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Turmeric, the yellow spice used in many Indian dishes, has shown potential as a
weapon against malaria.
Scientists at the Indian
Institute of Science (IISc) in Bangalore and the University of Michigan Medical
School, United States have shown that curcumin, the chemical that gives turmeric
its distinctive yellow colour, inhibits drug-resistant forms of P. falciparum.
The findings have been published in Biochemical and Biophysical Research
Communications in January 2005. (Reddy RC, Vatsala PG, Keshamouni VG, Padmanaban
G, Rangarajan PN. Curcumin for malaria therapy. Biochemical and Biophysical Research Communications.
2005;326(2):472-474).
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Turmeric |
Curcumin isolated
from the roots of the Curcuma longa plant has been shown to regulate a
number of biological responses. In addition to its anti-tumorigenic,
anti-oxidant, and anti-inflammatory effects, curcumin has been shown to possess
anti-microbial activity, shown to hinder the viability of Leishmania and
Trypanosoma. In the present study, curcumin inhibited the growth of P.
falciparum in a dose-dependent fashion, with an IC50 of 5 μM.
Increasing doses of curcumin resulted in decreased viability of P. falciparum,
with a dose of 50 μM leading to negligible proliferation. When tested in a
well-characterized in vivo P. berghei-rodent infection model, curcumin
had significant beneficial effects. Oral feeding of curcumin to P. berghei-infected
mice decreased blood parasitemia by 80–90% and enhanced their survival
significantly compared to vehicle-fed controls. Curcumin treatment resulted in
an overall survival rate of 29% compared to 0% in vehicle-fed animals by day 21
post-infection. Curcumin was administered 48 h after infection (3–5% parasitemia),
once daily for 5 days at a dose of 100 mg/kg body weight. This dose of curcumin
has not been demonstrated to result in toxic side effects in humans when
compared on a weight to weight basis. A phase 1 human trial using up to 8000 mg
of curcumin per day for 3 months found no toxicity from curcumin.
The exact mechanism(s) of curcumin’s antimalarial action is not clear. The
inhibition of parasite growth in culture suggests a direct mechanism of action
involving parasite biochemical processes. One of the possible targets for
curcumin action could be PfATP6, the parasite orthologue of mammalian
sarcoplasmic–endoplasmic reticulum Ca2+-ATPase (SERCA). Artemisinin
has recently been shown to inhibit PfATP6. It is therefore possible that
curcumin and artemisinin act through similar mechanisms.
Curcumin appears to be an ideal antimalarial molecule especially for use in
combination with antimalarials such as artemisinin not only to limit the use of
the latter but to overcome the problems of high cost, recrudescence, and drug
resistance. The authors suggest that in view of its abundance, non-toxic nature,
and demonstrated therapeutic effects in a variety of human diseases, it will be
useful to further investigate the potential of curcumin in developing low-cost
antimalarial therapies.
"Curcumin may offer a novel treatment for malarial infection and could
be an Indian contribution to arrest malaria," says Govindrajan Padmanabhan, scientist emeritus at IISc and one of the researchers.
Curcumin could be
developed into the world’s first low-cost, easy to produce/isolate, low-toxicity malaria drug and Phase
II clinical trials will be initiated to find out its efficacy
on humans. As turmeric has been used since long, the toxicity and side effects
of its derivative may not pose a big problem. If
found effective, it may become the ideal agent needed for global malaria control
programs and eradication of this deadly disease, the researchers hope.
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