Limonene, a natural compound present in lemons and oranges can be a indicator in early-stage diagnosis of liver disease, says a new study.
Limonene can be ingested or inhaled as it is a common additive in commercial food and drink. It is also used to give fruit flavors to some sweets and in cosmetics, perfumes and cleaning products.
According to researchers in the Molecular Physics Group at the University of Birmingham, liver disease has risen over the past decades due to over consumption of alcohol in the UK. Symptoms do not show up until it reaches the advanced stage. But still diagnosis is difficult and for advanced diseases like cirrhosis, liver transplant is the only treatment.
The team collected breath samples using a breath sampling protocol from cirrhosis patients and the controls. The breath samples were then put into a highly sensitive analytical instrument that measures the intensities of aroma molecules.
Researchers compared the Breath samples of a group of 31 patients suffering from cirrhosis with a healthy control group. Then pre-transplant samples of the liver disease sufferers were compared with a sub-cohort of 11 patients who went on to have a liver transplant.
The limonene levels were higher in patients before the transplant surgery. But after getting a new liver by transplantation, the limonene levels were found to be reduced in these patients. The results showed that cirrhosis patients were not able to metabolize limonene fully instead it was stored in their body fat.
Dr Margaret O'Hara, from the Molecular Physics Group and primary investigator on the project, said, "We already knew that people with liver disease have a very distinct smell on the breath and we wanted to find out what caused that smell. Now that we have found a biomarker for the disease in limonene, we can continue to verify how good it is for diagnosing liver disease."
Dr Chris Mayhew, Head of the Molecular Physics Group, said, "The group's results are astounding because they link limonene to the diseased liver rather than simply the diseased patient. A particularly important advantage of breath tests is that they offer the opportunity to assess the global function of the liver, rather than a localized test such as biopsy."
"Importantly, our work provides for the first time a potential pathway for non-invasive real-time detection of early-stage cirrhosis. If that is possible, then the disease could be reversed by drugs and lifestyle change which would lead to major socio-economic impacts," he added. The research was published in the journal EBioMedicine