Vitamin C could be a blessing for patients suffering from drug resistant TB as it kills drug resistant TB bacteria as found by researchers of Albert Einstein College of Medicine. This study was published in the journal of Nature Communication. TB therapy could also reduce if vitamin C added to currently used drugs.
The main cause of TB is M. tuberculosis. It was estimated that 8.7 million people suffered and 1.4 million people died due to TB in 2011 as reported by World Health Organization (WHO). Currently the major problem that is causing hurdle during the treatment of TB is the resistance that in increasing day by day. Approximately 650,000 people in the world are living with multi drug resistant TB (MDR) and 9% of who have extensively drug resistant TB (XDR-TB). This devastating bacterial infection is mostly common in developing and low income countries, according to the WHO.
Isoniazid is the first choice of drug used for the treatment of TB and now M. tuberculosis showing resistant against it. A molecule names as mycothiol is not present in isoniazid resistant bacteria as found by Dr. Jacobs and his colleagues.
“We hypothesized that TB bacteria that can’t make mycothiol might contain more cysteine, an amino acid,” said Dr. Jacobs. “So, we predicted that if we added isoniazid and cysteine to isoniazid-sensitive M. tuberculosis in culture, the bacteria would develop resistance. Instead, we ended up killing off the culture— something totally unexpected.”
It was suspected by Einstein team that cysteine could be the possible chemical that was killing the bacteria by acting as a reducing agent. Cysteine can damage DNA by facilitating the synthesis of free radicals (reactive oxygen species).
“To test this hypothesis, we repeated the experiment using isoniazid and a different reducing agent— vitamin C,” said Dr. Jacobs. “The combination of isoniazid and vitamin C sterilized the M. tuberculosis culture. We were then amazed to discover that vitamin C by itself not only sterilized the drug-susceptible TB, but also sterilized MDR-TB and XDR-TB strains.”
By conducing more research, they found the molecular mechanism could help in understating that how vitamic C produces toxic. It was Fenton reaction “causing iron to react with other molecules to create reactive oxygen species that kill the TB bacteria.”
“We don’t know whether vitamin C will work in humans, but we now have a rational basis for doing a clinical trial,” said Dr. Jacobs. “It also helps that we know vitamin C is inexpensive, widely available and very safe to use. At the very least, this work shows us a new mechanism that we can exploit to attack TB.”
Reference: Catherine Vilchèze, Travis Hartman, Brian Weinrick, William R. Jacobs Jr. Mycobacterium tuberculosis is extraordinarily sensitive to killing by a vitamin C-induced Fenton reaction. 2013. Nature Communication. doi:10.1038/ncomms2898