Not Just a Cosmetic Fix malariaparasiteneedstotakeupfrom
its host, but the parasite can be fatally
The future weapon against malaria may be a common ingredient found in
shampoo. Fenja Theden reports.
War II. Despite being “malaria-free”,
antimalarial drugs, such as chloroquine.
human host and back to the mosquito.
ular stage of the parasite’s life cycle,
overuse and indiscriminate treatment.
“The parasite can be fatally tricked into taking up pantothenol instead
of vitamin B5.”
in Africa. Dr Saliba feels that “Australia
is essential for the survival of the para-
site. The parasite can’t synthesise its
own vitamin B5, so it relies on its host’s
blood plasma to obtain the nutrient.
most affected by malaria, but also crucial
personnel going to malaria-infected areas
need to take precautions against malaria,
Giemsa-stained malaria parasites (blue/purple) among human red blood cells. (a) Two mature-stage parasites (known as trophozoites)
inside red blood cells. (b) Daughter parasites (known as merozoites) ready to invade new uninfected red blood cells. Three red blood
cells have already been invaded by merozoites, forming a young stage of the parasite known as a “ring”.
human body. The trials indicate that pantothenol lasts long
hopeful that the parasite would find it difficult to develop
enough in the body to be taken up by the parasite, but not
resistance because it “has to obtain this nutrient from the
long enough for all parasites to be killed. Thus, says Dr
plasma in order to grow. For resistance to develop, the para-
Saliba, if an infected person was given a dose of pantothenol,
site would need to synthesise vitamin B5 itself in high quan-
they would “convert most of it into vitamin B5 by the time
tities, and we currently have no evidence that it’s able to do
it’s actually had the chance to kill all the parasites”.
so. Alternatively, it needs to come up with a strategy for
But with a weakness in the parasite’s life cycle clearly
limiting the uptake of the analogues. This will be difficult as
identified, Dr Saliba is developing his antimalarial drugs
the mechanism would need to discriminate between vitamin
further. The research team has discovered that other
B5 and the structurally very similar analogues.
analogues of pantothenol, compounds similar to the real
“Also, a recent trend has been to combine new
vitamin B5, could be even better drugs. Nearly 50 compounds
compounds shown to kill the parasite with other compounds
have been tested so far, with about 15 of them able to kill
that kill the parasite in a completely different way. You essen-
tially hit two independent targets. This makes it even more
However, Dr Saliba says there are other constraints: “You
difficult for the parasite to become resistant to the drug
obviously want to find compounds that are able to kill the
combination as it would need to develop two separate resist-
parasite at low concentrations, so that they won’t be toxic
ance mechanisms simultaneously, or one mechanism that
to the human host. The concentration with which a couple
of our new compounds are able to kill the parasite is encour-
Dr Saliba hopes the new drugs will be used either to treat
people that have already contracted malaria or to prevent
But most drugs developed in the world face the same
a malaria episode by being taken during travel to malaria-
challenge: harmful organisms adapt and evolve to become
resistant to drugs. This has happened to conventional anti-
In research facilities around Australia and the world, the
malarial drugs. If these new antimalarial compounds were
race to save millions of lives from malaria continues every
to be used on a large scale, will the malaria parasite even-
day. Dr Saliba envisages a world in which people can live and
tually develop resistance towards the damage caused by
travel without fear of contracting the disease.
Fenja Theden has a background in molecular biology. She is currently undertaking a
Dr Saliba points out that it is very hard to predict whether
Graduate Diploma in Science Communication with the Centre for Public Awareness of
resistance to the analogues would develop. However, he is
Science at the ANU.
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