Essential Oil Composition, Polyphenolic Profile, Macronutrients, and Antioxidant Activity of Bay Laurel Leaves from Croatia

Bay laurel (Laurus nobilis L., Lauraceae) is an important Mediterranean aromatic species widely used as a culinary spice and a source of bioactive constituents. This study aimed to evaluate the essential oil (EO) composition, macronutrient content, polyphenolic profile and antioxidant activity of bay laurel along the Croatian Adriatic coast. A total of 49 volatile compounds were identified in dried leaves using GC–MS, representing 99.27–100.00% of the EO composition. The EOs were dominated by oxygenated monoterpenes (86.51–95.55%), with 1,8-cineole (42.40–56.83%), α-terpinyl acetate (6.89–12.76%), sabinene (6.10–8.65%), linalool (2.06–14.46%), and methyl eugenol (0.45–10.10%) as the major constituents. Polyphenolic profile obtained by spectrophotometric methods showed that total polyphenol content ranged from 6.03% to 9.65%, tannins from 1.81% to 4.76%, flavonoids from 0.23% to 0.71%, and total phenolic acids from 1.34% to 3.03% (rosmarinic acid equivalents) and 2.51% to 5.66% (chlorogenic acid equivalents). Furthermore, we highlighted the antioxidant activity of Croatian bay laurel using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) assays. Ethanolic extracts exhibited higher antioxidant activity than aqueous extracts, reaching 74.58–82.03% ABTS inhibition and 57.93–69.54% DPPH inhibition. This study provides the first integrated characterization of Croatian bay laurel leaves and highlights their antioxidant potential.