The influence of spatial distribution and transcriptional regulation of secondary metabolites on the bioactivities of Adenophora triphylla (Japanese lady bell)

The distribution of secondary metabolites in plant tissues plays a crucial role in determining their pharmacological properties. In this study, we investigated the dynamics of the bioactive compounds in <i>Adenophora triphylla</i>, a medicinal herb with diverse therapeutic applications. The anti-inflammatory properties of the EtOAc fraction from the aerial part extract (A_ EtF) exhibited an IC₅₀ value of 27.2 ± 2.3 μg/mL, significantly surpassing that of the EtOAc fraction from the root extract (R_EtF) with an IC₅₀ of 38.9 ± 2.9 μg/mL. Similarly, the anti-melanogenic activity of A_EtF (IC₅₀ = 68.9 ± 2.3 μg/mL) outperformed that of R_EtF (IC₅₀ = 90.0 ± 5.5 μg/mL). Analysis of the distinct chemical profiles of these tissues using UPLC-ESI-Q-TOF-MS revealed that the distribution of secondary metabolites contributes to the observed variations in pharmacological properties between the aerial parts and roots. Transcriptome analysis further elucidated spatially regulated genes associated with secondary metabolism, highlighting the role of AbtYABBYs as potential regulators of phenylpropanoid biosynthesis. To validate their function, these genes were transiently expressed in tobacco leaves via agro-infiltration, confirming their role in modulating polyphenolic compound biosynthesis. Our findings underscore the importance of understanding spatial gene expression patterns for harnessing the complete pharmacological potential of medicinal plants. This study provides valuable insights into the spatial regulation of secondary metabolism and lays the groundwork for targeted manipulation of plant bioactivity for therapeutic and industrial applications.