Exploring the provenance effect on chemical composition and pharmacological bioactivity of the moroccan essential oils of Laurus nobilis

Abstract

Even with the emerging modern medicine, traditional pharmacopoeia still has a great significance in primary health care in the Mediterranean countries. The purpose of this study is to investigate the provenance effect on the chemical profile and evaluate the antimicrobial and antioxidant activities of essential oils (EO) of Laurus nobilis (LN) harvested in two different forest regions in Morocco (Moulay Abdessalam/North of Morocco and Beni Mellal ‘Tagzirt’/Middle Atlas forests). The chemical analysis of the composition was performed using GC and GC-MS techniques. The antioxidant effects of the EOs were analyzed using 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl (DPPH) radical scavenging, ferric reducing/antioxidant power (FRAP) and Trolox equivalent antioxidant capacity (ABTS). Moreover, the antimicrobial activity of the EOs was carried out against four wood-rot fungi, three molds, and four bacterial strains. The best EO yield of the aerial part of LN was obtained from Tagzirt forest. GC and GC-MS analysis identified the 1,8-cineole, linalool, myrtenal, γ-terpineol, sabinene, eugenol, α-pinene and β-pinene as major compounds. In addition, the EO from LN of Tagzirt forest was found to have high antioxidant potential: 67.41±7.27 mg TE/g EO, 3.15±0.14 mg AAE/g EO and 126.13±10.69 mg TE/g EO for DPPH, FRAP and ABTS, respectively. Moreover, the EO from LN of Moulay Abdessalam forest showed 24.96 ± 2.41 mg TE/g EO for DPPH, 2.35±0.44 mg TE/g EO for FRAP, and 101.76±1.02 mg TE/g EO for ABTS. Also our study demonstrated that, the EO extracted from the laurel plant of the Tagzirt in Beni Mellal region was the most effective against the selected microorganisms. Our study showed promising antimicrobial and antioxidant properties of the EOs from LN. These findings will have potential impact in treating bacterial infections and prevent oxidative stress associated with several diseases if validated in vivo.