The Janus Corner

Scutellaria baicalensis (commonly known as Huang-Qin) is a plant used in traditional Chinese medicine (TCM) to treat fever, as well as liver and lung disorders. A recent study isolated the flavones wogonin and baicalin from the roots of this species and tested them for antioxidant capacity and antiviral activity.1 Interestingly, whilst these effects were noted, the authors also noted that wogonin and baicalin induced cell death in human cancer cells yet were nontoxic to normal human cell lines. Furthermore, wogonin and baicalin stopped tumour growth in an in vivo model system, indicating there efficacy and potential in cancer chemotherapy. Whilst many flavones have previously been linked with useful therapeutic properties the S. baicalensis root flavones wogonin and baicalin are unique in that they lack a hydroxyl group in their structure. Flavones are generally synthesised from naringenin, which contains the hydroxyl group. No known enzyme that removes the hydroxyl group has been found in S. baicalensis roots, making its mechanism of synthesis unique. The authors of the study determined that wogonin and baicalin were instead synthesised from a different precursor, chrysin (Figure 1). Understanding this pathway may enable the production of these bioactive flavones in large quantities.