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Potential Health Benefits of Berries

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Fruit and vegetable consumption is inversely related to the incidence of heart disease and several cancers. However, many people in countries in Northern latitudes do not eat the recommended “5-a-day” of fruit and vegetables. For such populations, a potentially important source of fruit may be locally grown soft fruits (eg. raspberries, blackberries, blueberries, blackcurrants). Such berries contain micronutrients such as vitamin C and folic acid which are essential for health. However, berries may have additional health benefits as they are also rich in phytochemicals such as anthocyanins which are glycosidic-linked flavonoids responsible for their red, violet, purple and blue colours. In vitro studies indicate that anthocyanins and other polyphenols in berries have a range of potential anti-cancer and heart disease properties including antioxidant, anti-inflammatory, and cell regulatory effects. Such experimental data has lead to numerous health claims on the internet implying that “berries are edible superstars that may protect against heart disease, cancers and ageing”. However, the bioavailabilty of polyphenols such as anthocyanins would appear to be limited, thus compromising their nutritional relevance. Consequently the aim of the article is to assess the current scientific evidence for claims that berries may have additional health benefits to those normally associated with consuming fruit and vegetables.
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Current Nutrition & Food Science, 2005, 1, 71-86 71
1573-4013/05 $50.00+.00 © 2005 Bentham Science Publishers Ltd.
Potential Health Benefits of Berries
Julie Beattie1, Alan Crozier2 and Garry G. Duthie3,*
1Centre for Public Health Nutrition Research, Department of Medicine, University of Dundee, Ninewells Hospital &
Medical School, Dundee DD1 9SY, UK. 2Graham Kerr Building, Division of Biochemistry and Molecular Biology,
Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK. 3Rowett Research Institute,
Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK.
Abstract: Fruit and vegetable consumption is inversely related to the incidence of heart disease and several cancers.
However, many people in countries in Northern latitudes do not eat the recommended “5-a-day” of fruit and vegetables.
For such populations, a potentially important source of fruit may be locally grown soft fruits (eg. raspberries, blackberries,
blueberries, blackcurrants). Such berries contain micronutrients such as vitamin C and folic acid which are essential for
health. However, berries may have additional health benefits as they are also rich in phytochemicals such as anthocyanins
which are glycosidic-linked flavonoids responsible for their red, violet, purple and blue colours. In vitro studies indicate
that anthocyanins and other polyphenols in berries have a range of potential anti-cancer and heart disease properties
including antioxidant, anti-inflammatory, and cell regulatory effects. Such experimental data has lead to numerous health
claims on the internet implying that “berries are edible superstars that may protect against heart disease, cancers and
ageing”. However, the bioavailabilty of polyphenols such as anthocyanins would appear to be limited, thus compromising
their nutritional relevance. Consequently the aim of the article is to assess the current scientific evidence for claims that
berries may have additional health benefits to those normally associated with consuming fruit and vegetables.
Keywords: Berries, soft fruit, micronutrients, anthocyanins, cancer, heart disease.
1. INTRODUCTION
In the United Kingdom ischemic heart disease (31%),
cancer (30%) and stroke (15%) were the principal causes of
death during 2001 [1]. A major contributing factor to the
aetiology of these chronic diseases is a poor diet [2-4]. Diet
in the developed world is a complex mixture of foods with
highly variable consumption patterns. For example, a review
of the “Scottish diet” highlighted poor dietary habits and
recommended reducing intake of cakes and pastries, fats,
sugar and confectionery, while increasing fruit, vegetable
and cereal consumption [5]. However, despite recommenda-
tions to eat an average of 400g of fruit and vegetables per
day, actual daily consumption in Scotland between 1993 and
2000 only rose from 190g to 200g [6]. This is unfortunate as
considerable evidence indicates that adequate fruit and
vegetable consumption has a role in preventing many
chronic diseases, including heart disease, stroke and several
cancers, [3, 7-12], long term consumption also being
associated with decreased premature mortality rates [13].
Reasons why some populations appear reluctant to
increase intakes of fruit and vegetables are complex.
However, the persistence of traditional dietary patterns may
reflect, in part, the historical expense and lack of availability
of fresh fruit and vegetables in Northern latitudes. For such
populations, a potentially important source of plant-based
food may be locally grown soft fruits (e.g. raspberries,
strawberries, blueberries, cranberries and blackcurrants). As
with other fruit and vegetables, berries are important dietary
*Address correspondence to this author at the Rowett Research Institute,
Greenburn Road, Bucksburn, Aberdeen AB21 9SB, UK; Tel: (0) 1224
716623; Fax: (0) 1224 716629; E-mail: ggd@rri.sari.ac.uk
sources of fibre and essential vitamins and minerals. They
also contain a vast number of other phytochemicals for
which there are no known deficiency conditions but which
may have marked bioactivities in mammalian cells of
potential health benefit. These include effects on oxidative
damage, detoxification enzymes, the immune system, blood
pressure, platelet aggregation, and anti-inflammatory, anti-
bacterial and anti-viral responses [14]. Compared with most
fruit, berries are unusual in that they are rich in
anthocyanins. These are glycosidic-linked flavonoids
responsible for their red, violet, purple and blue colours.
Therefore the aim of this review is to assess whether there is
a putative role for berries and in particular the anthocyanins
and other phytochemicals they contain, in the prevention of
chronic diseases.
2. SOFT FRUITS (BERRIES AND CURRANTS)
The most commonly consumed berries are strawberries
(Fragaria x ananassa), raspberries (Rubus idaeus),
blackberries (Rubus spp.), blueberries (Vaccinium
corymbosum), black currants (Ribes nigrum) and red currants
(Ribes rubrum). There are also a number of crosses between
raspberries and blackberries available such as the loganberry
(Rubus loganbaccuus). Edible berries have been a part of
man’s diet for centuries. The modern cultivated strawberry,
for example, is a descendent of a woodland variety grown by
the Romans which was then subsequently crossed with
American and Chilean varieties around 1750. Raspberries
have been cultivated in Europe since the Middle Ages and
blackberries may have been eaten since Neolithic times [15].
Despite this historical longevity most types of berries have
never been developed beyond local markets [16], reflecting
in part their susceptibility to decay post-harvesting. A
72 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
notable exception is the American cranberry (Vaccinium
macrocarpon) which is exported worldwide both as the berry
and as a juice.
3. ESSENTIAL MICRONUTRIENTS IN BERRIES
As with other fruits, berries contain a range of
micronutrients which are essential for health. In particular,
many types of berries contain a high level of vitamin C
(ascorbic acid), so much so that often only a handful of the
fruit can provide the recommended daily allowance (RDA).
As this vitamin has antioxidant activity, acts as a cofactor in
hydroxylation reactions which are required for collagen
synthesis, has a role in hormone synthesis, the immune
system, iron absorption, platelet aggregation, thrombus
formation and may have a role in preventing heart disease,
osteoporosis and a range of cancers, [17-22] berries are an
obvious dietary source for populations with sub-optimal
vitamin C status. The biological roles of vitamin C are
reviewed in detail in [23].
Berries can also be significant dietary sources of folic
acid, a water soluble B vitamin which as well as being
essential to prevent neural tube defects in new-borne babies
also may play a role in reducing risk of heart disease and
cancer through a range of mechanisms including lowering
homocysteine levels, catalysing nitric oxide formation and
maintaining DNA stability [24, 25]. For a recent review of
the physiology of folate and vitamin B12 in health and
disease, see [26].
4. PHYTOCHEMICALS IN BERRIES
Phytochemicals are not required for normal functioning
of the body and their absence does not result in a deficiency
condition. However, they may have bioactivity in
mammalian cells which could impact on health and disease.
Berries are a rich source of such phytochemicals, in
particular anthocyanins and flavonols. Concentrations in
berries will be influenced by many factors including
environmental conditions, degree of ripeness, cultivar,
cultivation site, processing and storage of the fruit [27-29].
The anthocyanins are conjugated anthocyanidins, which
provide the distinctive and vibrant palate of colours found in
dark berries. There are six anthocyanidins distributed
throughout the plant kingdom; cyanidin, malvidin,
delphinidin, peonidin, petunidin and pelargonidin (Fig. 1).
They form conjugates with a number of sugars, in particular
glucose, sophorose, rutinose, rhamnose, galactose, arabinose
and xylose (Fig. 2). The structures of the main anthocyanins
in berries are summarised in Figure 2 and listed in more
detail along with other phenolics in (Table 1). There is much
variety and while some fruits, such as cranberry (Vaccinium
macrocarpon) and elderberry (Sambucus nigra), contain
derivatives of only one type of anthocyanin (i.e. cyanidin), a
wide array of anthocyanins is found in blueberry (Vaccinium
corymbosum) and blackcurrant (Ribes nigrum). In general
the anthocyanin profile of a tissue is characteristic, and it has
been used in taxonomy, and for the detection of adulteration
of juices and wines. Blackcurrants are characterised by the
presence of the rutinosides and glucosides of delphinidin and
cyanidin [30], with the rutinosides being the most abundant.
Other anthocyanins and flavonol conjugates have been
Anthocyanidin R1R2Colour
Pelargonidin H H orang-red
Cyanidin OH H red
Delphinidin OH OH pink
Peonidin OCH3H bluish purple
Petunidin OCH3OH purple
Malvidin OCH3OCH3redish purple
Fig. (1). Structures of the major anthocyanins
noted, but at much lower concentrations [31, 32]. Whilst
redcurrants (Ribes rubrum) are very closely related to
blackcurrants, they contain mainly cyanidin diglycosides
with cyanidin monoglucosides present only as minor
components [33]. Strawberries (Fragaria x ananassa),
blackberries (Rubus spp.), and red raspberries (Rubus idaeus)
are all from the Rosaceae family but they have a diverse
anthocyanin content. The major anthocyanins in raspberries
and blackberries are derivatives of cyanidin, while in
strawberries pelargonidin glycosides predominate [33]. The
major components in blueberries are delphinidin-3-
galactoside and petunidin-3-glucoside, however, many minor
anthocyanins are also present [34, 33]. Cranberries belong to
the Ericaceae, the same family as blueberries, but have
cyanidin-based compounds as their major anthocyanins [35].
As with cranberries, blackberries and raspberries, the major
anthocyanins in elderberries are cyanidin-based, with
cyanidin-3-sambubioside and cyanidin-3-glucoside predo-
minating [36] (Table 1, Fig. 2).
Flavonols and other flavonoids are commonly quantified
as the aglycone after acid or enzyme hydrolysis to remove
sugar residues [37, 38]. Using this approach the myricetin,
quercetin and kaempferol content (Fig. 3) of edible berries
had been estimated [39]. Quercetin was found to be highest
in bog whortleberry (Vaccinium uliginosum) (15.8 mg/100
g), bilberry (Vaccinium myrtillus) (1.7 – 3.0 mg/100 g) and
in elderberries. In blackcurrant cultivars, myricetin was the
most abundant flavonol (8.9 – 20.3 mg/100 g), followed by
quercetin (7.0 – 12.2 mg/100 g) and kaempferol (0.9 – 2.3
mg/100 g) [40]. In comparison, the total anthocyanin content
of red raspberries is ca. 60mg/100g [41]. Specific flavonol
glycosides that have been identified in berries include
quercetin-3-glucoside, quercetin-3-rutinoside quercetin-3-
galactoside and quercetin-3-xylosylglucuronide, myricetin-3-
glucoside, myricetin-3-galactoside and myricetin-3-
rutinoside (Fig. 4, Table 1) [42-45].
Berries can contain substantial amounts of the flavan-3-ol
monomers (+)-catechin and (-)-epicatechin as well as dimers,
trimers and polymeric proanthocyanidins (Fig. 5). The
O
R1
OH
R2
OH
HO
OH
3
5
7
3'
5'
+
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 73
Fig. (2). Structures of the major anthocyanins in berries.
OHO
OH
O
OH
OH
O
OH
HO
OH
OH
HO
OHO
OH
O
OH
OH
O
O
HO
HO
HO
O
OH
HO
HO
OHO
OH
O
OH
OH
O
O
HO
HO
HO
O
OH
HO
HO
O
OH
HO
HO
CH3
OHO
OH
O
OH
OH
O
O
O
HO
HO
O
OH
HO
HO
O
OH
HO
HO
CH3
OHO
OH
O
OH
OH
O
OH
O
HO
HO
OH
O
OH
HO
HO
CH3
OHO
OH
O
OH
OH
O
OH
O
HO
HO
OHO
OH
O
OH
OH
O
OH
HO
HO
OHO
OH
O
OH
OH
O
OH
HO
OH
HO
OHO
OH
O
CH3
OH
O
OH
HO
HO
HO
OH
OHO
OH
O
OH
O
OH
HO
HO
HO
OHO
OH
O
OH
O
OH
HO
HO
HO
OH
Cyanidin-3-O-sambubioside
(Elderberry)
Cyanidin-3-O-sophoroside
(Raspberry)
Cyanidin-3-O-(2G-O-xylosylrutinoside)
(Redcurrant, Raspberr y)
Delphinidin-3-O-rutinoside
(Blakcurrant)
Cyanidin-3-O-rutinoside
(Blakcurrant, Blackberry)
Cyani din-3-O-arabinoside
(Cra nberry)
Dephinidin-3-O-galactoside
(Blueberry)
Cyanidin-3-O-gal actoside
(Cra nberry)
Petunidin-3-O-glucoside
(Blueberry)
Pelargo nidin-3-O-glucoside
(Strawberry)
Cyanidin-3-O-g lucoside
(Blac kberry, Strawberr y, Elderb erry)
+
+
74 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
concentration of the polymers is usually greater than the
monomers, dimers and trimers and overall, cranberries are a
particularly rich source of these compounds [46, 47]
(Table 2).
The hydroxybenzoate, ellagic acid (Fig. 6) has been
reported to be present in berries, particularly raspberries
(0.58 mg/100 g), strawberries (1.8 mg/100 g) and
blackberries (8.8 mg/100 g) [48]. Indeed ellagic acid has
been described as being responsible for > 50% of total
phenolics quantified in strawberries and raspberries [49]. In
reality, however, free ellagic acid levels are generally low,
although substantial quantities are detected along with gallic
acid after acid hydrolysis of extracts as a product of
ellagitannin breakdown (Fig. 6). For instance, red
raspberries, the health benefits of which are often promoted
Table 1. Endogenous Phenolics in Berries. Major Components Indicated in Bold Font
Common name Genus and species Family Phenolics Reference
Blackcurrant Ribes nigrum Grossulariaceae Del-3-Rut; Cy-3-Rut; Del-3-Glc; Cy-3-Glc
Peo-3-Rut, Mal-3-Rut
Mal-3-Rut, Mal-3-Glc, Myr-3-Rut, Myr-3-Glc,
Q-3-Rut, K-3-Glc
Matsumoto et al., 2001a
Frøytlog et al., 1998
Hakkinen and Auriola, 1998
Määttä et al., 2003
Redcurrant Ribes rubrum Grossulariaceae Cy-3-Glc-Rut, Cy-3-Soph, Cy-3-Glc, Cy-3-Xyl-Rut,
Cy-3-Rut Goiffon et al., 1999
Strawberry Fragaria ×
ananassa Rosaceae Pel-3-Glc, Cy-3-Glc, Pel-3-Ara
Ellagic acid Goiffon et al., 1999, Bridle
and Garcia-Viguera, 1997
Amakura et al., 2000
Blackberry Rubus spp. Rosaceae Cy-3-Sop, Cy-3-Glc-Rut, Cy-3-Glc, Cy-3-Rut, Q-3-Gal,
Q-3-Glc, Q-3-Rut, Q-3-XylGlcAC, lambertianin C Hong and Wrolstad, 1990
Cho et al., 2004,
Degénéve 2004
Red raspberry Rubus idaeus Rosaceae Cy-3-Sop, Cy-3-Glc-Rut, Cy-3-Rut, Cy-3-Glc,
Pel-3-Sop, Pel-3-Glc-Rut, Cy-3,5-DiGlc, Cy-3-Samb,
Pel-3-Glc, Pel-3-Rut, sanguiin H-6, lambertianin C, Q-
3-Rut, Q-3-Glc, Q-3-GlcAC
Boyles and Wrolstad, 1993
Mullen et al., 2002
Blueberry Vaccinium
corymbosum Ericaceae Del-3-Gal, Del-3-Glc, Cy-3-Gal, Del-3-Ara,
Cy-3-Glc, Pet-3-Gal, Cy-3-Arab, Pet-3-Glc,
Peo-3-Gal, Pet-3-Arab, Peo-3-Glc, Mal-3-Gal, Peo-3-
Arab, Mal-3-Glc, Mal-3-Arab, caffeoylquinic acids,
Q-3-Gal, Q-3-Glc, Q-3-Rut
Kader et al., 1996;
Goiffon et al., 1999;
Prior et al., 2001,
Cho et al., 2004
Cranberry Vaccinium
macrocarpum Ericaceae Cy-3-Gal, Cy-3-Ara, Cy-3-Gal, Cy-3-Ara, Myr-3-Gal,
Q-3-Gal, Q-3-Rham Huopalahti et al., 2000;
Prior et al., 2001;
Vvedenskaya et al., 2004
Elderberry Sambucus nigra Caprifoliaceae Cy-3-Samb-5-Glc, Cy-3,5-DiGlc,
Cy-3-Samb, Cy-3-Glc Bridle and Garcia-Viguera,
1997
Abbreviations: Cyanidin (Cy); Pelargonidin (Pel); Peonidin (Peo), Petunidin (Pet), Malvidin (Mal), Quercetin (Q), Myricetin (Myr), Kaempferol (K); Glucoside (Glc), Diglucoside
(DiGlc); Sophoroside (Sop); Xyloside (Xyl); Acetylxyloside (XylAc); Arabinoside (Ara); Acetylarabinoside (AraAc); Glucuronide (GlcAC); Xylosylglucuronide (XylGlcAC);
Acetylglucoside (GlcAc); Galactoside (Gal); Rhamnoside (Rham), Rutinoside (Rut); Sambubioside (Samb).
Fig. (3). Structures of the flavonol aglycones kaempferol, quercetin, isorhamnetin and myricetin.
O
OH
OH
OOH
HO O
OH
OH
OOH
HO
OH
O
O
H
OH
OOH
HO
OH
OH
Kaempferol Quercetin Myricetin
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 75
on the basis of a high ellagic acid content, contain ca. 100
µg/100 g of ellagic acid compared to ca. 30 mg/100g of
ellagitannins, mainly in the form of sanguiin H-6 and
lambertianin C (Fig. 6) [41]. Berries also contain a variety of
hydroxycinnamates including caffeoyl/feruloyl esters but
usually they are present in low concentrations [50] although
in other fruits compounds such as 5-caffeoylquinic acid
(chlorogenic acid) can accumulate in substantial
concentrations.
5. POTENTIAL HEALTH PROPERTIES OF BERRY
PHYTOCHEMICALS
There is a lack of epidemiological studies relating
consumption of berries to disease risk. However, flavonoid
intake and risk of CHD mortality was first investigated using
the 7-Countries Study – a cross-cultural correlation study
composed of 16 cohorts followed-up for 25 years after initial
baseline measurements collected around 1960 [51]. The
average intake of flavonols and flavones combined was
found to be inversely associated with CHD mortality,
statistically explaining 25% of the variability in CHD rates
across the cohorts. There have subsequently been at least 7
epidemiological studies that appear to corroborate Hertog’s
original findings although weak but inverse relationships
between intake and CHD have also been described [14].
Similarly, flavonoid intake has also been associated with
decreased risk of cancer in some but not all studies [52, 53].
Numerous in vitro studies also indicate that plant secondary
metabolites can potentially affect diverse processes in
mammalian cells which, if also occurring in vivo, could have
Fig. (4). Structures of flavonol glycosides.
OHO
OH O
O
OH
OH
O
OH
O
HO
HO
O
OH
HO
HO
CH3
OHO
OH O
O
OH
OH
O
OH
HO
HO
HO
OHO
OH O
O
OH
OH
O
OH
HO
HO
OH
OHO
OH O
O
OH
OH
O
O
HO
HO
HO
O
OH
HO
HO
OHO
OH O
O
OH
OH
O
OH
HO
HO
HO
OH
OHO
HO O
O
OH
O
O
OH
HO
HO
HO
O
HO OH
OH
OH
OHO
OH O
OH
OH
OO
HO OH
OH
O
H
Quercetin-3-glucoside Quercetin-3-galactoside Quercetin-3-xyloglucoside
Quercetin-3-rutinoside Myricetin-3-glucoside
Quercetin-3,4'-O-diglucoside Quercetin-4'-O-glucoside
76 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
anti-carcinogenic and anti-atherogenic implications. These
processes include gene expression, apoptosis, platelet
aggregation, LDL oxidation, blood vessel dilation, intercellu-
lar signalling, P-glycoprotein activation and the modulation
of enzyme activities associated with carcinogen activation
and detoxification (reviewed in [54]). For example, extracts
of bilberry, rich in delphinidin and malvidin glycosides
induce apoptosis in human leukaemia HL60 cells, the former
also inhibiting the growth of colon cancer HCT116 cells
[55]. Similarly, anthocyanins and hydroxycinnamic acids
from blueberry and cranberry protect endothelial cells
against TNFα induced inflammatory responses [56].
Other flavonols found in fruit including berries, such as
quercetin, have been shown to inhibit cyclooxygenase and
lipoxygenase activities [57]; both enzymes are involved in
the release of arachidonic acid, the initiator of a general
inflammatory response. Quercetin also exerts a preferential
Fig. (5). Structures of the flavan-3-ol monomers (+)-catechin and (-)-epicatechin and oligomeric proanthocyanidins.
Table 2. Concentration of Flavan-3-ol Monomers, Dimers and Trimers and Total Proanthocyanidins in Berries. Data Expressed as
mg/100g Fresh Weight ± Standard Deviation. n.d. – Not Detected; n.a. – Not Analysed; PA – Proanthocyanidins
Berry Monomers Dimers Trimers Total PAs Source
Blackcurrant 0.9 ± 0.2 2.9 ± 0.4 3.0 ± 0.3 122 ± 28 Gu et al., (2004)
Redcurrant 3.2 1.9 n.d. n.a de Pascual-Teresa et al., (2000)
Strawberry 4.2 ± 0.7 6.5 ± 1.3 6.5 ± 1.2 145 ± 25 Gu et al., (2004)
Blackberry 3.7 ± 2.2 6.7 ± 2.9 3.6 ± 1.9 27 ± 17 Gu et al., (2004)
Red raspberry 4.4 ± 3.4 11 ± 10 5.5 ± 5.7 30 ± 23 Gu et al., (2004)
Blueberry 4.0 ± 1.5 7.2 ± 1.8 5.4 ± 1.2 180 ± 51 Gu et al., (2004)
Cranberry 7.3 ± 1.5 26 ± 6.1 70 ± 13 419 ± 75 Gu et al., (2004)
O
OH
OH
HO
OH
OH O
OH
OH
HO OH
OH
O
OH
OH
HO OH
OH
O
OH
OH
HO OH
OH
O
OH
OH
HO OH
OH
(-)-Epicatechin (+)-Catechin
n
Oligomeric Procyanidins
n = 0, dimeric
n = 1, trimeric
n = 2, tetrameric
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 77
cytotoxic effect on dividing colon carcinoma HT29 and
CACO2 cells [58] and induces apoptosis in human
leukaemia HL60 cells following inhibition of growth.
Possible mechanisms of action could include, increased
expression of wild type p53 [59], reduction of Ki ras levels
[60] or p21 upregulation [61]. Quercetin also inhibited DNA
synthesis in human leukaemia HL60 cells [61, 62] and
animal studies indicate that the incidence of carcinogen
induced mammary tumours and lung tumours were
decreased by dietary administration of quercetin [63, 64].
Extensive research has been carried out on the potential anti-
cancer properties of ellagic acid, mediated in a number of
mechanisms [65] such as the inhibition of metabolic
activation of carcinogens [66], protection of DNA from
alkylation by binding sites that may react with carcinogens
[67] and the regulation of cell cycle progression and cell
death (apoptosis) in cancer cells.
Potential cardiovascular protective effects of
ellagitannins have also been reported as vasorelaxation assays
on rabbit aorta found that sanguin H-6 and lambertianin C,
were the active components of raspberry extracts responsible
for vasorelaxation activity [68]. The flavonols quercetin and
catechin were found to act synergistically to inhibit platelet
aggregation and adhesion to collagen [69], atherosclerotic
Fig. (6). Raspberries contain high concentrations of two ellagitannins, sanguiin H-6 and lambertianin C. When extracts are treated with acid
the ellagitannins are hydrolysed releasing substantial quantities of ellagic acid.
OH
HO
HO
HO
HO
OH
C
CO
O
OO
OO
C OCO
HO
HO
HO OH
OH
OC
OH
OH
HO
HO
HO
HO
OH
C
CO
O
O
OO
O
O
C O
CO
HO
HO
HO OH
OH
OC
OH
O
OH
OH
O
OH
OH
OH
OH
HO
HO
HO
HO
OH
C
CO
O
O
OO
OO
C OCO
HO
HO
OH OH
OH
OC
OH
OH
HO
HO
HO
HO
HO
C
CO
O
O
OO
O
O
C OCO
HO
HO
OH OH
OH
OC
OH
O
OH
OH
O
OH
HO
HO
HO
HO
HO
C
CO
O
O
OO
O
O
C O
CO
HO
HO
OH OH
OH
OC
OH
O
OH
OH
OOH
OH
OH
O
O
O
OH
HO O
OH
OH
O
Sanguiin H-6
Lambertianin C
Ellagic acid
O
78 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
lesions being reduced by 46% in apolipoprotein E deficient
mice when added to the diet [70].
Much attention has focussed on the ability of compounds
such as anthocyanins and flavonols to act as antioxidants.
This is possibly unsurprising as there is a substantial body of
epidemiological and experimental literature suggesting that
inadequate intakes of recognised nutritional antioxidants
such as vitamin E, vitamin C and carotenoids can lead to
oxidative damage of proteins, lipids and DNA in vivo. This,
in turn, may predispose the development of many chronic
diseases [71]. The antioxidant effectiveness of anthocyanins
and other polyphenols in vitro is essentially due to the ease
with which a hydrogen atom from an aromatic hydroxyl
group is donated to a free radical [72]. In addition, their
ability to chelate transition metal ions involved in radical-
forming processes such as Fenton reactions [73, 74] and the
induction of endogenous antioxidants [75] could also
contribute to antioxidant efficacy of the compounds.
Consequently, numerous studies have shown that many
phenolic compounds found in fruits and vegetables,
including berries, inhibit the oxidation of LDL and DNA in
vitro e.g. [76, 77].
6. ABSORPTION OF BERRY PHYTOCHEMICALS
Although phytochemicals found in berries may exert
numerous effects in vitro, they have to be absorbed from the
gut if they are to exert a similar effect in systemic cells and
tissues. This absorption will depend on numerous factors
including molecular structure, the amount consumed, the
food matrix, degree of bioconversion in the gut and tissues,
the nutrient status of the host and genetic factors. Ingestion
of fresh strawberries (240g), freeze dried blueberries (100g)
and berry juices have all been reported to increase the
antioxidant capacity of blood plasma by 14-30%. [78, 79]
[80-82] which suggests that some phytochemicals with
antioxidant properties are absorbed [83, 84]. However, this
view has recently been challenged as any change in plasma
antioxidant capacity after fruit consumption may be mainly
due to fructose mediated increases in uric acid rather than
fruit-derived antioxidants [85]. This is compatible with the
observation that the absorbtion of anthocyanins and other
flavonoids from the diet is relatively low.
Anthocyanins
A variety of anthocyanins appear in urine after
supplementation with berries or berry extracts but in very
low concentrations, usually 0.1%, or less, of the ingested
dose [86]. Anthocyanins have also been found in human
plasma in very low concentrations 0.5-1 h after consumption,
falling to near baseline levels within 6-8 h. After the
consumption of an elderberry extract by elderly women, the
main elderberry anthocyanins, cyanidin-3-glucoside and
cyanidin-3-sambubioside, were detected in plasma. [87].
Thus, glycosylated anthocyanins, unlike flavonol glycosides,
appear in the bloodstream. This may be a consequence of the
fact that, in contrast to quercetin glucosides, anthocyanin
glucosides are not hydrolysed by human small intestine β-
glucosidases [88]. Studies with rats indicate that anthocyanin
absorption occurs in the stomach as well as the small
intestine [89-91].
Although only unmodified anthocyanins have been
usually detected in urine after supplementation [86],
improved analytical techniques are now beginning to reveal
the presence of lower levels of methylated, glucuronidated
and sulphated metabolites. For instance after consumption of
elderberries, as well as cyanidin-3-glucoside and cyanidin-3-
sambubioside, urine was found to contain four metabolites,
peonidin-3-glucoside, peonidin-3-sambubioside, a peonidin
glucuronide and a cyanidin-3-glucosylglucuronide. This
demonstrates that methylation of the 3'-hydroxyl group had
occurred as well as glucuronidation at an as yet undetermi-
ned position (Fig. 8) [92]. In a study with strawberries,
which contain pelargonidin-3-glucoside, the predominant
anthocyanin to appear in urine was not the parent glucoside
but three pelargonidin glucuronides, a pelargonidin sulphate
and the aglycone pelargonidin [93].
Flavonols
The absorption and excretion of flavonols in humans and
model animal systems has been studied extensively.
Although these investigations have not involved berries,
flavonols that occur in berries such as quercetin-3-glucoside
and the disaccharide quercetin-3-rutinoside (Fig. 5) have
been extensively investigated. Flavonol aglycones, such as
quercetin (Fig. 3) are hydrophilic and can passively diffuse
across biological membranes. Flavonol glycosides, in
contrast, are more water-soluble molecules which greatly
limits their rate of diffusion through cell membranes. Thus, if
the glycosides, which occur in berries and are the major
components in other fruits and vegetables, are to be absorbed
into the circulatory system some form of transport system is
likely to be involved. On the basis of indirect evidence it has
been proposed that flavonol glucosides, such as quercetin-3-
glucoside, can be absorbed intact into the small intestine
using the sodium-dependent glucose transporter (SGLT1)
[94]. There is evidence that supports the involvement of
SGLT1 in the uptake of flavonol glucosides [95] [96].
However, other studies with human intestinal Caco-2 cell
monolayers have shown that quercetin-4'-glucoside is not
absorbed despite the operation of SGLT1 which was
demonstrated by the active transport of glucose [97]. Further
research is required to determine the mechanism(s) by which
flavonols and other flavonoids are transported from the
lumen of the gastrointestinal (GI) tract into the bloodstream.
Studies with human volunteers have been carried out
following consumption of lightly fried onions, which contain
especially high concentrations of flavonol conjugates, princi-
pally quercetin-4'-glucoside and quercetin-3,4'-diglucoside
(Fig. 4). Aziz et al. (1998) [98] reported that following
ingestion of 300g of lightly fried onions by human volunteers,
conjugatedquercetin (quercetin released by acid hydrolysis,
therefore probably originating from quercetin glucuronide
and sulphate metabolites – see below) appeared in plasma. A
peak plasma concentration of almost 2 µM was reached after
1 h and levels declined ca. 3-fold over the next 4 hours and
only trace quantities remained at 24 hours (Fig. 10A).
Subsequently Day et al. (2001) [99] used HPLC with MS
and diode array detection to analyse human plasma collected
1.5 h after ingestion of onions. A mixture of glucuronidated
and sulphated conjugates of quercetin and methylquercetin
were identified. In total 12 quercetin conjugates were
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 79
detected, the major components being quercetin-3-O-
glucuronide, its 3'-methylated derivative, isorhamnetin-3-
glucuronide, a quercetin diglucuronide and quercetin-3'-
sulphate (Fig. 7). There was, therefore, extensive metabolism
of the parent flavonol glucosides involving deglycosylation,
glucuronidation, sulphation and methylation. In a further
study a total of twenty three flavonol metabolites,
comprising a mixed range of sulphate, methyl, glucuronide
and glucoside derivatives of quercetin, were detected in
plasma and urine after the consumption of onions [100].
Quercetin glucosides are deglycosylated by β-
glucosidases in the small intestine, namely broad specific
cytosolic β-glucosidase (CBG) and lactase phloridzin
hydrolase (LPH) [101]. The aglycone does not accumulate
but is metabolised by uridine-5'-diphosphate glucuronyl-
transferases, sulphotransferases and/or catechol-O-
methyltransferases [102]. Studies with rats following
ingestion of [2-14C]quercetin-4'-glucoside indicate that as
well as transport in the bloodstream there is a substantial
efflux of the various quercetin metabolites back into the
lumen of the GI tract [103]. Quercetin metabolites which do
enter the circulatory system and gain access to the liver may
then be further methylated, glucuronidated or sulphated
[102]. Although there is evidence that enterohepatic
circulation returns quercetin metabolites to small intestine,
the extent to which this occurs is as yet unknown. The
disaccharide, quercetin-3-rutinoside, which is found in
berries, as well as apples and tea, is not a substrate for either
LPH or CBG. In addition, it has a lower and delayed peak
plasma concentration than quercetin-4'-glucoside [104]
indicating that it may be absorbed in the distal section of the
small intestine and/or the large intestine where it is probably
degraded by colonic bacteria [88].
Flavan-3-ols
Monomeric flavan-3-ols as well as dimers, trimers and
oligomers are present in berries (Table 2) but information on
the absorption and metabolism of these compounds comes
primarily from studies with (-)-epicatechin, (+)-catechin,
procyanidin-rich chocolate and grape seed extracts. (-)-
Epicatechin and (+)-catechin are absorbed in humans and
animals appearing in plasma and urine primarily as
glucuronidated, methylated and sulphated metabolites [105]
[106-110]. Peak plasma concentrations typically occur 1-2 h
after ingestion. Identified human plasma and urinary
metabolites include (-)-epicatechin-3'-glucuronide, 4'-methyl-
(-)-epicatechin-3'-glucuronide while in rats formation of 3'-
methyl-(-)-epicatechin, (-)-epicatechin-7-glucuronide, 3'-
methyl-(-)-epicatechin-7-glucuronide occurs (Fig. 9) [111].
There is conflicting evidence on the absorption and
metabolism of the oligomeric and polymeric flavan-3-ols in
humans and animals. Koga et al. (1999) [112] observed the
presence of (+)-catechin and (-)-epicatechin and an absence
of dimers in the plasma of rats following ingestion of a grape
seed extract. Extending this study, Donovan et al. (2002)
[113] fed rats a GSE, (+) catechin and procyanidin B3 meals.
While conjugated metabolites of (+)-catechin were detected
in plasma and urine after both the (+)-catechin and GSE
meals there was no evidence of absorption for the
procyanidins. However, in another study (-)-epicatechin and
(+)-catechin and trace amounts of procyanidin dimer B2 were
detected in sulfatase- and β-glucuronidase-treated human
plasma collected 30 min after ingestion of a cocoa beverage
rich in flavan-3-ol monomers and procyanidins [114]. In
keeping with this report, it has been shown that after oral
administration of B2 to rats, the dimer was absorbed and
excreted in urine with a portion of the procyanidin being
converted to (-)-epicatechin which undergoes post-ingestion
conjugation and methylation [109]. On balance, however, the
available evidence indicates that flavan-3-ol dimers, trimers
and oligomers are, at best, poorly absorbed [115].
Sanguiin H-6 and lambertianin C (Fig. 6) occur in high
concentrations in raspberries [68] and both blackberries and
Fig. (7). Flavonol metabolites detected in human plasma.
O
OH
OH
HO
HO O
OO
HO OH
OH
COOH
O
OH
OCH3
HO
HO O
OO
HO OH
OH
COOH
O
OH
OSO3
80 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
strawberries also contain substantial amounts of ellagitannins
[116]. These compounds which have a molecular weight in
excess of 1000 Da would appear to be too large to be
absorbed into the circulatory system. They are, however,
strong antioxidants [103] [116] and could exert protective
effects as they pass through the GI-tract. In addition, they
could also be depolymerised to some degree releasing gallic
acid and ellagic acid which would be absorbed more readily.
7. BIOAVAILABILITY OF BERRY PHENOLICS
In addition to absorption, the activity of phytochemicals
in vivo will also depend on the extent and manner of their
metabolism by liver and kidney, their rate of excretion and
the degree they are sequestered in body tissues. However,
generally the bioavailability of dietary flavonoids has been
difficult to assess. Quantitative analysis of quercetin in acid
hydrolysed urine collected over a 24 h period after ingestion
of onions accounted for 0.8% of the amount ingested and
extrapolations from the amounts present in the bloodstream
at peak plasma concentration also yielded a figure of 0.97%
(Fig. 10A) [98]. However, studies with ileostomy volunteers
in which ileal fluid was analysed after ingestion of onions
indicate that 50-75% of the onion flavonol glucosides are
absorbed [94] [117]. To what extent and in what form the
“missing” flavonols are bioavailable and sequestered in body
tissues remains to be determined.
Dietary phenolics and their metabolites which are not
absorbed in the small intestine pass into the large intestine
and there is currently much interest in their possible
catabolism by colonic bacteria resulting in ring fission and
the formation of low molecular weight catabolites such as
hippuric acid, benzoic acid and hydroxyphenylacetic acids
[118]. Some of these acidic urinary catabolites are also
products of other metabolic pathways unrelated to either
flavonoid or hydroxycinnamate breakdown and they are
present in substantial quantities in urine before
supplementation. The assumption that relatively minor
changes in the levels of these compounds are a direct
consequence of the breakdown of the ingested phenolic
compound is somewhat premature especially when, in the
absence of studies using isotopically labelled substrates,
detailed catabolic pathways are proposed [119-121].
Anthocyanins appear in plasma and are excreted in urine
in far smaller concentrations than flavonols. This is evident
in Figure 10 where the peak plasma concentration of the
cyanidin-3-glucoside and cyanidin-3-sambubioside was ca.
100 nM which is ca. 20-fold lower than the conjugated
quercetin that accumulated in plasma after eating onions.
Fig. (8). Elderberrries contain cyanidin-3-glucoside and cyandidn-3-sambubioside which are converted to a number of metabolites including
peonidin-3-glucoside and peonidin-3-sambubioside prior to excretion in urine.
O
OH
OH
OH
HO
O
O
HO
HO OH
HO
O
OH
OH
OH
HO
O
O
HO
HO O
HO
O
HO
HO OH
O
OCH3
OH
OH
HO
O
O
HO
HO OH
HO
O
OCH3
OH
OH
HO
O
O
HO
HO O
HO
O
HO
HO OH
+
Cyanidin-3-glucoside
+
Cyanidin-3-sambubioside
+
Peonidin-3-glucoside
+
Peonidin-3-sambubioside
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 81
Conjugated quercetin excreted after eating onions
corresponded to 0.98% of the amount ingested [98] while
figures for anthocyanins are typically 0.1% or less [86] with
one exception, the urinary excretion of anthocyanins from
strawberries which corresponded to 1.8% of the amount
consumed [93]. This was accredited to analysing the urine
immediately after collection as opposed to after storage of
frozen samples. However, studies with urine collected after
dosing with raspberries have failed to detect any differences
in the anthocyanin content of fresh or thawed frozen urine
with the recovery in both instances being ca. 0.1% (Borges
and Crozier, unpublished). The higher urinary recovery of
anthocyanins occurring after the ingestion of strawberries
may, therefore, be a special feature of pelargonidin-3-
glucoside.
It is unclear why plasma and urinary levels of
anthocyanins are usually much lower than those of flavonols
after supplementation. There are two possible factors that
may have an influence on absorption. As mentioned earlier,
anthocyanins are not hydrolysed by GI tract β-glucosidases
[88] and this may reduce the amounts that pass through the
gut wall into the bloodstream. However, a recent study in
which anthocyanin absorption was investigated after in situ
perfusion of the jejunum + ileum found that absorption
ranged from 10.7% for malvidin-3-glucoside to 22.4 % for
cyanidin-3-glucoside [90]. This is much higher than indirect
estimates of anthocyanin absorption based on either plasma
content or urinary excretion levels. A further factor to
consider, in addition to catabolism to hydroxyphenylacetic
acids and related compounds, is that at low pH anthocyanins
exist as flavylium cations but can undergo pH-dependent
structural changes [122]. They will be at ca. pH 6 in the GI
tract, the circulatory system and body tissues so there may be
conversion to other forms such as chalcones which are not so
readily detected as the red coloured flavylium ion.
Fig. (9). (-)-Epicatechin metabolites that are produced in humans (H) and rats (R).
Fig. (10). Pharmacokinetics of (A) conjugated quercetin levels in plasma after the consumption of onions by human volunteers (n = 5) (Aziz
et al. 1998) and (B) cyanidin-3-O-glycosides after the ingestion of an elderberry extract by elderly women (n = 4) (Cao et al. 2001). Data
presented as mean values ± standard error.
O
OH
O
HO
OH
OH
O
HO OH
OH
COOH
O
OCH3
O
HO
OH
OH
O
HO OH
OH
COOH
O
OH
OH
O
OH
OH
O
HO OH
HO
HOOC
O
OH
OCH3
HO
OH
OH
O
OH
OCH3
O
OH
OH
O
HO OH
HO
HOOC
(-)-Epicatechin-3'-glucoronide (H) 4'-Methyl-(-)-epicatechin-3'-glucuronide (H)
(-)-Epicatechin-7'-glucuronide (R) 3'-O-Methyl-(-)-epicatechin (R) 3'-Methyl-(-)-epicatechin-7-glucoronide (R)
82 Current Nutrition & Food Science, 2005, Vol. 1, No. 1 Duthie et al.
Flavan-3-ol monomers appear to be efficiently absorbed
into the bloodstream as Donovan et al. (2002) [113] fed rats
a single 20 mg (+)-catechin supplement and observed that
urinary excretion of (+)-catechin metabolites over a 24 h
period corresponded to 37% of the ingested dose. This is
much higher than equivalent figures obtained with flavonols
and anthocyanins and indicates that flavan-3-ol monomers
are efficiently absorbed from the GI-tract into the circulatory
system.
Although the term bioavailability is used freely in the
literature, information is only beginning to emerge on the
levels and identity of phenolic compounds and their in vivo
metabolites that appear in the circulatory system after
ingestion of berries and other fruits and vegetables.
Saturation of metabolic pathways by “pharmacological”
doses appear to be required to obtain the free form in the
blood [123]. Ingestion of nutritionally relevant amounts
results in extensive deglycosylation, glucuronidation,
sulphation and methylation reactions mediated by a range of
enzymes in the small intestine, liver and colon. The extent
and identity of these in vivo metabolites that accumulate in
body tissues is very poorly understood although information
is beginning to be obtained from feeding radiolabelled
flavonoids to model animal systems [103]. It is, however,
clear that in most instances once flavonoids and other
phenolics enter the circulatory system they undergo
extensive metabolism. Thus, if physiological studies, with
cell cultures and in vitro test systems, investigating potential
protective effects are to be of any relevance they should be
making use of genuine in vivo metabolites, like quercetin-3-
glucuronide and quercetin-3'-sulphate, and not aglycones or
glycosides which do not accumulate in the body [124]. This
should be borne in mind in relation to the following section
on possible health benefits of consuming berries.
8. STUDIES SUGGESTING HEALTH BENEFITS OF
BERRIES
8.1. Cancer
Cancer development is commonly recognised as a
microevolutionary process that requires the cumulative
action of multiple events. (1) initiation: induction of DNA
mutation in a somatic cell, (2) promotion: stimulation of
tumourigenic expansion of the cell clone, (3) progression:
malignant conversion of the tumour into cancer [125]. In
vitro studies suggest that certain berry extracts can moderate
such processes in particular by inhibiting the growth and
proliferation of cancer cells, inducing cell death [126], [55]
and impairing angiogenesis through inhibition of expression
of vascular endothelial growth factor VEGF [127]. Results
from animal models, however, are equivocal. For example,
inclusion of freeze dried black raspberries and strawberries
[128] in the diets of rats given a tumour initiator resulted in
decreased progression, incidence and multiplicity of
oesophageal tumours. However, similar effects were not
observed with blueberries [129]. A human intervention study
did find that after 5 weeks consumption of berry juice
(aronia, blueberry and boysenberry), there was a decrease in
oxidised DNA bases in peripheral blood mononuclear cells
[81] although whether this implies a decrease in risk of
developing cancer is uncertain.
8.2 Heart Disease
Uptake of oxidised low density lipoprotein cholesterol by
monocytes and macrophages in the vascular endothelium
may be a key event in the development of the plaque which
occludes the coronary arteries [130, 131]. Although in vitro
studies have shown that extracts from blackberry, cherry,
raspberry, blueberry and bilberry can inhibit LDL oxidation
[132, 133], results from intervention studies have been
disappointing. For example, no significant inhibition of LDL
oxidation was observed after volunteers had consumed 100g
of berries per day (blackcurrants, bilberries and
lingonberries) for 8 weeks [134]. Similarly, consumption of
berry juice did not affect plasma lipids, LDL oxidation,
platelet aggregation and adhesion molecule concentration in
a healthy population [135].
8.3. Immune System
Consumption of 330ml berry juice per day for 2 weeks is
reported to increase lymphocyte responsiveness to mitogen
activation, enhanced natural killer cell lytic activity and T-
lymphocyte specific cytokine secretion by human volunteers
suggesting enhanced immune function [81]. Whether such
potentially beneficial effects are specific to berries or reflect
a more general response to increased fruit intake is unclear.
8.4. Neurological Function
Diet may play a role in improving age-related
neurological dysfunction [136] and studies with aged rats
have reported that dietary berry extracts can protect against
and even reverse certain age-induced declines in brain
function such as those in learning, memory, motor
performance and neuronal signal transduction [137, 138],
[139, 140].
8.5. Urinary Tract Health
The effects of cranberries on urinary tract health have
been widely investigated since the 1920’s. It was previously
thought that acidification of the urine as a result of
consuming cranberries was responsible for the ameliorative
effects on urinary tract infections (UTI). However
cranberries contain proanthocyanidins which appear to
prevent adherence of p-fimbriated E.coli to the uroepithelial
cells [141], [142]. Other types of berries may have similar
properties e.g. the blueberry, which is also a Vaccinium
species. Several clinical trials of cranberry juice and
cranberry tablets have been published. Although a Cochrane
review [143], [144] found insufficient evidence to
recommend cranberry juice for treatment or prevention of
UTI, there are now more trials suggesting that cranberry
juice or tablets do have some protective effect [145]. For
example, women who consumed 50ml of a cranberry-
lingonberry concentrate for 6 months had a UTI recurrence
rate of 16% compared with 36% in the control group [146]
and Stothers (2002) [147] found absolute risk reductions of
12% for cranberry juice and 14% for cranberry juice tablets
for recurrence of UTI.
9. EFFECTS OF FOOD PROCESSING ON BERRIES
Advances in horticultural techniques and international
trade means it is often possible to obtain fresh berries out of
the traditional summer and autumn seasons. However,
Potential Health Benefits of Berries Current Nutrition & Food Science, 2005, Vol. 1, No. 1 83
berries generally have a short shelf life and as a result, they
are often preserved before eating. In addition, they are
widely used in juices, wines, liquors, jam, ice-cream yoghurt
and confectionery. Therefore, the effects of processing and
storage methods on micronutrient and phytochemicals
content needs to be considered when assessing potential
health benefits.
In general, vitamin C content of berries declines during
storage by up to 56% depending on duration and
temperature. However, concentrations of other phenolics
such as anthocyanins and ellagic acid remain relatively
unchanged and ellagitannin levels may actually increase
possibly indicating some endogenous metabolism post-
harvest [41, 148, 149]. However, losses in vitamin C (36%)
and flavonols (6-50%) have been reported during jam-
making and subsequent storage [29, 150-152]. In contrast,
concentrations of free ellagic acid initially increase after
manufacture due to thermal decomposition of the
ellagitannins in the berries [150]). Large losses in flavonols
and vitamin C may also occur during the manufacture of
berry juices although cold pressing methods may be less
destructive than those involving steam extractions [29].
10. CONCLUSIONS
Berries are rich sources of essential micronutrients,
particularly vitamin C and folic acid. They also contain
numerous phytochemicals. These have diverse effects in
vitro which suggest potential health benefits. However, until
more is known about the absorption and metabolic fate of
berry anthocyanins and flavonols in vivo, it would be unwise
to ascribe additional health promoting properties to berries
beyond those recognized for fruit and vegetables in general.
However, in populations with habitually low intakes of
plant-based foods, locally grown fresh or frozen berries are
an underused and potentially valuable dietary resource.
ACKNOWLEDGEMENTS
Julie Beattie was funded by the Scottish Executive
Health Department and the Scottish Executive
Environmental and Rural Affairs Department (SEERAD).
Garry Duthie is also grateful to SEERAD for financial
support.
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in berries. Journal of Agricultural and Food Chemistry 2000;
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Tomas-Barberan FA. Colour and anthocyanin stability of red
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78: 565-573.
Received: October 19, 2004 Accepted: December 01, 2004
... Currently, the world market does not have a wide range of herbal supplements from fruit and non-traditional officinal-technical raw materials (purees, pastes, concentrated juices, powders), which can be used to increase the biological value of jelly marmalade and as coloring agents [2,8]. In addition, most of these additives involve strict technological processing of raw materials, during which coloring materials and nutrients are lost: vitamins, dietary fiber, organic acids, glycosides, etc. [6,7]. ...
... To evaluate fruit and berry crops that are the most suitable in marmalade production technologies, both cultivated and wild raw materials were studied: apples, plums, cherries, black currants, red currants, blueberries, cranberries, blackberries, sloe, viburnum, figs, gooseberries, goji berry, elderberry, black cherry, physalis. All these cultures are widespread in the Central and West Europe and have long been used in the diets of the population, as well as in folk and official medicine for the prevention and therapy of nonspecific diseases [5,6]. ...
... Phenolic compounds present in the blueberry fruits' skin have antioxidant properties and are largely beneficial to the health of the blueberry fruits, depending on the physiological state and the storage conditions (Gao and Mazza, 1994;Michalska and Łysiak, 2015). Anthocyanins have been shown to improve the antioxidant capacity of berry fruits (Beattie et al., 2005). A significant decrease in the soluble solids, total phenolic, and anthocyanin contents of all samples was observed and the results are listed in Figure 4. ...
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In this study, the fungus Penicillium sp. was isolated from rotting postharvest blueberry fruits at different storage stages and identified into genera. Inoculation of this strain on the surface of fresh fruits was able to cause rotting. The strain was then used as a reference strain to test the chemical control effect of ozone fumigation during storage. The results showed that ozone fumigation had an obvious inhibitory effect on Penicillium sp. in a dose- and time-dependent manner. Meanwhile, ozone fumigation treatment could prevent the loss of fruit firmness, slow down the decrease of soluble solids, total phenolics, and anthocyanins, and maintain a lower activity of PPO and higher activities of POD and CAT. As far as we know, this is the first report on the effects of ozone fumigation on the postharvest pathogenic fungi Penicillium sp. and on the storage quality of postharvest blueberry collected from Majiang County, Guizhou province, China.
... In black currant cultivars, myricetin was the main flavonol (89-203 mg/kg), followed by quercetin (70-122 mg/kg) and kaempferol (9-23 mg/kg). Moreover, blackberries contained a flavonol profile complex with the presence of nine quercetin and three kaempferol derivatives, as well as two acylated quercetinderived compounds [37]. Furthermore, catechin, epicatechin, and epigallocatechin gallate are the most prevalent flavan-3-ols in berries ( Figure 1) [31,38]. ...
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Berry-derived polyphenols are bioactive compounds synthesized and secreted by several berry fruits. These polyphenols feature a diversity of chemical compounds, including phenolic acids and flavonoids. Here, we report the beneficial health effects of berry-derived polyphenols and their therapeutical application on gut-microbiota-related diseases, including inflammation and cancer. Pharmacokinetic investigations have confirmed the absorption, availability, and metabolism of berry-derived polyphenols. In vitro and in vivo tests, as well as clinical trials, showed that berry-derived polyphenols can positively modulate the gut microbiota, inhibiting inflammation and cancer development. Indeed, these compounds inhibit the growth of pathogenic bacteria and also promote beneficial bacteria. Moreover, berry-derived polyphenols exhibit therapeutic effects against different gut-microbiota-related disorders such as inflammation, cancer, and metabolic disorders. Moreover, these polyphenols can manage the inflammation via various mechanisms, in particular the inhibition of the transcriptional factor Nf-κB. Berry-derived polyphenols have also shown remarkable effects on different types of cancer, including colorectal, breast, esophageal, and prostate cancer. Moreover, certain metabolic disorders such as diabetes and atherosclerosis were also managed by berry-derived polyphenols through different mechanisms. These data showed that polyphenols from berries are a promising source of bioactive compounds capable of modulating the intestinal microbiota, and therefore managing cancer and associated metabolic diseases. However, further investigations should be carried out to determine the mechanisms of action of berry-derived polyphenol bioactive compounds to validate their safety and examinate their clinical uses.
... Strawberry is a fruit that has high nutritional value and is a substantial source of folate, vitamin C, fiber, potassium, flavonoids, anthocyanin, phytochemicals, antioxidants [1,2], and bioactive compounds that reduce the risk of cardiovascular incidents and thrombosis [3,4]. In addition, it provides anti-cancer benefits and helps prevent age-related memory loss [5,6]. ...
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In strawberry micropropagation, several challenges must be overcome to obtain quality plants and achieve high survival rate to ex vitro acclimatization. In this study, therefore, a set of protocols were evaluated to optimize explant (meristem) disinfection, in vitro growth (multiplication and rooting), and ex vitro acclimatization of strawberry. The results showed that explants treated with 1.0% NaClO for 5 min had a lower percentage of contamination, and achieved a higher percentage of viability, height, and number of leaves. In vitro growth was favored by the use of 1 mg L−1 zeatin, since it allowed greater seedling growth (number of shoots, seedling height, number of leaves, number of roots and root length), and a higher pre-acclimation rate (100%). In the acclimatization phase, plants grown in a substrate composed of compost + peat combined with 4 g of humic acid achieved better response in morphological and physiological variables. In fact, the results of this study could be used to cultivate strawberry plants of the ‘Aroma’ variety with high commercial quality.
... The quercetin content was 0.465 ± 0.058 mg/100 g fresh weight, while the gallic content was 88. 25 ...
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Blackberries are rich in antioxidants due to their high polyphenol and vitamin content, making them an excellent source of health protection. It is well known that good quality juices and fruit extracts can be obtained only from high quality fruits. The aim of this research is to characterize the antioxidant properties of garden blackberries fruits grown in Turia (Romania). Extracts were made from blackberry fruits with four different solvents, and the antioxidant capacity was studied by applying DPPH and FRAP assay. The total phenolic content (with Folin–Ciocâlteu reagent), total anthocyanin content (with the pH differential method), and total flavonoid content (with aluminum chloride colorimetric method) were also measured. The quercetin and gallic acid content were also determined by HPLC-DAD. As the best results were obtained with 90% v/v acidified acetonitrile, the Hansen parameters analysis was performed for the acetonitrile-water solvent mixture as a solvent and cyanidin-3-O-glucoside as a solute.
... lectin-enriched) can promote longevity. Beattie [165] have similarly concluded that there is considerable evidence that an adequate consumption of fruit and vegetables is advisable. This is to prevent the occurence of a series of chronic diseases such as stroke, several cancers, and heart disease. ...
... Anthocyanins have several health benefits, where their intake is associated with a lower risk of several chronic diseases due to vasoprotective and anti-inflammatory activities (Lietti and Picci, 1976), antioxidant , anticancer, chemoprotective (Karaivanova et al., 1990), and hypoglycemic properties (Tsuda et al., 2003). In addition, anthocyanins also are beneficial in the progression/managing/controlling of cardiovascular diseases and HIV-1 (Nakaishi et al., 2000;Stintzing et al., 2002;Cooke et al., 2005;Jang et al., 2005;Julie Beattie and Duthie, 2005;Talavéra et al., 2006). ...
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Alzheimer’s disease (AD) is characterized by the excessive deposition of extracellular amyloid-beta peptide (Aβ) and the build-up of intracellular neurofibrillary tangles containing hyperphosphorylated tau proteins. This leads to neuronal damage, cell death and consequently results in memory and learning impairments leading to dementia. Although the exact cause of AD is not yet clear, numerous studies indicate that oxidative stress, inflammation, and mitochondrial dysfunction significantly contribute to its onset and progression. There is no effective therapeutic approach to stop the progression of AD and its associated symptoms. Thus, early intervention, preferably, pre-clinically when the brain is not significantly affected, is a better option for effective treatment. Natural polyphenols (PP) target multiple AD-related pathways such as protecting the brain from Aβ and tau neurotoxicity, ameliorating oxidative damage and mitochondrial dysfunction. Among natural products, the cereal crop sorghum has some unique features. It is one of the major global grain crops but in the developed world, it is primarily used as feed for farm animals. A broad range of PP, including phenolic acids, flavonoids, and condensed tannins are present in sorghum grain including some classes such as proanthocyanidins that are rarely found in others plants. Pigmented varieties of sorghum have the highest polyphenolic content and antioxidant activity which potentially makes their consumption beneficial for human health through different pathways such as oxidative stress reduction and thus the prevention and treatment of neurodegenerative diseases. This review summarizes the potential of sorghum PP to beneficially affect the neuropathology of AD.
... (Japanese wineberry, native to east Asia). We chose Rubus species because they possess several readily measurable traits mappable to particular life history functions, they are semi-long-lived perennials whose trade-offs are not already well-documented, they display prominent constitutive physical defenses (among these prickles, hairs, and trichomes), and the genus contains hundreds of species all thought to produce edible, nutritious fruits (Beattie et al. 2005;Nile and Park 2014) that have considerable use potential for humans (Tontisirin et al. 2002;Muller and Krawinkel 2005;Tulchinsky 2010). Therefore, it may be particularly prescient to better understand this genus' reproductive limitations and behaviors. ...
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Little is known about limits to reproduction in plants, especially as to how their other life history functions (growth and defense) may constrain reproductive investment. Understanding these constraints can help researchers refine best practices for cultivating species like Rubus (Family: Rosaceae) that produce nutritious fruits as well as controlling invasive species. Here, we sought to elucidate potential trade-offs between growth, defense, and reproduction in native Rubus allegheniensis (common blackberry) and invasive R. phoenicolasius (wineberry) while accounting for the effects of varying insect herbivory and resource availability levels. We observed traits related to physical defense (e.g., prickle intensity), growth (e.g., cane length), and floral reproduction (e.g., ripe fruits) as well as carbon availability (e.g., canopy cover). We then used multiple regressions to characterize relationships between these variables for both species. We found potential evidence for two induced defenses in the invasive wineberry. Also, five models returned significant results indicative of trade-offs between reproduction and growth, reproduction and defense, and defense and growth in one or both species. Our results highlight the importance of understanding the defensive strategies utilized by these species because inducible defenses may result in trade-offs that could reduce yields and also increase the invasive potential of Rubus species.
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Introduction: Nutraceuticals are foods that offer nourishment or have therapeutic effects, such as the treatment and prevention of ailments. This review is an overview of the influence of the nutraceutical on the market, trade, medicinal system as well as lifestyle of almost every individual. Evidence Acquisition: Diet and nourishment are the foundation of living wellbeing and development. With advancements in clinical nutrition and increasingly growing awareness of nutritional principles of eatables, nutraceuticals have emerged as an important part of the healthcare system. Combined with the word nutrition and pharmaceutical, nutraceuticals constitute an evolving food category described as food or their products which give nutrition and health benefits, also prevent many diseases. Beriberi, pellagra, rickets, and scurvy are some of the diseases caused by the deficiency of nutraceuticals. Nutraceuticals are dietary supplements without harmful side effects; therefore, these have become a vital part of the nutritional as well as pharmaceutical class. Evidence Synthesis: This unique class of nutraceuticals includes vitamins, minerals, prebiotics, probiotics, plant extracts phytochemical components, fibers, carbohydrates, proteins, amino acids, omega fatty acids, enzymes, essential lipids, and other essential oils as the key nutraceutical ingredients. These nutraceuticals have been researched to be armorous for the battle against some of the century’s biggest health issues such as obesity, chronic disorders, stroke, osteoporosis, asthma, diabetes, cholesterol, etc. Conclusion: The focus of this study is to enlist a few of such nutraceuticals of great importance along with their applications. This analysis essentially sheds a light on the current Indian nutraceutical industry as well.
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Berries represent one of the most important and high-valued group of modern-day health-beneficial “superfoods” whose dietary consumption has been recognized to be beneficial for human health for a long time. In addition to being delicious, berries are rich in nutrients, vitamins, and several bioactive compounds, including carotenoids, flavonoids, phenolic acids, and hydrolysable tannins. However, due to their high value, berries and berry-based products are often subject to fraudulent adulteration, commonly for economical gain, but also unintentionally due to misidentification of species. Deliberate adulteration often comprises the substitution of high-value berries with lower value counterparts and mislabeling of product contents. As adulteration is deceptive toward customers and presents a risk for public health, food authentication through different methods is applied as a countermeasure. Although many authentication methods have been developed in terms of fast, sensitive, reliable, and low-cost analysis and have been applied in the authentication of a myriad of food products and species, their application on berries and berry-based products is still limited. The present review provides an overview of the development and application of analytical chemistry methods, such as isotope ratio analysis, liquid and gas chromatography, spectroscopy, as well as DNA-based methods and electronic sensors, for the authentication of berries and berry-based food products. We provide an overview of the earlier use and recent advances of these methods, as well as discuss the advances and drawbacks related to their application.
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Emerging evidence from our lab indicate that fruits and vegetables, in particular blueberry (BB) extracts, are able to ameliorate age-related declines in neuronal and cognitive function, common in disorders such as Alzheimer disease. The current study examined if the beneficial effects were also discernable with supplementation of BB extracts, in an already well balanced diet. Indeed, following an 8 week supplementation regime, age-related declines in several behavioral parameters such as balance, coordination, working memory and reference memory were still protected against. Similarly, BB extracts also potentiated oxotremorine enhancement of K+-evoked release of dopamine from striatal slices. Decline in the dopaminergic system have been shown to have a profound effect on cognitive functions. The improvement in dopamine release may have been due in part to the observed increase in striatal vitamin C levels. Although assessment of serum transaminase levels in BB supplemented animals appeared to suggest improved liver function, this was not thought to be the reason for the elevated vitamin C levels. The underlying mechanism for this is unclear. Together these findings highlight the diverse in vivo actions of dietary polyphenolics, a number of which may be important against age-related declines in certain brain functions. Furthermore they are to be able to mediate protective effects despite the diet containing sufficient concentrations of antioxidants.
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Anthocyanin and colour stability of red raspberry jams made from two different varieties (‘Zeva’ and ‘Heritage’) were analysed during 6 months, stored at three temperatures (20, 30 and 37°C). Also the influence of freezing the fruit, previously to jam manufacture, was evaluated. Different anthocyanin composition was detected for both cultivars and while ‘Zeva’ fruit had a higher total anthocyanin content, Heritage variety produced jams with a higher redness hue. The development of browning was directly related to storage temperature but not to thawing or the variety of fruit used. © 1998 Society of Chemical Industry.
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The aim of this review, a summary of the putative biological actions of flavonoids, was to obtain a further understanding of the reported beneficial health effects of these substances. Flavonoids occur naturally in fruit, vegetables, and beverages such as tea and wine. Research in the field of flavonoids has increased since the discovery of the French paradox,ie, the low cardiovascular mortality rate observed in Mediterranean populations in association with red wine consumption and a high saturated fat intake. Several other potential beneficial properties of flavonoids have since been ascertained. We review the different groups of known flavonoids, the probable mechanisms by which they act, and the potential clinical applications of these fascinating natural substances.
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Background and aim: The health-promoting effects of fruit- and vegetable-based diets are known to be associated with their antioxidative components. We found in our preliminary in vitro laboratory tests that extracts of many common Finnish edible berries are potent scavengers of peroxyl radicals and inhibitors of lipid peroxidation. We therefore designed the current study to evaluate both the long-term (8 weeks) and short-term (5 hours) effects of increased intake of three berries on antioxidant potential and lipid peroxidation. Methods and results: Healthy 60-year-old men were randomized to berry, supplement and control groups (20 men in each group). The berry group ate, in addition to their normal diet, a 100 g portion of deep-frozen berries (bilberries, lingonberries, or black currants) daily for 8 weeks. The other groups ingested daily 100 mg of alpha-tocopherol and 500 mg of ascorbic acid (supplement group) or 500 mg of calcium gluconate (control group). In the short-term experiment 6 men ate 80 g of each of the three berries in one go. Serum ascorbate concentrations increased significantly in both the berry and the supplement group. Serum alpha-tocopherol levels and the antioxidant potential (TRAP) in low density lipoprotein (LDL) increased in the supplement group only. In the berry group, slightly lowered LDL diene conjugation (p = 0.074) and slightly increased total serum TRAP (p = 0.084) values were observed. No changes were found in these measures in the supplement or the control group. In the short-term experiment, LDL TRAP showed a small increase (about 10%, p = 0.039) during five hours after the intake of 240 g berries. Conclusions: The effects of consumption of berries on antioxidant potential and diene conjugation in LDL particles in vivo appear to be small.
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Raspberries are rich in phenolic phytochemicals. To study the health benefits of raspberries, four fresh raspberry varieties (Heritage, Kiwigold, Goldie, and Anne) were evaluated for total antioxidant and antiproliferative activities. The total amount of phenolics and flavonoids for each of the four raspberry varieties was determined. The Heritage raspberry variety had the highest total phenolic content (512.7 +/- 4.7 mg/100 g of raspberry) of the varieties measured followed by Kiwigold (451.1 +/- 4.5 mg/100 g of raspberry), Goldie (427.5 +/- 7.5 mg/100 g of raspberry), and Anne (359.2 +/- 3.4 mg/100 g of raspberry). Similarly, the Heritage raspberry variety contained the highest total flavonoids (103.4 +/- 2.0 mg/100 g of raspberry) of the varieties tested, followed by Kiwigold (87.3 +/- 1.8 mg/100 g of raspberry), Goldie (84.2 +/- 1.8 mg/100 g of raspberry), and Anne (63.5 +/- 0.7 mg/100 g of raspberry). The color of the raspberry juice correlated well to the total phenolic, flavonoid, and anthocyanin contents of the raspberry. Heritage had the highest a/b ratio and the darkest colored juice, and the Anne variety showed the lowest phytochemical content and the palest color. Heritage raspberry variety had the highest total antioxidant activity, followed by Kiwigold and Goldie, and the Anne raspberry variety had the lowest antioxidant activity of the varieties tested. The proliferation of HepG(2) human liver cancer cells was significantly inhibited in a dose-dependent manner after exposure to the raspberry extracts. The extract equivalent to 50 mg of Goldie, Heritage, and Kiwigold fruit inhibited the proliferation of those cells by 89.4 +/- 0.1, 88 +/- 0.2, and 87.6 +/- 1.0%, respectively. Anne had the lowest antiproliferative activity of the varieties measured but still exhibited a significant inhibition of 70.3 +/- 1.2% with an extract equivalent to 50 mg of fruit. The antioxidant activity of the raspberry was directly related to the total amount of phenolics and flavonoids found in the raspberry (p < 0.01). No relationship was found between antiproliferative activity and the total amount of phenolics/flavonoids found in the same raspberry (p > 0.05).
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A scheme for the fractionation of flavonoid and nonflavonoid compounds is presented. The phenolic compounds of Highbush blueberries (cultivar ‘Coville’) were analysed by high performance liquid chromatography and thin-layer chromatography. Fifteen anthocyanins were identified as the 3-monoglucoside, 3-monogalactoside and 3-monoarabinoside of delphinidin, cyanidin, malvidin, peonidin and petunidin. No acyl anthocyanin was detected. Derivatives of malvidin and delphinidin were the most abundant; the 3-monogalactoside constituted 41% of the anthocyanin. Four flavonol glycosides were also identified as the kaempferol-3-O-glucoside, 3-O-glucoside, 3-O-galactoside and 3-O-rhamno-side of quercetin. The major phenolic acid was chlorogenic acid. After hydrolysis of the phenolic neutral fraction (FA), gallic, syringic and vanillic acids were identified by TLC. These acids appeared to be present in their ester forms, probably as glucoside esters.