**4. Discovery of oleocanthal**

358 Olive Oil – Constituents, Quality, Health Properties and Bioconversions

increased life expectancy (Hu, 2003, Visioli et al., 2005, Trichopoulou et al., 2005), reduced risk of developing disorders such as metabolic syndrome (Tortosa et al., 2007, Babio et al., 2008) and have decreased levels of systematic inflammation (Dai et al., 2009, Fragopoulou et

The traditional Mediterranean diet is defined as the pattern of eating observed in the olive growing areas of the Mediterranean region, namely Greece and Southern Italy in the 1960s. An integral component of this dietary pattern is the consumption of EVOO (Stark and Madar, 2002, Kok and Kromhout, 2004). EVOO, the pillar of Mediterranean recipes, is commonly incorporated into cooked dishes as well as in salads. Typically, the intake of EVOO ranges from 25 to 50 ml per day in the Mediterranean diet (Corona et al., 2009). Therefore, the apparent health benefits have been partially attributed to the dietary consumption of EVOO by Mediterranean populations. Figure 1 displays the Mediterranean

Fig. 1. Food pyramid reflecting the traditional Mediterranean diet. As depicted, EVOO is an

Historically, the health promoting properties of EVOO were attributed to the high concentration of monounsaturated fatty acids (MUFAs), in particular oleic acid, contained in EVOO. However other seed oils (i.e. sunflower, soybean, and rapeseed), which also contain high concentrations of oleic acid, do not exhibit the same health benefits as EVOO (López-

integral food component of this diet residing in the consume 'daily' food group.

**3. Olive oil phenolic compounds** 

diet pyramid featuring EVOO as a core component of this dietary pattern.

al., 2010, Panagiotakos et al., 2009).

The phenolic compound (-)- decarboxymethyl ligstroside aglycone was first reported in EVOO by Montedoro *et al.* (Montedoro and Servili, 1993) in 1993 (Figure 2). A decade after its discovery, Andrewes and colleagues (Andrewes et al., 2003) reported that decarboxymethyl ligstroside aglycone was responsible for the throat irritation and pungency elicited by some EVOOs. In 2005, Beauchamp *et al.* (Beauchamp et al., 2005) confirmed that the phenolic compound, decarboxymethyl ligstroside aglycone was indeed responsible for the throat irritation elicited by EVOOs post-ingestion. This confirmation was carried out by isolating the compound from various EVOOs and measuring the throat irritation elicited. However, at that stage, there was a possibility that co-elution of a minor component or a mixture of components along with decarboxymethyl ligstroside aglycone may collectively cause the localized throat irritation. Therefore, the authors chemically synthesized decarboxymethyl ligstroside aglycone and dissolved it in non-irritating corn oil. Throat irritation elicited by the synthesized decarboxymethyl ligstroside aglycone was found to be dose-dependent on the concentration of this phenolic in corn oil and mimicked that of EVOO containing this compound naturally. Decarboxymethyl ligstroside aglycone was thus deemed the sole throat irritant in EVOO and was named oleocanthal (*oleo* for olive, *canth* for sting, and *al* for aldehyde) (Beauchamp et al., 2005).

Fig. 2. Oleocanthal structure
