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Rooibos Tea and Health: A Systematic Review of the Evidence from the Last Two Decades


Abstract and Figures

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.
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Nutrion and Food Technology: Open Access
ISSN 2470-6086 | Open Access
Nutr Food Technol Open Access | NFTOA
Rooibos Tea and Health: A Systemac Review of the Evidence from the Last
Two Decades
Timothy Bond J1, and Emma Derbyshire J2*
1Tea Advisory Panel; Tea and Herbal Soluons, Bedford, United Kingdom
2Nutrional Insight, Epsom, Surrey, United Kingdom
Received: 08 May, 2020 | Accepted: 29 May, 2020 | Published: 05 Jun, 2020
Volume 6 - Issue 1
e health properties of rooibos tea have been ascribed to it being
caeine free and its abundant phenolic composition [9,10]. Rooibos
tea has a divergent polyphenol prole and is a rare dietary source of
dihydrochalcones-aspalathin and nothofagin which possess potent
antioxidant actions [11-13]. Aspalathin and nothofagin are the
main avonoids in Rooibos tea and have a particularly strong anti-
oxidative activity, though aspalathin tends to be lower in fermented
than unfermented foods [10,12,14]. is is relevant to health as the
antioxidants present in rooibos may help to protect against oxidative
stress which is known to induce inammation and other health
conditions [10,15].
Rooibos tea is naturally slightly sweet with caramel, oral, honey
and woody undertones [16]. It has been used both as a tisane, as
well as consumed traditionally for medicinal purposes and has been
popular in South Africa for generations [5,11]. Traditionally, rooibos
has been used for its medicinal properties in South Africa to help
alleviate allergies, asthma, dermatological conditions and infantile
colic [17]. Both the leaves and ne stems can be used as herbal tea,
predominantly in the traditional ‘fermented’ (oxidised/aerated) red-
brown form but also in its ‘unfermented’ (unoxidized/aerated) green
form [18]. Rooibos tea can also be extracted and dried, spray-dried/
freeze-dried to form powdered rooibos tea extract (RTE) which is also
abundant in polyphenols [5]. Traditionally fermented beverages such
as Kombucha have been produced eectively using rooibos leaves [19].
*Corresponding author: Emma Derbyshire J, Nutrional Insight, Epsom, Surrey, United Kingdom, E-mail: emma@nutri
Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades. Nutr Food
Technol Open Access 6(1):
Copyright: © 2020 Bond TJ, et al. This is an open-access arcle distributed under the terms of the Creave Commons Aribuon License,
which permits unrestricted use, distribuon, and reproducon in any medium, provided the original author and source are credited.
An expanse of research has invesgated the eects of black and green teas in relaon to aspects of health. Rooibos tea, also known as Red bush is
derived from the South African Cape fynbos plant, Aspalathus linearis, and is caeine 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 eects of Rooibos tea through a systemac review of the literature. A PUBMED search was undertaken (2000 up to June 2020) for human and
laboratory studies invesgang the ecacy of Rooibos in relaon to health. Seven human studies and 49 laboratory studies were idened. Overall
Rooibos tea consumpon seems to benet the lipid and redox proles of those at risk of cardiovascular disease. It also appears to possess other
promising ‘general’ eects on glycaemic control, bone, liver, cognive and respiratory health. Ongoing research using standardised intervenons is
now needed to help formulate congruent conclusions that are relevant to public health.
Keywords: Rooibos tea; Poly phenols; Health; Evidence-base
e pattern of health and disease is changing-continued shis in
longevity mean that multimorbidity and ‘disease clusters’ are now
on the rise [1]. It is well appreciated that lifestyle e.g. alterations in
diet, physical activity and avoiding smoking can improve outcomes
for medical conditions such as cardiovascular disease [2]. ere is
already an extensive body of evidence showing that drinking two
to three cups of tea daily could be benecial for health, including
reduced risk of cardiac death, coronary artery disease, stroke, type 2
diabetes mellitus and total mortality [3]. Benecial inter-relationships
have also been observed for several cancers, cognitive, skeletal and
maternal health [3]. Most of this research has focused on green, black
and oolong tea [4].
“Rooibos” is Afrikaans for “red bush” [5]. It is prepared from
unfermented and fermented plant material from the Cape fynbos
plant, Aspalathus linearis [6,7]. In South Africa, the proportion of
black tea drinkers has declined between 2011 and 2015, from 58.6%
to 51.5% whilst the percentage of Rooibos consumers has risen from
29.4% in 2011 to 30.9% in 2015.8 e demand for Rooibos tea is also
extending further aeld with South Africa exporting Rooibos tea to
more than 30 countries [8].
Such shis in consumption habits are being attributed to rising
awareness and interest in the health properties of Rooibos tea [8].
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provided six cups of fermented, traditional Rooibos daily (one tea bag
in 200ml with an infusion time of 5 minutes) for 6 weeks [21].
ree studies reported positive ndings in relation to aspects of
health [21,22,25]. One study used ex vivo samples from atopic adults
showing that extracts prepared from both fermented and unfermented
Rooibos inhibited basophil activation, an eect that was stronger using
the extract of fermented Rooibos [22]. ese ndings are aligned with
that from earlier laboratory models [26] and indicate that Rooibos
appears to possess anti-allergic eects by inhibiting antigen- and
calcium ionophore-stimulated degranulation. One of the largest trials
conducted on 40 participants observed signicant increases in plasma
total polyphenol levels, reductions in markers of lipid peroxidation,
improvements in lipid proles (low-density lipoprotein declined and
high-density lipoprotein increased) and redox status [21]. Eects were
observed aer drinking six cups of fermented (traditional) Rooibos
tea daily for 6 weeks [21]. Another trial looking into underpinning
mechanisms showed that freshly prepared Rooibos tea (made with 10g
tea in 400ml boiled water for 10min using a tea filter) signicantly
inhibited angiotensin-converting enzyme (ACE) activity, 30 and 60
minutes aer ingestion, indicating possible cardiovascular eects via
the inhibition of ACE activity [25].
Two human studies focused on aspects of metabolite absorption
and bioavailability [14,20]. In a human crossover study where 500 ml
unfermented Rooibos tea was ingested aspalathin (a dihydrochalcone
C-glucoside) was found to be particularly bioavailable [20]. An earlier
bioavailability trial comprised of 10 adults drinking a similar quantity
of Rooibos tea also showed that most metabolites were absorbed either
via the small or large intestine [14]. In two trials involving Rooibos
tea ingestion, one did not show any signicant eects on renal stone
formation [23] and the other showed that rooibos tea and plain water
similarly rehydrated 23 athletes [24].
Laboratory Studies
A wealth of research has studied the health eects and potential
mechanisms of Rooibos tea and its associated avonoids. Forty-nine
laboratory/mechanistic studies were identied and published over
the last two decades. Of these, eleven focused on aspects of oxidative
stress and antioxidant activity [10,12,27-35]. Four studies observed
improvements in dimensions of sperm function [36-39]. is included
enhanced sperm velocity, vitality, acrosome structure and membrane
integrity [36 38]. ese eects were attributed to high levels of
antioxidants found in Rooibos, sequestering reactive oxygen species
and lipid peroxidation [38,39].
Other research has focused on aspects of metabolic health. Some
work has found associations between unfermented/green Rooibos
extract and improvements in fasting blood glucose levels using type
2 diabetic mice [40]. Similarly, In vitro work showed that Rooibos
extract high in aspalathin had a sustained glucose lowering eect [41].
Other work indicated that aspalathin or nothofagin avonoids inhibit
glucose-mediated vascular hyperpermeability and inammation [42].
A further seven studies showed that Rooibos could improve insulin
resistance and have antidiabetic potential [43-49].
With regard to potential mechanisms aspalathin found in Rooibos
stimulated glucose uptake in muscle tissues and insulin secretion from
pancreatic beta-cells in a type 2 diabetes mouse model [48]. Work
by Ulicna O, et al. (2006) found that the antioxidant compounds in
Rooibos tea prevented oxidative stress concluding that it could be a
suitable adjunctive therapy for diabetic vascular conditions [49]. One
study using a cell model found that a fermented Rooibos infusion
prepared at ‘cup-of-tea’ strength and the soluble matter of the infusion
Increasingly, rooibos has been studied in human populations,
mainly for its antioxidant and cardio protective properties [14,20,21].
Alongside this, over the years a growing body of laboratory and
mechanistic studies have investigated how rooibos tea could impact
on health. Given the gaining popularity of rooibos tea, the current
publication collates evidence from human and laboratory studies,
published over the last two decades. Such a review does not appear
to have been undertaken previously. e present review focuses
on rooibos tea which has been gaining popularity both in its native
province the Western Cape of South Africa and worldwide in recent
years [8].
e National Centre for Biotechnology Information (NCBI) search
engine (PubMed) was used to extract relevant publications. Two
search phases were undertaken. In Phase 1 English-language human
studies published between January 2000 (month start) and June 2020
(month start) were screened. Publications were included if they used
Rooibos tea or RTE and studied a named health outcome. Studies were
excluded if they were conducted with children due to potential ethical
issues, focused on chemical proling, used a multi-intervention or did
not specify a distinctive health outcome. External health conditions
such as skin healing were also excluded.
e search terms “Rooibos”, “Red bush” or “Aspalathus linearis
were used. ED and TB identied the scientic publications. In Phase
1 the database search was restricted to human studies. In Phase 2 the
search was restricted to laboratory studies the same search terms were
applied. Data extracted from each human study included: (1) Study
(author, year, location and reference number), (2) Subjects (age,
gender, number), (3) Study design (type), (4) Tea intervention (type)
(5) Intervention type (dosage) and (6) Main ndings. Data extracted
from each laboratory/mechanistic study included: (1) Study (author,
year and reference number), (2) Study Design, (3) Intervention (type),
(4) Main outcome and (5) Main ndings.
In Phase 1 using the applied search terms 47 human studies were
identied. Of these, three were review papers, three had methods that
were unclear or not fully reported, ve were laboratory studies and 29
irrelevant as they did not investigate health outcomes. Subsequently,
aer these exclusions seven human studies were included in the nal
review. Of the human studies three were conducted in South Africa
[21-23], one in the USA [24], one in Italy [14], one in Sweden [25] and
one in Germany [20].
In Phase 2 91 laboratory studies were rst identied. Two of these
were excluded due to them being multi-interventions, two focused
on external (skin) conditions, four were review papers, seven had
methods that were unclear or not fully reported and 27 were irrelevant
as they did not measure health outcomes. is resulted in 49 laboratory
studies being included in the main paper. e algorithm of qualifying
papers is shown in gure 1.
Human Studies
Seven human studies were identied using Rooibos tea preparations
(Table 1) [14,20-25]. Sample sizes ranged from eight to 40 subjects.
Interventions also varied between studies. Most studies used Rooibos
infusions that had been seeped for approximately 10 minutes in hot
water infusions [20,23,25]. One study provided Rooibos tea (two 125
ml cups each made with two tea bags, low mineral content water and
a brewing time of 5 min at 90oC) for 30 days [23]. Other research
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Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
Nutr Food Technol Open Access 6(1): 3
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PubMed and Reference Search. “Rooibos” or “Red
bush” or “Aspalathus linearis” (2000-2020)
47 Human Studies
91 Laboratory Studies
40 papers excluded due to:
A review-3
Laboratory study-5
Methods not fully reported or unclear-3
Other (irrelevant)-29
42 papers excluded due to:
A review-4
External health conditions-2
Methods not fully reported or unclear-7
Other (irrelevant)-27
7 studies included
(Table 1)
(Table 2)
Figure 1: Algorithm for database search results.
inhibited adipogenesis, also implying a potential role in obesity
prevention [50]. ese ndings imply a potential role in glycaemic
Other research suggests benecial eects on aspects of bone health
[51,52], hepatoprotection [31,43,44,53], allergic response [26] and
immune function [54,55]. Rooibos tea has been found to improve
osteoblast activity [52] while fermented Rooibos was found to inhibit
osteoclasts and associated gene expression [51]. Some work has
discovered that Rooibos tea could help to stabilise the liver from injury
[12]. In another study Rooibos extract eased induced liver injury by
suppressing oxidative stress and the formation of pro-inammatory
cytokines [31]. A laboratory model showed that Rooibos tea acted as a
‘hepatoprotector’ showing histological regression of liver cirrhosis and
steatosis in an experimental model of liver cirrhosis [53].
Alongside these ndings, other evidence from laboratory
models suggests inter-relationships between Rooibos ingestion
and improvements in spatial memory, [56] reduced brain oedema
and neuronal apoptosis, [57] reductions in esophageal papilloma
size, [58] antispasmodic eects, [59,60] bronchodilation, [60] and
chemoprotection [61,62].
Overall there appears to be a growing body of evidence relating to
Rooibos tea and various biological health outcomes. e largest body
of evidence is currently derived from laboratory and mechanistic
studies although human research is emerging. Research focusing on
cardiovascular health looks particularly promising. e trial conducted
by Marnewick JL, et al. (2011) [21] was well conducted showing that
drinking six cups of fermented, traditional rooibos daily signicantly
improved the lipid prole and redox status which is relevant to adults
at risk for developing cardiovascular disease. Elsewhere other review
ndings also conclude that Rooibos appears to have preventative and
complementary therapeutic benets in the context of cardiovascular
disease [63].
e antioxidant properties of Rooibos tea and its ability to sequester
oxidative stress are also prominent in the research [27,34,49,64]. e
polyphenols aspalathin (present at >5 mg/l) and nothofagin (present
at <1 mg/L) found in Rooibos tea have been attributed to some of its
health benets [65,66]. Antioxidants such as these suppress oxidative
stress in the body which has been implicated in the pathophysiology of
certain diseases including Alzheimer’s disease [67]. Several laboratory
studies concentrated on aspects of sperm function [36-39]. Fermented
Rooibos, in particular, was found to improve several dimensions
including sperm concentration, viability and motility [38]. ese
ndings imply that Rooibos consumption could have a role to play
in supporting male fertility, namely by sequestering oxidative damage
by improving antioxidant defence mechanisms and subsequently
improving the sperm quality and function [39]. Human randomised
controlled trials are now needed to explore this.
Fermented Rooibos extracts have been found to inhibit human
basophil activation [22] a nding that supports earlier laboratory
research showing that Rooibos has allergen-dependent inhibitory
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Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
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Study (Author- Year-
Locaon- Reference
Subjects (age-
gender- number) Study design Tea Intervenon
(type) Tea Intervenon (dosage)
Main ndings (with any
reported signicant
Pedre s- et al. (2020)
[22] South Africa n=9 atopic adults
Used ex vivo
samples from
atopic paents
Fermented and
Rooibos extracts
Three opmised decreasing
concentraons of unfermented
(0.1- 0.03 or 0.01mg/ml) or
fermented Rooibos extracts
(0.05- 0.017 or 0.005mg/
ml) were used during the
Rooibos extracts inhibited
basophil acvaon in a
dose-dependent non-
allergen specic manner.
The inhibitory eect was
stronger using fermented
versus unfermented extract.
Rodgers A- et al. (2016)
[23] South Africa
n=8 calcium
oxalate (CaOx)
renal stone
30-day trial
Green tea from
Japan or Rooibos
from South Africa
Samples were prepared for
analysis by adding 250 ml of
boiling water to each teabag.
These were removed aer
brewing mes of 5 and 10 min.
Ingeson of Rooibos tea
does not reduce the risk
factors for CaOx stone
formaon in humans-
Breiter T- et al. (2011)
[20] Germany
n=12 healthy
24-hr crossover
Dierent Rooibos
Rooibos or a
10g Rooibos extracted with
500ml boiling water seeped from
10 minutes
On average a total of
0.76nmol of avonoids were
detected during their peak
concentraon aer intake of
the Rooibos tea- accounng
for 0.26% compared to the
total amount of avonoids
Marnewick JL- et al.
(2011) [21] South
n=40 volunteers 6-week trial Fermented/
tradional Rooibos
Six 200 ml cups daily (one tea
bag per cup; 5 minute infusion
Consumpon of fermented-
tradional Rooibos
signicantly improved the
lipid prole as well as redox
status- both relevant to
heart disease- in adults
at risk for developing
cardiovascular disease.
Persson IA- et al.
(2010) [25] Sweden
n=17 healthy
Three phase
crossover study.
Green tea- black
tea or Rooibos tea
(South Africa)
10g tea in 400ml 10 min infusion
freshly prepared and cooled so
the parcipants could drink it
within approximately 2min.
Oral intake of a single dose
of Rooibos tea signicantly
inhibited ACE acvity aer
30 min (p< 0.01) and aer
60 min (p< 0.05).Rooibos
tea may have cardiovascular
eects through inhibion of
ACE acvity.
Uer AC- et al. (2010)
[24] USA n=23 athletes
cross-over design
with three
dierent study
Rooibos tea-
beverage or boled
water (placebo)
NR (restricted access paper)
Rooibos tea was no more
eecve in promong
rehydraon than plain
Stalmach A- et al.
(2009) [14] Italy n=10 volunteers Bioavailability
Fermented or
Rooibos tea
The overall metabolite
levels excreted were 82
and 352 nmol- accounng
for 0.09 and 0.22% of the
avonoids in the fermented
and unfermented drinks-
respecvely. Most of the
aspalathin metabolites
were excreted within 5 h of
tea consumpon- implying
absorpon in the small
Table 1: Rooibos Tea & Health: Evidence from Human Trials.
Key: ACE- Angiotensin-Converng Enzyme; NR- Not Reported.
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Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
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Study (Author-
Year- Reference
Mechanisc study
Rooibos tea Intervenon
(type) Main outcomes Main ndings
Lawal AO- et al.
(2019) [27]
In vitro anoxidant
Aqueous extracts of
fermented Rooibos- green
Rooibos and Honey bush.
Oxidave stress
Herbal extracts oered protecon against diesel
exhaust parcles that induced oxidave stress and
inammatory response.
SE- al. (2019) [43]
In vitro- using liver
cells Aspalathin treatment Hepac insulin
Aspalathin improved insulin signalling and
mitochondrial bioenergecs.
SE- et al. (2019)
In vitro- using rats Aspalathin-enriched green
Rooibos extract
Hepac insulin
Green Rooibos extract showed potenal in
ameliorang hepac insulin resistance by improving
insulin sensivity via PI3K/AKT- FOXO1 and AMPK-
mediated pathways.
Morishita Y- et al.
(2019) [26]
Rat basophilic
leukaemia cells
Quercen- luteolin and
chrysoeriol were mixed
in the rao that occurs in
Rooibos tea extract
Allergic response
The mixture inhibited angen- and calcium
ionophore-smulated degranulaon to the same
degree as whole Rooibos tea extract. Flavonoids
underly the degranulaon inhibitory acvity of
rooibos tea.
Orlando P- et al.
(2019) [28]
Diabec and non-
diabec vervet
90 mg/kg of aspalathin-rich
green Rooibos extract for 28
Oxidave stress- LDL
Green Rooibos extract could counteract hyperglycemia-
oxidave stress and dyslipidemia- lowering
cardiovascular risk factors linked to diabetes.
Pyrzanowska J- et
al. (2019) [56]
male rats
Infusions- prepared using
1- 2 and 4 g of ‘fermented’
Rooibos leaves for 100 ml of
hot water.
Spaal memory
All treated rats showed improvement of long-
term spaal memory. Striatal dopamine and
3-methoxytyramine levels were increased in treated
Uličná O- et al.
(2019) [12]
Rats with carbon
induced liver
Rooibos tea administraon Anoxidant acvity-
liver damage
Improved histological features support the view of
anoxidant and membrane-stabilizing acvity of
Rooibos tea. This may play a role in the protecon of
the liver from injury caused by known toxins.
Dludla PV- et al.
(2018) [45] Diabec mice Aspalathin intervenon Glycaemic control
Meormin and a high dose (130 mg/kg) of
aspalathin ameliorated diabec symptoms i.e.
abnormally raised fasng plasma glucose levels.
Moosa S- et al.
(2018) [51] Murine study Rooibos tea extract Bone health
Fermented Rooibos had a more potent inhibitory
eect on osteoclasts and associated gene expression
than unfermented Rooibos extract.
Yang S- et al. (2018)
[71] Murine study Aspalathin and nothofagin
from green Rooibos Sepsis Aspalathin and nothofagin appear to protect mice
against sepsis-triggered renal injury.
Akinrinmade 0- et
al. (2017) [57]
Adult male Wistar
Fermented Rooibos herbal
Brain oedema-
neuronal apoptosis
Long-term consumpon of fermented Rooibos tea
signicantly reduced brain oedema and neuronal
Dludla PV- et al.
(2017) [46] Diabec mice Aspalathin intervenon Glycaemic control
Aspalathin maintained cellular homeostasis and
protected the myocardium against hyperglycemia-
induced oxidave stress by acvang Nrf2 and its
downstream target genes.
Johnson R- et al.
(2017) [72] In vitro Aspalathin intervenon Cardioprotecon Aspalathin co-treatment could protect the
myocardium from Dox-induced cardiotoxicity.
Johnson R- et al.
(2017) [73]
model Aspalathin intervenon Cardioprotecon
Aspalathin acvated Adipoq and modulated the
expression of Pparγ and Srebf1/2- decreasing
inammaon via Il6/Jak2 pathway- which increased
expression of Bcl2 prevenng myocardium apoptosis.
Table 2: Rooibos Tea and Health: Evidence from Laboratory Studies.
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Ros-Santaella JL- et
al. (2017) [36] Boar semen
Four concentraons both of
fermented and unfermented
Rooibos extracts
Sperm funcon
Rooibos extract enhanced sperm velocity- protected
acrosome structure- and preserved membrane
integrity during semen storage.
Johnson R- et al.
(2017) [74] In vitro Aspalathin intervenon Cardioprotecon
Aspalathin increased glucose oxidaon and
modulated fay acid ulizaon and induced a
favourable substrate shi in H9c2 cardiomyocytes
exposed to high glucose.
Nash LA- et al
(2016) [52] Saos2 cells
Rooibos- green and black tea
-normalized to 1 or 10 μg /
mL gallic acid equivalents.
Bone health Green- black and Rooibos tea improved osteoblast
acvity at a low level.
Kamakura R- et al.
(2015) [40]
Obese diabec
mice Green Rooibos extract Blood glucose-
andiabec potenal
Green Rooibos extract suppressed the increase in
fasng blood glucose levels in type 2 diabec model
Ku SK- et al. (2015)
Human umbilical
vein endothelial
cells and mice
Aspalathin and nothofagin
from green Rooibos
High glucose-induced
Treatment of aspalathin or nothofagin inhibited
high glucose-mediated vascular hyperpermeability-
adhesion of monocytes toward human umbilical vein
endothelial cells- and expression of cell adhesion
Lee W- et al. (2015)
Human umbilical
vein endothelial
cells and mice
Aspalathin and nothofagin
from green Rooibos
Aspalathin and nothofagin possess an-inammatory
funcons are could be a useful therapy for vascular
inammatory diseases.
Mazibuko SE- et al.
(2015) [47]
In vitro- using
Treated with green Rooibos
extract or aspalathin
Glucose and lipid
At a protein level green rooibos extract and
aspalathin suppressed markers of insulin resistance
i.e. insulin receptor substrate one.
van der Merwe JD-
et al. (2015) [29] Male Fischer rats Aspalathin-enriched green
Rooibos extract Anoxidant acvity
Glutathione reductase acvity signicantly (p<0.05)
increased aer 28 days- while glutathione content
was decreased aer 90 days- suggesng an altered
glutathione redox cycle.
Waisundara & Hoon
(2015) [30]
In vitro models
of diabetes and
Rooibos tea Oxidave stress-
diabetes- cancer
The Rooibos tea extract was observed to have
increased the CAT and SOD acvies in two in vitro
disease models.
Ajuwon OR- et al.
(2014) [31] Male Wistar rats Fermented Rooibos extract Hepatoprotecon-
Oxidave stress
Aqueous Rooibos extract aenuated LPS-induced
liver injury possibly by modulang oxidave stress
and suppressing pro-inammatory cytokines
Ayeleso AO- et al.
(2014) [37] Diabec rats Aqueous Rooibos tea extract
(2%) for 7 weeks. Sperm funcon
Signicant (p<0.05) elevated levels of wobble and
sperm linearity were observed following Rooibos tea
extract treatment
Canda BD- et al.
(2014) [32]
Forty male Wistar
Fermented Rooibos-
unfermented rooibos- a
rooibos-derived commercial
supplement- or water.
Oxidave stress-
Anoxidant acvity
Fermented Rooibos caused a decrease (p< 0.05) in
superoxide dismutase acvity.
Dludla PV- et al.
(2014) [33] Diabec rats Aqueous extract of
fermented Rooibos Oxidave stress
Aqueous extract of fermented Rooibos protected
cardiomyocytes- derived from diabec rats- against
experimentally induced oxidave stress and
Hong IS- et al.
(2014) [34] Laboratory model Rooibos tea Oxidave stress
Rooibos tea appears to (i) reverse the increase
in stress-related metabolites (ii) prevent lipid
peroxidaon- (iii) restore stress-induced protein
degradaon- (iv) regulate glutathione metabolism
and (v) modulate changes in the acvies of
anoxidant enzymes.
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Opuwari CS- et al.
(2014) [38] Male rats Fermented Rooibos Sperm funcon
Fermented Rooibos signicantly improved sperm
vitality (p<0.01)- but caused a signicant increase in
spontaneous acrosome reacon (p< 0.05)- whereas
unfermented did not.
Sanderson M- et al.
(2014) [50] In vitro Fermented Rooibos Obesity prevenon
Hot water soluble solids from fermented Rooibos
inhibited adipogenesis- suggesng its potenal in
prevenng obesity.
Schloms L- et al.
(2014) [75] Rats Rooibos Inammaon
In vivo studies demonstrate that Rooibos signicantly
decreased glucocorcoid levels in rats and steroid
metabolite raos linked to metabolic disorders.
Mazibuko SE- et al.
(2013) [76]
In vitro using
skeletal muscle
Treated with aspalathin-
enriched green
(unfermented) Rooibos
Insulin resistance Rooibos aenuated palmitate-induced insulin
resistance in C₂C₁₂ skeletal muscle cells.
Awoniyi DO- et al.
(2012) [39] Male Wistar rats
Fermented Rooibos- 'green'
Rooibos- Chinese green tea-
Rooibos supplement- green
tea supplement or water.
Sperm funcon
Both Rooibos extracts oered a measure of
protecon against induced oxidave damage by
increasing the anoxidant defence mechanisms
improving the sperm quality and funcon.
Muller CJ- et al.
(2012) [41] In vitro Rooibos extract high in
aspalathin content
In vivo the extract sustained a glucose lowering
eect comparable to meormin over a 6h period
aer administraon (25mg/kg body weight (BW)) to
STZ-induced diabec rats.
Pantsi WG- et al.
(2011) [77] Male Wistar rats Aqueous Rooibos and green
tea Cardioprotecon
Results demonstrate the cardio-protecve properes
of aqueous Rooibos extracts via the inhibion
of apoptosis which can possibly be related to its
avonol content.
Sissing O- et al.
(2011) [58] Male rats Rooibos- Honeybush and
Camellia sinensis teas
The mean total papilloma size was reduced by
unfermented Rooibos (87%).
Hendricks R- et al.
(2010) [54]
Whole blood
culture assays
Rooibos tea and Camellia
sinensis Immune funcon
Rooibos and black tea modulate immune funcon in
vitro. Rooibos tea smulated whole blood cultures
induced higher Interleukin-6- lower Interleukin-10-
and had no eect on Interferon gamma secreon
Baba H- et al.
(2009) [10]
Wister rats Rooibos tea and water. Oxidave stress-
Anoxidant acvity
Serum SOD levels were signicantly higher in the
Rooibos group compared to the controls (p< 0.05).
Kawano A- et al.
(2009) [48]
Type 2 diabetes
model mice in vivo
Aspalathin- a green Rooibos
tea component
Aspalathin appears to have benecial eects
on glucose homeostasis in type 2 diabetes by
smulang glucose uptake in muscle ssues and
insulin secreon from pancreac beta-cells.
Marnewick JL- et al.
(2009) [61] Rat liver Unfermented and fermented
Rooibos Chemo protecon
Unfermented rooibos signicantly (p<0.05) to
marginally (p<0.1) reduced the total number of foci
(>10microm). Fermentaon seems to reduce the
protecve eect of the herbal teas.
Gilani AH- et al.
(2006) [59]
Isolated ssue
Aqueous extract of Rooibos
Rooibos tea possessed a combinaon of dominant K
(ATP) channel acvaon and weak Ca(++) antagonist
mechanisms jusfying its use in hyperacve
gastrointesnal disorders.
Khan AU- et al.
(2006) [60]
Isolated ssue
Aqueous extract of Rooibos
The bronchodilator- anspasmodic and blood
pressure lowering eects of Rooibos tea appear to
be mediated predominantly through K (ATP) channel
acvaon with the selecve bronchodilatory eect.
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eects [26]. is research suggests promise for conditions such
as allergic rhinitis [22] but further investigations are needed.
Additionally, its eects on bone health [51,52], cognitive health
[56,57] and potential hepatoprotective eects [12,31,53] warrant
further exploration in the form of human trials. Recently, a review of
experimental evidence [68] concluded that blood glucose levels were
signicantly lower in diabetic rodent models treated with rooibos
extracts providing phenolic compounds. Other work suggests that
Rooibos extracts and its constituent C-glucosyl avonoids, and Z-2-
(β-D-glucopyranosyloxy)-3-phenylpropenoic acid may elicit positive
eects on cellular oxidative stress, inammation and transcription
factors that control genes regulating glucose and lipid metabolism
helping to attenuate features of metabolic disease [69].
In the present review human subjects tended to drink Rooibos
beverages aer they had been infused for approximately 10 minutes
[20,23,25]. Recently, from a consumer stance the ideal ‘optimal cup
of Rooibos tea has been dened as one that had been seeped for 10
minutes or longer [70]. Unfortunately, recent research shows that
only 15.9% of respondents consumed an ‘optimal cup’ of Rooibos in
an amount that enables its potential cardioprotective health benets
to be provided (dened as a minimum of 4 to 6 cups per day) [70].
Interestingly, compared with cold and regular-brewed Rooibos
infusions of unfermented/green and red Rooibos prepared by boiling
have the highest antioxidant capacities and total polyphenol proles
[9]. Such ndings suggest that more information needs to be imparted
to consumers’ regarding preparation methods and the potential health
benets that drinking Rooibos tea could bring.
With regard to limitations and future research directions greater
uniformity is needed in forthcoming studies. For example, some
studies used fermented and others unfermented Rooibos extracts or
infusions the fermented form appeared to have stronger impact on
some health eects [38,51]. Others used Rooibos tea and Rooibos
‘extracts’ or unfermented/green Rooibos. Production seasons and
grade quality could also alter the phenolic proles and antioxidant
capacity of Rooibos samples and should be considered [66]. Future
trials should also better encompass how ndings could be translated
into public health messages. For example, Marnewick JL, et al. (2011)
[21] asked volunteers to drinks six cups Rooibos tea daily for 6-weeks
to study its cardiovascular eects. Similar studies are now needed for
other health outcomes such as bone health, liver or brain (cognitive)
Considering such evidence Rooibos tea, like teas from Camellia
sinensis (e.g. black, green and oolong tea) could be regarded as a
‘general health’ tea, potentially providing an array of benets to human
health and wellbeing [56] Rooibos tea is naturally slightly sweet [16]
thus does not require the addition of extra sugar or articial sweeteners.
It is also caeine free with a favourable phenolic composition [9,10].
(Table 2)
Ulicná O- et al.
(2006) [49]
induced diabec
Aqueous and alkaline
extracts of Rooibos tea
Anoxidant compounds in rooibos tea parally
prevent oxidave stress and they are eecve in
both hydrophobic and hydrophilic biological systems.
van der Merwe JD-
et al. (2006) [78]
Comparave- in
Rooibos and honey bush tea
compared with black- oolong
and green teas
Anmutagenic acvity of the South African herbal
teas was mutagen-specic- aected by fermentaon.
Unfermented Rooibos was less eecve than
fermented Rooibos
Lee EJ- et al. (2004)
DNA strand
scission Rooibos tea Anoxidant acvity
Result suggests that total soluble phenolics- specially
avonoid- of Rooibos tea are responsible for several
kinds of anoxidant acvies and prevenve acvity
on peroxyl radical induced DNA strand scission.
Kucharská J- et al.
(2004) [35]
Rat model
of carbon
induced liver
Rooibos tea Oxidave stress
Rooibos tea restored liver concentraons of CoQ9H2
and alpha-tocopherol and inhibited the formaon of
Marnewick JL- et al.
(2004) [62] Male Fischer rats
Unprocessed (not oxidized)-
processed (oxidized) rooibos-
honey bush- green and black
Mutagenic response
The mutagenic response of aatoxin B1 against
Salmonella strain TA 100 was signicantly (p<0.05)
inhibited by cytosolic fracons from rats treated with
processed and unprocessed herbal teas.
Ulicná O- et al.
(2003) [53]
Rat model of liver
injury Rooibos tea Hepatoprotecon
Rooibos tea showed histological regression of
steatosis and cirrhosis in the liver ssue with a
signicant inhibion of the increase of liver ssue
concentraons of malondialdehyde- triacylglycerols
and cholesterol.
Kunishiro K- at al.
(2001) [55] In vitro and in vivo. Rooibos tea extract Immune funcon
Rooibos tea extract may facilitate the angen-
specic anbody producon through selecve
augmentaon of IL-2 generaon both in vitro and in
Key: ATP-Adenosine Triphosphate; CAT-Chloramphenicol Acetyltransferase; DNA-Deoxyribonucleic Acid; IL-Interleukin; LDL-Low-Density Lipoprotein;
LPS-Lipopolysaccharide; MDA- Malondialdehyde; ROS- Reacve Oxygen Species- SOD-Superoxide Dismutase; STZ- Streptozotocin.
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Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
Nutr Food Technol Open Access 6(1): 9
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In conclusion previous health research has tended to focus on
black or green tea. Rooibos is widely consumed in South Africa but
is gaining popularity globally. is has been attributed to the fact that
it is caeine free, naturally sweet and abundant in polyphenols with
potent antioxidant properties. Now, a growing body of evidence from
7 human studies and 49 laboratory studies suggests that Rooibos could
be regarded as a ‘general’ health tea. Evidence for cardioprotective
eects (especially lipid prole) looks promising, particularly as a
potential adjunctive therapy. It is suggested that future research now
builds on the other potential aspects of health including glycaemic,
bone, liver and cognitive wellness enhancing eects that also appear
to be emerging.
e views expressed are those of the authors alone and personnel
role in writing this review.
Conicts of Interest
e authors declare no conicts of interest.
e authors received funding provided by the Tea Advisory
Panel which is supported by an unrestricted educational grant from
association for the UK tea industry. UKTIA plays no role in producing
the outputs of the panel. Independent panel members include
nutritionists, biochemists, dietitians, dentist and doctors. See www.
1. Whiy CJM, MacEwen C, Goddard A, Alderson D, Marshall M, et al.
(2020) Rising to the challenge of mulmorbidity. BMJ 368: l6964.
2. Doughty KN, Del Pilar NX, Audee A, Katz DL (2017) Lifestyle
Medicine and the Management of Cardiovascular Disease. Curr
Cardiol Rep 19: 116.
3. Yi M, Wu X, Zhuang W, Xia L, Chen Y, et al. (2019) Tea Consumpon
and Health Outcomes: Umbrella Review of Meta-Analyses of
Observaonal Studies in Humans. Mol Nutr Food Res 63: e1900389.
4. Hayat K, Iqbal H, Malik U, Bilal U, Mushtaq S (2015) Tea and its
consumpon: Benets and Risks. Crit Rev Food Sci Nutr 55: 939-954.
5. Fukasawa R, Kanda A, Hara S (2009) An-oxidave Eects of Rooibos
Tea Extract on Autoxidaon and Thermal Oxidaon of Lipids. J Oleo
Sci 58: 275-283.
6. Beelders T, Kalili KM, Joubert E, de Beer D, de Villiers A (2012)
Comprehensive Two-Dimensional Liquid Chromatographic Analysis
of Rooibos (Aspalathus linearis) Phenolics. J Sep Sci 35: 1808-1820.
7. Johnson R, de Beer D, Dludla PV, Ferreira D, Muller CJF, et al.
(2018) Aspalathin from Rooibos (Aspalathus linearis): Aspalathin
From Rooibos (Aspalathus linearis): A Bioacve C-glucosyl
Dihydrochalcone with Potenal to Target the Metabolic Syndrome.
Planta Med 84: 568-583.
8. Rooibos Council (2016) Latest tea-consumpon gues p scale in
favour of rooibos.
9. Damiani E, Carloni P, Rocche G, Senizza B, Tianoet L, et al. (2019)
Impact of Cold versus Hot Brewing on the Phenolic Prole and
Anoxidant Capacity of Rooibos (Aspalathus linearis) Herbal Tea.
Anoxidants (Basel) 8: 499.
10. Baba H, Ohtsuka Y, Haruna H, Lee T, Nagata S, et al. (2009) Studies
of An-Inammatory Eects of Rooibos Tea in rats. Pediatr Int 51:
11. McKay DL, Blumberg JB (2007) A Review of the Bioacvity of South
African Herbal Teas: Rooibos (Aspalathus linearis) and Honeybush
(Cyclopia intermedia). Phytother Res 21: 1-16.
12. Ulicna O, Vancova O, Kucharska J, Janega P, Waczulíková I (2019)
Rooibos Tea (Aspalathus linearis) Ameliorates the CCl4-induced
Injury to Mitochondrial Respiratory Funcon and Energy Producon
in Rat Liver. Gen Physiol Biophys 38: 15-25.
13. Stander MA, Van Wyk BE, Taylor MJC, Long HS (2017) Analysis of
Phenolic Compounds in Rooibos Tea (Aspalathus linearis) With a
Comparison of Flavonoid-Based Compounds in Natural Populaons
of Plants From Dierent Regions. J Agric Food Chem 65: 10270-
14. Stalmach A, Mullen W, Pecorari M, Serani M, Crozier A (2009)
Bioavailability of C-linked Dihydrochalcone and Flavanone
Glucosides in Humans Following Ingeson of Unfermented and
Fermented Rooibos Teas. J Agric Food Chem 57: 7104-7111.
15. Erickson L (2003) Rooibos Tea: Research into Anoxidant and
Anmutagenic Properes. J Am Botan Council 59: 34-45.
16. Koch IS, Muller M, Joubert E, van der Rijst M, Næsc T (2012) Sensory
characterizaon of rooibos tea and the development of a rooibos
sensory wheel and lexicon. Food Res Int 46: 217-28.
17. Joubert E, Gelderblom WC, Louw A, de Beer D (2008) South
African Herbal Teas: Aspalathus linearis, Cyclopia spp. and Athrixia
Phylicoides--A Review. J Ethnopharmacol 119: 376-412.
18. Chen W, Sudji IR, Wang E, Joubert E, van Wyk BE, et al. (2013)
Ameliorave Eect of Aspalathin From Rooibos (Aspalathus linearis)
on Acute Oxidave Stress in Caenorhabdis elegans. Phytomedicine
20: 380-386.
19. Gaggia F, Baoni L, Galiano M, Nielsen DS, Jakobsen RR, et al.
(2018) Kombucha Beverage from Green, Black and Rooibos Teas:
A Comparave Study Looking at Microbiology, Chemistry and
Anoxidant Acvity. Nutrients 11: 1.
20. Breiter T, Laue C, Kressel G, Gröll S, Engelhardt UH, et al. (2011)
Bioavailability and Anoxidant Potenal of Rooibos Flavonoids
in Humans Following the Consumpon of Dierent Rooibos
Formulaons. Food Chem 128: 338-347.
21. Marnewick JL, Rautenbach F, Venter I, Neethling H, Blackhurst DM, et
al. (2011) Eects of Rooibos (Aspalathus linearis) on Oxidave Stress
and Biochemical Parameters in Adults at Risk for Cardiovascular
Disease. J Ethnopharmacol 133: 46-52.
22. Pedre S, Peter J (2020) Rooibos Herbal Tea Reduces Allergic
Basophil Acvaon in Adult Atopic Paents. J Ethnopharmacol 252:
23. Rodgers A, Mokoena M, Durbach I, Lazarus J, de Jager S, et al.
(2016) Do Teas Rich in Anoxidants Reduce the Physicochemical
and Peroxidave Risk Factors for Calcium Oxalate Nephrolithiasis in
Humans? Pilot Studies With Rooibos Herbal Tea and Japanese Green
Tea. Urolithiasis 44: 299-310.
24. Uer AC, Quindry JC, Emerenziani GP, Valiente JS (2010) Eects of
Rooibos Tea, Boled Water, and a Carbohydrate Beverage on Blood
and Urinary Measures of Hydraon Aer Acute Dehydraon. Res
Sports Med 18: 85-96.
Sci Forschen
Open HUB for Sc ie n t i f i c R e s e a r c h
Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
Nutr Food Technol Open Access 6(1): 10
Nutrion and Food Technology: Open Access
Open Access Journal
25. Persson IA, Persson K, Hagg S, Andersson RGG (2010) Eects of
Green Tea, Black Tea and Rooibos Tea on Angiotensin-Converng
Enzyme and Nitric Oxide in Healthy Volunteers. Public Health Nutr
13: 730-737.
26. Morishita Y, Ikeda K, Matsuno H, Ito H, Tai A (2019) Idencaon of
Degranulaon Inhibitors From Rooibos (Aspalathus linearis) Tea in
Rat Basophilic Leukaemia Cells. Nat Prod Res 33: 1472-1476.
27. Lawal AO, Davids LM, Marnewick JL (2019) Rooibos (Aspalathus
linearis) and Honeybush (Cyclopia Species) Modulate the Oxidave
Stress Associated Injury of Diesel Exhaust Parcles in Human
Umbilical Vein Endothelial Cells. Phytomedicine 59: 152898.
28. Orlando P, Chellan N, Louw J, Tiano L, Cirilli I, et al. (2019) Aspalathin-
Rich Green Rooibos Extract Lowers LDL-Cholesterol and Oxidave
Status in High-Fat Diet-Induced Diabec Vervet Monkeys. Molecules
24: 1713.
29. van der Merwe JD, de Beer D, Joubert E, Gelderblom WCA (2015)
Short-Term and Sub-Chronic Dietary Exposure to Aspalathin-
Enriched Green Rooibos (Aspalathus linearis) Extract Aects Rat
Liver Funcon and Anoxidant Status. Molecules 20: 22674-22690.
30. Waisundara VY, Hoon LY (2015) Free Radical Scavenging Ability of
Aspalathus Linearis in Two in Vitro Models of Diabetes and Cancer. J
Tradit Complement Med 5: 174-178.
31. Ajuwon OR, Ogunbeju OO, Marnewick JL (2014) Amelioraon
of Lipopolysaccharide-Induced Liver Injury by Aqueous Rooibos
(Aspalathus linearis) Extract via Inhibion of Pro-Inammatory
Cytokines and Oxidave Stress. BMC Complement Altern Med 14:
32. Canda BD, Ogunbeju OO, Marnewick JL (2014) Eects of
Consumpon of Rooibos (Aspalathus linearis) and a Rooibos-
Derived Commercial Supplement on Hepac Tissue Injury by Tert-
Butyl Hydroperoxide in Wistar Rats. Oxid Med Cell Longev 2014:
33. Dludla PV, Muller CJ, Louw J, Joubert E, Salie R, et al. (2014) The
Cardioprotecve Eect of an Aqueous Extract of Fermented Rooibos
(Aspalathus linearis) on Cultured Cardiomyocytes Derived From
Diabec Rats. Phytomedicine 21: 595-601.
34. Hong IS, Lee HY, Kim HP (2014) An-oxidave Eects of Rooibos Tea
(Aspalathus linearis) on Immobilizaon-Induced Oxidave Stress in
Rat Brain. PLoS One 9: e87061.
35. Kucharská J, Ulicná O, Gvozdjáková A, Sumbalová Z, Vancová O, et al.
(2004) Regeneraon of Coenzyme Q9 Redox State and Inhibion of
Oxidave Stress by Rooibos Tea (Aspalathus linearis) Administraon
in Carbon Tetrachloride Liver Damage. Physiol Res 53: 515-521.
36. Ros-Santaella JL, Pintus E (2017) Rooibos (Aspalathus linearis)
Extract Enhances Boar Sperm Velocity Up to 96 Hours of Semen
Storage. PLoS One 12: e0183682.
37. Ayeleso AO, Ogunbeju OO, Aboua YG, Brooks NL (2014) Eects
of Red Palm Oil and Rooibos on Sperm Molity Parameters in
Streptozotocin-Induced Diabec Rats. Afr J Tradit Complement
Altern Med 11: 8-15.
38. Opuwari CS, Monsees TK (2014) In Vivo Eects of Aspalathus linearis
(Rooibos) on Male Rat Reproducve Funcons. Andrologia 46: 867-
39. Awoniyi DO, Aboua YG, Marnewick J, Brooks N (2012) The Eects
of Rooibos (Aspalathus linearis), Green Tea (Camellia sinensis) and
Commercial Rooibos and Green Tea Supplements on Epididymal
Sperm in Oxidave Stress-Induced Rats. Phytother Res 26: 1231-
40. Kamakura R, Son MJ, de Beer D, Joubert E, Miura Y, et al. (2015)
Andiabec Eect of Green Rooibos (Aspalathus linearis) Extract
in Cultured Cells and Type 2 Diabec Model KK-A(y) Mice.
Cytotechnology 67: 699-710.
41. Muller CJ, Joubert E, de Beer D, Sanderson M, Malherbe CJ, et
al. (2012) Acute Assessment of an Aspalathin-Enriched Green
Rooibos (Aspalathus linearis) Extract With Hypoglycemic Potenal.
Phytomedicine 20: 32-39.
42. Ku SK, Kwak S, Kim Y, Bae JS (2015) Aspalathin and Nothofagin
From Rooibos (Aspalathus linearis) Inhibits High Glucose-Induced
Inammaon in Vitro and in Vivo. Inammaon 38: 445-455.
43. Mazibuko-Mbeje SE, Dludla PV, Johnson R, Joubert E, Louw J, et al.
(2019) Aspalathin, a Natural Product With the Potenal to Reverse
Hepac Insulin Resistance by Improving Energy Metabolism and
Mitochondrial Respiraon. PLoS One 14: e0216172.
44. Mazibuko-Mbeje SE, Dludla PV, Roux C, Ghoor S, Joubert E, et al.
(2019) Aspalathin-Enriched Green Rooibos Extract Reduces Hepac
Insulin Resistance by Modulang PI3K/AKT and AMPK Pathways. Int
J Mol Sci 20: 633.
45. Dludla PV, Gabuza KB, Muller CJF, Joubert E, Louw J, et al. (2018)
Aspalathin, a C-glucosyl Dihydrochalcone From Rooibos Improves
the Hypoglycemic Potenal of Meormin in Type 2 Diabec (Db/
Db) Mice. Physiol Res 67: 813-818.
46. Dludla PV, Muller CJ, Joubert E, Louw J, Essop MF, et al. (2017)
Aspalathin Protects the Heart Against Hyperglycemia-Induced
Oxidave Damage by Up-Regulang Nrf2 Expression. Molecules 22:
47. Mazibuko SE, Joubert E, Johnson R, Louw J, Opoku AR, et al. (2015)
Aspalathin Improves Glucose and Lipid Metabolism in 3T3-L1
Adipocytes Exposed to Palmitate. Mol Nutr Food Res 59: 2199-2208.
48. Kawano A, Nakamura H, Hata SI, Minakawa M, Miura Y, et al. (2009)
Hypoglycemic Eect of Aspalathin, a Rooibos Tea Component
From Aspalathus linearis, in Type 2 Diabec Model Db/Db Mice.
Phytomedicine 16: 437-443.
49. Ulicná O, Vancová O, Bozek P, Cársky J, Sebeková K, et al. (2006)
Rooibos Tea (Aspalathus linearis) Parally Prevents Oxidave Stress
in Streptozotocin-Induced Diabec Rats Physiol Res 55:157-164.
50. Sanderson M, Mazibuko SE, Joubert E, de Beer D, Johnson R, et
al. (2014) Eects of Fermented Rooibos (Aspalathus linearis) on
Adipocyte Dierenaon. Phytomedicine 21: 109-117.
51. Moosa S, Kasonga AE, Deepak V, Marais S, Magoshi BI, et al. (2018)
Rooibos Tea Extracts Inhibit Osteoclast Formaon and Acvity
Through the Aenuaon of NF-κB Acvity in RAW264.7 Murine
Macrophages. Food Funct 9: 3301-3312.
52. Nash LA, Ward WE (2016) Comparison of Black, Green and Rooibos
Tea on Osteoblast Acvity. Food Funct 7: 1166-1175.
53. Ulicna O, Greksak M, Vancova O, L Zlatos, S Galbavý, et al. (2003)
Hepatoprotecve Eect of Rooibos Tea (Aspalathus linearis) on
CCl4-induced Liver Damage in Rats. Physiol Res 52: 461-466.
54. Hendricks R, Pool EJ (2013) The in Vitro Eects of Rooibos and Black
Tea on Immune Pathways. J Immunoassay Immunochem 31: 169-
55. Kunishiro K, Tai A, Yamamoto I (2001) Eects of Rooibos Tea Extract
on Angen-Specic Anbody Producon and Cytokine Generaon
in Vitro and in Vivo. Biosci Biotechnol Biochem 65: 2137-2145.
Sci Forschen
Open HUB for Sc ie n t i f i c R e s e a r c h
Citaon: Bond TJ, Derbyshire EJ (2020) Rooibos Tea and Health: A Systemac Review of the Evidence from the Last Two Decades.
Nutr Food Technol Open Access 6(1): 11
Nutrion and Food Technology: Open Access
Open Access Journal
56. Pyrzanowska J, Fecka I, Mirowska-Guzel D, Joniec-Maciejak I,
Blecharz-Klin K, et al. (2019) Long-term Administraon of Aspalathus
linearis Infusion Aects Spaal Memory of Adult Sprague-Dawley
Male Rats as Well as Increases Their Striatal Dopamine Content. J
Ethnopharmacol 238: 111881.
57. Akinrinmade O, Omoruyi S, Dietrich D, Ekpo O (2017) Long-
term Consumpon of Fermented Rooibos Herbal Tea Oers
Neuroprotecon Against Ischemic Brain Injury in Rats. Acta
Neurobiol Exp (Wars) 77: 94-105.
58. Sissing L, Marnewick J, de Kock M, Swanevelder S, Joubert E, et al.
(2011) Modulang Eects of Rooibos and Honeybush Herbal Teas
on the Development of Esophageal Papillomas in Rats. Nutr Cancer
63: 600-610.
59. Gilani AH, Khan AU, Ghayur MN, Ali SF, Herzig (2006) Anspasmodic
Eects of Rooibos Tea (Aspalathus linearis) is Mediated
Predominantly through K+-Channel Acvaon. Basic Clin Pharmacol
Toxicol 99: 365-373.
60. Khan AU, Gilani AH (2006) Selecve Bronchodilatory Eect of
Rooibos Tea (Aspalathus linearis) and Its Flavonoid, Chrysoeriol. Eur
J Nutr 45: 463-469.
61. Marnewick JL, van der Westhuizen FH, Joubert E, Swanevelder
S, Swart P, et al. (2009) Chemoprotecve Properes of Rooibos
(Aspalathus linearis), Honeybush (Cyclopia intermedia) Herbal and
Green and Black (Camellia sinensis) Teas Against Cancer Promoon
Induced by Fumonisin B1 in Rat Liver. Food Chem Toxicol 47: 220-
62. Marnewick JL, Batenburg W, Swart P, Joubert E, Swanevelder S, et
al. (2004) Ex vivo Modulaon of Chemical-Induced Mutagenesis by
Subcellular Liver Fracons of Rats Treated With Rooibos (Aspalathus
linearis) Tea, Honeybush (Cyclopia intermedia) Tea, as Well as Green
and Black (Camellia sinensis) Teas. Mutat Res 558: 145-154.
63. Smith C, Swart A (2018) Aspalathus linearis (Rooibos)-A Funconal
Food Targeng Cardiovascular Disease. Food Funct 9: 5041-5058.
64. Dludla PV, Joubert E, Muller CJF, Louw J, Johnson R (2017)
Hyperglycemia-induced Oxidave Stress and Heart Disease-
Cardioprotecve Eects of Rooibos Flavonoids and Phenylpyruvic
acid-2- O-β-D-glucoside. Nutr Metab (Lond) 14: 45.
65. Lee W, Bae JS (2015) An-inammatory Eects of Aspalathin and
Nothofagin from Rooibos (Aspalathus linearis) In Vitro and In Vivo.
Inammaon 38: 1502-1516.
66. Joubert E, Beelders T, de Beer D, Malherbe CJ, de Villiers AJ, et al.
(2012) Variaon in Phenolic Content and Anoxidant Acvity of
Fermented Rooibos Herbal Tea Infusions: Role of Producon Season
and Quality Grade. J Agric Food Chem 60: 9171-9179.
67. Darvesh AS, Carroll RT, Bishayee A Geldenhuys WJ, Van der Schyf
CJ (2010) Oxidave Stress and Alzheimer’s Disease: Dietary
Polyphenols as Potenal Therapeuc Agents. Expert Rev Neurother
10: 729-475.
68. Sasaki M, Nishida N, Shimada M (2018) Benecial Role of Rooibos
in Diabetes Mellitus: A Systemac Review and Meta-Analysis.
Molecules 23: 839.
69. Muller CJF, Malherbe CJ, Chellan N, Yagasaki K, Miura Y, et al. (2018)
Potenal of Rooibos, Its Major C-glucosyl Flavonoids, and Z-2-(β-
D-glucopyranosyloxy)-3-phenylpropenoic Acid in Prevenon of
Metabolic Syndrome. Crit Rev Food Sci Nutr 58: 227-246.
70. Piek H, Venter I, Rautenbach F, Marnewick JL (2019) Rooibos Herbal
Tea: An Opmal Cup and Its Consumers. Health SA 24: 1090.
71. Yang S, Lee C, Lee BS, Park EK, Kim KM, et al. (2018) Renal Protecve
Eects of Aspalathin and Nothofagin From Rooibos (Aspalathus
linearis) in a Mouse Model of Sepsis. Pharmacol Rep 70: 1195-1201.
72. Johnson R, Shabalala S, Louw J, Kappo AP, Muller CJF (2017)
Aspalathin Reverts Doxorubicin-Induced Cardiotoxicity through
Increased Autophagy and Decreased Expression of p53/mTOR/p62
Signaling. Molecules 22: 1589.
73. Johnson R, Dludla PV, Muller CJ, Huisamen B, Essop MF, et al.
(2017) The Transcripon Prole Unveils the Cardioprotecve Eect
of Aspalathin against Lipid Toxicity in an In Vitro H9c2 Model.
Molecules 22: 219.
74. Johnson R, Dludla P, Joubert E, February F, Mazibuko S, et al.
(2016) Aspalathin, a Dihydrochalcone C-glucoside, Protects H9c2
Cardiomyocytes Against High Glucose Induced Shis in Substrate
Preference and Apoptosis. Mol Nutr Food Res 60: 922-934.
75. Schloms L, Smith C, Storbeck KH, Marnewick JL, Swart P, et al. (2014)
Rooibos Inuences Glucocorcoid Levels and Steroid Raos in Vivo
and in Vitro: A Natural Approach in the Management of Stress and
Metabolic Disorders? Mol Nutr Food Res 58: 537-549.
76. Mazibuko SE, Muller CJ, Joubert E, de Beer D, Johnson R et al. (2013)
Amelioraon of Palmitate-Induced Insulin Resistance in C2C12 Muscle
Cells by Rooibos (Aspalathus linearis). Phytomedicine 20: 813-819.
77. Pantsi WG, Marnewick JL, Esterhuyse AJ, Rautenbach F, van Rooyen
J (2011) Rooibos (Aspalathus linearis) Oers Cardiac Protecon
Against Ischaemia/Reperfusion in the Isolated Perfused Rat Heart.
Phytomedicine 18: 1220-1238.
78. van der Merwe JD, Joubert E, Richards ES, Manley M, Snijman PW, et
al. (2006) A Comparave Study on the Anmutagenic Properes of
Aqueous Extracts of Aspalathus linearis (Rooibos), Dierent Cyclopia
Spp. (Honeybush) and Camellia sinensis Teas. Mutat Res 611: 42-53.
79. Lee EJ, Jang HD (2004) Anoxidant Acvity and Protecve Eect on
DNA Strand Scission of Rooibos Tea (Aspalathus linearis). Biofactors
21: 285-292.
... The viability of Chinese hamster lung fibroblast V79-4 cells subjected to H 2 O 2 -induced oxidative stress was increased by rooibos extract, a protective effect linked to increased activity of the anti-oxidant enzymes, superoxide dismutase (SOD) and catalase (CAT) (Yoo et al., 2008). Human red blood cells, pretreated with rooibos extract, were less prone to oxidation when exposed to the free radicalgenerating azo compound, 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) (Blasa et al., 2011). Lawal et al. (2019) showed that pretreatment of human umbilical vein endothelial cells (HUVECs) with green and fermented rooibos extracts reduced ROS production caused by air pollutants, i.e. diesel exhaust particles. ...
Aspalathus linearis (Burm.f) R.Dahlgren, commonly referred to as ‘rooibos tea’, is the best-known indigenous South African herbal tea. It is considered the success story of indigenous product development and marketing, and it is a prime export product, marketed globally. Rooibos is endemic to the Fynbos Biome and is found in the far southwestern part (Nieuwoudtville) of the Northern Cape Province, but chiefly in the Citrusdal and Clanwilliam regions (Cederberg area) of the Western Cape Province. Rooibos tea is anecdotally consumed to relieve colic, indigestion, heartburn and nausea. It also reduces nervous tension, promotes sound sleep and improves appetite. Rooibos extracts are included as anti-oxidant in a wide range of nutraceutical products. The use of rooibos extract in products for topical application for a range of dermatological issues and in a collection of skin-care products is well-established in South Africa. The ‘fermentation’ process is important for the development of the characteristic aroma, flavour and colour of the ‘traditional’ tea product, notable for its red–brown colour. The phytochemistry of rooibos tea has been extensively investigated, especially with regard to the aspalathin (dihydrochalcone) content and that of other major flavonoids, and the quantitative differences between unfermented (green) and fermented rooibos. Much has been documented concerning the anti-oxidant activity of rooibos tea and its role in alleviating oxidative stress. The potential of rooibos, in particular green rooibos extract and aspalathin, in the prevention of metabolic syndrome has been the focus of many studies. Other investigations include antispasmodic, anticancer, bone health and antistress activities. High-performance liquid chromatography (HPLC) with diode array detection (DAD) has been used extensively for the quantification of aspalathin, other major flavonoids and Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid in rooibos. Other techniques, such as semi-automated high-performance thin-layer chromatography (HPTLC), ultra-performance liquid chromatography coupled to mass spectrometry (UPLC–MS), and mid-infrared (MIR) spectroscopy, were used to determine the chemical profiles of rooibos tea.
... Of particular interest to the current study context, rooibos herbal tea (brewed from unfermented or fermented Aspalathus linearis), is a widely consumed traditional South African tisane that has already been suggested as a functional food [17,18] due to its substantial and unique blend of bioactive polyphenols which have been linked to potent antioxidant actions [19][20][21]. Preparation of the rooibos extracts-e.g., choice of solvent and processing (fermentation or not)-has been demonstrated to affect potency of the antioxidant effect achieved, with green (unfermented) extracts showing greater antioxidant effect. Mechanisms reported mainly include hydrogen-ion donation and superoxide quenching [22]. ...
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In order to promote gastrointestinal health, significant increases in the prevalence of gastrointestinal disorders should be paralleled by similar surges in therapeutics research. Nutraceutical interventions may play a significant role in patient management. The current study aimed to determine the potential of Aspalathus linearis (rooibos) to prevent gastrointestinal dysregulation resulting from high-dose trace-amine (TA) exposure. Considering the substantial female bias in functional gastrointestinal disorders, and the suggested phytoestrogenicity of rooibos, the study design allowed for a comparison between the effects of an ethanol extract of green rooibos and 17β-estradiol (E2). High levels of ρ-tyramine (TYR) and agmatine (AGM), but not β-phenethylamine (PEA) or tryptamine (TRP), resulted in prostaglandin E2 (PGE2) hypersecretion, increased tight-junction protein (TJP; occludin and ZO-1) secretion and (dissimilarly) disrupted the TJP cellular distribution profile. Modulating benefits of rooibos and E2 were TA-specific. Rooibos pre-treatment generally reduced IL-8 secretion across all TA conditions and prevented PGE2 hypersecretion after exposure to both TYR and AGM, but was only able to normalise TJP levels and the distribution profile in AGM-exposed cells. In contrast, E2 pre-treatment prevented only TYR-associated PGE2 hypersecretion and TJP dysregulation. Together, the data suggest that the antioxidant and anti-inflammatory effects of rooibos, rather than phytoestrogenicity, affect benefits illustrated for rooibos.
... Congeneric fire-survival strategies are common in several Fynbos taxa, e.g., Proteaceae; Ericaceae and Fabaceae (Marais et al., 2014;Pausas and Keeley, 2014). Rooibos exhibits a plethora of health benefits and is widely used for commercial products such as tea, food products and cosmetics as it has powerful antioxidant properties due to the abundance of flavonoids and other phenolic compounds found throughout the plant (Van Heerden et al., 2003;Smith and Swart, 2018;Bond and Derbyshire, 2020). The commercial importance of rooibos and the value rooibos provides to the livelihood to the local farmers, thus provides further impetus in understanding phylogeographic patterns that are linked to both its metabolites and population genetic structure and evolutionary history (Feliner, 2014). ...
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Aspalathus linearis (Burm. F.) R. Dahlgren (Fabaceae) or rooibos, is a strict endemic fynbos species, limited to areas of the Cederberg (Western Cape) and the southern Bokkeveld plateau (Northern Cape) in the greater Cape Floristic Region (CFR) of South Africa. Wild rooibos, unlike the cultivated type, is variable in morphology, biochemistry, ecology and genetics. These ecotypes are broadly distinguished into two main groups, namely, reseeders and resprouters, based on their fire-survival strategy. This study aimed to test the hypothesis that wild rooibos ecotypes are distinct in genetic variability and that the ecotypes found in the Northern Cape are distinct from those in the Cederberg. Phylogeographical analysis of both chloroplast (trnLF intergenic region) and newly developed species-specific nuclear markers (microsatellites) was performed on six geographically representative wild rooibos populations. From the diversity indices, it was evident that the wild rooibos populations have low-to-moderate genetic diversity. The Jamaka population (Cederberg, Western Cape) had the lowest haplotype diversity (0.286), and the lowest nucleotide diversity (0.006) even though the data revealed large variations in haplotype diversity (h = 0.286 - 0.900) and nucleotide diversity (π = 0.006 - 0.025) between populations and amongst regions where wild rooibos populations are found. Our data suggests that populations of rooibos become less diverse from the Melkkraal population (Suid Bokkeveld, Northern Cape) down towards the Cederberg (Western Cape) populations, possibly indicative of clinal variation. The largest genetic differentiation was between Heuningvlei (Cederberg, Western Cape) and Jamaka (FST = 0.101) localities within the Cederberg mountainous region, and, Blomfontein (Northern Cape) and Jamaka (Cederberg) (FST = 0.101). There was also a significant correlation between geographical distance and genetic distance (R2 = 0.296, P = 0.044). The presence of three main clusters is also clearly reflected in the discriminant analysis of principal components (DAPC) based on the microsatellite markers. The correct and appropriate management of wild genetic resources of the species is urgently needed, considering that the Cederberg populations are genetically distinct from the Northern Cape wild plants and are delineated in accordance with ecological functional traits of reseeding or resprouting, respectively.
Introduction Rooibos (Aspalathus linearis) is a South African herbal tisane that is enjoyed throughout the world for its taste and emerging health benefits. Rooibos possesses a unique composite of phytochemicals known to encompass antioxidant and bioactive properties and has been suggested as an intervention for several disease conditions. The current study aims to provide a comprehensive bibliometric overview of the literature on Rooibos and its proposed health benefits to complement previous review articles. Methods: A bibliometric mapping analysis of the research on Rooibos was carried out, using data from the titles, abstracts, and keywords of articles published in leading journals and other peer-reviewed documents available in the Scopus database from 1962 to 2021 (21 September), and subsequently analyzed with the VOSviewer software. Results The search yielded 635 documents. The numbers of original articles (n = 525) and reviews (n = 51) were in the ratio of 10:1. More than half of the papers have been published since 2015. These publications were mainly published in journals representing the emerging ethnopharmacological potential of this tisane. Discussion/Conclusion The literature mainly focused on Rooibos bioactive effects against cancer, inflammation, and oxidative stress. Purified Rooibos phytocompounds that were frequently mentioned in the keywords of evaluated publications included aspalathin, quercetin, rutin and the umbrella term “polyphenols”. The accumulating research clearly underlines the benefits of Rooibos as both a preventative and complementary therapeutic functional food. This first attempt to visualize the bibliometrics and altmetrics of Rooibos and its health applications is a good starting point for further scientific work.
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Consumption of rooibos (Aspalathus linearis) as herbal tea is growing in popularity worldwide and its health-promoting attributes are mainly ascribed to its phenolic composition, which may be affected by the brewing conditions used. An aspect so far overlooked is the impact of cold brewing vs regular brewing and microwave boiling on the poly(phenolic) profile and in vitro antioxidant capacity of infusions prepared from red (‘fermented’, oxidized) and green (‘unfermented’, unoxidized) rooibos, the purpose of the present study. By using an untargeted metabolomics-based approach (UHPLC-QTOF mass spectrometry), 187 phenolic compounds were putatively annotated in both rooibos types, with flavonoids, tyrosols, and phenolic acids the most represented type of phenolic classes. Multivariate statistics (OPLS-DA) highlighted the phenolic classes most affected by the brewing conditions. Similar antioxidant capacities (ORAC and ABTS assays) were observed between cold- and regular-brewed green rooibos and boiled-brewed red rooibos. However, boiling green and red rooibos delivered infusions with the highest antioxidant capacities and total polyphenol content. The polyphenol content strongly correlated with the in vitro antioxidant capacities, especially for flavonoids and phenolic acids. These results contribute to a better understanding of the impact of the preparation method on the potential health benefits of rooibos tea.
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Type 2 diabetic patients possess a two to four fold-increased risk for Cardiovascular Diseases (CVD). Hyperglycemia, oxidative stress associated with endothelial dysfunction and dyslipidemia are regarded as pro-atherogenic mechanisms of CVD. In this study, high-fat diet-induced diabetic and non-diabetic vervet monkeys were treated with 90 mg/kg of aspalathin-rich green rooibos extract (Afriplex GRT) for 28 days, followed by a 1-month wash-out period. Supplementation showed improvements in both the intravenous glucose tolerance test (IVGTT) glycemic area under curve (AUC) and total cholesterol (due to a decrease of the low-density lipoprotein [LDL]) values in diabetics, while non-diabetic monkeys benefited from an increase in high-density lipoprotein (HDL) levels. No variation of plasma coenzyme Q10 (CoQ10) were found, suggesting that the LDL-lowering effect of Afriplex GRT could be related to its ability to modulate the mevalonate pathway differently from statins. Concerning the plasma oxidative status, a decrease in percentage of oxidized CoQ10 and circulating oxidized LDL (ox-LDL) levels after supplementation was observed in diabetics. Finally, the direct correlation between the amount of oxidized LDL and total LDL concentration, and the inverse correlation between ox-LDL and plasma CoQ10 levels, detected in the diabetic monkeys highlighted the potential cardiovascular protective role of green rooibos extract. Taken together, these findings suggest that Afriplex GRT could counteract hyperglycemia, oxidative stress and dyslipidemia, thereby lowering fundamental cardiovascular risk factors associated with diabetes.
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Aspalathin is a rooibos flavonoid with established blood glucose lowering properties, however, its efficacy to moderate complications associated with hepatic insulin resistance is unknown. To study such effects, C3A liver cells exposed to palmitate were used as a model of hepatic insulin resistance. These hepatocytes displayed impaired substrate metabolism, including reduced glucose transport and free fatty acid uptake. These defects included impaired insulin signaling, evident through reduced phosphatidylinositol-4,5-bisphosphate 3-kinase/ protein kinase B (PI3K/AKT) protein expression, and mitochondrial dysfunction, depicted by a lower mitochondrial respiration rate. Aspalathin was able to ameliorate these defects by correcting altered substrate metabolism, improving insulin signaling and mitochondrial bioenergetics. Activation of 5ʹ-adenosine monophosphate-activated protein kinase (AMPK) may be a plausible mechanism by which aspalathin increases hepatic energy expenditure. Overall, these results encourage further studies assessing the potential use of aspalathin as a nutraceutical to improve hepatocellular energy expenditure, and reverse metabolic disease-associated complications.
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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.
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The rooibos tea (RT) is a source of valuable dietary dihydrochalcones  aspalathin, and nothofagin and other polyphenols. Many in vitro and in vivo studies have shown that RT flavonoids have strong antioxidant effect and significantly reduce oxidative stress. We investigated the antioxidant activity and protective effect of an aqueous extract of RT on the liver mitochondria oxidative phosphorylation in rats with carbon tetrachloride-induced (CCl4-induced) liver damage. Mitochondrial respiration and ATP production was determined amperometrically using a Clark-type oxygen electrode. We found significantly decreased parameters of oxidative phosphorylation in the group having received CCl4 for 10 weeks. Simultaneous administration of RT increased oxygen uptake stimulated with ADP, and the rate of ATP generation in the mitochondria of rats, both having been impaired in rats treated with CCl4 only. Treatment with RT significantly decreased CCl4-induced elevated enzyme levels, improved capacity of the respiratory chain and energy production, presumably due to its potent and direct antioxidant activity, including inhibition of mitochondrial lipid peroxidation. Improved histological features support the view of antioxidant and membrane-stabilizing activity of RT. This fact may play a significant role in the protection of the liver from injury caused by known toxins, and from subsequent development of steatosis and fibrosis..
Scope: We sought to conduct an umbrella review to study the strength and validity of associations between tea consumption and diverse health outcomes. Methods and results: Meta-analyses of observational studies examining associations between tea consumption and health outcomes in all human populations and settings were screened. The umbrella review identified 96 meta-analyses with 40 unique health outcomes. Tea consumption showed more benefits than harms to health in this review. Dose-response analyses of tea consumption indicated reduced risks of total mortality, cardiac death, coronary artery disease, stroke and type 2 diabetes mellitus with increment of 2 to 3 cups per day. Beneficial associations were also found for several cancers, skeletal, cognitive, and maternal outcomes. Harmful associations were found for esophageal and gastric cancer when the temperature of intake was more than 55-60°C. Conclusion: Tea consumption, except for very hot tea, seems generally safe at usual levels of intake, with summary estimates indicating the largest reduction for diverse health outcomes at two to three cups per day. Generally, tea consumption seems more beneficial than harmful in this umbrella review. Randomized controlled trials are further needed to understand whether the observed associations are causal. This article is protected by copyright. All rights reserved.
Ethnopharmacological relevance: Everyday use of the herbal tea rooibos, produced from Aspalathus linearis (Brum.f) Dahlg. (Fabaceae) is customary in South Africa, a continuation of its historical use by indigenous people. Although evidence of its traditional indications is anecdotal, rooibos tea is regarded as a general health tea. Aims of the study: Available contemporary research indicates to broad cell protective activity of rooibos focusing on its antioxidative, anti-inflammatory, anti-hyperglycaemic and antithrombotic features affecting metabolic syndrome, cardiovascular risk and neuroprotection. Nevertheless little is known about its impact on brain functions. The present experiment aimed to evaluate the possible behavioural and neurochemical effects of long-term oral administration of "fermented" rooibos herbal tea (FRHT) infusions to adult male Sprague-Dawley rats. Materials and methods: Infusions, prepared using 1, 2 and 4 g of "fermented" (oxidised) A. linearis leaves for 100 ml of hot water, were characterised in terms of flavonoid content by ultra-high and high performance liquid chromatography (UHPLC-qTOF-MS, HPLC-DAD) and administered to rats as sole drinking fluid for 12 weeks. Spatial memory behaviour was assessed in a modified version of the Morris water maze. Dopamine, noradrenaline, serotonin and their metabolite levels (DOPAC, 3-MT, HVA, MHPG, 5-HIAA) were quantified in prefrontal cortex, hippocampus and striatum by HPLC-ECD. Body weight and blood glucose level were additionally estimated. Results: All FRHT-treated rats showed improvement of long-term spatial memory defined as increased number of crossings over the previous platform position in SE quadrant of the water maze. It was not accompanied by excessive motor activity. Striatal dopamine and its metabolite 3-MT (3-methoxytyramine) levels were increased in treated rats. There were no differences in body weight gain between control and treated animals but blood glucose level was significantly lower in the latter ones. Conclusion: The improvement of long-term memory in FRHT-treated rats and stimulating impact of FRHT on their dopaminergic striatal transmission support the wellness enhancing effect of rooibos tea, contributing to a better understanding of the neurological background of traditional habitual consumption of this herbal tea.
Background Previous evidence show foods and beverages rich in polyphenolic compounds to have favourable effects on the cardiovascular system. Hypothesis The current study assessed the modulation of oxidative stress and associated inflammation induced by diesel exhaust particles (DEP - SRM 2975) by pre-treatment of human umbilical vein endothelial cells (HUVECs) with aqueous extracts of rooibos [fermented (FR) as well as green form (GR)] and honeybush [fermented form (FH)]. Study design HUVEC are either exposed to DEP (10 µg/ml) for 4 h or pre-treated with 40 and 60 µg/ml of FR or GH or FR, or 50 µg/ml orientin (OR) for 6 h prior to DEP exposure. Methods In vitro antioxidant capacity of the extracts was assessed and the polyphenol contents were also assessed by HPLC. ROS, cell viability, lactate dehydrogenase leakage, lipid peroxidation, GSH:GSSG ratios, conjugated diene and protein carbonyl levels were determined as indices of oxidative stress and cytotoxicity. RT-qPCR and western blot were used to assess inflammatory cytokines and antioxidant genes expression. Results DEP caused a dose and time-dependent increase in ROS production, significant (p < 0.001) increase in protein carbonyl (PC) formation, thiobarbituric acid reactive substances and conjugated dienes levels (p < 0.01) and a significant reduction in glutathione (GSH) redox status. Pre-incubation with either the herbal extracts or orientin attenuated these effects. The significant increase in IL-1α, IL-6, IL-8, VCAM-1 and ATF4 gene expression caused by DEP (10 µg/ml) were also attenuated by the presence of the FR, GR and FH extracts, and OR . Pre-treatment with the rooibos extracts or flavone orientin enhanced cell viability, reduced LDH leakage, enhanced mRNA expression of NQO1 and Nrf2, but repressed CYP1B1 mRNA induced by DEP. Western blot showed both the herbal tea extracts and orientin to enhance NQO1 and γGSC protein induction by DEP. Conclusion Taken together, the herbal extracts offer protection against DEP-induced oxidative stress and inflammatory response.