Decomposition of a-Tocopheryl Glycosides in Rat Tissues

Background: The aim of our investigation was to estimate the stability of a-tocopheryl O-glycosides in relation to activity of exoglycosidases in selected rat tissues. Material and Methods: Acetylated glycosides were obtained in glucosidation of a-tocopherol using the Helferich method. The activity of exoglycosidases was determined by the Zwierz et al. method. Protein concentrations were determined by the biuret method. The concentration of released a-tocopherol was determined with the HPLC method. Results: The comparison of the amount of released a-tocopherol with the amount of released p-nitrophenol shows that glycoside bound in 2a-5a derivatives of a-tocopherol undergoes hydrolysis significantly harder than in appropriate 2b-5b p-nitrophenyl derivatives. Conclusion: The results indicate that tocopheryl O-glycosides are more resistant to enzymatic hydrolysis than appropriate p-nitrophenol O-glycosides 2a-5a. Among examined tocopheryl O-glycosides, galactoside 4 is the only compound that caused the significant increase in tocopherol concentration, as compared to its endogenic content.