engleski

The Phenolic Compounds: Tyrosol, Hydroxytyrosol and Oleuropein in Croatian Extra Virgin Olive Oils

Olive oil phenolic compounds, particularly tyrosol (Tyr), hydroxytyrosol (HO-Tyr), oleuropein (Ole), although being minor components, are of great importance, taking into account a broad spectra of their biomedicinal activity antimicrobial, antioxidant and anti-inflammatory features [1, 2, 3]. We determined Tyr, HO-Tyr, Ole in extra virgin olive oils (EVOO) obtained from three native Croatian olive cultivar, Bjelica, Buža and Črnica. The study comprises the comparision of the Croatian olive oil phenolic compound content with content in literature, in olive oils from Italy, Spain, Turkey, Greece and Tunisia. The oil was obtained using a small extracting system. The phenolic compounds extraction and HPLC analysis were performed applying in essence the procedure of Montedoro et al. [4]. The content of Tyr, HO-Tyr and Ole was reported here as mean value from all analyzed samples, and also the highest value in the individual sample. Table 1. The phenolic compounds (Tyr, HO-Tyr, Ole) content in the EVOO from Croatian native cultivar* and in the EVOOs from Italy, Greece, Spain, Turkey and Tunisia.** a - highest values ; b - mean values ± SD (standard deviation) ; * determined by HPLC method ; ** data from literature [6-15]. In the course of this preliminary study, we found that Croatian EVOOs from three investigated cultivar are particularly rich in Tyr, in comparison with EVOOs from other countries, Italy, Spain, Greece, Turkey and Tunisia. Among the Croatian cultivar, the olive oil from cultivar Bjelica is most abundant with Tyr, with mean value 35.3 mg/kg, and the highest value 140 mg/kg. According to the literature data, the Tyr content in the EVOO is always below 65 mg/kg [7]. The olive oil from cultivar Bjelica is also the richest in HO-Tyr, with mean value 5.24 mg/kg, and the highest value 14.8 mg/kg. The olive oil from cultivar Buža is the richest in Ole, with the highest value of 21.0 mg/kg (Table 1). The content of HO-Tyr and oleuropein determined in Croatian EVOOs are generally similar or even smaller in comparison with the literature data. This result could be promising for the use pharmaceutical quality olive oil, especially rich in Tyr, taking into regard the well known importance of this natural phenolic compound [2]. Keywords: olive oil, Croatia, tyrosol, hydroxytyrosol, oleuropein Acknowledgements: Support for this study was provided by the Ministry of Science, Education and Sports of the Republic Croatia Projects no. 006-0063082-0354, 0178052. References: 1. Cicerale, S. ; Lucas, L.J. ; Keast, R.S.J. Antimicrobial, antioxidant and anti-inflammatory phenolic activities in extra virgin olive oil. Curr. Opin. Biotech. 2012, 23, 129–135. 2. Abuznait, A.H. ; Qosa, H. ; Busnena, B.A. ; El Sayed, K.A. ; Kaddoumi, A. Olive-Oil-Derived Oleocanthal Enhances β-Amyloid Clearance as a Potential Neuroprotective Mechanism against Alzheimer’s Disease: In Vitro and in Vivo Studies. 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Olive oil; Croatia; tyrosol; hydroxytyrosol; oleuropein

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