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Medicinal Plant Research 2012, Vol.2, No.2, 6
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7
razors, kissing an infected person, or touching that
person's saliva (Friedman, 2006). A parent who has a
cold sore often spreads the infection to his or her child
in this way. Cold sores can also be spread to other
areas of the body. The first symptoms of cold sores
may include pain around your mouth and on your lips,
a fever, a sore throat, or swollen glands in your neck
or other parts of the body. Small children sometimes
drool before cold sores appear (Gershon et al., 2010).
After the blisters appear, the cold sores usually break
open, leak a clear fluid, and then crust over and
disappear after several days to 2 weeks. For some
people, cold sores can be very painful. Cold sores will
usually start to heal on their own within a few days.
But if they cause pain or make you feel embarrassed,
they can be treated. Treatment may include skin
creams, ointments, or sometimes pills (Carson et al.,
2008). Treatment may get rid of the cold sores only 1
to 2 days faster, but it can also help ease painful
blisters or other uncomfortable symptoms. The herpes
simplex virus that causes cold sores cannot be cured.
After you get infected, the virus stays in your body for
the rest of your life (Chuanasa et al., 2008). Docosanol,
a saturated fatty alcohol, is a safe and effective topical
application that has been approved by the United
States Food and Drug Administration for herpes
labialis in adults with properly functioning immune
systems. It is comparable in effectiveness to prescription
topical antiviral agents. Due to its mechanism of
action, there is little risk of drug resistance (El Sayed,
2000). The duration of symptoms can be reduced by
a small amount if an antiviral, anaesthetic or non-
treatment cream (such as zinc oxide or zinc sulfate) is
applied promptly (Chattopadhyay and Khan, 2008).
Effective antiviral medications include acyclovir and
penciclovir, which can speed healing by as much as
10%. Famcyclovir or valacyclovir, taken in pill
form, can be effective using a single day, high-dose
application and is more cost effective and convenient
than the traditional treatment of lower doses for 5~7
days (Garozzo et al., 2011). Lysine has been suggested
as a treatment for herpes labialis based on
in vitro
studies, but the evidence is inconclusive in humans
(Gebre-Mariam et al., 2006). Herpes simplex virus
(HSV) infections are efficiently treated with antiviral
drugs such as acyclovir (ACV). However, resistance
has been reported, mainly among immunocompromi-
sed patients (prevalence around 5%) and particularly
allogeneic bone marrow transplant patients (prevalence
reaching 30%) (Hammer et al., 2006). Resistance to
ACV is associated with mutations on one of the two
viral enzymes involved in the ACV mechanism of
action: thymidine kinase (TK) and DNA polymerase.
In 95% of the cases, ACV resistance is associated with
a mutation in the TK gene as this enzyme is not
essential for viral replication, unlike viral DNA
polymerase, which is rarely involved in resistance
(Hosono et al., 2008). Today, some of the herbal
extracts used in the treatment of herpes sores. In this
study the influence of alcoholic extract of the herb
tarragon and eucalyptus compared with the drug
acyclovir is reviewed.
1 Results
Trypan blue exclusion method showed that the
Eucalyptus globulus
and
Artemisia draconculus
extract
had no serious effect on the proliferation of cells, up
to concentration of 800 μg/mL (data not shown).
Therefore, we could draw a conclusion that the CC50
(the concentration which causes 50% cytotoxicity
effect) was more than 800 μg/mL.
Antiviral activity of the extract by TCID50 assay the
inhibition of virus yield by
Eucalyptus globulus
and
Artemisia draconculus
extract was evaluated by
TCID50 assay in Vero cells.
Eucalyptus globulus
extract showed strong antiviral activity against HSV
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1
when added during the early stages of viral infection.
The degree of inhibition showed to be proportional
to the concentration of the extract and when the
concentration was higher than 200 μg/mL
Eucalyptus
globulus
extract inhibited almost completely the virus
yield. The EC50 value of the extract when treated
during infection was 650 μg/mL and when treated
after infection the EC50 decreased to 200 μg/mL, then
the extract was more effective at low concentrations
when present after viral infection. The results showed
that compared to control wells with no
Artemisia
draconculus
, different concentrations of aqueous and
hydroalcoholic extracts of
Artemisia draconculus
could not reduce viral plaques significantly (data not
shown), however methanolic extracts of
Eucalyptus