Essential oil components and antioxidant activities of bay (Laurus nobilis l.) populations in Turkey

Aim: In this study, various solvent extraction of Laurus nobilis L. leaf and fruit samples grown in Ordu, İzmir, Hatay provinces were performed. Antioxidant activities, total phenolic and flavonoid contents of extracts were investigated. Leaf samples were analyzed for essential oil, and phytochemical compounds were discussed considering the time of collection, regional, seasonal and geographical location. Material and Method: Daphne leaf samples were obtained from three different time and fruit samples in December and their extracts were prepared by using various solvents. The free radical scavenging activity of the extracts was studied in-vitro using the DPPH radical Blois, the reducing capacity Oyaizu, the chelating activity of metal ions using the Dinis method. In addition, total phenolic and flavonoid contents of extracts were determined according to Folin-Ciocalteu and Zhishen methods, respectively. Essential oil analysis of laurel leaves was determined by GC-MS method. Results: It was determined that free radical removal activity increased with increasing concentration in all extracts and standards, the highest free radical removal activity belonged to Hatay and Ordu provinces respectively. The total phenolic content of ethanol leaf extracts was determined as Hatay, Ordu and İzmir, while the total flavonoid amount was determined as Hatay˃İzmir˃Ordu. Major components of leaf essential oils were eucalyptol, α-pinene, γ-terpinene. Conclusion: According to the ripening process, antioxidant activity was increased due to the amount of phenolic and flavonoid substances in laurel leaves and fruits. It was determined that phenolic, flavonoid content and antioxidant activity of laurel fruit samples were higher than leaf samples. Because of the antioxidant activity results are higher than the standards Laurus nobilis L. in areas such as food, chemistry, pharmacology, etc. is considered to be recommended as natural antioxidant source. Key Words: Antioxidant activity, Daphne, DPPH, Essential oil, Laurus nobilis, Metal chelating, Reduction capacity, Total phenolic content, Total flavonoid content.