Antimicrobial Potential Research Articles

Employing acetoacetamide as a key synthon for synthesizing novel thiophene derivatives and assessing their potential as antioxidants and antimicrobial agents

AbstractThe objective of this study is to synthesize novel heterocyclic scaffolds containing a thiophene moiety using easily accessible acetoacetamide as a key synthon. The reaction of acetoacetamide with diazonium salts resulted in the formation of the corresponding thiophene derivatives 4a–c. Additionally, the reaction of acetoacetamide derivative 3 with malononitrile, ethyl cyanoacetate, or 2‐cyanoacetamide, along with elemental sulfur, under refluxing in dioxane containing triethylamine afforded thiophene‐containing derivatives 5a–c. Furthermore, compound 3 reacted with phenyl isothiocyanate in dry dimethylformamide and K2CO3 to yield compound 7. In situ alkylation of the non‐isolable salt 6 was achieved by the addition of methyl iodide, resulting in the formation of methylthio‐thiophene‐2‐carboxamide 8. Compound 7 was employed with numerous alpha‐halogenated reagents in ethanol, affording thiazole derivative 9 and thiophene derivatives 10a and 10b, respectively. Moreover, compound 8 was reacted with hydrazine to produce the 1H‐pyrazole‐4‐carboxamide derivative 11. Additionally, refluxing acetoacetamide derivative 3 with malononitrile and/or ethyl cyanoacetate in dioxane, in the presence of catalytic amount of triethylamine afforded 4‐imino‐3,7‐dimethyl‐4H‐pyrido[1,2‐a]thieno[3,2‐e]pyrimidin‐9(5H)‐one derivatives 12a and 12b. Furthermore, the reactivity of acetoacetamide derivative 3 with 2‐cyanoacetohydrazide was investigated through refluxing the reactants in dioxane, which subsequently yielded the corresponding cyanoacetamide derivative 13. The chemical identity of the newly synthesized compounds was determined by employing infrared spectroscopy (IR), 1H NMR, and 13C NMR techniques. Newly synthesized heterocycles incorporating thiophenes were evaluated for their antioxidant and antimicrobial potentials. Notably, thiophene scaffolds 5a, 10b, 11, and 13 displayed notable antioxidant and antimicrobial activities.

Effects of Phyllanthus niruri antiseptic skin cream on surgical wounds in Felis catus after ovariosalpingohysterectomy

Studies highlight the cost-effectiveness and lower adverse effects of herbal remedies than allopathic medicines, making them attractive amidst growing microbial resistance concerns. This investigation explored the in vitro antiseptic properties of Phyllanthus niruri alcoholic extract (EA) against Escherichia coli, Staphylococcus aureus, Streptococcus spp., and Candida albicans. Various in vitro methods were employed, including disk diffusion, Minimum Inhibitory Concentration (MIC), and Bactericidal/Fungicidal Concentration (MBC/MFC). A skin cream formulation using P. niruri was developed, undergoing in vivo trials on ten feline subjects post-ovariosalpingohysterectomy (OSH). Felines were treated with P. niruri skin cream (100mg/ml), with 0.1% aqueous chlorhexidine as the positive control. Skin assessments included hyperemia, crust, edema, and exudation. Inhibition was observed in vitro at various EA concentrations, and cytotoxicity analysis showed no harm. The P. niruri skin cream at 100mg/ml exhibited consistent outcomes, with a minor deviation from the fifth day onwards, without compromising therapeutic efficacy (Tukey test, p < 0.05). The formulation demonstrated stable physical-chemical properties with no adverse feline reactions. These findings suggest the skin cream's in vivo antimicrobial potential as a future antiseptic alternative.

Synergistic Activity of Noble Trimetallic Nanofluids: Unveiling Unprecedented Antimicrobial Potential and Computational Insights.

Nanofluids hold significant promise in diverse applications, particularly in biomedicine, where noble trimetallic nanofluids outperformed their monometallic counterparts. The composition, morphology, and size of these nanofluids play pivotal roles in their functionality. Controlled synthesis methods have garnered attention, focusing on precise morphology, content, biocompatibility, and versatile chemistry. Understanding how reaction parameters such as time, reducing agents, stabilizers, precursor concentration, temperature, and pH affect size and shape during synthesis is crucial. Trimetallic nanofluids, with their ideal composition, size, surface structure, and synergistic properties, are gaining traction in antimicrobial applications. These nanofluids were tested against seven microorganisms, demonstrating a heightened antimicrobial efficacy. Computational analyses, including molecular docking, dynamics, density functional theory (DFT), molecular electrostatic potential (MESP) analysis, and absorption, distribution, metabolism, elimination, and toxicology studies (ADMET) provided insights into binding interactions, energy, reactivity, and safety profiles, affirming the antimicrobial potential of trimetallic nanofluids. These findings emphasize the importance of controlled synthesis and computational validation in harnessing the unique properties of trimetallic nanofluids for biomedical applications.

Scanning electron microscopic investigation on Chicory tribe (Compositae) botanical sources and their antimicrobial potential.

This study discusses the micro-level structural details of Cichorieae pollen sources elucidated by scanning electron microscopy (SEM) and explains their symmetry and morphometry. The in-depth knowledge from the electron ultrastructure of Asteraceae pollen has provided insights into enhanced pollen morphology, and the antimicrobial significance of species under study presents novel avenues for their natural defense mechanisms in the development of antimicrobial agents. In this research, both quantitative and qualitative features of pollen were examined. The pollen grains are prolate-spheroidal and oblate-spheroidal in shape, characterized by a maximum polar diameter of 55.6-61.0 μm and a maximum equatorial distance of 68.3-74.4 μm. SEM reveals various configurations such as echinate perforate-tectate, psilate, and echino-lophate perforate. The Cichorieae species have significant antimicrobial efficacy and are promising sources for the development of novel antimicrobial drugs with potential implications in pharmaceutical and healthcare industries. SEM analysis of Cichorieae pollens has provided remarkable insights into their unique structures, revealing diverse shapes and surface ornamentations, which can be used for accurate Asteraceae species identification. RESEARCH HIGHLIGHTS: SEM provides unique pollen surface structures and patterns of Chicory pollen grains. Chemical composition of Chicory botanical sources provides valuable information on their potential as antimicrobial agents. SEM imaging reveals specialized fenestrate grain structures of taxonomic importance.

Construction and Docking Studies of Novel Pyrimido[4,5-b]quinolines as Antimicrobial Agents.

In order to develop novel antimicrobial agents, we prepared quinoline bearing pyrimidine analogues 2-7, 8 a-d and 9 a-d and their structures were elucidated by spectroscopic techniques. Furthermore, our second aim was to predict the interactions between the active compounds and enzymes (DNA gyrase and DHFR). In this work, fourteen pyrimido[4,5-b]quinoline derivatives were prepared and assessed for their antimicrobial potential by estimating zone of inhibition. All the screened candidates displayed antibacterial potential with zone of inhibition range of 9-24 mm compared with ampicillin (20-25 mm) as a reference drug. Moreover, the target derivatives 2 (ZI=16), 9 c (ZI=17 mm) and 9 d (ZI=16 mm) recorded higher antifungal activity against C. albicans to that exhibited by the antifungal drug amphotericin B (ZI=15 mm). Finally, the most potent pyrimidoquinoline compounds (2, 3, 8 c, 8 d, 9 c and 9 d) were docked inside DHFR and DNA gyrase active sites and they recorded excellent fitting within the active regions of DNA gyrase and DHFR. These outcomes revealed us that compounds (2, 3, 8 c, 8 d, 9 c and 9 d) could be lead compounds to discover novel antibacterial candidates.

Screening of Bioactive Compounds, Antioxidant and Antimicrobial Properties in the Leaf Extracts of Two Castanopsis Species

ABSTRACT The phytochemical compounds in the leaf extracts of Castanopsis indica and C. tribuloides were evaluated, and their antioxidant and antimicrobial potential were assessed. The TPC was found to be 193.12 and 159.49 mg GAE g−1 dry weight, and the TFC was 108.12 and 96.49 mg QE g−1 dry weight, for C. indica and C. tribuloides, respectively. C. indica had higher DPPH scavenging activity, with an IC50 value of 15.10 μg mL−1. Both extracts showed substantial antimicrobial activity against the tested bacteria. GC-MS analysis showed the presence of 76 VoCs in C. indica leaf, and 71 VoCs in C. tribuloides.

Influence of Sporophyte Emergence on Phytochemical Constituents and Antimicrobial Activity of Hyophila Involuta (Pottiaceae) – A Bryophyte Species

Hyophila involuta (Hook) Jaeg., a sample collected from a natural population in the Biological Garden, Obafemi Awolowo University, Nigeria, was sorted into non-sporophytic and sporophytic gametophytes. This was with a view to investigating the possible influence of sporophyte emergence on the bioactive constituents and the antimicrobial potentials of the moss plant. Aqueous extracts of each of the non-sporophytic and the sporophytic gametophyte samples were prepared, and each was subjected to qualitative and quantitative phytochemical screening, gas chromatography-mass spectrometry (GC-MS) analyses, and antimicrobial potentials tests on selected bacteria and fungi following standard procedures. The results showed both extracts testing positive for alkaloids, cardiac glycosides, saponins, and steroids. Quantitatively, alkaloids and cardiac glycosides concentrations were higher in the non-sporophytic than in the sporophytic gametophytes. Nevertheless, the saponins content was higher in sporophytic gametophytes. GC-MS analyses revealed 40 and 46 bioactive compounds in the non-sporophytic and the sporophytic gametophyte samples respectively. The most prominent compound was 1, 13-tetradecadiene (13.62%) in the non-sporophytic gametophyte but cycloheptasiloxane tetradecamethyl- (13.78%) in the sporophytic game-tophyte. Furthermore, the sporophytic gametophyte extract inhibited the growth of Escherichia coli, Pseudomonas aeruginosa, and Candida pseudotropicalis while the non-sporophytic gametophyte extract only inhibited the growth of P. aeruginosa at a minimum inhibitory concentration of 40 mg/mL except for C. pseudotropicalis (20 mg/mL). This study, therefore, provided insight for investigating the medicinal values of bryophytes and concluded that the emergence of sporophytes on gametophytes of a bryophyte species can vary significantly the synthesis of its biologically active compounds and its antimicrobial activity.

T6SS nuclease effectors in Pseudomonas syringae act as potent antimicrobials in interbacterial competition.

The phytopathogen Pseudomonas syringae employs an active type VI secretion system (T6SS) to outcompete other microorganisms in the natural environment, particularly during the epiphytic growth in the phyllosphere. By examining two T6SS clusters in P. syringae MB03, T6SS-1 is found to be effective in killing Escherichia coli cells. We highlight the excellent antibacterial effect of two T6SS DNase effectors, namely, Tde1 and Tde4. Both of them function as nuclease effectors, leading to DNA degradation and cell filamentation in prey cells, ultimately resulting in cell death. Our findings deepen our understanding of the T6SS effector repertoires used in P. syringae and will facilitate the development of effective antibacterial strategies.

Biomedical and therapeutic potential of marine-derived Pseudomonas sp. strain AHG22 exopolysaccharide: A novel bioactive microbial metabolite

Abstract Microbial exopolysaccharides (EPSs) are gaining interest as alternatives to chemical antioxidants and pharmaceuticals. This study mines the promising biomedical and antimicrobial potential of a marine bacterium, a prolific EPS producer, isolated from the Red Sea. Pseudomonas sp. strain AHG22 generated an EPS weighing 6.98 g·L−1, coded EPSF8, subjected to FT-IR and HPLC chemical analysis. EPSF8 was then investigated for antioxidant assessment by 2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2, ABTS˙ + , nitric oxide, total antioxidant capacity (TAC), and ferric reducing antioxidant power (FRAP). EPSF8 had an IC50 of 46.99 μg·mL−1 in the DPPH antioxidant assay and antioxidant capacities of 219.45 μg·mg−1 ascorbic acid equivalent (AAE) in the TAC assay and 54.15 μg·mg−1 AAE in the FRAP assay. The in vitro anti-inflammatory effect of EPSF8 was tested against 5-lipoxygenase (5-LOX) and cyclooxygenase-2 (COX-2) enzymes and compared with the drugs ibuprofen and celecoxib used as controls. The IC50 values of 5-LOX, COX-2, ibuprofen, and celecoxib were found to be 14.82, 15.49, 1.5, and 0.28 μg·mL−1, respectively. Additionally, EPSF8 revealed antidiabetic activity toward α-amylase and α-glucosidase, and the IC50 values were 93.1 and 127.28 μg·mL−1, compared to those of acarbose (50.93 and 4.13 μg·mL−1, respectively). Anti-obesity activity of EPSF8 by lipase inhibition revealed IC50 = 56.12 μg·mL−1 compared to orlistat (IC50 = 20.08 μg·mL−1) as a control. EPSF8 displayed antibiofilm and bactericidal activity against Gram-positive (G +ve) and Gram-negative (G −ve) ATCC pathogenic bacterial strains. It had a minimum bactericidal concentration/minimum inhibitory concentration ratio ≤2, indicating a broad bactericidal spectrum. Furthermore, EPSF8 is evidenced to have a promising anti-butyrylcholinesterase activity for the control of Alzheimer’s disease. The findings of the present analysis suggest that the isolated Pseudomonas sp. strain AHG22 EPS can potentially be explored as a promising green therapeutic compound.

Endophytic fungi-assisted biomass synthesis of eco-friendly formulated silver nanoparticles for enhanced antibacterial, antioxidant, and antidiabetic activities

Fungi-mediated biosynthesis of silver nanoparticles is one of the promising nanomanufacturing processes. Using endophytic fungi isolated from potential medicinal plants has emerged as a novel approach for producing several metal oxide nanoparticles in a green and cost-effective manner. The present study validates the biomimetic synthesis of silver nanoparticles of endophytic fungus (Phyllosticta capitalensis Henn.) (Phyllo-AgNPs) isolated from the leaves of Annona muricata and the effect of process variables, i.e., reductant concentration, ratio of AgNO3 to reductant concentration, reaction time and reaction pH to achieve maximum efficiency using the factorial design approach. The nanoparticle formation was confirmed by absorption peaks between 400 nm and 500 nm, followed by their characterization by UV–visible spectroscopy, TEM, SEM-EDX, XRD, particle size, and zeta potential analysis. The in-vitro antioxidant, antidiabetic and antimicrobial potential (agar well dfiffusion and minimum inhibitory concentration) of Phyllo-AgNPs at various concentrations were assessed. The Phyllo-AgNPs scavenged the 2,2-diphenyl-1-picrylhydrazyl radical and inhibited the activity of α-amylase and α-glucosidase enzymes at an IC50 of 31.75 ± 0.70, 39.32 ± 1.12 and 28.56 ± 1.08 μg/mL, respectively. The antimicrobial potential was determined against Listeria monocytogenes, Staphylococcus aureus, Escherichia coli and, Salmonella typhimurium. The study revealed the therapeutic potential of Phyllo-AgNPs against pathogenic microorganisms. Additionally, the in-vitro antioxidant and antidiabetic activities showed improved results compared to the standard (ascorbic acid and acarbose). By taking note of this, Phyllo-AgNPs can be further studied for pre-clinical trials, which would be beneficial in developing novel medicines with no adverse effects for the benefit of mankind.

Complexes of Gold(III) with Hydrazones Derived from Pyridoxal: Stability, Structure, and Nature of UV-Vis Spectra.

Pyridoxal and pyridoxal 5'-phosphate are aldehyde forms of B6 vitamin that can easily be transformed into each other in the living organism. The presence of a phosphate group, however, provides the related compounds (e.g., hydrazones) with better solubility in water. In addition, the phosphate group may sometimes act as a binding center for metal ions. In particular, a phosphate group can be a strong ligand for a gold(III) ion, which is of interest for researchers for the anti-tumor and antimicrobial potential of gold(III). This paper aims to answer whether the phosphate group is involved in the complex formation between gold(III) and hydrazones derived from pyridoxal 5'-phosphate. The answer is negative, since the comparison of the stability constants determined for the gold(III) complexes with pyridoxal- and pyridoxal 5'-phosphate-derived hydrazones showed a negligible difference. In addition, quantum chemical calculations confirmed that the preferential coordination of two series of phosphorylated and non-phosphorylated hydrazones to gold(III) ion is similar. The preferential protonation modes for the gold(III) complexes were also determined using experimental and calculated data.

Metronidazole-loaded zinc oxide / graphene nanoparticles: synthesis, analysis, drug delivery, and antibacterial efficiency

In our study, zinc oxide (ZnO) nanoparticles (NPs) were prepared by precipitation (economically and in high quality) at a temperature range of 60°C to 80°C and at pH 8, and were then adorned with graphene (G) plates. To determine its antimicrobial potential, the ZnO/G complex was loaded with metronidazole. The morphology and diameter of the ZnO nanocomposite before and after the loading were validated by scanning electron microscopy. The average size of the ZnO NPs was found to be 20–40 nm, while X-ray diffraction examined how the physical features of these NPs varied from those of its individual components with an average size of 28.1 nm. The assessment of the ZnO/G com¬plex’s antibacterial efficacy against Gram-positive and Gram-negative bacteria was the main aim of our work. The agar well diffusion technique was used in order to assess the antibacterial activity of the ZnO/G complex with and without metronidazole. Our study demonstrates that the ZnO/G complex possesses antibacterial activity and might increase the antibiotic action by inhibiting Gram-positive bacteria (more than Gram-negative ones). It is, therefore, concluded that the ZnO/G NPs could be of use in formulating nano-drug conjugates that could act as antimicrobial agents.

Lamiales epidermal dynamics: Unveiling antimicrobial resilience in a structural symphony.

This research on Lamiales epidermal anatomy not only provides in-depth understanding of their structural traits but also highlights the significance of uncovering the inherent antimicrobial resilience embedded within these plants. Such insights hold promise for advancing natural product-based approaches in medicine, potentially contributing to the development of novel antimicrobial agents inspired by Lamiales unique biological defense mechanisms. Scanning microscopic tools were utilized to conduct foliar epidermal anatomy of nine species that belong to seven genera and four families within the Lamiales order, Plantaginaceae, Scrophulariaceae, Verbenaceae, and Lamiaceae. This approach aimed to gather both qualitative and quantitative data, facilitating the assessment of taxonomic microanatomical significance. The shape of epidermal cells and their anticlinal walls; number of epidermal cells, stomata, and trichomes; type of stomata and trichomes; length and width of epidermal cells, trichomes, stomatal pore, guard cells, and subsidiary cells; and stomatal index were determined statistically. Most of the species examined were amphistomatous and showed extensive array of trichomes diversity. The exploration of Lamiales epidermal micromorphology and their antimicrobial potential were significant for their implications in multidisciplinary fields. The pharmacological research to utilize sustainable agricultural practices prompts avenues to strengths of Lamiales order for the development of novel antimicrobial solutions and ecological benefits. RESEARCH HIGHLIGHTS: Diverse trichome morphometry reveals a wide array of trichome structures across Lamiales species. Epidermal microscopic architecture variability of epidermal cell shapes and sizes signifies the interspecies variability. Secondary metabolite localization within microanatomical structures elucidates potential hotspots for antimicrobial compound production.

Evaluation of the active compound and antibacterial activity of a Salvia rosmarinus extract against pathogenic bacteria

When bacteria attach to the human body, they have many defense mechanisms. These mechanisms pose a global health risk. Medicinal plants can be used to control such bacterial attack mechanisms. The aim of this study was to assess the antimicrobial potential of an aqueous extract of Salvia rosmarinus and other plant extracts against some clinical bacterial isolates. The antimicrobial activity against Gram-positive and Gram-negative bacteria (S. aureus, E. coli, P. aeruginosa, Proteus spp., and Klebsiella spp.) was determined by using the agar well diffusion method. When compared to an alcoholic extract, the aqueous extract of Salvia rosmarinus inhibited the studied bacterial isolates with greater efficiency.

Quantitative Analysis of Swertiamarin Content from Fagraea fragrans Leaf Extract using HPLC Technique and its Correlation to Antibacterial Activity

The rise in drug resistance poses escalating challenges for antibacterial medications, leading to an urgent demand for the exploration and innovation of new antibacterial drugs. Fagraea fragrans Roxb., belonging to the Gentianaceae family, is one of the common herbal medicines which can be found abundantly in Southeast Asia. The secoiridoid glucoside swertiamarin, one of the major compounds in F. fragrans leaf, exhibits antimicrobial effects. To guarantee the medicinal effectiveness of F. fragrans leaves, it is essential to identify a standardized analytical method for quantifying the active compound. In this study, the optimized HPLC method following ICH guideline was validated for the quantitative analysis of swertiamarin content in F. fragrans leaf in terms of linearity (y = 5733.5x - 369.1; R2 = 0.9999), accuracy (93.57-96.39% recovery), precision (0.91% RSD for repeatability precision; 1.19% RSD for intermediate precision), limit of detection (0.73 µg/mL), limit of quantitation (2.23 µg/mL), specificity (peak purity index = 0.999995) and robustness (% RSD <1).The maximum wavelength of swertiamarin was found to be at 238 nm. The amount of swertiamarin content in F. fragrans leaf extract conducted from the validated HPLC method was found to be 0.0259 ± 0.0005 g/100 g crude drug. The leaf extract exhibited antimicrobial activity against clinical isolates of Enterobacter cloacae, Klebsiella pneumonia, and Escherichia coli at 0.125 mg/mL, and Pseudomonas aeruginosa at 0.5, showing minimum inhibitory concentration (MIC) values. Whereas swertiamarin exhibited even lower MIC values. The developed HPLC analysis effectively determines swertiamarin content as a chemical marker to ensure the antimicrobial potential of F. fragrans leaves.

Elaborately engineered Au(I)‐based AIEgens: Robust and broad‐spectrum elimination abilities toward drug‐resistant bacteria

Elaborately engineered Au(I)‐based AIEgens: Robust and broad‐spectrum elimination abilities toward drug‐resistant bacteria

Investigation on antioxidant, antimicrobial, anti-inflammatory, and neuropsychiatry potential of phyto-mediated ZnONPs using Colebrookea oppositifolia

The present study reports the phyto-mediated synthesis of ZnONPs using methanol extracts and n-Butanol fractions from the roots and leaves of C. oppositifolia. The synthesized nanoparticles were characterized using XRD, FE-SEM, HR-TEM, and XPS techniques to determine their crystallite structure, elemental composition, surface topography, and physio-chemical properties. Furthermore, the biological potential of ZnONPs was evaluated for antioxidant, antimicrobial, anti-inflammatory, and in vitro cytotoxic potential on SH-SY5Y neuroblastoma cell lines. Notably, LEME-ZnONPs exhibited exceptional antioxidant activity with an IC50 of 30.200μg/mL in the DPPH assay. The antimicrobial efficacy was also remarkable, displaying high maximum activity against bacterial strains, evidenced by zones of inhibition (ZOI) measuring 15.67±0.58mm (E. coli) and 14.67±0.58mm (S. aureus) for RTME-ZnONPs, attributable to their small crystallite size. Similarly, against antifungal strains, LEBF-ZnONPs (60.94±0.83%) and RTBF-ZnONPs (60.85±0.74%) exhibited potency to inhibit both F. oxysporum and R. necatrix due to their small particle size. Furthermore, LEBF-ZnONPs demonstrated superior anti-inflammatory properties, registering an impressive 98.681%, outperforming Diclofenac sodium (96.835%). Importantly, the phyto-mediated ZnONPs exhibited minimal cytotoxicity on SH-SY5Y cell lines at 62.5μg/mL, a concentration employed as an experimental model to assess neuronal function. The multifaceted applications of phyto-mediated ZnONPs extend across various fields, including pharmaceutical sciences, agriculture, and the treatment of neurological diseases.

Boosting antimicrobial potency: Micro encapsulated polymyxin in hydroxypropyl beta cyclodextrin ‘sugar cage’ and alginate via spray drying with coating

Boosting antimicrobial potency: Micro encapsulated polymyxin in hydroxypropyl beta cyclodextrin ‘sugar cage’ and alginate via spray drying with coating

A Comprehensive Study on Peppermint Oil and Cinnamon Oil as Nanoemulsion: Preparation, Stability, Cytotoxicity, Antimicrobial, Antifungal, and Antioxidant Activity.

Recent studies have shown that nanoemulsions prepared with essential oils have significant antimicrobial potential against multidrug-resistant pathogens due to increased chemical stability. Nanoemulsion also promotes controlled and sustained release, which increases their bioavailability and efficacy against multidrug-resistant bacteria. This study aimed to investigate the antimicrobial, antifungal, antioxidant, and cytotoxicity properties of cinnamon essential oil and peppermint essential oil as nanoemulsions compared to pure forms. For this purpose, analyses of the selected stable nanoemulsions were carried out. The droplet sizes and zeta potentials of peppermint essential oil nanoemulsions and cinnamon essential oil nanoemulsions were found to be 154.6±1.42 nm and -17.1±0.68 mV and 200.3±4.71 nm and -20.0±0.81 mV, respectively. Although the amount of essential oil used in nanoemulsions was 25% w/w, antioxidant and antimicrobial activities were found to be more effective compared to pure essential oils. In cytotoxicity studies on the 3T3 cell line, both essential oil nanoemulsions showed higher cell viability than pure essential oils. At the same time, cinnamon essential oil nanoemulsions exhibited a higher antioxidant property than peppermint essential oil nanoemulsions and showed superiority in the antimicrobial susceptibility test conducted against four bacteria and two fungi. Cell viability tests determined that cinnamon essential oil nanoemulsions showed considerably higher cell viability compared to pure cinnamon essential oil. These findings indicated that the prepared nanoemulsions in the current study might positively influence the dosing regimen and clinical outcomes of antibiotic therapy.

Quantitative and Qualitative Determination of Polyphenolic Compounds in Castanea sativa Leaves and Evaluation of Their Biological Activities

The aim of the study was to evaluate the polyphenol profile of Castanea sativa leaf methanolic extract and further evaluate its biological activities in vitro. After purification with an RP-18 resin, the extract was assessed for its polyphenol profile by UPLC-PDA-MS/MS, as well as for the antioxidant potential (ABTS, CUPRAC, ChA, ROS scavenging methods), anticancer, antiobesity, antidiabetic and antimicrobial potential. Eighteen polyphenols were identified and the dominant compounds were chestatin followed by quercetin 3-O-glucoside. The total phenolic content of the extract showed a value of 1426.55 mg/100 g d.w. The obtained preparation showed the ability to scavenge O2•− (0.067 mg/mL) and OH• (0.207 mg/mL) radicals and had a stronger anti-obesity than anti-diabetic effect. Additionally, this extract exhibited a strong anticancer activity against the Caco-2 line (153.54 µg/mL), with anti-migratory and anti-proliferative activity. In turn, among the tested strains, the highest activity was demonstrated against Staphylococcus aureus. Moreover, the effects demonstrated were strongly dependent on the content of polyphenols. In conclusion, C. sativa is a promising source of natural antioxidant, antibacterial, antiobesity, antidiabetic and chemopreventive compounds for food-pharma industry; however, further experimental studies are needed to validate its pharmacological properties.