A chemical compound found in common herbicides could help fight hospital-acquired human fungal pathogenic infections, which claim an estimated two million lives per year.

A team of international researchers discovered that the chemical chlorimuron ethyl also targets a range of fungal infections that are potentially fatal to humans, particularly people undergoing treatments which place the immune system under stress.

The researchers tested five different families of compounds, to see if they could inhibit a key enzyme,  acetohydroxyacid synthase (AHAS),  from the fungal species, Candida albicans and Cryptococcus neoformans.

One of the five, chlorimurion ethyl (CE), was a stand-out candidate. Authors show that CE and itraconazole (a P450 inhibitor) can act synergistically to further improve potency. They also show in Candida albicans-infected mice that CE is highly effective in clearing pathogenic fungal burden in the lungs, liver, and spleen, thus reducing overall mortality rates.

"In studies in the petri dish and with mice, it was highly effective at preventing proliferation of growth," the author said.

"By inhibiting this enzyme (AHAS) you're removing a key metabolic step that makes three types of amino acids, which these infections need to grow.

"And most importantly, humans don't have this enzyme - we obtain these amino acids from our food - so there's very little chance that these compounds will be toxic to humans, a factor which limits the use of many of the other currently prescribed antifungal drugs."

"We're only at the early stage of this journey, but we're excited to see the prospects for new treatments in the future," author said.

https://www.uq.edu.au/news/article/2018/10/common-herbicide-compound-may-save-millions-of-lives

http://www.pnas.org/content/early/2018/09/18/1809422115