Identification of Throuba Thassos, a Traditional Greek Table Olive Variety, as a Nutritional Rich Source of Oleuropein

Abstract

The content of polyphenols in table olives is highly influenced by the olive variety and the debittering process applied on the fruits. Nine commercial types of Greek table olives were examined for their content in oleuropein and hydroxytyrosol. A very simple extraction procedure and a chromatographic methodology were applied for the simultaneous quantitation of oleuropein (OE) and hydroxytyrosol (HT) in drupes, using boiling water extraction followed by direct HPLC analysis. Hydroxytyrosol was found in all the types of olives that were studied. Kalamata olives and Green "tsakistes" of the variety Megaritiki contained the highest quantity of hydroxytyrosol (1.8-2.0 mg/fruit) followed by Greek-style "chondrolies" with quantity 1.0 mg/fruit. Oleuropein was found in small quantities in two cases, but in the case of Throuba Thassos which is processed by dry salt in a traditional Greek way, oleuropein was found in important quantities (1.2 mg/fruit) recorded over a 4-year period. This is the most important finding of this study showing that this particular table olive type is a nutritional rich source of oleuropein. Additionally, assuming a usual consumption of 20 olive fruits per day, an approximate quantity of 25 mg of oleuropein per day can be considered as safe for human use, since it can be found in the usual diet.

Comparison of some chemical parameters of a naturally debittered olive (Olea europaea L.) type with regular olive varieties

“…Hurma type of olive does not require processing steps used in table olive preparation to remove bitter tasting phenolic compounds of olive. Similar sweet olives were also reported in studies from Greece and Tunisia (Jemai, Bouaziz, & Sayadi, 2009;Zoidou et al, 2009). Since natural debittering of olives is confined to only certain areas in a few countries it is generally associated with factors such as climate and/or soil.…”

“…However, there are a few studies in literature about the changes in olive composition during this natural phase. A study about sweet Thassos olive which is grown in Thassos Island of Greece showed that oleuropein responsible for bitter taste is hydrolysed to hydroxytyrosol and its derivatives by b-glucosidase enzyme, which is produced by fungi and bacteria during ripening (Zoidou et al, 2009). Same trend was also observed in a study about Dhokar olives which are cultivated in southern region of Tunisia (Jemai et al, 2009).…”

Oleuropein is a Powerful Sensitizer of Doxorubicin-mediated Killing of Prostate Cancer Cells and Exerts Its Action via Induction of Autophagy

“…The structure elucidation of oleuropein was carried out using spectroscopic and spectrometric methods as well as comparison with literature data [14]. Specifically, 1D&2D NMR spectra (COSY, COSYLR, HSQC-DEPT, HMBC) were recorded in deuterated methanol (CD 3 OD -Merck), on a Buker Avance III spectrometer (Bruker Biospin GmbH, Reinsteten, Germany) operating at 600.…”

Oleuropein as an inhibitor of peroxisome proliferator-activated receptor gamma

“…The purified oleuropein (95 %) was entirely in the glucoside form and was free of any aglycone forms. The structure elucidation of oleuropein was carried out using spectroscopic and spectrometric methods, as well as comparison with literature data (Zoidou et al 2010). Specifically, 1D and 2D NMR spectra (COSY, COSYLR, HSQC-DEPT, HMBC) were recorded in deuterated methanol (CD3OD-Merck), on a Bruker Advance III spectrometer (Bruker Biospin GmbH, Reinsteten, Germany) operating at 600.11 MHz for 1H and at 150.11 MHz for 13C, with a 5-mm inverse detection probe.…”