Stir-frying modulates chemical transformation in atractylodes macrocephala essential oil: Mechanistic insights into...

Atractylodes macrocephala Koidz. (BZ) is a widely used traditional Chinese medicinal herb, commonly subjected to stir-frying to enhance its therapeutic properties. The essential oil of BZ (BZO), comprising its principal bioactive constituents, undergoes notable changes during thermal processing, although the precise chemical and structural transformations remain inadequately understood. In this study, both raw and systematically stir-frying BZ samples were analyzed to elucidate the effect of processing. Morphological observations revealed progressive microstructure disruption with increasing stir-frying duration. Essential oils were extracted via ultrasonic-assisted petroleum ether extraction and analyzed by GC-MS to determine volatile composition. Stir-frying significantly reduced oil yield and altered the constituent profile: while raw BZO was rich in atractylon, processed BZO exhibited substantial depletion of atractylon and a marked increase in atractylenolides I, II, and III. These compositional changes were further validated by HPLC, which demonstrated a time-dependent conversion of atractylon into its lactone derivatives. Collectively, the results reveal a clear chemical transformation pathway during processing and provide a scientific basis for understanding the traditional processing rationale. This study offers a robust analytical framework for optimizing processing parameters and implementing quality control in both raw and processed BZ preparations.