Researchers have discovered novel stilbene O-methylase (SbSOMT) in sorghum, an enzyme which is responsible for catalysing the production of O-methylated stilbenes.
The team was led by Dr Clive LO from the School of Biological Sciences at The University of Hong Kong (HKU), who collaborated with laboratories at the University of Queensland (UQ), Australia, and the HKU School of Biomedical Sciences (SBMS), as well as scientists in Mainland China and Japan.
Stilbenes are natural compounds found in plants with promising nutraceutical properties, known to provide a range of health benefits such as anti-aging, anti-neurodegeneration, anti-diabetes, and chemo-preventive properties.
While resveratrol, found in grapes and red wine, is the most well-known stilbene, there has been increasing interest in other types of stilbenes that could offer additional health benefits.
O-methylated stilbenes, which are produced by introduction of a methyl group (-CH3) to a hydroxyl (-OH) group on the stilbene backbone, are promising compounds for research.
The team conducted phylogenetic analysis to study the evolutionary relationships between different organisms, and found that SbSOMT is unique to Sorghum plants
Some plant species, such as sorghum and wild sugarcane, have been found to produce different types of O-methylated stilbenes in response to abiotic or biotic stress and may have greater potency and bioavailability than non-methylated stilbenes.
This makes these plant species particularly interesting for research on the biosynthesis of O-methylated stilbenes and potential applications in developing functional foods, nutraceuticals, and pharmaceuticals.
The discovery offers a new avenue for producing O-methylated stilbenes in larger quantities and at lower costs, which could lead to the development of new functional foods, nutraceuticals, and pharmaceuticals that harness the potential health benefits of these compounds. The research findings have recently been published in Nature Communications.
Stilbenes background
O-methylation is a chemical process that can significantly enhance the potency and bioavailability of stilbenes. However, the biosynthesis of O-methylated stilbenes has not been well-studied, and further research is needed to generate specific stilbene compounds.
The research team conducted a study that showed how sorghum and wild sugarcane could produce different types of O-methylated stilbenes, such as pinostilbene, pterostilbene and isorhapontigenin.
They used advanced genetic techniques, including CRISPR-Cas9 mutagenesis and sorghum transformation, to identify the key enzyme, SbSOMT, that mediates the specific chemical modification of stilbene called 3,5-bis-O-methylation in sorghum. This modification affects the biological activity of the stilbene, including its antioxidant and anti-inflammatory properties.
The team also conducted phylogenetic analysis to study the evolutionary relationships between different organisms, and found that SbSOMT is unique to Sorghum plants and originated from a group of related proteins called caffeic acid O-methyltransferases (COMTs) commonly found in all other grasses.
In addition, the team presented the first crystal structure for SbSOMT in collaboration with HKU SBMS protein structural biologists.
