The chemical composition and antibacterial, insecticidal, and antioxidant properties of the essential oil from Mentha pulegium L. (M. pulegium) growing in Morocco were investigated in this work. To achieve this goal, the oils were obtained by using hydrodistillation before being characterized by GC-MS. The antibacterial and antifungal activities were conducted against pathogenic strains using the disc diffusion and MICS bioassays. The insecticidal activity was carried out versus C. maculatus using contact and inhalation tests. The antioxidant activity was performed by using DPPH and total antioxidant capacity bioassays. The chemical analysis of the oil showed that 20 compounds were identified, which represented 98.91% of the total oil. In the oil, the main components detected were R-(+)-pulegone (76.35%), carvone (5.84%), dihydrocarvone (5.09%), and octanol-3 (2.25%). The essential oil has moderate-to-strong broad-spectrum antibacterial and antifungal properties; the results showed that B. subtilis was the most sensitive strain to M. pulegium oil, with the largest inhibition diameter (25 ± 0.33). For the antifungal activity, the results obtained indicated that Aspergillus niger was the most sensitive fungal strain to M. pulegium oil with an inhibition percentage up to 100%. Regarding the insecticidal activity, the inhalation test showed a high efficacy (100% mortality), and a lethal concentration of LC50 = 1.41 + 0.48 μL/L air was obtained after 24 hours of exposure. Moreover, the contact test showed that a total reduction in fertility and emergence was obtained with a dose of 20 μL/mL of acetone. Regarding the antioxidant activity, the sample concentration necessary to inhibit 50% of HE radicals (IC50) was 7.659 mg/mL (DPPH) and 583.066 57.05 mg EAA/g EO (TAC).

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In this study, the chemical composition and the antioxidant and antifungal activities of essential oil from Laurus nobilis flowers were examined. The essential oil was prepared using steam distillation in a modified Clevenger-type apparatus. The chemical composition of the obtained essential oil and chemotypes was determined using gas chromatography coupled with mass spectrometry (GC/MS) and gas chromatography with flame ionization detection (GC-FID). Twenty-five volatile compounds were identified, which made up 92.07% of the total essential oil content. The essential oil yield was 1.06% and the most abundant compounds were 1.8-cineole (45.01%), α-caryophyllene (7.54%), germacradienol (6.13%), limonene (4.69%), α-pinene (3.04%), and germacrene D (3.14%). The antifungal activity of the obtained essential oil was tested against seven fungal strains: Aspergillus clavatus, A. niger, Chaetomium globosum, Cladosporium cladosporioides, Myrothecium verrucaria, Penicillium citrinum, and Trichoderma viride. The results indicated that essential oil from L. nobilis flowers exhibited significant antifungal activity against the tested fungal strains with minimum inhibitory concentrations (MICs) ranging from 0.05 to 0.46 mg/mL. The essential oil of L. nobilis also exhibited strong total antioxidant capacity (TAC) as indicated by its ability to scavenge free radical DPPH. Taken together, this study indicates that the essential oil from L. nobilis flowers possesses significant antifungal and antioxidant activities, possibly due to the high level of 1,8-cineole.

Antioxidant, antifungal and insecticidal activities of essential oil (EO) extracted from the Moroccan lavender (Lavandula dentata) were investigated and their chemical constituents determined. Gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry analyses (GC-MS) were used to examine the phytochemical composition of EO. Antioxidant potential was examined in vitro by use of three tests: DPPH inhibition, reducing power (FRAP) and total antioxidant capacity (TAC). Antifungal activity was assessed by calculating inhibition of growth of Alternaria alternata, Botrytis cinerea and Fusarium oxysporum. Repellent potential and toxicity of EO by contact and inhalation were performed against Callosobruchus maculatus. Sixteen constituents were detected in the EO of Lavandula dentata. The major component was linalool (45.06%) followed by camphor (15.62%) and borneol (8.28%). EO exhibited a significant antioxidant activity, as measured by DPPH and FRAP assays, with IC50 and EC50 values of 12.95 ± 1.300 mg/mL and 11.88 ± 0.23 mg/mL, respectively. EO of lavender exhibited total antioxidant capacity of 81.28 ± 2.28 mg AAE/g EO. EO of lavender showed an inhibitory effect on mycelial growth against tested fungi and was 100% in the case of B. cinerea. EO caused total mortality of adult C. maculatus from 5 µL/L air with LC50 value of 4.01 µL/L air. Significant reduction in numbers of eggs laid (99.2%) and emergence (100%) was observed in a dose-dependent manner up to maxima of 100% and 99.2%, respectively. EO of lavender also showed a moderate potency to repel insects with a mean of 34.44%. EO of Moroccan Lavandula dentata has potential to be an effective natural agent against free radical damage and could be an environmentally friendly alternative bio-fungicide and bio-insecticide.

Since some synthetic insecticides cause damage to human health, compounds in plants can be viable alternatives to conventional synthetic pesticides. Dittrichia viscosa L. is a perennial Mediterranean plant known to possess biological activities, including insecticidal properties. The chemical composition of an essential oil (EOD) from D. viscosa, as well as its antioxidant, antimicrobial, and insecticidal effects on the cowpea weevil (Callosobruchus maculatus) were determined. Forty-one volatile compounds were identified in EOD, which accounted for 97.5% of its constituents. Bornyl acetate (41%) was a major compound, followed by borneol (9.3%), α-amorphene (6.6%), and caryophyllene oxide (5.7%). EOD exhibited significant antioxidant activity in all tests performed, with an IC50 of 1.30 ± 0.05 mg/mL in the DPPH test and an EC50 equal to 36.0 ± 2.5 mg/mL in the FRAP assay. In the phosphor-molybdenum test, EOD results ranged from 39.81 ± 0.7 to 192.1 ± 0.8 mg AAE/g E. EOD was active on E. coli (9.5 ± 0.5 mm), S. aureus (31.0 ± 1.5 mm), C. albicans (20.4 ± 0.5 mm), and S. cerevisiae (28.0 ± 1.0 mm), with MICs ranging from 0.1 mg/mL to 3.3 mg/mL. We found that 1 µL of EOD caused 97.5 ± 5.0% insect mortality after 96 h in the inhalation test and 60.0 ± 8.3% in the ingestion assay. The median lethal concentration (LC50) was 7.8 ± 0.3 μL EO/L, while the effective concentration in the ingestion test (LC50) was 15.0 ± 2.1 μL EO/L. We found that 20 µL of EOD caused a reduction of more than 91% of C. maculatus laid eggs.