Determination of oxyphylla A enantiomers in the fruits of Alpinia oxyphylla by a chiral HPLC-MRM-MS 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 as a novel chiral compound that possesses potential therapeutic value for Parkinson's disease (PD) before. A chiral HPLC-MRM-MS method was developed to separate oxyphylla A enantiomers and identified the presence of natural (S)-oxyphylla A for the first time. Twelve samples of dried A. oxyphylla fruits were analyzed at which a large variation of abundance of enantiomers was observed. Moreover, (S)-oxyphylla A was less abundant in all tested samples while fruits harvested from Hainan and Guangdong tended to have the relatively higher total concentrations of enantiomers. Additionally, enantiomers exhibited comparable neuroprotective effects in zebrafish model of PD without observed toxicity phenotype. The optimized enantioseparation method will be crucial for the quality control of A. oxyphylla and researches of bioactivities facilitate the development of oxyphylla A as a potential therapeutic for neurodegenerative diseases.