A promising small molecule derived from an Asian herb has successfully inhibited infection of human white blood cells, thus preventing Ebola virus disease in mice, US researchers report.
Robert Davey, a scientist at the Texas biomedical research institute and his team found that Tetrandrine showed to be a potent small molecule inhibiting infection of human white blood cells in lab experiments.
Tetrandrine is isolated from the root of Stephania tetrandra S. Moore, a Chinese medicinal herb which has been used traditionally as a remedy for neuralgia and arthritis.
Ebola virus begins its entry into a cell by first binding to several types of cell surface proteins.
Then the virus is taken into the cell and follows an endosomal route or membrane-bound route that transports the virus to various cell compartments.
From previous studies, Davey said that during this endosomal process, he knew that calcium signalling in cells, which allow cells to transmit electrical charges to one another, controls many of the processes in the cell and was important for Ebola virus infection.
"We were not able, however, to pinpoint the mechanisms involved in this process," Davey said.
In new research, the team discovered that two pore channels (TPCs) are the key calcium sensor involved in Ebola virus infection.
In addition to identifying this critical mechanism to infection, Davey's team also showed that drugs targeting this interaction show some efficacy as potential treatments against Ebola virus disease.
They found Tetrandrine protected mice from disease without obvious side effects and was the best candidate for further animal testing.
"It was the most potent compound tested, gave little evidence of cytotoxicity and required a smaller dose to be effective and tolerated," the authors wrote.
"When we tested in mice, the drugs stopped virus replication and saved most of them from disease," Davey pointed out.
Essentially, this drug shows an ability to stop the virus before it has a chance to interact with cellular factors, thus stopping the virus from continuing its infection process.
The next step is to test both the safety and effectiveness of the interaction of the drug with Ebola virus in non-human primates.
According to the World Health Organisation (WHO), the latest outbreak of Ebola virus disease has caused the death of more than 9,400 people worldwide.
The research was detailed in the journal Science.
