Antioxidant and Biocidal Activities from Natural Sources: an Overview - Natural Antioxidants and Biocides from Wild Medicinal Plants - page 2

properties, as judged by the 1,1-diphenyl-2-
picrylhydrazyl (DPPH) assay and other
in vitro antioxidant assays. Our results indi-
cate that many of the compounds from these
families have excellent activity as antioxi-
dants and have powerful effects on the
metabolism of insects, bacteria and fungi.
The naturally occurring compounds that we
have isolated represent a valuable resource
for both useful nutraceutical and biocide
activities.

(Fernandes et al ., 2004). Several methods
have been developed to measure the anti-
oxidant activity in biological samples,
including oxygen radical absorption capacity
(ORAC), ferric reducing antioxidant power
(FRAP), DPPH, crocin radical scavenging and
inhibition of the formation of thiobarbituric
acid reactive species (TBARS) (Taruscio
et al ., 2004) as a more complete tool for anti-
oxidant measurements (Schinella et al .,
2002; Prior et al ., 2005).
Berries from South America constitute
a rich dietary source of phenolic antioxi-
dant and bioactive properties (Céspedes
et al ., 2010a; Schreckinger et al ., 2010a,b).
The Chilean wild black-berry Aristotelia
chilensis (Mol) Stuntz (Elaeocarpaceae), an
edible black-coloured fruit that reaches its
maximum ripeness between December and
March, is widely consumed during these
months in Central and South Chile and the
western region of Argentina. We reported
the alkaloid composition of the leaves of
A. chilensis (Céspedes et al ., 1990, 1993,
1995; Silva et al ., 1997); other botanical
characteristics were previously reported
(Céspedes et al ., 1995, 2008, 2010a). This
plant has enjoyed popularity as an ethno-
medicine for many years and has been used
as an anti-inflammatory agent, for kidney
pains, stomach ulcers, diverse digestive
ailments (tumours and ulcers), fever and
cicatrization injuries. The berries have tra-
ditionally been consumed as a treatment
for diarrhoea and dysentery. Araucanian
people prepare a liquor known as 'tecu' by
macerating the fruits in ethanol for use in
religious rituals and consumption as a
daily beverage (Muñoz-Pizarro, 1966).
Some recent studies indicate that
extracts from the fruits of A. chilensis have
good antioxidant properties (Pool-Zobel
et al ., 1999) and cardioprotective activity
(Céspedes et al ., 2008). Yet other studies
report the composition of extract constitu-
ents (Escribano-Bailon et al ., 2006; Céspedes
et al ., 2010a). The inhibitory activity of an
anthocyanin-rich ethanol extract of this
fruit against aldose reductase, adipogenesis
and the inhibition of expression of lipo-
polysaccharide (LPS)-induced nitric oxide

1.2 Antioxidants

Antioxidants are substances that delay the
oxidation process by inhibiting poly-
merization chains initiated by free radicals
and other subsequent oxidizing reactions
(Halliwell, 1991, 1999). This concept is
fundamental to food chemistry, in which
synthetic antioxidants such as butylated
hydroxy toluene (BHT) have long been used
to preserve quality of food by protecting
against oxidation-related deterioration.
A growing body of literature points to the
importance of natural antioxidants from a
large number of plants that could be used to
reduce oxidative damage, not only in foods
but also in the human body. This might
provide protection against chronic diseases,
including cancer and neurodegenerative
diseases, inflammation and cardiovascular
disease. Adverse conditions within the
environment, such as smog and UV radia-
tion, in addition to diets rich in saturated
fatty acids, increase oxidative damage in
the body. Given this constant exposure
to oxidants, antioxidants may be necess-
ary to counteract chronic oxidative effects,
thereby improving the quality of life
(Roberts et al ., 2003).
The increasing interest in the measure-
ment of the antioxidant activity of different
plant samples is derived from the over-
whelming evidence of the importance of
reactive oxygen species (ROS), including
superoxide (O 2 •− ), peroxyl (ROO •− ), alkoxyl
(RO •− ), hydroxyl (HO •− ), and nitric oxide
(NO • ) radicals in ageing and chronic disease