Effect of cultivation on chemical composition and bioactivities of essential oils from Artemisia herba-alba Asso grown in Morocco

Green enrichment of argan oil (Argania spinosa L.) with thyme (Thymus vulgaris L.) and oregano (Origanum vulgare L.) leaves: Evaluating quality and stability improvements

This study aimed to assess the impact of enriching argan oil (AO) (Argania spinosa L.) using the maceration technique with thyme (Thymus vulgaris L.) and oregano (Origanum vulgare L.) leaves (TL and OL) at two proportions (5 and 10%). The oxidative stability of the control and enriched oils was examined under accelerated conditions at a temperature of 60 °C for 120 days (4 months). Quality indices (Free fatty acids (FFA), peroxide value (PV), p-anisidine value (p-AV), ultraviolet absoptions (K232 and K270), Rancimat test, fatty acids composition, sensory attributes, simple phenolic contents (SPC) and antioxidant activity (DPPH•) were determined. As a simple, inexpensive and green method, enrichment by maceration yielded advantageous results. Compared to the control (68.05 ± 1.10 mg GAE/kg), the SPC significantly increased in enriched oils reaching notably 250.9 ± 9.1 mg GAE/kg when adding 10% of TL. Also, the enriched oil samples showed the lowest PV, p-AV and ultraviolet absorptions compared with the control. However, no noticeable changes were reported in fatty acids composition and iodine value. In terms of sensory attributes, enrichment by maceration masked the rancid odour caused by oxidation. These scientific discoveries inherently yield economic advantages by enabling the diversification of product offerings, simultaneously catering to a broader market seeking high-quality oils infused with herbs, including both AO and aromatic plants.

Promising Algerian essential oils as natural acaricides against the honey bee mite Varroa destructor (Acari: Varroidae)

Varroosis induced by Varroa destructor Anderson and Trueman represents the most pathogenic and destructive disease affecting the western honey bee, Apis mellifera. In this study, we investigated the acaricidal activity against the Varroa mite using essential oils (EOs) from the aerial parts of four autochthonous Algerian herbal species, namely Artemisia herba alba, Artemisia campestris, Artemisia judaica and Ruta montana. EOs were obtained by means of hydrodistillation and their composition was characterized by gas chromatography-mass spectrometry. The toxicity of the selected EOs toward V. destructor and A. mellifera adult honey bees was evaluated using the complete exposure method. The results indicate the predominance of davanone (66.9%) in A. herba alba, β-pinene (19.5%) in A. campestris, piperitone (68.7%) in A. judaica and 2-undecanone (70.1%) in R. montana EOs. Interestingly, the LC50 values coupled to bee mortality rates revealed that all tested oils exhibited significant acaricidal efficiency with selectivity ratio (SR) values of 10.77, 8.78, 5.62 and 3.73 for A. campestris, A. judaica, A. herba alba, and R. montana, respectively. These values were better than that of thymol (SR = 3.65), the positive control. These findings suggest that these EOs could be used as plant-derived veterinary acaricides to control varroosis in field conditions.

Chemical Composition and Larvicidal Properties of Essential Oils from Wild and Cultivated Artemisia campestris L., an Endemic Plant in Morocco

The Asteraceae family is well known for its toxic and repellent activity against mosquitoes. In this study, essential oils (EOs) extracted from the aerial parts of both wild and cultivated Artemisia campestris L. plants were tested for larvicidal activity against Culex pipiens (Diptera: Culicidae), a pest mosquito widely suspected to be the vector responsible for West Nile virus transmission. The research aims at comparing the chemical composition and insecticidal activity of cultivated and wild A. campestris EOs. The EOs were obtained by hydrodistillation from the plant's aerial parts and were analyzed using GC-MS. Furthermore, the larviciding experiment was carried out following the standard WHO protocol. The result showed that wild and cultivated plant EOs differed only quantitatively, while the qualitative profile revealed a nearly identical chemical composition. Camphor (18.98%), car-3-en-5-one (11.25%), thujone (6.36%), chrysanthenone (6.24%), filifolone (4.56%), and borneol (3.56%) dominate the wild plant EO. Camphor (21.01%), car-3-en-5-one (17%), chrysanthenone (10.15%), filifolone (7.90%), borneol (3.38%), and thujone (3.08%) are the major compounds of the cultivated plant. Cultivation did not affect the EO production since the yield of the cultivated plant was 0.5 ± 0.1% and 0.6 ± 0.2% for the wild plant. The cultivated A. campestris EO had the highest insecticidal activity (LC50 = 9.79 µg/ml), and no significant difference was noticed between wild and cultivated A. campestris EO in terms of LC90. These findings could pave the way for a new method of producing biocides to control major disease vectors and offer a potential alternative for pest control.

Simplex-centroid design as innovative approach in the optimization of antimicrobial effect of Thymus satureioides, Myrtus communis and Artemisia herba alba essential oils against Escherichia coli, Staphylococcus aureus and Candidatropicalis

Essential Oils (EOs) known since Antiquity, and initially obtained by maceration of aromatic plants, are used as diseases' remedies because they contain valuable therapeutic components. Antimicrobial effect's evaluation of formulations established by an augmented centered mixing plan for three Moroccan medicinal and aromatic plants' essential oils (EOs): Thymus satureioides (T. satureioides), Myrtus communis (M. communis) and Artemisia herba alba (A. herba alba) against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida tropicalis (C. tropicalis). The identification of E.Os chemical compounds was made using Gaz chromatography (GC) and Gaz chromatography coupled to Mass spectrometry (GC/MS).Whereas, the optimization of their antimicrobial effect was performed by experimental design methodology (mixture design) coupled to microdilution method based on Minimal Inhibitory Concentrations (MICs) determination. Results showed that the main components are borneol (34.26%) and α-pinene (31.21%); borneol (27.15%) and 1,8-cineole (21.33%); camphor (14.67%), chrysanthenone (14.10%), and β-thujone (12.60%) for T. satureioides, M. communis and A. herba alba respectively. Optimal mixtures composed of 60% and 40% of T. satureioides and M. communis E.Os; 72% and 28% of T. satureioides and A. Herba alba E.Os; 75% of thyme E.O and 25% of mugwort E.O; predicted the highest antimicrobial effect against E. coli, S. aureus and C. tropicalis, respectively. This study highlights the antimicrobial effect of EOs tertiary mixtures through using mixture design methodology, which may contribute to a successful application in pharmaceutical, food, or cosmetic industries.

Chemical Composition and Antimicrobial Activity of Artemisia herba-alba and Origanum majorana Essential Oils from Morocco

Essential oils (EOs) are one of the most important groups of plant metabolites responsible for their biological activities. This study was carried out to study the chemical composition and the antimicrobial effects of Artemisia herba-alba and Origanum majorana essential oils against some Gram-positive and Gram-negative bacteria, and a fungal strain isolated from spoiled butter. The plants were collected in the region Azzemour of South West Morocco and the EOs, extracted by hydrodistillation, were analyzed by GC-MS. The antimicrobial activity was determined using the agar paper disc method. The main components of A. herba-alba EO were cis-thujone, trans-thujone and vanillyl alcohol; in O. majorana EO terpinen-4-ol, isopulegol and β-phellandrene predominated. Both essential oils exhibited growth inhibiting activities in a concentration-dependent manner on several microorganism species. Our results demonstrated that O. majorana and A. herba-alba EOs could be effective natural antibacterial agents in foods.