bHLH transcription factors: Key regulators of bioactive component biosynthesis in medicinal plants

Medicinal plants synthesize valuable active components, including terpenoids, alkaloids, and flavonoids, which exhibit significant potential for treating chronic diseases and immune disorders. The biosynthesis of these compounds is often regulated by bHLH transcription factors, a large and evolutionarily conserved family of regulatory proteins in plants. This review focuses on summarizing the research from the past decade concerning the roles of bHLH TFs in the biosynthesis of these bioactive compounds. It outlines the key regulatory networks within terpenoid, alkaloid, and flavonoid pathways, thereby enhancing our understanding of secondary metabolism and providing a basis for improving natural product yields.