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is an essential need in body systems. The
use of plants in traditional medicine is
widespread all over the world. This know-
ledge is still a source for the development of
novel pharmacological agents. The preserv-
ative effect of many plant species and herbs
suggests the presence of antioxidants and
anti-genotoxic constituents in their tissues
(Hirasa and Takemasa, 1998).
We investigated the oxidative DNA
damage-protecting activity and antioxi-
dant potential of
Z. punctata
ethanolic
extract (aerial parts) as well as of 2¢,4¢-dihy-
droxychalcone (DHC) and 2¢,4¢-dihydroxy-
3¢-methoxy chalcone (DHMC) employing
a variety of
in vitro
methods (Vattuone
et al
., 2008). The protective effect of differ-
ent quantities of the extract from
Z. punc-
tata
(and the isolated constituents) on the
breakdown of supercoiled DNA (pBR 322
was used) by the action of the free radical
HO
•
generated by the UV irradiation
(8000 mW/cm, 5 min) on H
2
O
2
was ana-
lysed by electrophoresis in agarose horizon-
tal slab gels stained with ethidium bromide.
The electrophoretic pattern showed two
bands on the agarose gel electrophoresis:
the faster one corresponded to the native
supercoiled circular DNA and the slower
moving band (faint) was the open circular
form in the control. This band is intensi-
fied by exposure of the pBR 322 to UV in
the presence of H
2
O
2
, indicating that HO
•
generated from UV-photolysis of H
2
O
2
pro-
duced DNA strand scission. Moreover,
this band diminished when the UV irra-
diation of H
2
O
2
was made in the presence
of DHC or DHMC, demonstrating the pro-
tective effect of DHC and DHMC on DNA.
Although both O
2
−
and H
2
O
2
are potentially
cytotoxic, most of the oxidative damage in
biological systems is caused by HO
•
,
which is generated by the reaction between
O
2
−
and H
2
O
2
in the presence of metal ions
(Guitteridge, 1984). The free-radical scav-
enging and antioxidant capacity of the
same samples was assessed with
in vitro
(cell free) tests for their simplicity and
sometimes reasonable cost. The stable
1,1-diphenyl-2-picrylhydrazyl radical
(DPPH
•
; Kato
et al
., 1988) and the 2,2¢-azi-
nobis-(3-ethylbenzthiazoline-6-sulfonic
acid (ABTS) radical cation (Re
et al
., 1999)
were used. In the two assays, DHC was
more effective (percentage inhibition)
than DHMC and the ethanol extract with
both scavengers. There was a dose-
dependent response in both methods.
They were also effective in superoxide
scavenging assay (Nishikimi
et al
., 1972)
in a concentration-dependent manner. In
general, the free-radical scavenging activity
is an accepted mechanism of antioxidants
to inhibit peroxidation. Lipoperoxidation
was measured in the absence and presence
of a stress agent (5 mmol/l FeCl
3
). The oxi-
dized lipids were quantified measuring
the production of thiobarbituric acid-
reactive substances (TBARS) (Ohkawa
et al
., 1979). In all instances, DHC was
more efficient than DHMC and the ethanol
extract.
12.5
Conclusions
Zuccagnia punctata
Cav. has promising
potential in the treatment of conditions
such as diarrhoeal gastroenteritis, and as an
antifungal, antibacterial, anti-inflammatory,
cytoprotective, antioxidant and antican-
cer agent, among others (Anto
et al
., 1995;
Edenharder and Tang, 1997; López
et al
.,
2001; Quiroga
et al
., 2001; De la Rocha
et al
.,
2003; Uchiumi
et al
., 2003; Zampini
et al
.,
2005; Vattuone
et al
., 2008). It is worth
taking into account that
Z. punctata
exhib-
its antioxidant and anti-inflammatory
effects because oxidative injury under-
lines many of these diseases. The diverse
pharmacological activities of
Z. punctata
extracts and the isolated phytochemicals
have, however, only been assayed
in vitro
or using laboratory animals, and the
obtained results are not necessarily port-
able to humans. On the grounds of the low
toxicity of the extracts and derived phyto-
chemicals and their use as a source of
medicinal agents (mainly leaves and
twigs), backed by proven activity of both
the traditional formulations (infusions,
decoctions and tinctures) and their derived
phytochemicals (chalcones, flavanones,
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