**3. Results**

#### *3.1. Characterisation of Natural Extracts (HPLC)*

The antioxidant and antimicrobial capacities of these extracts depend on the concentration of the phenolic compounds. Extracts obtained from *Rosmarinus officinalis* L. contained 8.10% of rosmarinic acid (RA), and 5.76% of diterpenes (NOS and NOVS), more specifically, carnosic acid and carnosol. P had 41.38% of total punicalagins, as principal bioactive compounds. Otherwise, hydroxytyrosol extracts, obtained from different parts of the olive tree (*Olea europaea*) during the manufacture of olive oil, had different concentrations of the bioactive compound: HYT-F had 11.25% hydroxytyrosol, while HYT-L presented 7.26%. HPLC chromatograms for each extract are presented in Figure 1.

**Figure 1.** *Cont*.

**Figure 1.** HPLC chromatograms for natural extract. (**a**) RA: Rosemary extract rich in Rosmarinic Acid, (**b**) NOS: Rosemary extract rich in diterpenes and NOVS: Rosemary extract rich in diterpenes and with lecitin as emulsifier, (**c**) P: Pomegranate extract, (**d**) HYT-F: Hydroxytyrosol extract obtained from olive fruit, (**e**) HYT-L: Hydroxytyrosol extract obtained from olive leaf.

#### 3.1.1. Total Phenolic Content (TPC)

Determination of the total phenolic content by means of the Folin–Ciocalteau method allows a comparative evaluation of the content of this kind of compounds, considering, at molecular level, the significant structural difference between the various polyphenols present in the extracts being analysed. The results obtained (mg GAE/g) are shown in Table 2.

HYT-F showed the highest quantity of phenolic compounds, with 41.44 mg GAE/g, followed by P, NOS, RA, HYT-L, and NOVS. This last one with 35.95 mg GAE/g, 13.2% less than the first extract. All the extracts showed more than 35 mg GAE/g. In that way, hydroxytyrosol (HYT-F and HYT-L), rosmarinic (RA, NOS and NOVS), and pomegranate extracts had similar total phenolic amounts, between 36 and 41 mg GAE/g.
