Chilean Plants as a Source of Polyphenols - Natural Antioxidants and Biocides from Wild Medicinal Plants - page 126

antioxidant parameter [TRAP], total anti-
oxidant response [TAR], thiobarbituric acid
reactive substances [TBARS], diphenyl-1-
picrylhydrazyl [DPPH] and oxygen radical
absorbance capacity [ORAC] methods). It is
important to understand that these methods
do not give the same results because differ-
ent radicals are used. In some cases, a plant
extract that shows the best AC with a spe-
cific method will not necessarily show the
best AC with another method. For this rea-
son, there is no single method appropriate
to measure the total efficacy of an antioxi-
dant. In assessing antioxidant activity it is
important to concentrate on the mechanism
of action, because there are many ways to
generate free radicals, many ways in which
a free radical can be quenched by an anti-
oxidant, many factors that can influence
this reaction and an almost infinite number
of possible targets of the free radicals (Parr
and Bolwell, 2000). Despite wide usage of
these chemical AC methods, their ability to
predict in vivo activity has not been clearly
demonstrated (Mermelstein, 2008). The cur-
rent challenge is the study of AC in in vivo
models and polyphenols bioavailability in
the human body.

lowest (661 mTE; TE, Trolox equivalents)
inhibiting activity of free radicals, whereas
H. remyanus showed the highest (3784 mTE).
The chemical characterization of the stud-
ied species showed important levels of
flavonoids and coumarins, with flavonoids
predominating in H. taeda , coumarins in
H. multifolius and both of them in H. baylahuen
and H. remyanus .
Avello and Pastene (2005) evaluated the
AC (ORAC method) in plasma before and
after the intake of Ugni molinae leaf infusion
(1%). In this study healthy volunteers (nor-
mal-lipidemic and non-diabetic) drank this
infusion twice a day for 3 days. The results
indicated a significant increase (from 2258
to 3108 mM TE/l) in the AC in plasma from
volunteers. A similar study (Avello et al. ,
2008) evaluated the AC (TBARS method) in
plasma before and after the intake of
Aristotelia chilensis leaf infusions (1%). The
TPC in the infusion was 0.074 mM GAE
(gallic acid equivalents). In this study
healthy volunteers (no smoking and body
mass index within the normal range) drank
this infusion twice a day for 3 days (doses
described by ethno-medicine for the treatment
of various illnesses). The results showed an
average increase of the AC at 24 h observed
by means of TBARS (30.27%).
Rojo et al . (2009) studied the antioxi-
dant capacities of 12 herbal teas widely con-
sumed by South-American populations.
The plant species ( Adesmia melanthes,
Senecio nutans, Chuquiraga atacamensis,
Fabiana densa, Fabiana squamata, Lampaya
medicinalis, Azorella compacta, Baccharis
tola, Opuntia ignescens, Acantholippia
deserticola, Parastrephia lepidophylla and
Parastrephia lucida ) were collected fresh in
the province of Colchane located at 3500 m
above sea level, in the Chilean administra-
tive region of Tarapacá. Herbal infusions
were prepared from plants grown under
similar climatic conditions and were
assessed for their TPC and in vitro AC
(Trolox equivalent antioxidant capacity
[TEAC]-DPPH, TEAC-crocin and FRAP).
Although the results indicated TPC between
37 mg GAE/l ( B. tola ) and 314 GAE/l
( F. densa ), by far the most potent antioxidant
species according to the FRAP assay were

8.3.1 Plant infusions

Plant infusions have been deeply rooted
among South Andean indigenous cultures such
as Aymara, Quechua (Villagrán et al ., 2003)
and Mapuche (Montes and Wilkomirsky,
1987). Additionally, drinking an herbal infu-
sion after a meal is a very common custom
in Chile (Montes and Wilkomirsky, 1987;
Montenegro, 2002). Vogel et al . (2005) stud-
ied the antioxidant properties (lipid peroxi-
dation in erythrocytes and DPPH) of four
Chilean Haplopappus species commonly
named Baylahuén ( Haplopappus baylahuen,
Haplopappus taeda, Haplopappus multifo-
lius and Haplopappus remyanus ) to clarify
their medicinal effects, because some confu-
sion exists about the taxonomic identifica-
tion of these species. H. baylahuen showed
the lowest AC. In DPPH analyses an infusion
(10%) of H. baylahuen also showed the