Biological Essence of Component Complexity in Herbal Medicine： Based on Changed Metabolism of Scutellaria baicalensis Under Drought Stress / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the biological essence of the content variation of differential primary and secondary metabolites in fresh<italic> </italic>roots of <italic>Scutellaria baicalensis </italic>under drought stress. Method:The changes of metabolites were analyzed by ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass/mass （UHPLC-ESI-Q-TOF-MS/MS）. Result:A total of 11 differential compounds were identified from the roots of <italic>S. baicalensis</italic> （VIP≥2）. Under drought stress， citric acid content increased and shikimic acid content decreased， indicating that the drought stress weakened the primary metabolism but strengthened secondary metabolism. Drought stress raised the content and regulated the proportion of various secondary metabolites by modulating the biosynthesis and biotransformation of them. To be specific， the content of free flavonoids with many phenolic hydroxyl groups and high biological activity and pharmacological activity， such as baicalin， wogonoside， baicalein， wogonin， chrysin， eriodictyol， 5，2'，6'-trihydroxy-7，8-dimethoxyflavone， 5，8-dihydroxy-6，7-dimethoxyflavone， and 3，5，7，2'，6'-pentahydroxyflavanone， was significantly increased. The massive compounds， like an intricate buffer， maintain metabolism stable as quickly and accurately as possible through biosynthesis and biotransformation， thus responding to the changing environment， which reveals how the quality of genuine regional drugs is influenced and why compounds in herbal medicine are complex. Conclusion:Secondary metabolites with low content but high activity are important influencing factors of medicinal material quality and metabolites with high content and high activity are evaluation indicators of genuine regional drug quality.