Study on the Stereoselective Pharmacokinetics and Neuroprotective Effects on HT22 Cells of Pinocembrin Enantiomers

Pinocembrin, as a natural dihydroflavone compound, is currently in the clinical phase II research stage as a candidate new drug due to its significant therapeutic effect on stroke. However, there is no report on the systematic study of the pharmacokinetic and pharmacological activity differences of the enantiomers of pinocembrin. This study comprehensively investigated the stereoselective properties of pinocembrin enantiomers through integrated pharmacokinetic, network pharmacological and neuroprotective evaluations on HT22 cells. The results demonstrated distinct stereoselective characteristics in rat plasma between the enantiomers of pinocembrin following intravenous administration, with the plasma concentration of (+)-pinocembrin consistently being higher than that of (-)-pinocembrin. Pharmacokinetic studies of individual enantiomers administered intravenously demonstrated no evidence of stereochemical inversion between the two enantiomers of pinocembrin in either plasma or brain tissue of rats. Network pharmacology analysis revealed multiple potential therapeutic targets related to ischemic stroke pathophysiology, particularly involving apoptosis regulation and inflammatory responses. Both (+)-pinocembrin and (-)-pinocembrin exhibited protective effects against OGD/R-induced injury in HT22 cells at concentrations of 6.25-50 μM and 12.5-50 μM, respectively; however, no statistically significant difference was observed between the two enantiomers. Western blot analysis further revealed that (+)-pinocembrin significantly upregulated the Bax/Bcl-2 ratio and the p-Akt/Akt ratio, suggesting that its neuroprotective effects are mediated through modulation of apoptosis and activation of the Akt signaling pathway. These findings provide a foundation for understanding the stereoselective pharmacological properties of pinocembrin and suggest potential therapeutic applications leveraging the unique characteristics of each enantiomer for neuroprotective interventions.