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Natural substances extracted from plants have been increasingly studied and recognized, recently. Essential oils (EOs), for example, possess antioxidant and antibacterial properties, enabling their application across different sectors like agro-food, pharmaceuticals, and cosmetics. In Morocco, exceptional plant diversity, mirroring the diversity of ecosystems, has not yet revealed all its secrets. Therefore, the aim of this study is to determine the chemical composition and evaluate the antibacterial and antioxidant activities of EOs from Thymus zygis L. ssp. gracilis and Eucalyptus camaldulensis Dehnh. collected in the El Hoceima and Mamora regions, respectively. The EOs were extracted by hydrodistillation employing a Clevenger-type apparatus. Gas chromatography/mass spectrometry (GC/MS) analyses identified 54 constituents representing 92.65% of the total for T. zygis and 55 components representing 99.60% for E. camaldulensis. The primary components found in the EO of T. zygis are δ-terpineol (27.64%), followed by δ-3-carene (15.7%), thymol (14.17%), and dehydrolinalool (4.99%). The main compounds in E. camaldulensis EO are 1,8-cineole (43.61%), γ-terpinene (11.71%), α-terpineol (10.58%), and p-cymene (4.93%). The antioxidant properties of these oils were investigated by utilization of the 2,2-diphenyl-1-picrylhydrazyl method and the ferric reducing antioxidant power (FRAP) test. The antibacterial activity was assessed against two Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and two Gram-negative bacteria (Micrococcus luteus and Escherichia coli). Both EOs showed significant antioxidant activity but were less effective than reference antioxidants quercetin and catechin. Antibacterial studies demonstrated strong activity of T. zygis and E. camaldulensis EOs against the studied bacteria, as well as good inhibitory properties (minimum inhibitory concentration).

The use of combined essential oils (EOs) is a new technique that can improve their preservative effects while minimizing their sensory impact in foods. The aim of this study was to determine the chemical profile of three essential oils (EOs) extracted from Lavandula stoechas L. (Ls), Thymus zygis L. (Tz), and Eucalyptus camaldulensis Dehnh (Ec) and to evaluate their synergistic antibacterial activity for optimal inhibition against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus using an augmented Simplex centroid mixing scheme. The essential oils were extracted by hydrodistillation and analyzed via gas chromatography–mass spectrometry. Anti-bacterial potency was evaluated by disk diffusion. Chemical analysis revealed the main compounds in Lavandula stoechas (Ls) essential oil: camphor (36.15%), followed by fenchone (16.57%) and Z-8-hydroxy linalool (8.28%). The Thymus zygis (Tz) essential oil is dominated by δ-terpineol (27.64%), δ-3-carene (15.7%), and thymol (14.17%). In contrast, the Eucalyptus camaldulensis (Ec) essential oil contains mainly 1,8-cineole (43.61%), γ-terpinene (11.71%), and α-terpineol (10.58%). The optimal mixture is the binary association of 40% E. camaldulensis EO and 60% T. zygis EO, which provides an effective inhibition diameter (ID) of 13.37 mm to inhibit S. aureus. Furthermore, the formulation of 27% and 73% EOs of E. camaldulensis and T. zygis, respectively, corresponds to the mixture required to achieve the optimum inhibition diameter (ID = 11.55 mm) against E. coli. In addition, the mixture of 29% EO of E. camaldulensis and 71% EO of T. zygis is the optimum mixture to inhibit B. subtilis, with an inhibition diameter of 12.31 mm. These findings highlight the potency of antibacterial formulations of these essential oils and suggest that they might be used as substitutes for conventional drugs to prevent the development of bacteria responsible for serious infections and food spoilage. [ABSTRACT FROM AUTHOR]

Wood tar essential oils have garnered attention for their potential therapeutic benefits and industrial applications. However, despite their historical significance, comprehensive analyses comparing artisanal and laboratory-produced variants are notably absent in current literature. Therefore, this research aims to bridge this gap by conducting chemical analysis to identify key constituents in artisanal and laboratory-produced essential oils of wood tar, as well as their antimicrobial and antioxidant activities. The DPPH and FRAP assays were employed to assess antioxidant activity to determine EC50 values. The results of the study revealed the following major phytoconstituents in the tar: β-himachalene (30.24%; 22.78%), α-himachalene (16.06%;14.23%), and γ-Gurjunene (9.69%;7.88%). Similarly, for AJTEO and LJTEO, the major constituents observed were α-Cedrene (32.85%; 27.89%), Terpinen-4-ol (7.06%;10.13%), and β-Cedrene (3.51%; 4.85%). In the antimicrobial assessment, laboratory wood tar EO shows stronger inhibition against tested organisms than artisanal wood tar EO. Juniper tar EO was more effective than cedar tar EO. LCTEO displayed potent antioxidant activity, with an EC50 value of 16.09 µg/mL, followed by ACTEO at 17.659 µg/mL. AJTEO and LJTEO exhibited robust antioxidant effects with EC50 values <1.25 µg/mL. In the FRAP assay, LCTEO demonstrated potent antioxidant activity with a value of 395.66 ± 0.02 µg/mL, while ACTEO showed an EC50 of 532.71±0.053 µg/mL. AJTEO displayed an EC50 value of 293.3±0.012 µg/mL, and LJTEO exhibited an EC50 of 238.12±0.014 µg/mL. This research compares artisanal and laboratoryproduced wood tar essential oils and their potential for application in pharmacy and cosmetic industries as antimicrobial and antioxidant agents. [ABSTRACT FROM AUTHOR]