Metabolite profiling reveals organ-specific flavone accumulation in and identifies a scutellarin isomer isoscutellarein 8--β-glucuronopyranoside.

is a genus of plants containing multiple species with well-documented medicinal effects. and are among the best-studied species, and previous works have established flavones to be the primary source of their bioactivity. Recent genomic and biochemical studies with and have advanced our understanding of flavone biosynthesis in . However, as over several hundreds of species occur throughout the world, flavone biosynthesis in most species remains poorly understood. In this study, we analyzed organ-specific flavone profiles of seven species, including , , and two species native to the Americas ( to Texas and to Central and South America). We found that the roots of almost all these species produce only 4'-deoxyflavones, while 4'-hydroxyflavones are accumulated exclusively in their aerial parts. On the other hand, and also accumulated high levels of 4'-deoxyflavones in their aerial parts, different with the flavone profiles of and . Furthermore, our metabolomics and NMR study identified the accumulation of isoscutellarein 8--β-glucuronopyranoside, a rare 4'-hydroxyflavone, in the stems and leaves of several species including and , but not in and . Distinctive organ-specific metabolite profiles among species indicate the selectivity and diverse physiological roles of flavones.