Inhibition of prolyl oligopeptidase by flavonoids isolated from the roots of Allexis obanensis (Baker f.) Melch

Background: Prolyl oligopeptidase is a cytosolic serine peptidase that hydrolyzes peptides containing proline at the carboxy terminus of proline residues. It has been associated with several neurodegenerative diseases. Therefore, it is a target in the management of these disease conditions. Methods: Allexis obanensis was taken through cold extraction, subjected to column chromatography and flavonoids isolated via high-performance liquid chromatographic technique. The flavonoids obtained were investigated for their in vitro prolyl oligopeptidase inhibitory activity. Results: The flavonoids isolated include: 4.4”’- dimethoxylophirone A [1] and 7-hydroxy-3-(3-hydroxy-4 méthoxyphenyl)-5-méthoxy-4H chromen-4-one [2]. They inhibited prolyl oligopeptidase at low IC50 concentrations of 7.201±3.021 µM and 6.223±2.002 µM respectively. Conclusion: The results obtained from this study proves the potential of these flavonoids as prolyl oligopeptidase inhibitors, by inference, their potentiality in the management of neuropsychiatric disorders.