The latest findings are of significance to developing countries where malaria and HIV are serious public health concerns, and which bear 80 per cent of the global burden of cervical cancer. India alone has one-third of the world's cervical cancer cases.
Earlier studies had confirmed the anti-microbial, anti-tumour and anti-inflammatory properties of turmeric's main component, curcumin.
Scientists at the Indian Institute of Science (IISc) in Bangalore and the University of Michigan Medical School, United States, showed that curcumin inhibits drug-resistant forms of Plasmodium falciparum, the parasite that causes cerebral malaria.
When they fed curcumin to mice infected with Plasmodium bergheii, a related parasite that causes rodent malaria, the number of parasites in the mice's blood fell by 80 to 90 per cent.
In tests, curcumin completely protected up to 29 per cent of infected mice, say the scientists.
"Curcumin may offer a novel treatment for malarial infection," says Govindrajan Padmanabhan, scientist emeritus at IISc and one of the authors of the research, which was published in Biochemical and Biophysical Research Communications in January.
In a separate study, Bhupesh Prusty and Bhudev Das of the Institute of Cytology and Preventive Oncology in New Delhi reported that curcumin could help prevent cervical cancer, which is associated with the human papilloma virus (HPV) in 90 per cent of the cases.
The virus has two key genes — E6 and E7 — which bind to a protein in normal human cells to make them (the cells) cancerous. Curcumin binds with the same human protein, preventing the virus from doing so, say the researchers in the January 2005 issue of International Journal of Cancer.
In laboratory studies, two hours after the scientists introduced curcumin to infected cells, the viral genes began to unbind from the human protein.
Das told SciDev.Net that his institute was planning to start human trials in two or three months. A capsule containing curcumin will be inserted into the vagina of women infected with HPV daily for three to four weeks.
The capsule dissolves slowly, releasing the curcumin powder, which will eventually be expelled in the urine.
In a further demonstration of turmeric's potential to help tackle killer diseases, when scientists at the Jawaharlal Nehru Centre for Advanced Scientific Research in Bangalore 'fed' curcumin to HIV-infected cells in the laboratory, the virus stopped replicating.
They say curcumin could be used to help formulate a combination of drugs to treat HIV infection.
Tapas Kundu, associate professor at the centre, told SciDev.Net that curcumin stops an enzyme called p300 from performing its normal role of controlling the activity of human genes. Because HIV integrates itself into human genetic material, when p300 stops working, the virus can no longer multiply.
Kundu believes the same mechanism could explain curcumin's other anti-bacterial and anti-viral properties.
The p300 enzyme belongs to a class called histone acetylase transferase (HAT) enzymes, which scientists hope could lead them to treatments for a variety of cancers, asthma and neurological disorders.
The findings were reported in the December 2004 issue of Journal of Biological Chemistry.
Biochemical and Biophysical Research Communications 326, 472 (2005)
Link to abstract
International Journal of Cancer 113, 951 (2005)
Link to abstract