High Resolution-magic Angle Spinning NMR Study of Olive Leaves

In recent years HR-MAS ¹H NMR spectroscopy has proven to be a useful tool for the rapid determination of the metabolic profile of several solid and semisolid foods, such as fruits and vegetables, cheese and meat. Olive leaves are today recognized as direct sources of bioactive compounds and natural antioxidants (flavonoids, secoiridoids) suitable as food additives, and their extracts form the basis of beauty care products and pharmaceutical supplements. Thus, olive leaves are emerging as a new and potentially important product for olive tree growing regions. In this report we present the application of ¹H and ¹³C HR-MAS 1D and 2D NMR spectroscopy for the characterization and analysis of triterpenoids in solid olive leaves using CDCl₃ for locking. Our data show that HR-MAS NMR spectroscopy is a powerful tool for the direct compositional analysis of triterpenoids in olive leaves without the need for any sample pretreatment or solvent extraction steps.