A 'toothbrush' containing medication is used to treat tuberculosis (TB). It's actually a compound from the South African "toothbrush tree" that inactivates a drug target for tuberculosis in a previously unseen way. Can plant compounds fight drug-resistant TB microbes better than the drugs that the bacteria has become resistant to by mutating in order to live in an atmosphere of other antibiotics? The plant compounds inactivate the TB microbes that have resistant other drugs, and research is continuing.
This points to plant extracts or plants used for thousands of years as ethnic tradition that now have been scientifically tested. It reveals the old adage that there are potentially new TB drugs in the pipeline from unusual sources. This compound is effective against resistant strains of TB, that ordinary drugs can't reach.
The research from Norwich BioScience Institutes is published in the current issue of the Journal of Biological Chemistry. Ethnobotany is the field, and it's goal is ethno diversity in plants and soil to solve global problems. The plant-derived antibiotics diospyrin and related naphthoquinone compounds are being studied. The research focuses on the plant-derived antibiotics from the natural sources of living trees to see why they may work better against the drug-resistant types of TB microbes.
Plant compounds show promise against inactivating drug-resistant types of TB germs
Tuberculosis causes more deaths worldwide than any other bacterial disease. At the same time as rates are increasing, resistance strains are emerging due, in part, to non-compliance with the treatment required. Many current drugs are nearly 50 years old and alternatives are needed to the long, demanding treatment schedules.
The compound under research, diospyrin, binds to a novel site on a well-known enzyme, called DNA gyrase, and inactivates the enzyme. DNA gyrase is essential for bacteria and plants but is not present in animals or humans. It is established as an effective and safe drug target for antibiotics.
"The way that diospyrin works helps to explain why it is effective against drug-sensitive and drug-resistant strains of tuberculosis," explained Professor Tony Maxwell from the John Innes Centre, in the January 14, 2013 news release, "Medicinal toothbrush tree yields antibiotic to treat TB in new way."
In traditional medicine the antibacterial properties of the tree are used for oral health and to treat medical complaints such bronchitis, pleurisy and venereal disease. Twigs from the tree are traditionally used as toothbrushes.
Many antibiotics originate from plants or soil
Most antibiotics originate from naturals sources, such as the soil bacteria Streptomyces. Antibiotics derived from plants are less common, but they are potentially rich sources of new medicines. "Extracts from plants used in traditional medicine provide a source for novel compounds that may have antibacterial properties, which may then be developed as antibiotics," said Professor Maxwell, according to the news release. "This highlights the value of ethnobotany and the value of maintaining biodiversity to help us address global problems."
The work on diospyrin and related naphthoquinone compounds is being continued by Professor Maxwell as part of the efforts of a consortium of European researchers, More Medicines For Tuberculosis (MM4TB). The collaboration between 25 labs across Europe is dedicated to the development of new drugs for TB.
The work was carried out by postdoctoral researcher Fred Collin and will be continued by South African research assistant Natassja Bush. It is published in the Journal of Biological Chemistry.
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