Biology Reference
In-Depth Information
classified into different groups. On the basis
of the number of phenol rings that they con-
tain and of the structural elements that bind
these rings to one another, polyphenols can
be divided into phenolic acids, flavonoids,
stilbenes and lignans. The flavonoids,
which share a common structure consisting
of two aromatic rings (A and B) that are
bound together by three carbon atoms that
form an oxygenated heterocycle (ring C),
may themselves be divided into six sub-
classes as a function of the type of heterocy-
cle involved: flavonols, flavones, isoflavones,
flavanones, anthocyanidins and flavanols
(catechins and proanthocyanidins). In addi-
tion to this diversity, polyphenols may be
associated with various carbohydrates and
organic acids and with one another (Manach
et al
., 2004). Flavonoid properties related to
their antioxidant (Chung
et al
., 2009;
Guabiraba
et al
., 2010; Justino and Vieira,
2010; Sadowska-Woda
et al
., 2010; Zhang
et al
., 2010) and anti-inflammatory activity
have been extensively reported during
recent years. Inflammation and oxidative
stress are associated with several diseases,
and flavonoids have been intensively inves-
tigated for anti-inflammatory and antioxi-
dant properties.
Many plants described in lists of THM
do not have any scientific evidence sup-
porting their BA or traditional medicinal
uses (e.g.
Centaurium cachanlahuen,
Ephedra chilensis, Lampaya medicinalis,
Libertia sessiliflora, Otholobium glandulo-
sum
and
Polypodium feuillei
) according to
an exhaustive search in Web of Science
®
(provided by Pontificia Universidad Católica
of Chile). On the other hand, there is some
scientific evidence for other kinds of PNP,
such as terpenoids (e.g.
Laretia acaulis,
Luma chequen, Margyricarpus pinnatus
and
Maytenus boaria
) and alkaloids (e.g.
Peumus boldus
). Therefore, scientific evi-
dence supports the BA of some species that
have not been described in THM lists (e.g.
Gevuina avellana, Laurelia sempervivens,
Satureja parvifolia
and
Ugni molinae
).
Within this search, different BA could be
attributed to the presence of polyphenols in
Chilean plants. Table 8.2 summarizes infor-
mation from scientific articles published
between 2000 and 2010. Previous scientific
publications have been compiled by Muñoz
et al
. (2001) and Montenegro (2002).
Antimicrobial (i.e. antifungal, antibac-
terial and nematicidal), analgaesic and anti-
inflammatory are the main BAs studied in
Chilean plants that could be related to the
presence of polyphenols (Table 8.2). Among
this research
Buddleja globosa
has been the
most important species studied. Some
polyphenols have been described in this
research - most of them are flavonoids.
Nevertheless, some of these articles did not
identify the polyphenols contained in plant
extracts. For this reason, it is very difficult
to establish a clear relationship between
certain polyphenols identified in these
plants and the type of BA described.
Important exceptions were Guglielmone
et al
. (2002, 2005) and Céspedes
et al
. (2006)
whose research isolated some flavonols
(quercetine types) and five lignans (secoiso-
lariciresinol, pinoresinol, eudesmin, lar-
iciresinol and lariciresinol-4-methyl ether)
from
Flaveria bidentis
and
Araucaria arau-
cana,
and demonstrated their anticoagulant
and antimicrobial activity, respectively.
8.3
Polyphenols and Antioxidant
Capacity in Chilean Plants
Given that the majority of the BAs of
polyphenols may be also attributed to their
antioxidant capacity (AC), the determina-
tion of total phenol content (TPC) and AC of
a species is currently a scientifically valid
tool to determine its antioxidant and phar-
macological potential. Since the 1990s
studies have been published about the pres-
ence of polyphenols and the AC of Chilean
plants. These articles consider chromato-
graphic techniques (HPLC) connected to
different types of detectors (UV, DAD and
ESI-MS) for the identification of polyphe-
nols. Various
in vitro
methods have also
been used for the quantification of TPC
(Folin-Ciocalteau method), total antioxi-
dant capacity (TAC; differential pH method)
and AC (e.g. ferric ion reducing antioxi-
dant power [FRAP], total radical trapping
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