Comparative study on the chemical composition of laurel (Laurus nobilis L.) leaves from Greece and Georgia and the antibacterial activity of their essential oil

Galina Stefanova; Tanya Girova; Velizar Gochev; Magdalena Stoyanova; Zhana Petkova; Albena Stoyanova; Valtcho D Zheljazkov

doi:10.1016/j.heliyon.2020.e05491

Comparative study on the chemical composition of laurel (Laurus nobilis L.) leaves from Greece and Georgia and the antibacterial activity of their essential oil

Heliyon. 2020 Dec 21;6(12):e05491. doi: 10.1016/j.heliyon.2020.e05491. eCollection 2020 Dec.

Authors

Galina Stefanova¹, Tanya Girova², Velizar Gochev², Magdalena Stoyanova³, Zhana Petkova², Albena Stoyanova³, Valtcho D Zheljazkov⁴

Affiliations

¹ Lotos Expert OOD, 4000 Plovdiv, Bulgaria.
² Department of Biochemistry and Microbiology and Department of Chemical Technology, Paisii Hilendarski University of Plovdiv, 24 Tzar Asen St., 4000 Plovdiv, Bulgaria.
³ Department of Analytical Chemistry and Physical Chemistry, Department of Tobacco, Sugar, Vegetable and Essential Oil Technology, University of Food Technologies, 26 Maritza Blvd., 4002 Plovdiv, Bulgaria.
⁴ Oregon State University, Department of Crop and Soil Science, 109 Crop Science Building, 3050 SW Campus Way, Corvallis, OR 97331, USA.

Abstract

Laurel (Laurus nobilis L.) is a plant species from Lauraceae family, and is native to the Mediterranean region. The goal of this study was to compare chemical composition of laurel leaves and antibacterial activity of its essential oil (EO) from wild-grown trees in Greece and Georgia. The laurel leaves from the two native habitats had dissimilar concentrations of phenolic acids. Of the conjugated flavonols and flavons, kaempferol (1981.3 μg/g) and apigenin (1433.6 μg/g) were the major representatives in the leaves from Greece, while luteolin (839.1 μg/g) and kaempferol (688.1 μg/g) were the major ones in the leaves from Georgia, respectively. The EO content was 1.42% and 4.54% in the leaves from Greece and Georgia, respectively. The main EO constituents of the Greek laurel plants were 1,8-cineole (30.8%), α-terpinyl acetate (14.9%), α-terpineol (8.0%), sabinene (7.9%), and terpinen-4-ol (6.0%). The main EO constituents of the Georgian laurel plants were 1,8-cineole (29.2%), α-terpinyl acetate (22.6%), sabinene (12.2%), and methyleugenol (8.1%). The EO antimicrobial activities against 20 microorganisms were determined. Among the Gram-positive bacteria, the Enterococcus faecalis strain was the most sensitive, followed by Staphylococcus aureus ATCC 6538. Among the Candida species, C. albicans ATCC 10231 was the most sensitive to the laurel leaf EOs.

Keywords: Agricultural science; Biochemistry; Chemistry; Essential oil; Food science; Laurel; Natural product chemistry; Polyphenolsw.