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Essential oils (EOs) and plant extracts, rich in beneficial chemical compounds, have diverse applications in medicine, food, cosmetics, and agriculture. This study investigates the antibacterial activity of nine essential oil constituents (EOCs) against Escherichia coli , focusing on the effects of treatment pH and biosynthetic requirements. The impact of EOCs on bacterial inactivation in E. coli strains was examined using both nonselective and selective culture media. Computer-assisted drug design (CADD) methods were employed to identify critical binding sites and predict the main binding modes of ligands to proteins. The EOCs, including citral, α-terpinyl acetate, α-terpineol, and linalool, demonstrated significant bacterial inactivation, particularly under acidic conditions. This study revealed that EOCs have an effect on the presence of sublethal damage to both the cytoplasmic membrane and the outer membrane in Gram-negative bacteria. Adding penicillin G to the repair medium prevents the recovery of sublethal injuries in E. coli treated with α-terpinyl acetate, α-terpineol, linalool, and citral, indicating that peptidoglycan synthesis is essential for recovering from these injuries. However, penicillin G did not hinder the recovery process of most sublethally injured cells treated with the other assessed EOCs. Molecular docking studies revealed the favorable binding interactions of α-terpinyl acetate, α-terpineol, linalool, and citral with the β-lactamase enzyme Toho-1, indicating their potential as effective antibacterial agents. The findings suggest that EOCs could serve as viable alternatives to synthetic preservatives, offering new strategies for combating antibiotic-resistant bacteria.

The present work aimed to develop rapid approach monitoring using a simple selective method based on a positive hemolysis test, oil spreading activity and emulsification index determinations. It is the first to describe production of biosurfactants (BS) by the endophytic Pantoea alhagi species. Results indicated that the new BS evidenced an E24 emulsification index of 82%. Fourier-transform infrared (FTIR) results mentioned that the described BS belong to the glycolipid family. Fatty acid profiles showed the predominance of methyl 2-hyroxydodecanoate in the cell membrane (67.00%) and methyl 14-methylhexadecanoate (12.05%). The major fatty acid in the BS was oleic acid (76.26%), followed by methyl 12-methyltetradecanoate (10.93%). Markedly, the BS produced by the Pantoea alhagi species exhibited antimicrobial and anti-biofilm activities against tested human pathogens. With superior antibacterial activity against Escherchia coli and Staphylococcus aureus, a high antifungal effect was given against Fusarium sp. with a diameter of zone of inhibition of 29.5 mm, 36 mm and 31 mm, obtained by BS dissolved in methanol extract. The DPPH assay indicated that the BS (2 mg/mL) showed a higher antioxidant activity (78.07 inhibition percentage). The new BS exhibited specific characteristics, encouraging their use in various industrial applications.

To combat emerging antimicrobial-resistant microbes, there is an urgent need to develop new antimicrobials with better therapeutic profiles. For this, a series of 13 new spiropyrrolidine derivatives were designed, synthesized, characterized and evaluated for their in vitro antimicrobial, antioxidant and antidiabetic potential. Antimicrobial results revealed that the designed compounds displayed good activity against clinical isolated strains, with 5d being the most potent (MIC 3.95 mM against Staphylococcus aureus ATCC 25923) compared to tetracycline (MIC 576.01 mM). The antioxidant activity was assessed by trapping DPPH, ABTS and FRAP assays. The results suggest remarkable antioxidant potential of all synthesized compounds, particularly 5c , exhibiting the strongest activity with IC 50 of 3.26 ± 0.32 mM (DPPH), 7.03 ± 0.07 mM (ABTS) and 3.69 ± 0.72 mM (FRAP). Tested for their α -amylase inhibitory effect, the examined analogues display a variable degree of α -amylase activity with IC 50 ranging between 0.55 ± 0.38 mM and 2.19 ± 0.23 mM compared to acarbose (IC 50 1.19 ± 0.02 mM), with the most active compounds being 5d , followed by 5c and 5j , affording IC 50 of 0.55 ± 0.38 mM, 0.92 ± 0.10 mM, and 0.95 ± 0.14 mM, respectively. Preliminary structure-activity relationships revealed the importance of such substituents in enhancing the activity. Furthermore, the ADME screening test was applied to optimize the physicochemical properties and determine their drug-like characteristics. Binding interactions and stability between ligands and active residues of the investigated enzymes were confirmed through molecular docking and dynamic simulation study. These findings provided guidance for further developing leading new spiropyrrolidine scaffolds with improved dual antimicrobial and antidiabetic activities.

The main objective of this research was to study the biological characteristics in terms of antioxidant and antimicrobial activities of Ajuga iva and determine the best analytical and extraction methods applicable to this specie and studied compounds. A short screening of its nutritional value in terms of chemical composition is also included. A. iva leaves were analyzed for crude protein (CP), cell wall [neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL)], minerals, fatty acids, essential oils, and phenolic compounds. Mature aerial parts of A. iva were randomly collected during the Spring season from Mograne-Zaghouan, Tunisia. Leaves of A. iva contained 13.4 ± 0.4% CP, 26.3 ± 0.35% NDF, 20.2 ± 0.42% ADF, and 5.13 ± 0.21% ADL. Mineral content (13.0 ± 0.45%) was mainly composed of potassium (4.5% g DM) and magnesium (4.25% DM). Leaves of A. iva had linolenic (26.29 ± 0.760%) and linoleic (37.66 ± 2.35%) acids as the main components of the acid profile. Thymol was found to be the most dominant (23.43%) essential oil, followed by 4-vinylguaiacol (14.27%) and linalool (13.66%). HPLC-PDA-ESI-MS/MS analysis pointed out the presence of phytoecdysteroids. Phenolic acids and flavonoids, such as glycosylated derivatives of naringenin, eriodyctiol, and apigenin, were detected in the methanol extract of A. iva leaves. Our results underline the importance of choosing proper extraction methods and solvents to extract and characterize the described compounds profile of A. iva leaves. Results also show A. iva leaves as a potential source of functional ingredients with beneficial health-promoting properties. Overall, leaves of A. iva have low biological activities (antioxidant and antimicrobial activities) with a chemical composition suitable as a feed for ruminants in rangeland pasture. It also has low-grade antibacterial or medicinal characteristics when fed to ruminants.