Determination of Oxyphylla A Enantiomers in the Fruits of Alpinia oxyphylla by a Chiral High-Performance Liquid Chromatography–Multiple Reaction Monitoring–Mass Spectrometry Method and Comparison of Their In Vivo Biological Activities

(R)-Oxyphylla A, a natural product isolated from Alpinia oxyphylla Miquel as a food and medicinal plant, has been reported previously as a novel chiral compound that possesses a potential therapeutic value for Parkinson's disease (PD). A chiral high-performance liquid chromatography–multiple reaction monitoring–mass spectrometry method was developed to separate oxyphylla A enantiomers and to identify the presence of natural (S)-oxyphylla A for the first time. Twelve samples of dried A. oxyphylla fruits were analyzed in which a large variation in the abundance of enantiomers was observed. Moreover, (S)-oxyphylla A was less abundant in all tested samples, whereas fruits harvested from Hainan and Guangdong tended to have relatively higher total concentrations of enantiomers. Additionally, enantiomers exhibited comparable neuroprotective effects in the zebrafish model of PD without observed toxicity phenotype. The optimized enantioseparation method will be crucial for the quality control of A. oxyphylla and research on bioactivities facilitates the development of oxyphylla A as a potential therapeutic for neurodegenerative diseases.