July 24 (UPI) -- Adding an extract from the yellow spice turmeric into eye drops was effective in treating early stages of glaucoma in a study with rats.
Researchers from University College London and Imperial College London tested a new way to deliver curcumin, which comes from turmeric, to the back of the eye using drops. Previously, there were solubility problems involving circumin in oral form.
The findings, which were published Monday in Scientific Reports, are also a promising way to use the eye drops as a diagnostic tool for others conditions, the researchers believe.
"Curcumin is an exciting compound that has shown promise at detecting and treating the neurodegeneration implicated in numerous eye and brain conditions from glaucoma to Alzheimer's disease, so being able to administer it easily in eye drops may end up helping millions of people," study lead author, Dr. Francesca Cordeiro, of the UCL Institute of Ophthalmology, Western Eye Hospital and Imperial College London, said in a press release.
Glaucoma affects 3.54 percent of the world's population between the ages of 40 and 80, and can lead to irreversible blindness in 1 in 10 cases, according to a previous study.
In glaucoma, there is a loss of retinal ganglion cells, a type of neuron near the surface of the retina.
When administered orally, curcumin previously protected retinal ganglion cells. But because it does not easily dissolve and become absorbed into the bloodsteam, oral administration is difficult. For it to be effective, patients would need to up to 24 tablets a day, which might cause gastrointestinal side effects.
Instead, the researchers developed a nanocarrier in which curcumin is contained within a surfactant combined with a stabilizer, both of which are safe and already used in products for the eyes.
This method increases the drug's solubility by a factor of almost 400,000 and targets the curcumin in the eyes instead of throughout the body, researchers said.
After testing the solution in cells, researchers administered it twice a day in rats for three weeks. They found the retinal ganglion cell loss was significantly reduced compared with controls.
Researchers are now focusing on using the drops to diagnose Alzheimer's disease -- curcumin is known to bind to the amyloid beta protein deposits in Alzheimer's.
"We are now researching diagnostic uses for these eye drops alongside other ways to visualize the retina, as eye tests can be an opportunity to detect signs of neurodegeneration with a simple, non-invasive test," said co-lead author Dr. Ben Davis, of the Institute of Ophthalmology and Imperial College London.
Alzheimer's disease can be detected in the retina with fluorescence to highlight the malignant proteins.