Onion, artemisinin could help fight tuberculosis

Onion and artemisinin may become instrumental in the fight against one of the world’s deadliest diseases – tuberculosis (TB), researchers have said.

Researchers believe the antibacterial properties extracted from the Persian shallot, a type of onion, could increase the effects of existing antibiotic treatment.

In the ongoing study, led by Birkbeck, University of London and University College London, the research team conducted tests on four different molecules from the shallots, which are a staple of Iranian cooking.

They found all four showed a significant reduction in the presence of the bacteria in the multidrug-resistant TB. It inhibited the growth of the isolated TB cells by more than 99.9 per cent.

By inhibiting the key intrinsic resistance properties of the TB, the researchers said this could help “reverse the tide” of strains of TB which have developed resistance to antibacterial drugs.

Although the research is still in its early stages and clinical trials would need to follow, the team concluded that the chemical compounds may work as templates for the discovery of new drug treatment to combat strains of TB.

According to these researchers in the journal, Scientific Reports, the molecules, which were tested in a laboratory, could be combined with existing antibiotics to form new anti-TB drugs.

Also, researchers at the Michigan State University in 2016 edition of the journal Nature Chemical Biology, screened more than 500,000 different compounds in the laboratory and found that artemisinin is capable of blocking a defensive mechanism used by the TB-causing bacterium, Mycobacterium tuberculosis (Mtb).

The researchers were looking for molecules that might somehow prevent Mtb from sensing the oxygen deprivation. The idea was to stop the bacteria from becoming dormant so that it would be more susceptible to antibiotics. One of the compounds they identified was artemisinin, an extract of Artemisia annua.

Tuberculosis germs need oxygen to thrive in the body. The immune system starves this bacterium oxygen to control the infection. The team found that artemisinin attacks a molecule called heme, which is found in the Mtb oxygen sensor.

By disrupting this sensor and essentially turning it off, the artemisinin stopped the disease’s ability to sense how much oxygen it was getting.

From their assessment, they said that artemisinin could significantly speed up the delivery of existing antibiotics, and in the case of TB, that shorter treatment window could make all the difference.

While it’s a promising start, the scientists acknowledge that there’s a lot more research to be done before artemisinin can be used in TB treatments.

Meanwhile, experts also say that supplementing the diet with Vitamin A may help in controlling the spread and risk of TB.

A 2017 study, published in the journal Clinical Infectious Diseases, shows that people with vitamin A deficiency may be 10 times more likely to develop TB, especially if they are living with individuals who are infected with the disease.

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Moreover, this risk was 20 times higher among young people between the age of 10 and 19 years. But just how vitamin A might affect the risk for TB has, up until now, remained unclear.

Vitamin A which is also known as retinol is found in animal products like milk, eggs, and liver. These can be used up by the body directly. The other type, Provitamin A or the carotenoids, are found in fruits and vegetables and need to be converted by the body into retinols.

The richest sources of beta-carotene are yellow and orange coloured fruits like mango, papaya, apricot and vegetables such as carrots, spinach, lettuce, tomatoes, sweet potatoes, and broccoli.

Meanwhile, a survey of medicinal plants used in the treatment and management of TB show they vary from one region to another. In Ogun State, medicinal plants frequently used include Cola acumminata (obi abata), Garcinia kola (leaf of bitter kola tree), Vitallaria parodoxa (shea nut oil), Costus afer (ginger lily, or bush-cane stem), Pycnanthus angolensis (stem bark of African nutmeg) and Aframomum melegueta (Alligator pepper fruit).

Also, in 2014 researchers at the National Institute for Pharmaceutical Research and Development (NIPRD) Abuja screened 12 medicinal plants and wonder cure concoction used in Nigeria unorthodox medicine for TB.

They reported in the 2018 edition of  African Journal of Biotechnology that plants extracts Allium cepa (onion), Allium ascalonicum (Alubosa elewe in Yoruba), Terminalia glaucescences (idi (Yoruba), baushe (Hausa), edo (Ibo)) and Securidaca longependunculata (violet plant or Epeta in Yoruba) showed activity against TB.

Also, in 2011, other researchers in the African Journal of Biomedical Research demonstrated that Uvaria afzelli (gbogbonishe in Yoruba; Umimiofia in Igbo and Osu-umimi in Ukwani) and Tetracera alnifolia (opon tree in Yoruba) may be of therapeutic importance in the treatment of tuberculosis.