Phenolic compounds of olive fruit: One- and two-dimensional nuclear magnetic resonance characterization of nuzhenide and its distribution in the constitutive parts of fruit

The phenolic composition of peel, pulp, and seed of the olive fruit was studied for several Italian cultivars used for oil extraction. The seed contained a compound never previously detected in peel and in pulp. The spectroscopic characterization of this compound proved, for the first time, the presence of nuzhenide in the olive seed. Study of the phenolic composition showed that oleuropein, demethyloleuropein, and verbascoside were present in all of the constitutive parts of the fruit; by contrast, nuzhenide was exclusively present in the seeds of all the cultivars at all ripening stages studied.