Chemical Composition of Essential Oils of Bulbs and Aerial Parts of Two Cultivars of Allium sativum and Their Antibiofilm Activity against Food and Nosocomial Pathogens

A Mini-Review of the Main Effects of Essential Oils from Citrus aurantifolia, Ocimum basilicum, and Allium sativum as Safe Antimicrobial Activity in Poultry

Poultry production is accompanied by the use of antimicrobial agents because no production step is free of microorganisms. In the absence of antimicrobial treatments with synthetic drugs, essential oils are among the most cited natural alternatives used to prevent and treat microbial contamination in poultry. Although there are several studies on the antimicrobial properties of essential oils, there is still no review that simultaneously compiles information on the leading antimicrobial role of essential oils from Citrus aurantifolia (CAEO), Ocimum basilicum (OBEO), and Allium sativum (ASEO) in poultry. Awareness of the antimicrobial role of these substances opens the door to encouraging their use in natural antimicrobial protocols and discouraging harmful synthetics in poultry. This review aimed to compile information on applying CAEO, OBEO, and ASEO as antimicrobials in poultry farming. The available literature suggests that these essential oils can proportionately align with the poultry industry's demands for microbiologically safe food products.

Pulicaria incisa (Lam.) DC. as a Potential Source of Antioxidant, Antibacterial, and Anti-Enzymatic Bioactive Molecules: Phytochemical Constituents, In Vitro and In Silico Pharmacological Analysis

Plants with medicinal benefits are a crucial source of compounds for developing drugs. This study was designed to determine the chemical composition, antibacterial, antibiofilm, antioxidant, and anti-enzymatic activities of Pulicaria incisa (Lam.) DC. We also reported the molecular interaction between identified molecules and several receptors associated with antimicrobial and antibiofilm activities. A total of seventeen and thirteen compounds were identified in aqueous and methanolic extracts of P. incisa, respectively. The methanolic extract yielded a higher total content of polyphenols and flavonoids of about 84.80 ± 2.8 mg GAE/g and 28.30 ± 1.2 mg QE/g, respectively. Significant antibacterial activity was recorded for both extracts, with minimum inhibitory concentration (MIC) values ranging from 30 to 36 µg/mL, and the result was comparable to the reference antibiotic control. Antibiofilm assays revealed that both extracts were able to reduce the attachment of bacterial cells to 96-well plates, but the highest antibiofilm activity was recorded against Staphylococcus aureus. The methanolic extract also showed anti-enzymatic potency and high antioxidant activity, as demonstrated by all assays used, including DPPH, FRAP, and ABTS. These results were further validated by in silico approaches, particularly the molecular interaction of the identified compounds with the targeted receptors. These findings present P. incisa as a significant source of antibacterial, antibiofilm, antioxidant, and anti-enzymatic molecules.

Chemical Composition, Antibacterial Properties, and Anti-Enzymatic Effects of Eucalyptus Essential Oils Sourced from Tunisia

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.

Chemical Composition, Phytotoxic and Antibiofilm Activity of Seven Eucalyptus Species from Tunisia

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.

Chemical Composition and Phytotoxic, Antibacterial and Antibiofilm Activity of the Essential Oils of Eucalyptus occidentalis, E. striaticalyx and E. stricklandii

The Eucalyptus genus (Myrtaceae) is characterized by a richness in essential oils (EO) with multiple biological activities. This study reports the chemical composition and the phytotoxic and antimicrobial activities of the EOs from Tunisian E.occidentalis, E.striaticalyx and E.stricklandii. The EOs were analyzed using GC/MS and their phytotoxicities were assessed against the germination and seedling growth of Sinapis arvensis, Trifolium campestre and Lolium rigidum. Antimicrobial activity was investigated 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. All EOs were rich in oxygenated monoterpenes (36.3-84.8%); the EO of E.occidentalis was rich in sesquiterpenes, both oxygenated and hydrocarbon (40.0% and 15.0%, respectively). Eucalyptol was the main constituent in all samples. The EOs showed phytotoxic activity on seed germination and seedling growth, depending both on chemical composition and weed. The EOs show a remarkable antibacterial potential resulting in a significant inhibition of the formation of bacterial biofilm and its metabolism, depending on the EO and the strain, with activity on the mature biofilm as well. Therefore, these Eucalyptus EOs could have potential applications both in the food and health fields.