Laurus nobilis L. (laurel, Lauraceae) and Prunus armeniaca L. (apricot, Rosaceae) are important industrial crops and display significant biological properties, including antimicrobial activity. In this work, essential oils (EOs) prepared from the leaves of both species from Morocco were evaluated for the first time for possible synergistic in vitro antibacterial and antifungal effects with some conventional antimicrobial drugs, namely fluconazole, ciprofloxacin and vancomycin. Samples were further evaluated for chemical composition by gas chromatography–mass spectrometry (GC-MS). The main volatile compounds detected in L. nobilis were eucalyptol (40.85%), α-terpinyl acetate (12.64%) and methyl eugenol (8.72%), while P. armeniaca was dominated essentially by (Z)-phytol (27.18%), pentacosane (15.11%), nonacosane (8.76%) and benzaldehyde (7.25%). Regarding antimicrobial activity, both EOs inhibited significantly all the microorganisms tested. The EO from L. nobilis had the highest activity, with minimal inhibitory concentrations (MICs) ranging from 1.39 to 22.2 mg/mL for bacteria and between 2.77 and 5.55 mg/mL for yeasts. Conversely, the combination of the studied EOs with ciprofloxacin, vancomycin and fluconazol resulted in a noteworthy decrease in their individual MICs. In fact, of the 32 interactions tested, 23 (71.87%) demonstrated total synergism and 9 (28.12%) a partial synergistic interaction. The EO from L. nobilis exhibited the highest synergistic effect with all the antibiotics used, with fractional inhibitory concentration (FIC) index values in the range of 0.266 to 0.75 for bacteria, and between 0.258 and 0.266 for yeast. The synergistic interaction between the studied EOs and standard antibiotics may constitute promising anti-infective agents useful for treating diseases induced by antibiotic-resistant pathogens.

Chenopodium ambrosioides (L.) is a medicinal and aromatic plant widely used in the Moroccan traditional medicine for its important pharmacological properties. In order to contribute to the valorization of this plant, the current study aimed at evaluating, for the first time, the variation in the yield, chemical composition, and insecticidal and phytotoxic activities of C. ambrosioides essential oil (CAEO) isolated from leaves and inflorescences. The results obtained showed that the CAEO yields vary significantly according to the distilled plant part, with 0.75 ± 0.15% for the leaves and 1.2 ± 0.34% for the inflorescences. CAEO profiling showed quantitative more than qualitative differences. Leaf CAEO was rich in δ-3-carene (61.51%), followed by p-cymene (14.67%) and 1,2:3,4-diepoxy-p-menthane (6.19%). However, inflorescence CAEO was dominated by the same compounds but with variable levels (δ-3-Carene: 44.29%; 1,2:3,4-diepoxy-p-menthane: 19.46%; and p-cymene: 17.85%). The CAEOs from the leaves and inflorescences showed a very interesting inhibiting effect on the germination and growth of the three species used, namely Medicago sativa, Linum rusitatissimum, and Raphanus sativus. However, there was no significant difference between these CAEOs. Similarly, for the insecticidal activity, CAEOs exhibited an important and similar toxicity against Tribolium confusum adults with LD₅₀ of 4.30 and 4.46 μL/L of air and LD₉₀ of 6.51 and 9.62 μL/L air for toxicity by fumigation, while values for contact toxicity on filter paper were 0.04 and 0.05 μL/cm² for LD₅₀ and 0.08 and 0.09 μL/cm² for LD₉₀.

The association of essential oils (EOs) with antibiotics provides a promising solution towards combating resistant bacteria. Thus, the aim of this study was to examine for the first time the possible synergistic interaction between EOs of three Moroccan thymes, namely Thymus leptobotrys (carvacrol [79.1%]), Thymus pallidus (γ-terpinene [29.6%], thymol [26.8%] and p-cymene [18.9%]) and Thymus ciliatus (carvacrol [26.2%], p-cymene [19.6%], thymol [17.3%] and γ-terpinene [14.6%]) and the antibiotic cefixime against selected pathogenic bacteria. The results showed that all thyme EOs presented interesting antibacterial potency and important synergistic effects with cefixime. Thymus leptobotrys EO showed the strongest efficacy against all tested bacteria (minimum inhibitory concentration values 0.14 mg/mL to 73.92 mg/mL), and the best synergistic effect (fractional inhibitor concentration indices: 0.26 to 0.5; gain: 4- to 130-fold). This synergistic interaction between the studied thyme EOs and cefixime may provide a basis for future applications for the control of antibiotic-resistant bacteria.

Essential oils (EOs) from aromatic plants are valuable sources of bioactive compounds with potential applications as natural antimicrobials and antioxidants. This study investigated the chemical composition, antimicrobial and antioxidant activities, and in silico pharmacological properties of EOs extracted from Laurus nobilis, Thymbra capitata, and Mentha piperita, three medicinal species traditionally used in northern Morocco. Hydrodistillation yielded 1.12–1.53% oils, and GC–MS analysis revealed distinct chemotypes: L. nobilis was rich in eucalyptol, linalool, methyleugenol, and α-terpinyl acetate; T. capitata was dominated by carvacrol (80.95%), and M. piperita contained high proportions of linalool (57.37%) and linalyl acetate (28.56%). Antimicrobial assays demonstrated strong activity of all oils against Gram-positive and Gram-negative bacteria as well as Candida species, with T. capitata showing the most potent and broad-spectrum effects (MIC 0.073–9.47 mg/mL), attributed to its high carvacrol content. Antioxidant assays (DPPH and ferric reducing power) identified L. nobilis as the most active radical scavenger (IC₅₀ = 0.037 mg/mL), followed by T. capitata, whereas M. piperita displayed weaker activity. PCA confirmed that phenolic monoterpenes drive both antimicrobial and antioxidant potency, while oxygenated terpenes and sesquiterpenes contribute more selectively. ADMET predictions indicated generally favorable absorption and low toxicity, although o-cymene and carvacrol presented potential safety concerns. Molecular docking revealed α-terpinyl acetate as the most versatile ligand, with strong binding to bacterial, fungal, and oxidative enzymes, whereas other compounds exhibited more selective affinities. Collectively, these findings highlight the potential of Moroccan EOs, particularly T. capitata and L. nobilis, as promising natural alternatives to synthetic antimicrobial and antioxidant agents.

Ce travail vise de comparer, pour la première fois, l’activité insecticide des huiles essentielles des espèces de thyms originaires du Sud-Ouest marocain (Thymus satureioides Coss., Thymus broussonetii Boiss., Thymus maroccanus Ball., Thymus ciliatus (Desf.) Benth., Thymus pallidus Batt., et Thymus leptobotrys Murb. L’étude de la toxicité de ces huiles essentielles a été réalisée par le test de contact sur papier-filtre. Les résultats obtenus ont montré que toutes les huiles essentielles testées ont présenté un effet insecticide important vis-à-vis des adultes de Tribolium castaneum Herbst. Toutefois, l’huile essentielle de Thymus leptobotrys (thym à carvacrol) a montré la toxicité la plus élevée, avec des valeurs de DL50 et DL90 de 0,08 et 0,19 μl/cm2, respectivement, et des valeurs de LT50 et LT90, allant de 32,80 à 17,18 heures et de 69,37 à 32,05 heures, respectivement. Ces données suggèrent que les huiles essentielles de ces thyms, particulièrement celle de Thymus leptobotrys, peuvent présenter une matière première pour le développement de nouveaux produits bio-insecticides contre Tribolium castaneum, l’un des principaux ravageurs des denrées alimentaires stockées dans l’Afrique du Nord.

The association of essential oils (EOs) with antibiotics provides a promising solution towards combating resistant bacteria. Thus, the aim of this study was to examine for the first time the possible synergistic interaction between EOs of three Moroccan thymes, namely Thymus leptobotrys (carvacrol [79.1%]), Thymus pallidus (γ-terpinene [29.6%], thymol [26.8%] and p-cymene [18.9%]) and Thymus ciliatus (carvacrol [26.2%], p-cymene [19.6%], thymol [17.3%] and γ-terpinene [14.6%]) and the antibiotic cefixime against selected pathogenic bacteria. The results showed that all thyme EOs presented interesting antibacterial potency and important synergistic effects with cefixime. Thymus leptobotrys EO showed the strongest efficacy against all tested bacteria (minimum inhibitory concentration values 0.14 mg/mL to 73.92 mg/mL), and the best synergistic effect (fractional inhibitor concentration indices: 0.26 to 0.5; gain: 4- to 130- fold). This synergistic interaction between the studied thyme EOs and cefixime may provide a basis for future applications for the control of antibiotic-resistant bacteria.