, H., Lee, T., Nagata, S., Maeda, M. Yamashiro, Y., Shimizu, T.
2009. Studies of anti-inflammatory effects of Rooibos tea in rats. Pediatrics International 51, 700704.
Bramati, et al. 2002. Quantitative characterization of flavonoid compounds in Rooibos tea. Journal of
Agricultural and Food Chemistry, September 2002.
Burt, et al. 1995. Prevelance of hypertension in the US adult population. Hypertension, 1995.
Dludla, P.V., Muller, C.J., Louw, J. Joubert, E., Salie, R., Opoku, A.R. & Johnson, R. 2013. The
car4dioprotective effect of an aqueous extract of fermented rooibos (Aspalathus linearis) on cultured
cardiomyocytes derived from diabetic rats. Phytochmedicine. Nov. pii: S0944-7113(13)00438-8. doi:
10.1016/j.phymed.2013.10.029.
Gilani, A.H., Khan, A.U., Ghayur, M.N., Ali, S.F. & Herzig, J.W. 2006. Antispasmodic effects of
Rooibos tea (Aspalathus linearis) is mediated predominantly through K+-channel activation. Basic
Clin Pharmacol Toxicol, Nov, 99(5):365-73.
Hong, I.S., Lee, H.Y. & Kim, H.P. 2014. Anti-oxidative effects of rooibos tea (Aspalathus linearis) on
immobilization-induced oxidative stress in rat brain. PloS One, Jan. 9(1):e87061.
Ichiyama, K., Tai, A., Yamamoto, I. 2007. Augmentation of antigen-specific antibody production and
IL-120 generation with a fraction from rooibos (Aspalathus linearis) tea. Bioscience, Biotechnology
and Biochemistry 71, 589602.
Juráni, M., Lamošová, D., Máčajová, M., Kostál, L., Joubert, E., Greksák, M. 2008. Effect of
rooibos tea (Aspalathus linearis) on Japanese quail growth, egg production and plasma metabolites.
British Poultry Science 49, 5564.
Khan, A., Gilani, A.H., 2006. Selective broncholdilatory effect of rooibos tea (Aspalathus linearis) and
its flavonoid, chrysoeriol. European Journal of Nutrition 45, 463469.
Kearmey, et al. 2005. Global burden of hypertension: analysis of worldwide data. Lancet, 2005.
Kawano, A., Nakamura, H., Hata, S., Minakawa, M., Miura, Y. & Yagasaki, K. 2009. Hypoglycemic
effect of aspalathin, a rooibos tea component from Aspalathus linearis, in type 2 diabetic model db/db
mice. Phytomedicine, 16(5):437-43.
Kunishiro, K., Tai, A & Yamamoto, I. 2001. Effects of rooibos tea extract on antigen-specific
antibody production and cytokine generation in vitro and in vivo. Biosci Biotechnol Biochem, Oct,
65(10):2137-45.
Life is Beautiful. 2012. A lifestyle booklet published by the Cancer Association of South Africa.
Marnewick, J.L., Joubert, E., Joseph, S., Swanevelder, S., Swart, P., Gelderblom, W.C.A. 2005.
Inhibition of tumour promotion in mouse skin by extracts of rooibos (Aspalathus linearis) and
honeybush (Cyclopia intermedia), unique South African herbal teas. Cancer Letters 224, 193202.
Nakano, M., Nakashima, H. & Itoh, Y. 2011. Anti-human immunodeficiency virus activity of
oligosaccharides from rooibos tea (Aspalathus linearis) extracts in vitro. Leukemia, April 11 suppl
3:128-30.
Pantsi, W.G., Marnewick, J.L., Esterhuyse, A.J., Rautenbach, F. & van Rooyen, J. 2011. Rooibos
(Aspalathus linearus) offers cardiac protection against ischaemia/reperfusion in the isolated perfused
rat heart. Phytomedicine, 18(14):1220-8.
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
Approved for Distribution by Ms Elize Joubert, Acting CEO
July 2014 Page 8
Persson, I.A., Persson, K., Hägg, S., Andersson, R.G.G. 2010. Effects of green tea, black tea and
Rooibos tea on angiotensin-converting enzyme and nitric oxide in healthy volunteers. Public Health
Nutrition 3(5), 730737.
Rooibos Tea
Hemera Technologies/PhotoObjects.net/Getty Images
Rooibos Tea 2
https://www.google.co.za/search?q=rooibos+tea&source=lnms&tbm=isch&sa=X&ei=FWoUU4GpMYe
mhAfup4Fw&ved=0CAcQ_AUoAQ&biw=1120&bih=661&dpr=0.9#facrc=_&imgdii=_&imgrc=7Lv5FgE
A3hbLuM%253A%3BiNW_G4DYDBK6BM%3Bhttp%253A%252F%252Fnancycurteman.files.wordpre
ss.com%252F2013%252F06%252Frooibos-tea-
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%252Fsouth-african-foods-in-murder-casts-a-spell%252F%3B349%3B247
Rooibos Tea Bags
https://www.google.co.za/search?q=rooibos+tea&source=lnms&tbm=isch&sa=X&ei=cVa2U6HlFqjj4Q
SQ_IGgAg&sqi=2&ved=0CAYQ_AUoAQ&biw=1517&bih=714&dpr=0.9#facrc=_&imgdii=_&imgrc=hm
osBy9vb_fr9M%253A%3B49JHoweddBDW_M%3Bhttp%253A%252F%252Fwww.liffiton.com%252Fs
outhafrica%252Fimages%252Frooibos.jpg%3Bhttp%253A%252F%252Fwww.liffiton.com%252Fsouth
africa%252Ffood.php3%3B250%3B179
Rooibos Tea Plant
https://www.google.co.za/search?q=green+rooibos+tea&source=lnms&tbm=isch&sa=X&ei=VRYDU8
X9Fcry7Ab1zYCgBw&ved=0CAcQ_AUoAQ&biw=1517&bih=714&dpr=0.9#facrc=_&imgdii=_&imgrc=
8rkUghygqbFSKM%253A%3BebEn1Jr4i_FObM%3Bhttp%253A%252F%252Fwww.driefonteinrooibos
.co.za%252Fdriefontein-fairtrade-
rooibos%252Fimages%252Frooibosplant.jpg%3Bhttp%253A%252F%252Fwww.driefonteinrooibos.co
.za%252Frooibos.php%3B250%3B444
Rooibos Tea Plantation
https://www.google.co.za/search?q=green+rooibos+tea&source=lnms&tbm=isch&sa=X&ei=VRYDU8
X9Fcry7Ab1zYCgBw&ved=0CAcQ_AUoAQ&biw=1517&bih=714&dpr=0.9#facrc=_&imgdii=nvNz-
x8Ak91g1M%3A%3BQ5tH7ijbUw1-oM%3BnvNz-x8Ak91g1M%3A&imgrc=nvNz-
x8Ak91g1M%253A%3BG5gGJbyokd8xyM%3Bhttp%253A%252F%252Fwww.globalfusiontrading.co
m%252Flibrary%252Fcollage.jpg%3Bhttp%253A%252F%252Fwww.globalfusiontrading.com%252Fro
oibostea.htm%3B540%3B259
Sanderson, M., Mazibuko, S.E., Joubert, E., de Beer, D., Johnson, R., Pheiffer, C., Louw, J. &
Muller, C.J. 2014. Effects of fermented rooibos (Aspalathus linearis) on adipocyte differentiation.
Phytomedicine, Jan, 21(2):109-17.
SA Rooibos Council
http://www.health24.com/Diet-and-nutrition/Beverages/Is-green-rooibos-better-than-red-20130210
Stellenbosch University
http://dx.doi.org/10.1016/j.jsbmb.2011.11.003).
Teafrog.wordpress.com
http://teafrog.wordpress.com/2008/03/21/rooibos-tea-different-types/
Uličná, O., Vančová, O., Božek, P., Čársky, J., Šebeková, K., Boor, P., Nakano, M., Greksák, M.
2006. Rooibos tea (Aspalathus linearis) partially prevents oxidative stress in streptozotocin-induced
diabetic rats. Physiology Research 55, 157164.
Van der Merwe, J.D., Joubert, E., Richards, E.S., Manley, M., Snijman, P.W., Marnewick, J.L.,
Gelderblom, W.C.A. 2006. A comparative study on the antimutagenic properties of aqueous extracts
Researched and Authored by Prof Michael C Herbst
[D Litt et Phil (Health Studies); D N Ed; M Art et Scien; B A Cur; Dip Occupational Health]
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of Aspalathus linearis (rooibos), different Cyclopia spp. (honeybush) and Camellia sinensis teas.
Mutation Research 611, 4253.
Wikipedia
http://en.wikipedia.org/wiki/Rooibos
ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Exposure to chronic psychological stress may be related to increased reactive oxygen species (ROS) or free radicals, and thus, long-term exposure to high levels of oxidative stress may cause the accumulation of oxidative damage and eventually lead to many neurodegenerative diseases. Compared with other organs, the brain appears especially susceptible to excessive oxidative stress due to its high demand for oxygen. In the case of excessive ROS production, endogenous defense mechanisms against ROS may not be sufficient to suppress ROS-associated oxidative damage. Dietary antioxidants have been shown to protect neurons against a variety of experimental neurodegenerative conditions. In particular, Rooibos tea might be a good source of antioxidants due to its larger proportion of polyphenolic compounds. An optimal animal model for stress should show the features of a stress response and should be able to mimic natural stress progression. However, most animal models of stress, such as cold-restraint, electric foot shock, and burn shock, usually involve physical abuse in addition to the psychological aspects of stress. Animals subjected to chronic restraint or immobilization are widely believed to be a convenient and reliable model to mimic psychological stress. Therefore, in the present study, we propose that immobilization-induced oxidative stress was significantly attenuated by treatment with Rooibos tea. This conclusion is demonstrated by Rooibos tea's ability to (i) reverse the increase in stress-related metabolites (5-HIAA and FFA), (ii) prevent lipid peroxidation (LPO), (iii) restore stress-induced protein degradation (PD), (iv) regulate glutathione metabolism (GSH and GSH/GSSG ratio), and (v) modulate changes in the activities of antioxidant enzymes (SOD and CAT).
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Diabetic cardiomyopathy (DCM) is a disorder of the heart muscle that contributes to cardiovascular deaths in the diabetic population. Excessive generation of free radicals has been directly implicated in the pathogenesis of DCM. The use of antioxidants, through dietary supplementation, to combat increased cellular oxidative stress has gained popularity worldwide. Aspalathus linearis (rooibos) is a popular herbal tea that contains a novel antioxidant, aspalathin. Literature has reported on the antidiabetic, anti-inflammatory and free radical scavenging effects of rooibos. However, its protective effect against DCM has not been established. Therefore, this study investigated whether chronic exposure to an aqueous extract of fermented rooibos (FRE) has an ex vivo cardioprotective effect on hearts obtained from streptozotocin (STZ) induced diabetic rats. Adult Wistar rats were injected with 40 mg/kg of STZ. Two weeks after STZ injection, cardiomyocytes were isolated and cultured. Cultured cardiomyocytes were treated with FRE (1 and 10 μg/ml), vitamin E (50 μg/ml), and n-acetyl cysteine (1 mM) for 6 h, before exposure to either hydrogen peroxide (H2O2) or an ischemic solution. Cardiomyocytes exposed to H2O2 or an ischemic solution showed a decrease in metabolic activity and glutathione content with a concomitant increase in apoptosis and intracellular reactive oxygen species. Pretreatment with FRE was able to combat these effects and the observed amelioration was better than the known antioxidant vitamin E. This study provides evidence that an aqueous extract of fermented rooibos protects cardiomyocytes, derived from diabetic rats, against experimentally induced oxidative stress and ischemia.
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Rooibos (Aspalathus linearis) contains a rich complement of polyphenols, including flavonoids, considered to be largely responsible for its health promoting effects, including combatting obesity. The purpose of this study was to examine the effect of fermented rooibos hot water soluble solids on in vitro adipocyte differentiation by using differentiating 3T3-L1 adipocytes. Hot water soluble solids were obtained when preparing an infusion of fermented rooibos at "cup-of-tea" strength. The major phenolic compounds (>5mg/g) were isoorientin, orientin, quercetin-3-O-robinobioside and enolic phenylpyruvic acid-2-O-β-d-glucoside. Treatment of 3T3-L1 adipocytes with 10μg/ml and 100μg/ml of the rooibos soluble solids inhibited intracellular lipid accumulation by 22% (p<0.01) and 15% (p<0.05), respectively. Inhibition of adipogenesis was accompanied by decreased messenger RNA (mRNA) expression of PPARγ, PPARα, SREBF1 and FASN. Western blot analysis exhibited decreased PPARα, SREBF1 and AMPK protein expression. Impeded glycerol release into the culture medium was observed after rooibos treatment. None of the concentrations of rooibos hot water soluble solids was cytotoxic, in terms of ATP content. Interestingly, the higher concentration of hot water soluble solids increased ATP concentrations which were associated with increased basal glucose uptake. Decreased leptin secretion was observed after rooibos treatment. Our data show that hot water soluble solids from fermented rooibos inhibit adipogenesis and affect adipocyte metabolism, suggesting its potential in preventing obesity.
Article
Rooibos, a unique South African herbal tea, is known to be an important source of unique polyphenolic compounds. In the present study we have quantified the main polyphenolic compounds in both fermented/traditional and unfermented/"green" rooibos (Aspalathus linearis) and evaluated its cardioprotective effects against ischaemia/reperfusion injury. Male Wistar rats consumed aqueous rooibos and green tea (Camellia sinensis) extracts (2%, w/v) for 7 weeks before their hearts were rapidly excised and perfused in a working heart perfusion apparatus. The results showed that the rooibos supplemented hearts significantly improved aortic output recovery after reperfusion when compared to the green tea supplemented hearts. Additionally, we showed that the rooibos extracts, containing the highest amount of flavonols, significantly decreased the level of cleaved caspase-3 and PARP, both pro-apoptotic proteins, during reperfusion when compared to green tea. Green tea supplementation increased phosphorylation of total PKB/Akt, Akt (threonine 308) and Akt (serine 473). The rooibos extracts did not cause significant change in the levels of the pro-survival PKB/Akt (threonine 308 and serinet 473). The GSH/GSSG ratio in the hearts of the green tea supplemented group was significantly (p<0.05) lower when compared to RF (37.78±28.63), RU (33.20±4.13) and C (45.50±14.96). The results clearly demonstrate the cardio-protective properties of aqueous rooibos extracts via the inhibition of apoptosis which can possibly be related to the flavonol content of this unique South African herbal tea.
Article
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.
Article
Effects of aspalathin, a green rooibos tea component, on glucose metabolism were studied in vitro and in vivo. We first examined the effect of aspalathin on glucose uptake by cultured L6 myotubes and on insulin secretion from cultured RIN-5F pancreatic beta-cells in vitro, and then investigated the effect of dietary aspalathin on fasting blood glucose level and conducted an intraperitoneal glucose tolerance test (IPGTT) using type 2 diabetes model mice in vivo. Aspalathin dose-dependently and significantly increased glucose uptake by L6 myotubes at concentrations 1-100 microM. It also significantly increased insulin secretion from cultured RIN-5F cells at 100 microM. Dietary aspalathin (0.1-0.2%) suppressed the increase in fasting blood glucose levels of db/db mice for 5 weeks. In IPGTT, aspalathin improved impaired glucose tolerance at 30, 60, 90, and 120 min in db/db mice. These results suggest that aspalathin has beneficial effects on glucose homeostasis in type 2 diabetes through stimulating glucose uptake in muscle tissues and insulin secretion from pancreatic beta-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
Rooibos tea contains a large amount of flavonoids and acts as a potent antioxidant. In this study, we examined the effects of Rooibos tea extract on antigen-specific antibody production and cytokine generation in vitro and in vivo. The primary in vitro anti-ovalbumin (anti-OVA) or sheep red blood cell (SRBC) antibody production in murine splenocytes was markedly stimulated by the addition of the tea extract at concentrations of 1-100 microg/ml. On the other hand, a nonspecific antibody response elicited with lipopolysaccharide (LPS) in purified splenic B-cells was not modified by the extract. Rooibos tea extract caused an increase in the generation of interleukin 2 (IL-2) both in OVA- and anti-CD3-primed splenocytes at concentrations ranging from 10 microg/ml to 1000 microg/ml. In contrast, this tea extract suppressed the generation of interleukin 4 (IL-4) in OVA-primed splenocytes. Moreover, the reduction of OVA-induced antibody production in serum of the cyclosporin A (CyA) -treated rats can be significantly restored and the IL-2 generation in murine splenocytes was stimulated, following oral administrations of Rooibos tea extract. Thus, our findings suggested that Rooibos tea extract may facilitate the antigen-specific antibody production through selective augmentation of IL-2 generation both in vitro and in vivo. Collectively, Rooibos tea intake may be of value in prophylaxis of the diseases involving a severe defect in Th1 immune response such as cancer, allergy, AIDS, and other infections.
Article
Rooibos tea originates from the leaves and stems of the indigenous South African plant Aspalathus linearis. It has gained much attention for clinical purposes in the case of nervous tension, allergies (dermatitis), and various indigestive problems. Recently, antioxidative activity was also attributed to the tea on the basis of its flavonoid content. Therefore, an HPLC method using a C(18) reversed phase column was developed for the assay of 10 flavonoids in aqueous and methanolic infusions. Main compounds determined were the dihydrochalcone aspalthin, rutin, and orientin, and their content was in the range of 1.0 to 1.3 mg/g. The identity of detected flavonoids was confirmed by comparing their retention times and UV and MS spectra with those of corresponding standards. In addition, the MS analysis showed evidence of the presence of other compounds such as nothofagin, dihydroisoorientin, and dihydroorientin.
Article
Reliable information about the prevalence of hypertension in different world regions is essential to the development of national and international health policies for prevention and control of this condition. We aimed to pool data from different regions of the world to estimate the overall prevalence and absolute burden of hypertension in 2000, and to estimate the global burden in 2025. We searched the published literature from Jan 1, 1980, to Dec 31, 2002, using MEDLINE, supplemented by a manual search of bibliographies of retrieved articles. We included studies that reported sex-specific and age-specific prevalence of hypertension in representative population samples. All data were obtained independently by two investigators with a standardised protocol and data-collection form. Overall, 26.4% (95% CI 26.0-26.8%) of the adult population in 2000 had hypertension (26.6% of men [26.0-27.2%] and 26.1% of women [25.5-26.6%]), and 29.2% (28.8-29.7%) were projected to have this condition by 2025 (29.0% of men [28.6-29.4%] and 29.5% of women [29.1-29.9%]). The estimated total number of adults with hypertension in 2000 was 972 million (957-987 million); 333 million (329-336 million) in economically developed countries and 639 million (625-654 million) in economically developing countries. The number of adults with hypertension in 2025 was predicted to increase by about 60% to a total of 1.56 billion (1.54-1.58 billion). Hypertension is an important public-health challenge worldwide. Prevention, detection, treatment, and control of this condition should receive high priority.