The humble onion could have a major impact in the fight against antibiotic resistance in cases of tuberculosis (TB), a study has suggested.
Researchers believe the antibacterial properties of the Persian shallot - a staple of Iranian cooking - could increase the effects of existing antibiotic treatment and reverse the tide of already existing drug resistance.
As many as 50 million people worldwide are currently infected with multi-drug resistant TB meaning it is vital to develop new antibacterials.
Natural products from plants and microbes have "enormous potential" as a source of new antibiotics, they said.
The ongoing study, led by Birkbeck, University of London and University College London (UCL), saw the research team conduct tests on four different synthesised compounds from the shallots.
They found all four showed a significant reduction in the presence of the bacteria in the multidrug-resistant TB - the most promising candidate of which inhibited growth of the isolated TB cells by more than 99.9%.
The team concluded that the chemical compounds may work as templates for the discovery of new drug treatment to combat strains of TB, which have previously developed resistance to anti-bacterial drugs.
The study was led by Dr Sanjib Bhakta, of Birkbeck's Department of Biological Sciences, along with Professor Simon Gibbons, head of UCL's Department of Pharmaceutical and Biological Chemistry.
Dr Bhakta said: "Despite a concerted global effort to prevent the spread of tuberculosis, approximately 10 million new cases and two million deaths were reported in 2016.
"As many as 50 million people worldwide are currently infected with multi-drug resistant TB, which means it's vital to develop new antibacterials.
"In searching for new antibacterials, we tend to focus on molecules that are potent enough to be developed commercially as new drug entities by themselves.
"However, in this study we show that by inhibiting the key intrinsic resistance properties of the TB, one could increase the effects of existing antibiotic treatment and reverse the tide of already existing drug resistance."
Prof Gibbons said: "Natural products from plants and microbes have enormous potential as a source of new antibiotics.
"Nature is an amazingly creative chemist and it is likely that plants such as the Persian shallot produce these chemicals as a defence against microbes in their environment.
"Dr Bhakta and I will be dedicating our research to discovering new antibiotics and understanding how they function. We believe that nature holds the key for new antibiotic chemotypes."
The research is published in the journal Scientific Reports.