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(Last modification:
20. May 2010)
Resveratrol and derivatives in grapevine (Vitis vinifera)
From Wikipedia
Pictures taken from Wikipedia (German,
English,
Italian,
and French
versions).
Notes
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This is not an attempt to be comprehensive; it just tries to summarize
the stilbene secondary products in grapevine
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20.05.2010: addition of a page with stilbenes identified in Vitis
vinifera in the period from 1995 to end of 2008:
more...
Resveratrol
(cis-
and trans-forms, with the trans-form more abundant than the cis-form)
and the other major stilbene components, pterostilbene (3,5-dimethyl
resveratrol), piceid (resveratrol glucoside), epsilon-viniferin (a
resveratrol dimer), and alpha-viniferin (a resveratrol trimer) were first
discovered as phytoalexins in leaves (Langcake
and Pryce, 1976; Pryce and
Langcake, 1977; Langcake
and Pryce, 1977a; Langcake
and Pryce, 1977b; Langcake
et al., 1979; Blaich and
Bachmann, 1980; Langcake,
1981). The structures are shown in Fig. 1.
Fig. 1
Resveratrol (trans- and cis-forms) and its most often occurring
derivatives. The colors mark the resveratrol monomers.
All of them,
in particular resveratrol, its glucoside piceid, and pterostilbene were found in
all tissues investigated (e.g.
Lamikanra et al., 1996; Adrian
et al., 2000; Versari et al.,
2001; Wang et al., 2009).
Others were first identified in cell suspension cultures, e.g. piceatannol
and its glucoside (astringin) (De
Lima et al., 1999), delta-viniferin and pallidol (Fig. 2) (Waffo-Téguo
et al., 2001; Pezet et al.,
2003) ).
Most of us,
however, are interested in the presence in berries/grapes, and later in the wine
produced from them. Generally, the substances described in Fig. 1 are also in
the berries and in the wine (see for example
Lamuela-Raventos and Waterhouse,
1993; Waterhouse and
Lamuela-Raventos, 1994;
Goldberg et al., 1995;
Lamikanra et al., 1996; Sato et
al., 1997; De Lima et al.,
1999; Romero-Pérez et al.,
1999; Versari et al., 2001;
Cantos et al., 2002;
Moreno-Labanda et al., 2004;
Vitrac et al., 2005;
Sun et al., 2006;
Naugler et al., 2007).
Fig. 2.
Resveratrol derivatives (piceatannol, astringin), and some oligomers.
The colors mark the
resveratrol monomers.
In addition
to those, a number of resveratrol derivatives have been described; sometimes in
fairly high concentrations. The structures are given in Fig. 2:
a) Pallidol
and its glucosides (Baderschneider
and Winterhalter, 2000;
Naugler et al., 2007; He et al.,
2009) (first identified in another member of the Vitaceae, Cissus pallida,
Khan et al., 1986),
b)
Vitisin A (Schwarz et al.,
2003; Seya et al., 2009),
Ampelopsin B, a resveratrol dimer (Seya
et al., 2009),
c) Hopeaphenol (Guebailia
et al., 2006; Seya et al., 2009)
(two molecules of ampelopsin B; originally isolated many years ago from another
plant (Coggon et al., 1965;
Coggon et al., 1966)).
I am
sure that this list is not complete; in particular the variety Vitis vinifera
'Kyohou' and other Vitis species do contain additional oligostilbenes (see e.g.
Ito et al., 1999). The
pharmacology of most of these substances has not been thoroughly investigated,
as far as I know.
The biosynthesis is not understood. It
is not clear whether the resveratrol derivatives are synthesized enzymatically,
or whether they are made during the fermentation or wine maturation by oxidative
processes (see for example
Cichewicz et al., 2000).
Some
general comments on resveratrol in grapes/wine
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The
different grapevine varieties show a large variation in their production of
resveratrol and derivatives in the berries. It is probably safe to state that red grapes and
red wine contain more resveratrol than the white varieties. However, this
can vary from year to year, and depends on several factors, e.g the climate
(see for example Goldberg et
al., 1995), stress conditions, for example UV (see e.g.
Bais et al., 2000;
Adrian et al., 2000;
Cantos et al., 2001;
Versari et al., 2001;
Cantos et al., 2002;
Cantos et al., 2003), and
fungal/bacterial infections (see
Jeandet et al., 1995).
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In the
berries, most of the resveratrol is localized in the skins, see e.g.
Kiraly-Veghely et al., 1998;
Sun et al., 2006;
Fornara et al., 2008),
and the type of fermentation largely determines how much of the available
resveratrol gets into the wine: it will much in those cases where the grape
skin stays together with the juice for a long time (e.g. as with many red
wine fermentations), and comparably little if the contact time is short (as
with many white wine fermentations).
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Enzymes of resveratrol biosynthesis and the derivatives
The
biosynthesis of resveratrol is discussed elsewhere in much detail (more...),
and therefore the focus here will be on Vitis.
cDNAs for
resveratrol synthase
have been described (Melchior
and Kindl, 1990; Sparvoli et
al., 1994). The results indicate that this stilbene synthase (STS) is encoded in a large gene family
in Vitis vinifera (Sparvoli
et al., 1994).
An interesting question is whether this
enzyme
is likely to use the
aldol switch mechanism discovered with the
stilbene synthase (STS) from
Scots pine (Pinus sylvestris) (Austin
et al., 2004). However, the amino acid residues
characteristic for the aldol switch appear to be missing in the resveratrol
synthase, and thus it may
be possible that there may be alternative mechanisms for the STS-type
ring-folding (more...).
The functional analysis with recombinant enzymes showed that 4-coumaroyl-CoA
is the preferred substrate, as would be expected from the abundance of
resveratrol. However, piceatannol and astringin are probably synthesized from
caffeoyl-CoA, the starter molecule containing already two vicinal hydroxyl
groups. Interestingly, in humans resveratrol can be hydroxylated to piceatannol
by cytochrome P450 CYP1B1 (Potter
et al., 2002). This is probably the reason why some websites claim that
piceatannol is a degradation product of resveratrol. A bit narrow-minded, it ignores the
situation in the plants.
The enzyme can be expressed in all plant tissues, and it is induced by a variety of stress
conditions. Of particular interest is of course the situation in berries because
they are the basis for the later amount of Resveratrol in the wine, and
thus there are publications, e.g. on the localization in the berries (Fornara
et al., 2008), the expression in healthy grapes (Gatto
et al., 2008), on the expression during ripening, wilting, and UV-treatment:
(Versari et al., 2001), and
the induction by UV which could lead to a substantial increase in resveratrol
yield (Bais et al., 2000;
Cantos et al., 2002;
Cantos et al., 2003).
The synthesis of pterostilbene (see Fig. 1) requires an
O-methyltransferase
(OMT), and a cDNA for such a protein has been described (Schmidlin
et al., 2008). Indeed, the transgenic co-expression of the STS and this
OMT in tobacco led to pterostilbene, the dimethylated product, suggesting that the OMT carries out both
methylations.
The formation of piceid (Fig. 1) and astringin (Fig. 2) requires a
glucosyltransferase, and a
cDNA for such protein has been described (Hall
and De Luca, 2007). Interestingly, the analysis of a recombinant protein
showed that it is poly-functional: it glucosylates resveratrol, flavonoids, and
coumarins at higher pH (8 to 10), and hydroxybenzoic acids and hydroxycinnamic acids at a
lower pH (5.5 to 7). The authors also showed that Vitis labrusca grape berries
accumulated both stilbene glucosides and hydroxycinnamic acid glucose esters,
consistent with the bi-functional role of this enzyme in stilbene and
hydroxycinnamic acid modification.
Genome
sequences
There are
large-scale efforts to establish the sequences of the complete genome (Jaillon
et al., 2007; Velasco et al.,
2007; Doddapaneni et al.,
2008; Grimplet et al., 2009),
and there is little doubt that this will greatly contribute to analyzing and
understanding the genes controlling and catalyzing the biosynthesis of these
interesting secondary products.
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