Phenolic Compounds of Olive Fruit:  One- and Two-Dimensional Nuclear Magnetic Resonance Characterization of Nüzhenide and Its Distribution in the Constitutive Parts of Fruit

Abstract

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 nüzhenide 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, nüzhenide was exclusively present in the seeds of all the cultivars at all ripening stages studied.

Characterization of phenolic compounds in olive stones of three moroccan varieties

“…High levels of nuzhenide derivatives were indeed detected in the seed extracts of the three cultivars analysed. These data confirmed the previously reported data indicating that nuzhenide is located mainly in olive seed (Servili et al 1999).…”

“…When the analysis was performed in the positive ion mode, the protonated ion signal was observed with a weak intensity at m/z 687, while the most intense peak signal in the obtained mass spectrum was observed at m/z 709 corresponding to the sodiated adduct of [M+Na] + of nuzhenide. These data confirmed thus that this compound correspond to nuzhenide which has already been identified in Olea europaea seeds (Servili et al 1999). …”

“…The main phenolic compounds in olive fruit are oleuropein and ligstroside, two glucosides of elenolic acid with 2-(3,4-dihydroxyphenyl) ethanol (hydroxytyrosol) and 2-(4-hydroxyphenyl) ethanol (tyrosol), respectively. Servili characterized maturation-induced changes in the phenolic content of the complete olive fruit, encompassing peel, pulp, and seeds in three different olive cultivars (Servili et al 1999). Nuzhenide was detected in the olive seeds of all different varieties and at all stages of maturation.…”

“…The structures of the tentatively identified compounds representing the major detected peaks and summarizing the obtained data for each of the detected chromatographic peak are discussed below. Compounds identification was based on retention data and ESI mass spectra and by comparison with literature data (Servili et al 1999, Silva 2006, Duran et al 1994, Luaces et al 2007, Owen et al 2003, Silva et al 2010, Cardoso et al 2005, Angelino et al 2011, Rodriguez et al 2008, Rodriguez et al 2008, Obied et al 2007, Lozano-Sanchez et al 2011. The identification of the detected compounds was based on the search of the main molecular ions detected in the both used polarities and also on some of the useful observed fragmentations.…”

“…In the olive fruit, a wide range of phenolic structures has been reported including simple phenolic acids such as coumaric acid derivatives , phenolic glucosides, phenolic oleosides and flavonoids (Ragazzi et al 1973, Vazquez et al 1974, Vlahov 1992. Olive seeds and husks contain relatively few phenolic species, but encompass simple phenolics including tyrosol and caffeic acid, in conjunction with flavonoids and secoiridoids (Maestro-Durán et al 1994, Servili et al 1999. The olive stones and seeds are an important byproduct generated in the olive oil extraction and pitted table olive industries.…”