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This study aimed to investigate the chemical composition and some biological activities of the essential oils (EOs) from needles of Pinus canariensis, P. jeffreyi, and P. taeda cultivated in Tunisia. The chemical composition of the EOs revealed the presence of 119 components, with monoterpene hydrocarbons (in EOs of P. canariensis and P. taeda) and sesquiterpene hydrocarbons (in P. jeffreyi EO) being the main chemical classes. The EOs showed significant inhibitory effects on the germination and seedling and radical growth of the weeds, Sinapis arvensis, Lolium rigidum, and Trifolium campestre. The EO of P. jeffreyi exhibited the highest phytotoxicity, while T. campestre was the most tolerant seed. The EOs showed antibiofilm activity against Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli) pathogenic bacterial strains, depending on the EO, and the concentration tested. Overall, the EOs displayed efficacy against mature biofilms and were effective also against the metabolism of the sessile cells in the biofilm. These findings provide valuable insights into the potential applications of these EOs in phytotoxic and antibiofilm strategies, for agriculture, food and pharmaceutical fields. [ABSTRACT FROM AUTHOR]

Citrus, which belongs to the Rutaceae family, is a very widespread genus in the Mediterranean Basin. In Tunisia, various parts of these spontaneous or cultivated plants are used in common dishes or in traditional medicine. The purpose of this work was to investigate C. limon and C. paradisi essential oil (EO). The samples were studied for their chemical composition using SPME/MS, as well as their antibacterial and antifungal activities. Prothrombin time (PT) and activated partial thromboplastin time (aPTT) methods were used to evaluate the anticoagulant potentialities. The obtained results show that both essential oils are rich in monoterpenes hydrocarbons, whereby limonene is the main compound in C. paradisi EO (86.8%) and C. limon EO (60.6%). Moreover, C. paradisi EO contains β-pinene (13.3%), sabinene (2.2%) and α-pinene (2.1%). The antibacterial assay of the essential oils showed important bactericidal and fungicidal effects against all strains tested. In fact, the MICs values of C. limon EO ranged from 0.625 to 2.5 mg/mL against all Gram-positive and Gram-negative bacteria, and from 6.25 to 12.5 mg/mL for Candida spp. strains, while C. paradisi EO was more active against all bacteria with low MICs values ranging from 0.192 to 0.786 mg/mL, and about 1.5 mg/mL against Candida species. Both tested Citrus EOs exhibited interesting anticoagulant activities as compared to heparin. The molecular docking approach was used to study the binding affinity and molecular interactions of all identified compounds with active sites of cytidine deaminase from Klebsiella pneumoniae (PDB: 6K63) and the C (30) carotenoid dehydrosqualene synthase from Staphylococcus aureus (PDB: 2ZCQ). The obtained results show that limonene had the highest binding score of −4.6 kcal.mol−1 with 6K63 enzyme, and −6.7 kcal.mol−1 with 2ZCQ receptor. The ADME profiling of the major constituents confirmed their important pharmacokinetic and drug-like properties. Hence, the obtained results highlight the potential use of both C. limon and C. paradisi essential oils as sources of bioactive compounds with antibacterial, antifungal, and anti-coagulant activities. [ABSTRACT FROM AUTHOR]

This study was conducted to examine the chemical composition of the essential oils (EOs) from six Tunisian Eucalyptus species and to evaluate their anti-enzymatic and antibiofilm activities. The EOs were obtained through hydro-distillation of dried leaves and subsequently analyzed using GC/MS. The main class of compounds was constituted by oxygenated monoterpenes, particularly prominent in E. brevifolia (75.7%), E. lehmannii (72.8%), and E. woollsiana (67%). Anti-enzymatic activities against cholinesterases, α-amylase, and α-glucosidase were evaluated using spectrophotometric methods. Notably, the E. brevifolia, E. extensa, E. leptophylla, E. patellaris, and E. woollsiana EOs displayed potent acetylcholinesterase (AChE) inhibition (IC50: 0.25–0.60 mg/mL), with E. lehmannii exhibiting lower activity (IC50: 1.2 mg/mL). E. leptophylla and E. brevifolia showed remarkable α-amylase inhibition (IC50: 0.88 mg/mL), while E. brevifolia and E. leptophylla significantly hindered α-glucosidase (IC50 < 30 mg/mL), distinguishing them from other EOs with limited effects. Additionally, the EOs were assessed for their anti-biofilm properties of Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) bacterial strains. The E. extensa EO demonstrated the main antibiofilm effect against E. coli and L. monocytogenes with an inhibition > 80% at 10 mg/mL. These findings could represent a basis for possible further use of Eucalyptus EOs in the treatment of human microbial infections and/or as a coadjutant in preventing and treating Alzheimer's disease and/or diabetes mellitus. [ABSTRACT FROM AUTHOR]

Eucalyptus species are known to produce metabolites such as essential oils (EOs) that play an important role in the control of weeds, pests and phytopathogenic fungi. The aims of this study were as follows: (i) to determine the chemical composition of the EOs derived from eight Eucalyptus species growing in Tunisia, and (ii) to study their possible antifungal and herbicidal activities. EOs were obtained by hydrodistillation from the dried leaves of eight Eucalyptus species, namely, E. angulosa, E. cladocalyx, E. diversicolor, E. microcoryx, E. ovata, E. resinifera, E. saligna and E. sargentii, and the determination of their composition was achieved by GC and GC-MS. The EOs' antifungal activities were tested against four Fusarium strains, and the EOs' herbicidal properties were evaluated on the germination and seedling growth of three annual weeds (Trifolium campestre, Lolium rigidum and Sinapis arvensis) and three cultivated crop species (Lepidium sativum, Raphanus sativus and Triticum durum). The EO yields ranged between 0.12 and 1.32%. The most abundant components found were eucalyptol, α-pinene, p-cymene, trans-pinocarveol, α-terpineol and globulol. All EOs showed significant antifungal activity against the four phytopathogenic Fusarium strains. E. cladocalyx EO exhibited the highest level of antifungal activity, and the greatest inhibition of seed germination was obtained even at lowest concentrations used. These findings suggested that E. resinifera, E. ovata and E. cladocalyx EOs could have applications in agriculture as possible biopesticides, as Fusarium antagonists and as bioherbicides. [ABSTRACT FROM AUTHOR]

Eucalyptus species have been widely employed in the projects of reforestation in Tunisia. Although their ecological functions are controversial, these plants are indeed important to counteract soil erosion, and represent a fast-growing source of fuelwood and charcoal wood. In the present study, we considered five Eucalyptus species, namely Eucalyptus alba, E. eugenioides, E. fasciculosa, E. robusta, and E. stoatei cultivated in the Tunisian Arboreta. The aim was to carry out the micromorphological and anatomical characterization of the leaves, the extraction and phytochemical profile of the essential oils (EOs), and the evaluation of their biological properties. Four of the EOs showed the prevalence of eucalyptol (1,8-cineole) varying from 64.4 to 95.9%, whereas a-pinene predominated in E. alba EO (54.1%). These EOs showed in vitro antioxidant activity, and reduced the oxidative cellular stress as shown by their activity on reactive oxygen species (ROS) production, and modulation of the expression of antioxidant enzymes, such as glutamate-cysteine ligase (GCL) and heme oxygenase-1 (Hmox-1). Moreover, the EOs inhibited the production of nitric oxide (NO), showing anti-inflammatory activity. The data collected suggest that these EOs may be considered a promising therapeutic strategy for inflammation-based diseases and may represent an additional value for the economy of Tunisia. [ABSTRACT FROM AUTHOR]

This study was carried out to characterize the chemical composition of the essential oils from seven Eucalyptus species (E. griffithsii, E. hemiphloia, E. lesouefii, E. longicornis, E. pyriformis, E. viminalis, and E. wandoo), as well as their phytotoxic and antibacterial activities. The essential oils were analyzed by GC/MS and the potential in vitro phytotoxicity was evaluated against germination and radical elongation of Raphanus sativus, Lolium multiflorum, and Sinapis arvensis seeds. The antibiofilm activity was studied against both Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus and Listeria monocytogenes) bacteria. The inhibition of biofilm formation and its metabolism was determined at different times. Eucalyptol was the most abundant component in all essential oils studied (ranging from 40.8% for E. lesouefii EO to 73.6% for E. wandoo) except for that of E. pyriformis where it was present but at 15.1%. E. pyriformis was the most active against both germination and radical elongation of S. arvensis. The action of all essential oils proved to be highly effective in inhibiting the bacterial adhesion process of the five strains considered. In light of these results, these essential oils could have potential applications both in the agricultural and health fields. [ABSTRACT FROM AUTHOR]

Eucalyptus species are characterized by their richness in essential oils (EOs) with a great diversity of biological activities. This study reports the chemical composition and the phytotoxic and antibiofilm activities of the EOs of six Eucalyptus species growing in Tunisia: E. bicostata, E. gigantea, E. intertexta, E. obliqua, E. pauciflora and E. tereticornis. Four EOs were rich above all in oxygenated monoterpenes (25.3–91.4%), with eucalyptol as the main constituent. However, in the EOs of E. pauciflora and E. tereticornis, sesquiterpene hydrocarbons (28.8–54.0%) were the main class of constituents; piperitone was the main constituent of both EOs. The phytotoxicity of the EOs was tested against germination and radicle elongation of the weeds Sinapis arvensis and Lolium multiflorum and the crop Raphanus sativus, resulting in the different inhibition of seed germination and radicle elongation depending on both chemical composition and the seed tested, with remarkable phytotoxicity towards S. arvensis and R. sativus. Furthermore, almost all EOs showed antibacterial potential, resulting in significant inhibition of bacterial biofilm formation and the metabolism of Gram-positive (Staphylococcus aureus subsp. aureus and Listeria monocytogenes) and Gram-negative (Acinetobacter baumannii, Pseudomonas aeruginosa and Escherichia coli) bacterial strains, in addition to acting on mature biofilms. The EOs were inhibitory against all bacterial strains tested and usually reluctant to undergo the action of conventional antibiotics. Therefore, these EOs may be considered for applications both as herbicides and in food and health fields. [ABSTRACT FROM AUTHOR]

The chemical composition of the essential oils of Melaleuca armillaris Sm., Melaleuca styphelioides Sm. and Melaleuca acuminata F. Muell., collected in Tunisia, was studied by means of GC and GC-MS analysis. In all, 46 compounds were identified, 38 for M. armillaris, 20 for M. acuminata and eight for M. styphelioides, respectively. The presence of a sesquiterpenic fraction (52.2%) characterized the oil from M. armillaris; M. sthypheliodes oil was rich in methyl eugenol, a phenolic compound (91.1%), while M. acuminata oil is mainly constituted by oxygenated monoterpenoids (95.6%). The essential oils were evaluated for their in vitro potentially phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of five seeds was inhibited at the highest doses tested, while germination of all seeds was not affected. Moreover, the essential oils showed low antimicrobial activity against eight selected microorganisms. [ABSTRACT FROM AUTHOR]

Several foods are used in both the nutraceutical and health sectors; vegetable oils, for example, can prevent the onset of numerous diseases. The properties of these oils are related to their chemical composition and primarily to the presence of fatty acids. The present work aimed to determine the chemical profiles of Argania spinosa , Pinus halepensis, and Pistacia altantica oils, used in traditional Tunisian foods, and to evaluate some biological properties. We evaluated their antioxidant, anti-enzymatic, antimicrobial, and anti-inflammatory properties. Linoleic acid was the main component of the three oils . P. atlantica oil showed more significant inhibitory activity against the enzymes studied than A. spinosa and P. halepensis . All three oils showed similar antioxidant and anti-inflammatory activity. Furthermore, A. spinosa and P. halepensis oils showed antibiofilm activity against P. aeruginosa , with 30-40% inhibition. These results focus on the possible use of these oils in the nutraceutical and healthcare sectors.

Aromatic plants can interfere in the Mediterranean ecosystem, mainly by the introduction in the environment of volatile compounds. For this reason, we studied the chemical composition and the possible phytotoxic and antimicrobial activities of the essential oil extracted from leaves of Tunisian Artemisia herba-alba Asso. The chemical composition of the essential oil, obtained by hydrodistillation, was analyzed by GC and GC-MS. In all, 24 compounds were identified. The main components were camphor (39.1%), chrysanthenone (15.0%) and cis-thujone (7.8%). The essential oil was evaluated for its in vitro phytotoxic activity against germination and initial radical growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of the five seeds was affected to different extents by the oil, while germination was not affected. The oil, when tested against eight selected bacterial strains, showed low antimicrobial activity. The chemical composition of the oil of A. herba-alba can help in the chemosystematics of this complex genus. However, the recorded biological activities seem to be neither ecologically nor medicinally significant.