Advancements in the Biotransformation and Biosynthesis of the Primary Active Flavonoids Derived from .

is a classical Chinese herbal medicine, which has been used extensively to treat various diseases, such as sexual dysfunction, osteoporosis, cancer, rheumatoid arthritis, and brain diseases. Flavonoids, such as icariin, baohuoside I, icaritin, and epimedin C, are the main active ingredients with diverse pharmacological activities. Currently, most flavonoids are extracted from plants, but this method cannot meet the increasing market demand. Biotransformation strategies promised huge potential for increasing the contents of high-value flavonoids, which would promote the full use of the herb. Complete biosynthesis of major flavonoids by microbial cell factories would enable industrial-scale production of flavonoids. This review summarizes the structures, pharmacological activities, and biosynthesis pathways in the plant, as well as the extraction methods of major flavonoids, and advancements in the biotransformation and complete microbial synthesis of flavonoids, which would provide valuable insights for future studies on herb usage and the production of flavonoids.