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ABSTRACTThe goal of this work was to investigate the chemical composition of Aloysia citriodoraessential oil and its biological activities as antioxidant, antibacterial, antifungal and anti-inflammatory potentials depending on the collection region. The highest essential oil yields were in Gabes and Kairouan at the Arid bioclimatic zone. Sixty volatile compounds were identified by GC-FID-MS. The major compounds were limonene and spathulenol in Gabes at the Middle Arid. However, (E)-citral (known as geranial) was the major compound of Belli and Kairouan belonging to the Upper Semi-Arid and Upper Arid areas, respectively. The essential oil extracted from the inferior sub-humid bioclimatic zone (Boussalem) had spathulenol and caryophyllene oxide as predominant components. Inversely to DPPH and ABTS, the antioxidant activities using reducing power assay of A. citriodoraessential oils significantly increased from the inferior sub-humid (Boussalem) to the Upper Arid (Kairouan) bioclimatic areas. Independently of region, A. citriodoraessential oil exhibited an interesting antibacterial, antifungal and anti-inflammatory potential.

The study aimed to investigate the impact of fractionation on Schinus molleessential oil composition and antimicrobial properties. The crude oil was fractionated using open-column chromatography, and gas chromatography–mass spectrometry (GC–MS) identified Dl-limonene as chemotype (31.14%). Unfractionated oil showed substantial antimicrobial effectiveness against various microorganisms, including Enterococcus faecalisATCC 29212, with inhibition zones (IZ) ranging between 12 and 29 mm. After fractionation, the hydrocarbon fraction exhibited enhanced antimicrobial properties, with inhibition zones of 40 mm and 45 mm and a minimum inhibitory concentration (MIC) of 0.031 mg/mL against methicillin-resistant Staphylococcus aureusand Enterococcus faecalisATCC 29212. Additionally, the oil demonstrated robust insecticidal activity against Tribolium castaneum(RD50= 0.010 µL/cm2; LD50= 0.019 µL/cm2) and Rhyzoperta dominica(RD50= 0.015 µL/cm2; LD50= 0.010 µL/cm2), and potent anti-inflammatory activity by suppressing nitric oxide production (51.41% at 62.5 μg/mL) without cytotoxicity toward RAW 264.7 macrophage cells. These results underscore the applicability of Schinus molleessential oil as efficient antimicrobial, insecticidal, and anti-inflammatory agents in agricultural, food, and pharmaceutical sectors.

Eucalyptusstands out as a crucial species for forest cultivation, particularly due to its widespread industrial applications particularly the production of essential oils (EOs). Given the international significance of EucalyptusEOs and their potential to enhance environmental and socioeconomic conditions, the aim of this work is to investigate the chemical composition and pharmacological activities of EOs from nine understudied Eucalyptusspecies. Results showed that oxygenated monoterpenes dominated the chemical profiles, with 1,8-cineole being the predominant component in most species. E. wandoo, E. punctata, and E. diversifoliaexhibited the most effective antiradical actions. All EOs demonstrate α-glucosidase inhibitory effects with IC50values ranging from 1.86 to 3.11 mg/mL. In cytotoxicity assessments, E. wandoodisplayed a remarkable 28-fold higher IC50against Vero than MCF-7. Results highlighted potent anti-inflammatory properties surpassing the positive control for all studied species, with E. punctataexhibiting the best IC50value of 4.42 µg/mL. The tested major compounds, α-pinene and eucalyptol, demonstrated lower efficacy compared to the EOs across all tested activities. This research provides valuable insights for selecting Eucalyptusspecies and underlines the importance of this natural product in order to preserve its natural habitats and implementing reforestation efforts in other areas.

The extraction of oil from oilseeds is conventionnaly performed using n-hexane. However, due to its toxicity and drawbacks, there is a growing need to explore greener solvents. In this study, 2-methyloxolane (2-MeOx) was selected to evaluate its potential as a replacement for n-hexane in extracting lipophilic compounds from Pistacia lentiscusseeds. Hansen solubility parameters were used to predict the solubility of target compounds in the selected solvents. Experimental analyses were focused on the extraction yield, fatty acid composition, sterol and tocopherol contents. As n-hexane, ours results indicated that 2-MeOx yielded similar performance in terms of extraction yield, fatty acid composition, sterol and tocopherol contents. Additionally, 2-MeOx extract demonstrated a high polyphenol content and exhibited strong antioxidant potential. Furthermore, it was shown that green extracted oil at low concentration had no cytotoxicity against macrophages. Moreover, the oil exhibited anti-inflammatory activity and suppressed nitric oxide (NO) secretion considerably on LPS-stimulated macrophages with IC50value of 33.04 µg/mL.

ABSTRACTThe present study investigated the antibacterial, antifungal and allelopathic activities of Pistacia lentiscusessential oils (EOs) isolated at the vegetative, flowering and fructification stages. The chemical composition of EOs varied according to both the phenological stages and the used mix plant parts. The main chemical class was sesquiterpene hydrocarbons with the predominance of germacrene D, δ-cadinene and β-caryophyllene. The antibacterial activity was evaluated against five collection strains. At the vegetative stage, P. lentiscusEO was the most effective against Listeria monocytogenesand Echerchia colias compared to the other stages. P. lentiscusEO also exhibited significant antifungal activity against the phytopathogenic strain Botrytis cinerea. Microscopic observation showed that EO induced swelling and crumbling of B. cinereaconidia. Moreover, P. lentiscusEO at the vegetative stage possessed significant allelopathic activity by inhibiting low concentration the germination and radical elongation of Raphanus sativusand radical elongation of Lepidium sativum.