Inhibition of P-450 by aucubin: is the biological activity of aucubin due to its glutaraldehyde-like aglycone?

The inhibition of ethoxy coumarin O-deethylase (ECOD) activity by aucubin and its aglycone was examined in a microsomal system and in freshly isolated hepatocytes. Aucubin was found to be inactive but the aglycone was found to be a potent time-dependent inhibitor of ECOD activity in both systems. The close structural similarity between the aglycone of aucubin and glutaraldehyde suggests a similar mechanism of enzyme inhibition through protein cross-linking by Schiff reactions. The similarity between the 2 compounds was demonstrated through their closely similar binding spectra to bovine serum albumin. The biological activities reported for the aglycone are suggested to be due to this similarity to glutaraldehyde.