Advances in pharmacology, biosynthesis, and metabolic engineering of Scutellaria -specialized metabolites

Scutellaria Linn., which belongs to the family Lamiaceae, is a commonly used medicinal plant for heat clearing and detoxification. In particular, the roots of S. baicalensis and the entire herb of S. barbata have been widely used in traditional medicine for thousands of years. The main active components of Scutellaria, including: baicalein, wogonin, norwogonin, scutellarein, and their glycosides have potential or existing drug usage. However, the wild resources of Scutellaria plants have been overexploited, and degenerated germplasm resources cannot fulfill the requirements of chemical extraction and clinical usage. Metabolic engineering and green production via microorganisms provide alternative strategies for greater efficiency in the production of natural products. Here, we review the progress of: pharmacological investigations, multi-omics, biosynthetic pathways, and metabolic engineering of various Scutellaria species and their active compounds. In addition, based on multi-omics data, we systematically analyze the phylogenetic relationships of Scutellaria and predict candidate transcription factors related to the regulation of active flavonoids. Finally, we propose the prospects of directed evolution of core enzymes and genome-assisted breeding to alleviate the shortage of plant resources of Scutellaria. This review provides important insights into the sustainable utilization and development of Scutellaria resources.