Stilbenes are natural compounds found in various plants that show potential benefits to human health, with a unique chemical structure consisting of two aromatic rings linked by a double bond. While resveratrol, found in grapes and red wine, is the most well-known stilbene, there is growing interest in other types of stilbenes that may provide additional health benefits.
O-methylated stilbenes, which are made by introducing a methyl group (-CH3) to a hydroxyl (-OH) group in the stilbene backbone, are promising compounds for research.
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 the development of functional foods, nutraceuticals, and pharmaceuticals.
Recently, a research team led by Dr. Clive LO from the School of Biological Sciences at The University of Hong Kong (HKU) collaborated with the laboratories of the University of Queensland (UQ), Australia, and the HKU School of Biomedical Sciences (SBMS), as well as scientists in Mainland China and Japan, to discover a novel stilbene O-methylase (Sborg) responsible for the production of the enzyme O-methylase in O-methylase. methylated stilbenes.
The discovery offers a new way to produce O-methylated stilbenes in larger quantities and at a lower cost, which may lead to the development of new functional foods, nutraceuticals, and pharmaceuticals that utilize the potential health benefits of these compounds. The results of the research were recently published in the Communication in Nature.
Stilbenes background
Stilbenes are natural compounds found in plants with promising nutraceutical properties, known to provide a variety of health benefits such as anti-aging, anti-neurodegeneration, anti-diabetes, and chemo-preventive properties. O-methylation is a chemical process that improves the potency and bioavailability of stilbenes. However, the biosynthesis of O-methylated stilbenes has not been well studied, and more research is needed to generate specific stilbene compounds.
The research team conducted a study that showed how sorghum and wild sugarcane can produce different types of O-methylated stilbenes, such as pinostilbene, pterostilbene and isorhapontigenin. They used advanced genetic techniques, including CRISPR-Cas9 mutagenesis and transformation of sorghum, to identify the key enzyme, SbSOMT, which mediates a specific chemical change in stilbene called 3,5-bis-O-methylation in sorghum. This change affects the biological activity of stilbene, including its antioxidant and anti-inflammatory properties.
The team also conducted a phylogenetic analysis to study the evolutionary relationship between different organisms, and found that SbSOMT is unique to Sorghum plants and originates 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.
Importance of research
The researchers discovered that SbSOMT uses a chemical reaction similar to COMTs in the grass family, but it binds differently to the stilbene molecule. This different binding mode allows SbSOMT to modify the stilbene molecule in a specific way that produces different types of O-methylated stilbenes in sorghum. These different types of stilbenes are characterized by the location of the O-methyl group in the stilbene molecule, either in the A-ring or the B-ring.
In sorghum, SbSOMT modifies stilbenes in a way that produces A-ring O-methylated stilbenes, such as pinostilbene and pterostilbene. Meanwhile, wild sugarcane uses a common COMT enzyme to modify stilbenes to produce B-ring O-methylated stilbenes, such as isorhapontigenin. The difference between A-ring and B-ring O-methylated stilbenes is due to the specific way that SbSOMT interacts with the stilbene molecule, which includes the hydrophobic Ile144 and Phe337 residues of the SbSOMT enzyme.
Research has found that sorghum and wild sugarcane can be used to produce O-methylated stilbenes. These compounds have health benefits and can be used in nutraceuticals (which are like food supplements). The team also discovered the enzymes responsible for producing these compounds in these plants.
Their findings suggest that we can use molecular breeding and transgenic methods to produce specific types of O-methylated stilbenes with many health benefits. This may open up new possibilities for creating healthier food and supplement options.
More information:
Andy CW Lui et al, Regioselective stilbene O-methylations in Saccharinae grasses, Communication in Nature (2023). DOI: 10.1038/s41467-023-38908-5
Provided by The University of Hong Kong
Citation: New enzyme unlocks potential for health-promoting compounds in sorghum (2023, July 20) retrieved 20 July 2023 from https://phys.org/news/2023-07-enzyme-potential-health-promoting-compounds-sorghum.html
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