The Chinese skullcap, Scutellaria baicalensis - otherwise known in Chinese medicine as Huang-Qin - is traditionally used as a treatment for fever, liver and lung complaints.

Previous research on cells cultured in the lab has shown that certain compounds called flavones, found in the roots of this plant, not only have beneficial anti-viral and anti-oxidant effects, but they can also kill human cancers while leaving healthy cells untouched. In live animal models, these flavones have also halted tumor growth, offering hope that they may one day lead to effective cancer treatments, or even cures.

As a group of compounds, the flavones are relatively well understood. But the beneficial flavones found in Huang-Qin roots, such as wogonin and baicalin, are different: a missing - OH (hydroxyl) group in their chemical structure left scientists scratching their heads as to how they were made in the plant.

The lead author of the paper published in Science Advances, explains: "Many flavones are synthesized using a compound called naringenin as a building block. But naringenin has this -OH group attached to it, and there is no known enzyme that will remove it to produce the flavones we find in Huang-Qin roots."

Working in collaboration with Chinese scientists, the team explored the possibility that Huang-Qin's root-specific flavones (RSFs) were made via a different biochemical pathway. Step-by-step, the scientists unravelled the mechanism involving new enzymes that make RSFs using a different building block called chrysin.
"We believe that this biosynthetic pathway has evolved relatively recently in Scutellaria roots, diverging from the classical pathway that produces flavones in leaves and flowers, specifically to produce chrysin and its derived flavones," said the Professor.

"Understanding the pathway should help us to produce these special flavones in large quantities, which will enable further research into their potential medicinal uses". 

https://www.jic.ac.uk/news/2016/04/scientists-discover-how-chinese-medicinal-plant-makes-anti-cancer-compound/