1.1 Curcumin
Curcumin (diferuloylmethane with molecular weight of 368.38 g/mol) is a polyphenol derived from the turmeric (Curcuma longa) plant. Curcumin (Fig. 1a) has
been used extensively in ayurvedic medicine for centuries because it is nontoxic
and has a variety of therapeutic properties, including anti-oxidant, analgesic, antiinflammatory, antimicrobial, and antiseptic activities. Curcumin is reported to act
on several biological pathways involved in mutagenesis, oncogene expression, cell
cycle regulation, apoptosis, tumorigenesis, and metastasis and, hence, is a potential
anticancer agent. Curcumin has shown an antiproliferative effect in multiple
cancers, and is an inhibitor of the transcription factor nuclear factor-kb (NF-kb)
and downstream gene products including c-myc, Bcl-2, cyclooxygenase-2 (COX-2),
inducible nitric oxide synthase (iNOS), cyclin D1, tumor necrosis factor-a (TNF-a),
interleukins, and matrix metalloproteins (e.g. matrix metalloproteinase 9, MMP-9)
[14–18].
1.2 Epigallocatechin-3-Gallate
The habitual consumption of green tea (Camellia sinensis), a popular beverage
worldwide, has been associated with chemopreventive efficacy. Green tea
contains high amounts of the potent antioxidants polyphenols, which may reduce
the risk of many chronic diseases including cardiovascular disease and cancer
[19–24]. The cancer chemopreventive effects of green tea are reported to
be mediated by its polyphenols, known as catechins. The major catechins in
green tea are (À)-epigallocatechin-3-gallate (EGCG), (À)-epicatechin-3-gallate,
(À)-epigallocatechin, and (À)-epicatechin. EGCG (Fig. 1b) is the major catechin in
green tea and accounts for 50–80%, representing 200–300 mg per brewed cup of
green tea [4]. Green tea polyphenols have been shown to be chemopreventive for
several types of cancers, including those of the liver, prostate, stomach and breast
[25–28].
1.3 Resveratrol
Resveratrol (3,5,4
0 -trihydroxystilbene: C 14 H 12 O 3 , molecular weight 228.25 g/mol)
is a non-flavonoid polyphenolic compound abundant in grapes, peanuts, and other
foods that are commonly consumed as part of the human diet [29]. The compound
was first isolated from the root of Polygonum cuspidatum, a plant used in traditional
Chinese and Japanese medicine [30]. Resveratrol (Fig. 1c) exists as two structural
isomers: cis-(Z) and trans-(E). The trans-isomer is biologically more active than the
cis-isomer, probably due to its non-planar conformation [31, 32]. Despite its poor
water solubility, resveratrol exhibits high membrane permeability and can be
206
S. Maya et al.
Curcumin (diferuloylmethane with molecular weight of 368.38 g/mol) is a polyphenol derived from the turmeric (Curcuma longa) plant. Curcumin (Fig. 1a) has
been used extensively in ayurvedic medicine for centuries because it is nontoxic
and has a variety of therapeutic properties, including anti-oxidant, analgesic, antiinflammatory, antimicrobial, and antiseptic activities. Curcumin is reported to act
on several biological pathways involved in mutagenesis, oncogene expression, cell
cycle regulation, apoptosis, tumorigenesis, and metastasis and, hence, is a potential
anticancer agent. Curcumin has shown an antiproliferative effect in multiple
cancers, and is an inhibitor of the transcription factor nuclear factor-kb (NF-kb)
and downstream gene products including c-myc, Bcl-2, cyclooxygenase-2 (COX-2),
inducible nitric oxide synthase (iNOS), cyclin D1, tumor necrosis factor-a (TNF-a),
interleukins, and matrix metalloproteins (e.g. matrix metalloproteinase 9, MMP-9)
[14–18].
1.2 Epigallocatechin-3-Gallate
The habitual consumption of green tea (Camellia sinensis), a popular beverage
worldwide, has been associated with chemopreventive efficacy. Green tea
contains high amounts of the potent antioxidants polyphenols, which may reduce
the risk of many chronic diseases including cardiovascular disease and cancer
[19–24]. The cancer chemopreventive effects of green tea are reported to
be mediated by its polyphenols, known as catechins. The major catechins in
green tea are (À)-epigallocatechin-3-gallate (EGCG), (À)-epicatechin-3-gallate,
(À)-epigallocatechin, and (À)-epicatechin. EGCG (Fig. 1b) is the major catechin in
green tea and accounts for 50–80%, representing 200–300 mg per brewed cup of
green tea [4]. Green tea polyphenols have been shown to be chemopreventive for
several types of cancers, including those of the liver, prostate, stomach and breast
[25–28].
1.3 Resveratrol
Resveratrol (3,5,4
0 -trihydroxystilbene: C 14 H 12 O 3 , molecular weight 228.25 g/mol)
is a non-flavonoid polyphenolic compound abundant in grapes, peanuts, and other
foods that are commonly consumed as part of the human diet [29]. The compound
was first isolated from the root of Polygonum cuspidatum, a plant used in traditional
Chinese and Japanese medicine [30]. Resveratrol (Fig. 1c) exists as two structural
isomers: cis-(Z) and trans-(E). The trans-isomer is biologically more active than the
cis-isomer, probably due to its non-planar conformation [31, 32]. Despite its poor
water solubility, resveratrol exhibits high membrane permeability and can be
206
S. Maya et al.