Search Results (748)

Objectives: This study investigates the occurrence and characteristics of extended-spectrum β-lactamase (ESBL)-producing and polymyxin-resistant Escherichia coli isolated from raw milk cheese and chicken carcasses in Egypt. In addition, the study evaluates the antibacterial activity of various algal extracts from Padina pavonica and Polycladia myrica, collected from the Red Sea, Egypt, against selected virulent and multidrug-resistant E. coli isolates. Methods: A total of 200 samples, comprising raw milk cheese samples (n = 100) and chicken carcass samples (n = 100), were examined for the presence of E. coli. Antimicrobial susceptibility testing was performed for all isolates using the disk diffusion and broth microdilution techniques. Phenotypic confirmation of various resistance traits was conducted to confirm resistance patterns. PCR screening was performed for various resistance genes and virulence-associated genes. Phylogenetic grouping analysis of the E. coli isolates examined was also performed. Two algal extracts of P. pavonica and P. myrica were screened using gas chromatography–mass spectrometry and evaluated against our panel of virulent MDR foodborne E. coli isolates using the resazurin-based microtiter dilution method. Results: Among the 200 food samples, E. coli was recovered from 14% of samples and confirmed by using phoA gene detection. Of the recovered isolates, 64.3% were multidrug-resistant (MDR), with the majority originating from chicken carcasses (88.9%). Most isolates (92.9%) carried ≥3 virulence genes, with iss (100%), iutA (92.9%), and eaeA (89.3%) being the predominant determinants. Potential EPEC profiles were the most frequently detected (60.7%), followed by EHEC profiles (28.6%), whereas potential STEC/non-EHEC hybrid and ExPEC profiles were detected in 7.1% and 3.6% of isolates, respectively. The bla_CTX-M gene predominated among ESBL determinants (96.4%), while bla_SHV, bla_CMY-2, and mcr-1 were also detected. Notably, mcr-1 was identified in 82.1% of isolates, with frequent co-occurrence of mcr-1 and ESBL genes. Phylogenetic analysis revealed that most isolates belonged to group B1 (85.7%), whereas groups D and B2 accounted for 10.7% and 3.5%, respectively. In vitro antibacterial assays demonstrated that the P. pavonica methanol and ethyl acetate extracts and the P. myrica ethyl acetate extract exhibited inhibitory activity against MDR E. coli, with minimum inhibitory concentrations (MICs) ranging from 2.5 to 10 mg/mL. Overall, the P. myrica extract showed stronger antibacterial activity (MICs, 2.5–5 mg/mL) than the P. pavonica extracts (MICs, 5–10 mg/mL), highlighting their potential as natural antibacterial agents against MDR E. coli. Conclusions: These findings raise important public health concerns, as contaminated food products can act as reservoirs for the dissemination of multidrug-resistant (MDR) E coli, thereby increasing the risk of human infections ranging from mild gastrointestinal illnesses to severe, potentially life-threatening diseases. In addition, the present findings demonstrate the promising antibacterial activity of methanolic and ethyl acetate extracts of P. myrica and P. pavonica against MDR E. coli isolates, supporting their potential as sources of natural antibacterial compounds and warranting further investigation of their efficacy, mechanisms of action, and active constituents. Full article

The composition and bioactivities of dry methanol extracts from roots, leaves and fruits of cultivated Pastinaca sativa subsp. sativa (Ps) and wild-growing P. sativa subsp. urens (Pu) and P. hirsuta (Ph) were investigated. Their compositions were analyzed by LC-DAD-QTOF-MS/MS, total phenolics and antioxidant activity were measured spectrophotometrically, antimicrobial activity was assessed by microdilution (14 strains), and cytotoxicity was evaluated by the MTT assay (four cell lines). Chemical analysis revealed 45 compounds. While Ps leaf extract had the highest rutin content (13.21 mg/g), Ph leaf and fruit extracts were the richest in total quercetin glycosides and their derivatives (103.70 and 163.93 mg/g); Ph leaf extract was also rich in chlorogenic acid (58.08 mg/g). Extract amounts corresponding to established furanocoumarin intake thresholds were calculated (e.g., regarding leaf extracts, up to 5.46 g for Ph). Ph leaf extract showed the highest total phenolic content (70.07 mg quercetin equivalents/g), FRAP value (0.97 mmol Fe²⁺/g) and anti-DPPH activity (64.56 mg quercetin equivalents/g). The best antimicrobial activity was observed against Micrococcus luteus (MIC = 0.156–2.5 mg/mL; MBC = 5–10 mg/mL), a known food spoilage bacterium, with Ps leaf extract being the most active. Ps fruit extract showed weak-to-moderate cytotoxicity; others were generally non-cytotoxic. The investigated parsnips, including Ps agricultural waste, represent potential sources of bioactive polyphenols for food applications. Full article

The emergence of carbapenem-resistant Gram-negative bacteria has intensified the search for natural compounds capable of restoring antibiotic efficacy by targeting β-lactamase-mediated resistance. This study investigated the antibacterial, β-lactamase inhibitory, and in silico potential of Schinus terebinthifolia leaf phytobiotics. Soxhlet (STS), maceration (STM), and essential oil (STEOL) extracts were evaluated against carbapenem-resistant Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa using agar diffusion, broth microdilution, checkerboard, and colorimetric β-lactamase inhibition assays. In parallel, the phytochemicals identified by GC–MS and LC–MS were virtually screened against the VIM and OXA-48-like β-lactamases using PyRx, followed by drug-likeness prediction using SwissADME. All phytobiotics exhibited significant antibacterial activity and synergistically enhanced the efficacy of cefotaxime against the majority of the tested bacterial strains (ΣFICI ≤ 0.5). Moreover, they markedly inhibited β-lactamase activity, with complete inhibition achieved at MIC/2. Among the tested phytobiotics, STS exhibited the greatest β-lactamase inhibitory potency, with an IC₅₀ of 49.8 μg/mL. Virtual screening identified diosmetin, catechin, quercetin, ellagic acid, and epicatechin gallate as the most promising candidate β-lactamase inhibitors, exhibiting strong binding affinities toward VIM and OXA-48-like β-lactamases. SwissADME analysis further indicated favorable drug-like properties for the top-ranked compounds. Collectively, these findings suggest that S. terebinthifolia phytobiotics have promising antibacterial and β-lactamase-inhibitory potential and may represent a source of candidate compounds for further investigation as antibiotic adjuvants against carbapenem-resistant Gram-negative pathogens. Full article

Streptococcus pyogenes is a pathogen that causes skin infections worldwide. Currently, there is growing interest in herbal formulations as potential sources of antibacterial agents. This in vitro study investigated the antibacterial and antibiofilm activities of herbal formulation ethanolic extract (HFE), alone and combined with specific antibiotics, against S. pyogenes. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of HFE were determined using the broth microdilution method. Bactericidal activity was further evaluated using time-kill assays. Bacterial cell morphology was examined using electron microscopy. The interaction between HFE and specific antibiotics was assessed using the checkerboard assay. The MIC and MBC values of HFE against S. pyogenes ATCC 19615 were 16 and 32 µg/mL, respectively, while all clinical isolates showed MIC and MBC values of 8 µg/mL. Time-kill curve analysis demonstrated HFE’s bactericidal activity within 2 h and induced ultrastructural changes in S. pyogenes cells. HFE also exhibited antibiofilm activity against both biofilm formation and established biofilms. The checkerboard assay showed indifferent interactions, with a fractional inhibitory concentration (FIC) index of 0.57–3.00 for all HFE combinations against S. pyogenes. These findings suggest the potential of HFE as a natural health product for the management of S. pyogenes infections. Full article

With the continuous escalation of antimicrobial resistance, drug repurposing based on approved drugs has emerged as a promising strategy for the development of novel anti-infective agents. This study aimed to evaluate the antibacterial effect of the FDA-approved drug Ponatinib hydrochloride against multidrug-resistant S. aureus. Broth microdilution assay showed that ponatinib hydrochloride exhibited potent activity against Gram-positive bacteria, while the MICs against Gram-negative bacteria were all >100 μM. In addition, the MICs against 15 clinical multidrug-resistant S. aureus isolates ranged from 6.25 to 25 μM. Time-kill assay further revealed a pronounced concentration- and time-dependent bactericidal effect, with bacterial viability reduced to nearly the detection limit within 24 h at 4 × MIC. Anti-biofilm assays showed that ponatinib hydrochloride significantly inhibited S. aureus biofilm formation and disrupted mature biofilms. Moreover, serial passaging for 30 days did not induce an obvious increase in resistance. Mechanistic investigations demonstrated that ponatinib hydrochloride increased membrane permeability, induced intracellular reactive oxygen species (ROS) accumulation, and markedly reduced ATP levels. Finally, in a mouse infection model, ponatinib hydrochloride significantly improved the survival of infected mice, with a survival rate of 70% observed in the 15 mg/kg treatment group, while also reducing bacterial burdens and pro-inflammatory cytokine levels in tissues. Collectively, ponatinib hydrochloride exhibits potent antibacterial activity against multidrug-resistant S. aureus both in vitro and in vivo and represents a promising candidate for anti-MRSA therapy. Full article

The increasing prevalence of antimicrobial resistance has stimulated interest in non-antibiotic small molecules that can restore or potentiate the activity of established antibacterial agents. In this study, a focused series of low-molecular-weight chromene derivatives was synthesized, structurally characterized, and evaluated primarily as antibacterial adjuvants rather than as stand-alone antibiotics. The experimental strategy was designed to distinguish intrinsic antibacterial activity from potentiating activity in combination with a partner antibiotic. Initial susceptibility testing was followed by combination experiments in selected bacterial strains, with particular emphasis on changes in the minimum inhibitory concentration (MIC) of meropenem or doripenem in the presence of each test compound. Broth microdilution combination assays demonstrated that compound 3a significantly reduced the MIC of meropenem and doripenem against methicillin-resistant Staphylococcus aureus (MRSA). The observed adjuvant effect suggests that chromene scaffolds may serve as promising candidates for the development of next-generation β-lactam enhancers aimed at overcoming carbapenem resistance. Full article

Background/Objectives: Conventional cancer treatments such as radiation therapy, chemotherapy, and surgery often severely reduce a patient’s quality of life due to their side effects. This underscores the urgent need to develop less toxic and more effective alternative therapies. Medicinal plants and their derivatives represent a valuable source for discovering such agents. In this study, we investigated the anticancer and antibacterial properties of ethanolic (EE), methanolic (ME), and aqueous (AE) leaf extracts from the Lebanese Eucalyptus camaldulensis. Methods: The cytotoxicity of the extracts and cis-diamminedichloroplatinum(II) (CDDP) was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against four human cancer cell lines: two breast cancer lines (MCF-7 and MDA-MB-231), colorectal carcinoma cells (HCT-116), and lung carcinoma epithelial cells (A-549). Morphological changes in the cells were observed via inverted phase-contrast microscopy. The antibacterial potential was determined through minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) broth microdilution assays, agar well diffusion, and time-kill tests. The antibiofilm activity of the extracts against Staphylococcus haemolyticus, Streptococcus intermedius, Escherichia coli, and Leclercia adecarboxylata was assessed using antibiofilm screening. Results: All three extracts demonstrated significant anticancer activity against the four cell lines, with particular potency against A-549 cells. The AE showed the greatest cytotoxic effect, with IC50 values ranging from 97.1 to 163.3 µg/mL after 24 h of treatment. Furthermore, all extracts induced notable morphological changes in the cancer cells. The MIC and MBC results indicated a bactericidal effect for the EE (MBC range: 1.5625–50%), ME (MBC range: 6.25–50%), and AE (MBC range: 3.125–100%). Agar well diffusion assays revealed inhibition zones of 8.1 to 20.1 mm, while time-kill tests showed bacterial inhibition within 1 to 24 h of incubation. The antibiofilm assays demonstrated that the extracts inhibited biofilm production and eradicated 50% of pre-formed biofilms. Conclusions: These findings suggest that Lebanese Eucalyptus camaldulensis leaf extracts are a promising source of bioactive compounds with both antibacterial and anticancer properties. Full article

β-thujaplicin (BTJ) is an organic compound with medicinal potential. Its activity against pathogenic Streptococcus species has been insufficiently investigated. This study aimed to evaluate the antimicrobial activity of β-thujaplicin against more than 30 reference and clinical isolates of Streptococcus pyogenes, Streptococcus agalactiae, and Streptococcus pneumoniae, and to assess its effect on the intrinsic low-level resistance of these bacteria to aminoglycosides. Susceptibility of β-thujaplicin and selected aminoglycosides was determined using the broth microdilution method. The modulatory effect of β-thujaplicin on aminoglycoside activity was assessed using the checkerboard assay, with interactions evaluated based on the fractional inhibitory concentration index (FICI). β-thujaplicin exhibited antimicrobial activity against S. pyogenes and S. pneumoniae, with minimum inhibitory concentration (MIC) values ranging from 16 to 32 µg/mL, exceeding the activity of amikacin (AN). Synergistic interactions between β-thujaplicin (2–8 µg/mL) and aminoglycosides were observed in 100% of S. pneumoniae strains tested, 50% of S. pyogenes, and 80% of S. agalactiae isolates. In the presence of β-thujaplicin, aminoglycoside MICs decreased by 2- to 64-fold depending on the species. β-thujaplicin demonstrates in vitro bactericidal activity against most tested Streptococcus strains and exhibits synergistic effects when combined with aminoglycosides. These findings suggest that β-thujaplicin may reduce the natural resistance of strepto-cocci to these antibiotics. Full article

Origanum saccatum P.H. Davis and O. solymicum P.H. Davis are two endemic species of section Amaracus distributed in Türkiye and characterized by close morphological and genetic relationships. Although their volatile and non-volatile compounds and several biological activities have previously been investigated, the antimicrobial and cytotoxic activities of methanol and ethyl acetate extracts of both species have not been systematically compared within a common experimental framework. In this study, the volatile profiles of the two species were compared, while the antimicrobial and cytotoxic activities of their methanol and ethyl acetate extracts were evaluated comparatively. Essential oils were obtained by hydrodistillation and analyzed by GC-FID/GC-MS. Antimicrobial activity was determined by the broth microdilution method, and cytotoxicity was evaluated against A549, MCF-7, and NIH/3T3 cells using the MTT assay. Both essential oils showed a p-cymene-rich profile, although substantial differences were observed in the proportions of γ-terpinene (3.1–24.4%), thymol (4.0–18.2%), borneol (0.6–15.6%), linalool (0.1–10.4%), and carvacrol (0.1–3.4%). The ethyl acetate extracts showed generally lower MIC values (125–250 µg/mL) than the corresponding methanol extracts (500–1000 µg/mL) against the most responsive microorganisms. Ethyl acetate extracts also showed the strongest cytotoxic activity with IC₅₀ values of 6.74–14.49 µg/mL, although the response varied depending on species and cell line. The O. saccatum ethyl acetate extract showed the highest selectivity toward MCF-7 among the tested extracts, with a selectivity index of 3.176. To the best of our knowledge, this is the first report of the cytotoxicity of these two species against A549 and MCF-7 cells. The findings provide a comparative assessment of their volatile profiles and solvent-dependent biological properties. Full article

Lavandula × intermedia (lavandin) is among the most cultivated Lavandula species, valued for its high essential oil yield and broad applications across different industries. Although it has traditionally been regarded as inferior to true lavender (Lavandula angustifolia), particularly within the field of perfumery, growing evidence suggests that lavandin essential oil holds comparable value in non-perfumery sectors, where its utility is increasingly recognized. The objectives of this study were to identify the volatile profiles of lavandin essential oils from two ‘Budrovka’ accessions from Hvar, Croatia, and to evaluate their cytotoxic activities against MDA-MB-231, MCF-7, and OVCAR-3 cell lines, as well as their antimicrobial activities against foodborne pathogens and spoilage organisms. Both oils were dominated by linalool. L1 showed higher proportions of linalool (52.50%) and linalyl acetate (11.96%) and a lower camphor content, yielding a profile closer to the compositional characteristics generally associated with lavender oils used in aromatic applications, while L2 was comparatively richer in borneol (10.18%) and camphor (3.04%), giving it a composition more typical of essential oils traditionally used for massage and topical applications, although suitability for such uses was not directly evaluated in this study. Both oils exhibited in vitro antimicrobial activity against all tested organisms, including, to the authors’ knowledge, the first reported activity against P. fragi, as well as reduced cellular metabolic activity in MDA-MB-231 and MCF-7 cells. These preliminary findings suggest that lavandin ‘Budrovka’ could represent a promising multifunctional natural raw material, warranting further investigation for its potential exploitation in the pharmaceutical and food-related industries. Full article

Lavandula multifida L., commonly known as Egyptian lavender or fern leaf lavender, is widely recognized and used as a medicinal plant throughout Mediterranean countries. While L. multifida has been extensively studied, research has largely centered on its essential oil, with limited data available on the composition and bioactivities of its organic extracts. This study characterized the phytochemical profiles of L. multifida extracts and evaluated their antioxidant capacity, effects on cancer cell viability, and antimicrobial activity using multiple in vitro assays. Phytochemical characterization included the quantification of total phenolic and flavonoid contents and HPLC/ESI-QTOF-MS profiling of methanolic (LM), aqueous (LAQ), and ethyl acetate (LEA) extracts. Antioxidant activity was assessed using four complementary in vitro assays (DPPH, ABTS, FRAP, and TAC). The effects of the extracts on cell viability were assessed using the MTT assay in human triple-negative breast cancer (MDA-MB-231) and colon adenocarcinoma (HCT116) cell lines, while antimicrobial activity was determined using the agar well diffusion and broth microdilution methods. Phytochemical profiling of L. multifida extracts revealed diverse metabolites dominated by fatty acids (mainly oxylipins), together with phenolic acids, flavonoids, terpenes, and other minor constituents. The methanolic extract showed the strongest DPPH scavenging effect (IC₅₀ = 14.19 µg/mL), LAQ showed the highest FRAP value (246.62 µg TE/mg), and LEA demonstrated the greatest ABTS (IC₅₀ = 28.07 µg/mL) and TAC (367.16 µg AAE/mg) activities. LEA also produced the greatest reductions in cell viability, reaching approximately 97% in HCT116 cells and 83% in MDA-MB-231 cells, with corresponding IC₅₀ values of 27.85 ± 2.48 and 63.71 ± 3.05 µg/mL, respectively. LM and LAQ showed the largest bacterial inhibition zones, while LEA, despite weaker diffusion activity, exhibited the greatest potency (MIC = 0.5–2 mg/mL; MBC = 0.5–5 mg/mL) and a unique antifungal effect (MIC = 2 mg/mL; MFC = 4 mg/mL). These findings underscore the potential of L. multifida extracts as a natural reservoir of bioactive compounds with notable antioxidant, anticancer, and antimicrobial activities, suggesting their relevance for future pharmaceutical development. Full article

Objectives: The study determined antimicrobial resistance profiles of surgical wound multidrug-resistant (MDR) isolates belonging to the ESKAPE group and evaluated antibacterial and antibiofilm activities of geraniol (G), carvacrol (C) and eugenol (E), individually and in the selected mixtures. The cytotoxicity of monoterpenes and combinations was also assessed. Methods: The antibacterial and antibiofilm activity against tested isolates of Enterococcus faecium, Staphylococcus aureus MRSA, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp. was assessed in microdilution and crystal violet assay, respectively, while cytotoxicity was estimated in XTT assay on human MRC-5 fibroblasts. Results: C showed the strongest antibacterial activity (MIC 0.32 ± 0.24 mg mL⁻¹). Monoterpenes induced synergism in certain combinations (FICI 0.09–0.31). All individual monoterpenes inhibited biofilm formation, but G was the most active (38.78–84.72%, p < 0.05). The most pronounced biofilm eradication was observed for C (25.21–61.34%, p < 0.05). G-C mixtures showed notable inhibition of biofilm formation in all isolates except P. aeruginosa, but, on the contrary, induced biofilm eradication against P. aeruginosa only. Cytotoxicity was not detected with the applied concentrations of monoterpenes, while the G-C mixtures exhibited lower cytotoxicity than povidone-iodine (p < 0.05) used as the control. Conclusions: All monoterpenes and G-C mixtures proved significant antibacterial and antibiofilm potential against ESKAPE isolates and acceptable impact on cell viability. Practical significance: The results highlight the potential of plant monoterpenes and their binary combinations as complementary agents for controlling MDR ESKAPE pathogens and biofilm-associated infections following surgical procedures. Further in vivo and safety studies are needed to confirm their applicability in clinical settings. Full article

Melilotus officinalis (L.) Lam. (yellow sweet clover) is a medicinally valuable Fabaceae species with recognized antioxidant and antimicrobial properties, yet the impact of cultivation system on its secondary metabolism remains poorly characterized for Central Asian populations. This study compared wild and in vitro-grown Melilotus officinalis from northern Kazakhstan (Astana city), examining phenolic composition, organic acids, antioxidant capacity, and antimicrobial activity as functions of cultivation system. Hydroethanolic extracts were analyzed by HPLC-DAD-ESI-Orbitrap MS/MS and UFLC-PDA, while antioxidant activity was assessed by TBARS and ABTS assays and antimicrobial activity by broth microdilution against eight bacterial and two fungal strains. Thirteen phenolic compounds were tentatively identified, revealing higher total flavonoid content in in vitro plants, dominated by apigenin di-C-pentoside isomers and vicenin-3, whereas wild plants showed greater diversity of phenolic acids and flavonols, including kaempferol and quercetin glycosides. Despite lower total phenolics, wild extracts more effectively inhibited lipid peroxidation, while ABTS radical scavenging was comparable between sources, and antimicrobial effects were strain-specific. Oxalic acid was approximately three-fold higher in in vitro material, a biochemical feature relevant for downstream use. These findings indicate that cultivation system substantially shapes the secondary metabolite profile and bioactivity of this regionally important medicinal species. Full article

Antimicrobial resistance is a growing global health challenge, highlighting the need for new bioactive compounds from medicinal plants. Vepris nobilis is traditionally used in East Africa for treating infections and respiratory disorders; however, its essential oil (EO) composition and antimicrobial mechanisms remain poorly characterized. This study investigated the chemical composition and antimicrobial activity of V. nobilis EO, along with an in silico evaluation of its major constituent, germacrene D. The EO was extracted by hydrodistillation and analyzed using gas chromatography-mass spectrometry (GC–MS). Its antimicrobial activity was evaluated against 26 bacterial and 4 fungal strains using disc diffusion, broth microdilution, and MBC/MFC (Minimum Bactericidal Concentration/Minimum Fungicidal Concentration) assays. Germacrene D showed stronger activity than the EO, particularly against both multidrug resistant (MDR) and non-MDR Gram-negative bacterial strains (MIC = 10 µg/mL), with bactericidal and fungicidal effect. Molecular docking of germacrene D against two clinically relevant enzymes—dehydrosqualene synthase (CrtM) from Staphylococcus aureus and SWISS-modeled sterol 14-α-demethylase (CYP51) from Penicillium funiculosum—suggested potential interactions with both targets, with a favorable predicted binding affinity for CrtM (−7.654 kcal/mol) and for CYP51 (−5.898 kcal/mol). These findings provide preliminary insights into a possible antimicrobial mechanism, although experimental validation is needed to confirm this hypothesis. ADMET analysis suggested favorable drug-like properties despite limited solubility. These findings provide scientific support for the traditional use of V. nobilis leaves in the treatment of respiratory infections and highlight germacrene D as a promising lead compound for further antimicrobial development. Full article

The composition of honey is complex and can vary depending on its botanical and geographical origin. This study evaluated the phenolic acid profile (PAP), antioxidant activity, and antimicrobial properties of honey samples from different geographical origins, such as Romania (nine types: multiflower, thyme, manna, hawthorn, black locust, linden, rapeseed, mint, and pasture), Malaysia (Tualang), New Zealand (Manuka), and Spain (chestnut). Twelve different varieties of honey were analyzed, one sample for each type, and all analyses were performed in triplicate. Phenolic acids were extracted by solid-phase extraction (SPE) using C18 cartridges, followed by high-performance liquid chromatography with diode-array detection (HPLC-DAD) analysis at 310 nm. Antioxidant activity was assessed using the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays. Antimicrobial activity was evaluated by agar diffusion and broth microdilution to determine the minimum inhibitory concentration (MIC), while microbial anti-adherence activity was assessed using the crystal violet staining assay to determine the minimum anti-adherence inhibitory concentration (MAIC). The tested microorganisms included the reference strains Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, and Candida albicans ATCC 10231, as well as two C. albicans isolates (24114 and 5329). Several phenolic acids, including chlorogenic, caffeic, ferulic, trans-cinnamic, 3-O-methylgallic, p-coumaric, and syringic acids, were identified at varying concentrations across the analyzed honey samples. Rapeseed honey exhibited the highest overall concentration of phenolic acids. Among the honey samples analyzed, chestnut honey had the highest concentration of cinnamic acid, mint honey the highest concentration of ferulic acid, and multiflower honey the highest concentration of syringic acid. Tualang honey exhibited the highest antioxidant activity by both methods, reaching 2.103 mg TE/g honey for DPPH and 1.701 mg TE/g honey for ABTS. Tualang honey also exhibited the strongest antimicrobial activity against C. albicans and P. aeruginosa, whereas multifloral honey was the most active against E. faecalis. The analyzed honey extracts differed in their phenolic acid composition and biological activities, including antioxidant, antimicrobial, and anti-adherence effects of microorganisms on substrates. While associations were observed between selected phenolic acids and some of the evaluated biological activities, the overall biological properties of honey are more likely to arise from the combined contribution of multiple bioactive constituents than from individual compounds alone. The novelty of this study lies in the comparative assessment of the PAP obtained following SPE, and the biological activities of different types of honey from various botanical and geographical sources. Full article