Effect of photodynamic therapy with 5-aminolevulinic acid and EDTA-2Na against mixed infection of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa.

BACKGROUND: The increasing abundance of drug-resistant bacteria is a global threat. Photodynamic therapy is an entirely new, non-invasive method for treating infections caused by antibiotic-resistant strains. We previously described the bactericidal effect of photodynamic therapy on infections caused by a single type of bacterium. We showed that gram-positive and gram-negative bacteria could be killed with 5-aminolevulic acid and 410 nm light, respectively. However, clinically, mixed infections are common and difficult to treat. OBJECTIVE: We investigated the bactericidal effects of photodynamic therapy on mixed infections of methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. METHODS: We compared bacterial growth with and without photodynamic therapy in vitro. Then, in vivo, we studied mixed infections in a mouse skin ulcer model. We evaluated the rates of ulcer area reduction and transitions to healing in treated and untreated mice. In addition, a comparison was made between PDT and existing topical drugs. RESULTS: We found that photodynamic therapy markedly reduced the growth of both methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, in culture, and it reduced the skin ulcer areas in mice. PDT was also more effective than existing topical medicines. CONCLUSION: This study showed that photodynamic therapy had antibacterial effects against a mixed infection of gram-positive and gram-negative bacteria, and it promoted skin ulcer healing. These results suggested that photodynamic therapy could be effective in both single- and mixed-bacterial infections.

Characterization and antimicrobial activity of endophytic fungi from medicinal plant Agave americana.

Endophytic microorganisms associated with medicinal plants are of particular interest as they are a potential source of new bioactive chemicals effective against novel emerging and drug-resistant pathogens. Agave americana is a tropical medicinal plant with antibacterial, antifungal, and anticancer properties. We studied the biodiversity of fungal endophytes of A. americana and their antimicrobial production potential. Isolated endophytic fungi were classified into 32 morphotypes (15 from stem and 17 from leaf) based on their cultural and morphological characteristics. Among the fungal crude extracts tested, 82% of isolates from the leaves and 80% of the isolates from the stem showed antibacterial activity against the bacterial strains (Escherichia coli ATTC 25902, Staphylococcus aureus ATTC 14775, and Bacillus subtilis NRRL 5109) tested. Extracts from four fungal isolates from leaves showed antifungal activity against at least one of the fungal strains (Candida albicans ATTC 10231 and Aspergillus fumigatus NRRL 5109) tested. Crude extracts of seven fungal isolates showed a zone of inhibition of more than 11 mm at 10 mgml-1 against both Gram-positive and Gram-negative bacteria tested. Penicillium, Colletotrichum, Curvularia, Pleosporales, Dothideomycetes, and Pleurotus are the main endophytes responsible for bioactive potential. These results indicate that A. americana harbors endophytes capable of producing antimicrobial metabolites.

Solanum tuberosum tuber-driven starch-mediated green-hydrothermal synthesis of cerium oxide nanoparticles for efficient photocatalysis and antimicrobial activities.

In this study, we are reporting for the first time the utilization of Solanum tuberosum tuber-driven, starch-mediated, green-hydrothermally synthesized cerium oxide nanoparticles (G-CeO2 NPs) for the antibacterial activity and photodegradation of cationic (methylene blue, MB) and anionic (methyl orange, MO) dyes separately and in combination, aimed at environmental remediation. The XRD analysis confirms the fluorite structure of G-CeO2 NPs, displaying an average crystallite size of 9.6 nm. Further, XPS confirms the existence of 24% of Ce3+ oxidation states within G-CeO2 NPs. Morphological studies through FE-SEM and TEM reveal that starch-driven OH- ion production leads to a high percentage of active crystal facets, favoring the formation of Ce3+-rich CeO2 NPs. Photocatalytic experiments conducted under UV-A illumination demonstrate the superior degradation performance of G-CeO2 NPs, with MB degradation reaching 93.4% and MO degradation at 77.2% within 90 min. This outstanding catalytic activity is attributed to the mesoporous structure (pore diameter of 5.63 nm) with a narrow band gap, a large surface area (103.38 m2g-1), and reduced charge recombination, as validated by BET, UV-visible, and electrochemical investigations. The identification of photogenerated intermediates is achieved through LCMS, while the mineralization is monitored via total organic carbon analysis. Moreover, the scavenging experiments point towards the involvement of reactive oxygen species in organic oxidation, demonstrating efficiency over five consecutive trials. Additionally, G-CeO2 NPs exhibit potent antibacterial activity against both gram-positive and gram-negative bacteria. This study presents an innovative, and efficient approach to environmental remediation, shedding light on the potential of G-CeO2 NPs in addressing environmental pollution challenges.

Design, biological characteristics, and antibacterial mechanism of high therapeutic index antimicrobial peptides with PRRP as central axis.

As the important components of biological innate immunity, antimicrobial peptides (AMPs) were found in a variety of organisms including insects, plants, animals, bacteria, fungi, etc. However, high hemolytic activity, high toxicity, and poor stability of natural AMPs hinder serious their application as therapeutic agents. To overcome these problems, in this study we use PRRP as a central axis, and peptides were designed based on the sequence template XRRXXRXPRRPXRXXRRX-NH2, where X represents a hydrophobic amino acid like Phe (F), Ile (I), Val (V), and Leu (L). The designed peptides LR18, FR18, and IR18 showed effective antimicrobial activity against some Gram-positive bacteria and Gram-negative bacteria, low cytotoxicity to mammalian cells, and had a tendency to form α-helical structures in membrane-mimetic environments. Among them, peptide LR18 (X: L) showed the highest geometric mean average treatment index (GMTI = 42.7) against Gram-negative bacteria, and FR18 (X: L) showed the highest GMTI (22.86) against Gram-positive bacteria. LR18 and FR18 also showed better salt, temperature, pH, and trypsin stability. LR18 and FR18 exert their antimicrobial effects mainly through destroying bacteria cell membrane. Briefly, peptide LR18 and FR18 have the potential to serve as a therapeutic agent to reduce antibiotic resistance owing to its high therapeutic index and great stability.

Effects of Roasting Conditions on Antibacterial Properties of Vietnamese Turmeric (Curcuma longa) Rhizomes.

Processing with heat treatment has been reported to alter several therapeutic effects of turmeric. In Vietnamese traditional medicine, turmeric has been long used for bacterial infections, and roasting techniques are sometimes applied with this material. However, there have been no studies investigating the effects of these thermal processes on the plant's antibacterial properties. Our study was therefore performed to examine the changes that roasting produced on this material. Slices of dried turmeric were further subjected to light-roasting (80 °C in 20 min) or dark-roasting (160 °C in 20 min) processes. Broth dilution and agar-well diffusion methods were applied to examine and compare the effects of ethanol extracts obtained from non-roasted, light-roasted and dark-roasted samples, on a set of 6 gram-positive and gram-negative bacteria. In both investigations, dark-roasted turmeric was significantly less antibacterial than non-roasted and light-roasted materials, as evident by the higher values of minimum inhibitory concentrations and the smaller diameters of induced inhibitory zones. In addition, dark-roasting was also found to clearly reduce curcumin contents, total polyphenol values and antioxidant activities of the extracts. These results suggest that non-roasting or light-roasting might be more suitable for the processing of turmeric materials that are aimed to be applied for bacterial infections.

Differentiating Dyes: A Spectroscopic Investigation into the Composition of Scarlet Bloodroot (Haemodorum coccineum R.Br.) Rhizome.

Haemodorum coccineum, commonly known as scarlet bloodroot, is a plant native to New Guinea and the northern most parts of Australia. The highly coloured H. coccineum is used by communities in Larrakia country for dyeing garments and occasionally to treat snake bites. Previous studies into H. coccineum have focused on its taxonomic classification, with this being the first evaluation of the chemical composition of the plant. Haemodoraceae plants are reported to contain phenylphenalenones (PhPs), which are highly conjugated polycyclic oxygenated aromatic hydrocarbons. We report the characterisation of 20 compounds extracted from the rhizome of H. coccineum: four sugars and 16 compounds belonging to the PhP family. The compounds include five aglycones and seven glycosylated compounds, of which four contain malonate esters in their structures. Characterisation of these compounds was achieved through 1D and 2D NMR, MS analysis and comparison to the known phytochemistry of other species from the Haemodorum genus. Preliminary anti-microbial activity of the crude extract shows significant inhibition of the growth of both gram-positive and gram-negative bacteria, but no activity against Candida albicans.

Preparation, characterization, bacteriostatic efficacy, and mechanism of zinc/selenium-loaded sodium humate.

In recent years, metal-based complexes including selenium (Se) and zinc (Zn)-containing compounds have been widely explored for their therapeutic properties due to their roles in biological processes and modulation of diverse molecular targets. Humic acid, as a metal complexing agent, is also widely used in biomedical field. In this work, three kinds of modified sodium humate (HNa), including Zn-HNA, Se-HNa, and Zn/Se-HNa, were prepared by ion exchange reaction method. The modified HNa was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and elemental mapping. The bacteriostatic activity and mechanism of modified HNa against gram-positive and gram-negative bacteria were investigated by testing bacterial inhibition zone, minimum inhibitory concentration, and capacity to destroy integrity of the bacterial membrane, promoting ROS generation level and prevention of biofilms. FTIR results showed that HNa could combine with zinc ions and selenite ions. The main XRD peaks did not change significantly. In the modified HNa, the particle shape was irregular. Compared to HNa, Zn-HNA, and Se-HNa, Zn/Se-HNa showed the strongest bacteriostatic activity. Zn/Se-HNa exhibited high bacteriostatic activity against gram-negative bacteria (Escherichia coli, Salmonella typhimurium, Klebsiella pneumoniae) and gram-positive bacteria (Staphylococcus aureus), but showed weak antibacterial activity against another gram-positive bacteria, Bacillus subtilis. The bacteriostasis was achieved by altering the permeability of bacterial cell membranes, generating ROS, and preventing the formation of biofilms. In conclusion, Zn/Se-HNa has high bacteriostatic activity, making it a suitable alternative to antibiotics in fields like the treatment of trauma infections and animal husbandry. KEY POINTS: • Preparate and characterize zinc- and selenium-loaded sodium humate (Zn/Se-HNa). • The combination of Zn and Se enhanced the bacteriostatic activity of HNa. • Zn/Se-HNa alters the permeability of bacterial cell membranes and promotes generation of ROS.

Photocatalytic evaluation of synthesized MnO2/Fe3O4 NCs by Q. infectoria extract for removal Ni(II) and phenol: Study phytochemical, kinetics, thermodynamics, and antibioactivity.

In the present study, the plant extract of the Quercus infectoria galls was used as a reducing, capping, and stabilizer agent for green synthesized MnO2 nanoparticles (NPs) and MnO2/Fe3O4 nanocomposites (NCs) due to its reduction ability from polyphenol and antioxidant content. The green synthesized nanomaterials have been characterized by various techniques such as FTIR, UV-vis, XRD, SEM, EDS, and TEM. The average size of about 7.4 and 6.88 nm was estimated for the NCs crystals of SEM images and XRD analysis by the Scherrer and Williamson-Hall methods. The green synthesized MnO2/Fe3O4 NCs (dosage: 0.1 g) have shown high photocatalytic activity for the removal of Ni(II) in acidic and basic solutions under visible irradiation (220 V lamp). The removal efficiency for the Ni(II) solution (3.6 × 10-3 M) at pH = 3 was increased to pH = 12 from 56 % to 98 %. The oxidase-like activity of MnO2/Fe3O4 NCs at different dosages (0.05, 0.1, and 0.15 g) for the removal and colorimetric of phenol (1 g/40 mL) in the presence 4-AAp (1 g) was seen after only 28, 13, and 5 s, respectively. The kinetic evaluation results showed the pseudo-second-order kinetics model closely matched the adsorption capacity theoretical values qe,cal (578.03, 854.70, 892.85, and 917.43 mg.g-1) and experimental values qe,exp (521.84, 839.74, 887.86, and 913.22 mg.g-1) at different initial pH solution (3-12) for Ni(II) removal. In addition, the investigation of isotherm models revealed that the Langmuir model (R2 = 0.9955) explains a better estimate for a monolayer and favorable removal of Ni(II) ions onto NCs. Also, the low Temkin constant, BT < 0 (0.0200 kJ.mol-1), and positive ∆H° value (0.103 kJ.mol-1.K-1) illustrated that Ni(II) removal is physical sorption and endothermic process. However, the obtained thermodynamic results showed the negative values ΔG° with the increase in temperature (303-318 K) toward a spontaneous removal process of Ni(II). Finally, the plant antioxidant (200 to 3200 µg/mL) and antimicrobial activities (0.001 to 0.1 g/mL) for plant extract, MnO2 NPs, and MnO2/Fe3O4 NCs were evaluated against Gram-positive and Gram-negative bacteria species.

L-glutamine sensitizes Gram-positive-resistant bacteria to gentamicin killing.

IMPORTANCE: Methicillin-resistant Staphylococcus aureus (MRSA) infection severely threatens human health due to high morbidity and mortality; it is urgent to develop novel strategies to tackle this problem. Metabolites belong to antibiotic adjuvants which improve the effect of antibiotics. Despite reports of L-glutamine being applied in antibiotic adjuvant for Gram-negative bacteria, how L-glutamine affects antibiotics against Gram-positive-resistant bacteria is still unclear. In this study, L-glutamine increases the antibacterial effect of gentamicin on MRSA, and it links to membrane permeability and pH gradient (ΔpH), resulting in uptake of more gentamicin. Of great interest, reduced reactive oxygen species (ROS) by glutathione was found under L-glutamine treatment; USA300 becomes sensitive again to gentamicin. This study not only offers deep understanding on ΔpH and ROS on bacterial resistance but also provides potential treatment solutions for targeting MRSA infection.

Phytochemical Composition and Antioxidant and Anti-Inflammatory Activities of Humboldtia sanjappae Sasidh. & Sujanapal, an Endemic Medicinal Plant to the Western Ghats.

Ethnomedicinal plants are important sources of drug candidates, and many of these plants, especially in the Western Ghats, are underexplored. Humboldtia, a genus within the Fabaceae family, thrives in the biodiversity of the Western Ghats, Kerala, India, and holds significant ethnobotanical importance. However, many Humboldtia species remain understudied in terms of their biological efficacy, while some lack scientific validation for their traditional uses. However, Humboldtia sanjappae, an underexplored plant, was investigated for the phytochemical composition of the plant, and its antioxidant, enzyme-inhibitory, anti-inflammatory, and antibacterial activities were assessed. The LC-MS analysis indicated the presence of several bioactive substances, such as Naringenin, Luteolin, and Pomiferin. The results revealed that the ethanol extract of H. sanjappae exhibited significant in vitro DPPH scavenging activity (6.53 ± 1.49 µg/mL). Additionally, it demonstrated noteworthy FRAP (Ferric Reducing Antioxidant Power) activity (8.46 ± 1.38 µg/mL). Moreover, the ethanol extract of H. sanjappae exhibited notable efficacy in inhibiting the activities of α-amylase (47.60 ± 0.19µg/mL) and ß-glucosidase (32.09 ± 0.54 µg/mL). The pre-treatment with the extract decreased the LPS-stimulated release of cytokines in the Raw 264.7 macrophages, demonstrating the anti-inflammatory potential. Further, the antibacterial properties were also evident in both Gram-positive and Gram-negative bacteria. The observed high zone of inhibition in the disc diffusion assay and MIC values were also promising. H. sanjappae displays significant anti-inflammatory, antioxidant, antidiabetic, and antibacterial properties, likely attributable to its rich composition of various biological compounds such as Naringenin, Luteolin, Epicatechin, Maritemin, and Pomiferin. Serving as a promising reservoir of these beneficial molecules, the potential of H. sanjappae as a valuable source for bioactive ingredients within the realms of nutraceutical and pharmaceutical industries is underscored, showcasing its potential for diverse applications.

In vitro biofilm inhibition efficacy of Aerva lanata flower extract against Gram negative and Gram-positive biofilm forming bacteria and toxicity analysis using Artemia salina.

A biofilm consists of Gram positive and Gram-negative bacteria enclosed in a matrix. Industrial biofouling is caused by biofilms, which can exhibit antimicrobial resistance during infections. Many biofilm studies find that nearly all biofilm communities consist of Gram positive and Gram-negative bacteria. It is therefore necessary to better understand the conserved themes in biofilm formation to develop therapeutics based on biofilm formation. Plant extracts can effectively combat pathogenic bacterial biofilms. This study evaluated the antibacterial and antibiofilm activity of Aerva lanata flower extract against Staphylococcus aureus and Pseudomonas aeruginosa. Methanol extract of dried A. lanata flower was tested against S. aureus and P. aeruginosa to determine the antibacterial activity (10, 25, 50, 75, 100 µg/mL) resulted in a maximum of 0.5-1 log reduction and 2 log reduction in comparison to the control or untreated bacterial cells respectively. A. lanata showed maximum biofilm inhibition up to 1.5-fold and 1-fold against P. aeruginosa and S. aureus. Light microscopic analysis of biofilm treated with A. lanata extract showed efficient distortion of the biofilm matrix. Further, the in vivo analysis of A. lanata in the Artemia salina brine shrimp model showed >50% survival and thus proving the efficacy of A. lanata extract in rescuing the brine shrimps against P. aeruginosa and S. aureus infection.

Green synthesis of Multifunctional Zinc oxide Nanoparticles from Cordia myxa gum; and their Catalytic Reduction of Nitrophenol, Anticancer and Antimicrobial Activity.

In situ exfoliated natural polysaccharide Cordia myxa (CMX) is used to promote the utilization of zinc-oxide nanoparticles for eco-friendly catalytic hydrogenation of p-nitrophenol (p-NP) and microbial growth inhibition. Polysaccharide-mediated biosynthetic nanocomposite materials are interesting because they are cheap, green, and environmentally friendly. This study uses CMX gum as a bioreduction to produce multifunctional, environmentally friendly zinc-oxide nanocomposites (ZnO NPs). The process involves a low reaction time and temperature and utilizes CMX as a reducing and stabilizing agent. The structural, morphological, and optical properties of the CMX-ZnO nanocomposite were characterized. The biosynthetic CMX-ZnO NPs exhibited robust catalytic activity and recycling capacity for rapidly oxidizing hazardous p-NPs. The complete reduction of 4-NP to CMX-ZnO NPs in excess NaBH4 was achieved within 15 min, with recyclability and pseudo-first-order kinetics with a rate constant of 0.2571 min-1. Additionally, human colon cancer (HCT116) and 3T3L1 cell lines were remarkably sensitive to the cytotoxic effects of ZnO nanoparticles. CMX-ZnO NPs exhibited potent antibacterial properties against human pathogenic gram-positive and gram-negative bacteria (Bacillus, Salmonella, E. coli, and Pseudomonas aeruginosa) based on the zone of inhibition measured by the disc-diffusion method. The significant antibacterial activity of CMX-ZnO NPs can overcome the current limitations associated with removing water-soluble organic pollutants and microbiological contaminants for long-term environmental sustainability.

Hydroxychloroquine-Loaded Chitosan Nanoparticles Induce Anticancer Activity in A549 Lung Cancer Cells: Design, BSA Binding, Molecular Docking, Mechanistic, and Biological Evaluation.

The current study describes the encapsulation of hydroxychloroquine, widely used in traditional medicine due to its diverse pharmacological and medicinal uses, in chitosan nanoparticles (CNPs). This work aims to combine the HCQ drug with CS NPs to generate a novel nanocomposite with improved characteristics and bioavailability. HCQ@CS NPs are roughly shaped like roadways and have a smooth surface with an average size of 159.3 ± 7.1 nm, a PDI of 0.224 ± 0.101, and a zeta potential of +46.6 ± 0.8 mV. To aid in the development of pharmaceutical systems for use in cancer therapy, the binding mechanism and affinity of the interaction between HCQ and HCQ@CS NPs and BSA were examined using stopped-flow and other spectroscopic approaches, supplemented by molecular docking analysis. HCQ and HCQ@CS NPs binding with BSA is driven by a ground-state complex formation that may be accompanied by a non-radiative energy transfer process, and binding constants indicate that HCQ@CS NPs-BSA was more stable than HCQ-BSA. The stopped-flow analysis demonstrated that, in addition to increasing BSA affinity, the nanoformulation HCQ@CS NPS changes the binding process and may open new routes for interaction. Docking experiments verified the development of the HCQ-BSA complex, with HCQ binding to site I on the BSA structure, primarily with the amino acids, Thr 578, Gln 579, Gln 525, Tyr 400, and Asn 404. Furthermore, the nanoformulation HCQ@CS NPS not only increased cytotoxicity against the A549 lung cancer cell line (IC50 = 28.57 ± 1.72 µg/mL) compared to HCQ (102.21 ± 0.67 µg/mL), but also exhibited higher antibacterial activity against both Gram-positive and Gram-negative bacteria when compared to HCQ and chloramphenicol, which is in agreement with the binding constants. The nanoformulation developed in this study may offer a viable therapy option for A549 lung cancer.

Antibacterial peptide PMAP-37(F34-R), expressed in Pichia pastoris, is effective against pathogenic bacteria and preserves plums.

BACKGROUND: Recently, researchers have focused on the search for alternatives to conventional antibiotics. Antimicrobial peptides are small bioactive peptides that regulate immune activation and have antibacterial activity with a reduced risk of bacterial resistance. Porcine myeloid antibacterial peptide 37 (PMAP-37) is a small-molecule peptide with broad-spectrum antibacterial activity isolated from pig bone marrow, and PMAP-37(F34-R) is its analogue. In this study, PMAP-37(F34-R) was recombinantly expressed in Pichia pastoris, and the recombinant peptide was further investigated for its antibacterial properties, mechanism and preservative in plums. RESULTS: To obtain a Pichia pastoris strain expressing PMAP-37(F34-R), we constructed a plasmid expressing recombinant PMAP-37(F34-R) (pPICZα-PMAP-37(F34-R)-A) and introduced it into Pichia pastoris. Finally, we obtained a highly active recombinant peptide, PMAP-37(F34-R), which inhibited the activity of both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration is 0.12-0.24 µg/mL, and it can destroy the integrity of the cell membrane, leading to cell lysis. It has good stability and is not easily affected by the external environment. Hemolysis experiments showed that 0.06 µg/mL-0.36 µg/mL PMAP-37(F34-R) had lower hemolysis ability to mammalian cells, and the hemolysis rate was below 1.5%. Additionally, 0.36 µg/mL PMAP-37(F34-R) showed a good preservative effect in plums. The decay and weight loss rates of the treated samples were significantly lower than those of the control group, and the respiratory intensity of the fruit was delayed in the experimental group. CONCLUSIONS: In this study, we constructed a recombinant Pichia pastoris strain, which is a promising candidate for extending the shelf life of fruits and has potential applications in the development of new preservatives.

Antioxidant, Volatile Compounds; Antimicrobial, Anti-Inflammatory, and Dermatoprotective Properties of Cedrus atlantica (Endl.) Manetti Ex Carriere Essential Oil: In Vitro and In Silico Investigations.

Cedrus atlantica (Endl.) Manetti ex Carriere is an endemic tree possessing valuable health benefits which has been widely used since time immemorial in international traditional pharmacopoeia. The aim of this exploratory investigation is to determine the volatile compounds of C. atlantica essential oils (CAEOs) and to examine their in vitro antimicrobial, antioxidant, anti-inflammatory, and dermatoprotective properties. In silico simulations, including molecular docking and pharmacokinetics absorption, distribution, metabolism, excretion, and toxicity (ADMET), and drug-likeness prediction were used to reveal the processes underlying in vitro biological properties. Gas chromatography-mass spectrophotometry (GC-MS) was used for the chemical screening of CAEO. The antioxidant activity of CAEO was investigated using four in vitro complementary techniques, including ABTS and DPPH radicals scavenging activity, ferric reductive power, and inhibition of lipid peroxidation (ß-carotene test). Lipoxygenase (5-LOX) inhibition and tyrosinase inhibitory assays were used for testing the anti-inflammatory and dermatoprotective properties. GC-MS analysis indicated that the main components of CAEO are ß-himachalene (28.99%), α-himachalene (14.43%), and longifolene (12.2%). An in vitro antimicrobial activity of CAEO was examined against eleven strains of Gram-positive bacteria (three strains), Gram-negative bacteria (four strains), and fungi (four strains). The results demonstrated high antibacterial and antifungal activity against ten of them (>15 mm zone of inhibition) using the disc-diffusion assay. The microdilution test showed that the lowest values of MIC and MBC were recorded with the Gram-positive bacteria in particular, which ranged from 0.0625 to 0.25 % v/v for MIC and from 0.5 to 0.125 % v/v for MBC. The MIC and MFC of the fungal strains ranged from 0.5 to 4.0% (MIC) and 0.5 to 8.0% v/v (MFC). According to the MBC/MIC and MFC/MIC ratios, CAEO has bactericidal and fungicidal activity. The results of the in vitro antioxidant assays revealed that CAEO possesses remarkable antioxidant activity. The inhibitory effects on 5-LOX and tyrosinase enzymes was also significant (p < 0.05). ADMET investigation suggests that the main compounds of CAEO possess favorable pharmacokinetic properties. These findings provide scientific validation of the traditional uses of this plant and suggest its potential application as natural drugs.

Preliminary phytochemical screening and antibacterial effects of root bark of Ferula communis (Apiaceae).

INTRODUCTION: Plants are widely used in traditional medicine because they contain a high concentration of antimicrobial agents, serving as the foundation for medicines. The aim of this study was preliminary identification of phytochemicals and assesses the antimicrobial activity of extracts of Ferula communis root bark. METHODS: Plant was collected, and standard qualitative procedures were conducted. The plant samples were extracted with 99.9% methanol and 80% ethanol. To identify phytochemicals found in plants, a preliminary phytochemical analysis was performed. Agar diffusion tests, minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were performed to evaluate antibacterial activity. RESULT: The preliminary phytochemical analysis of the ethanol and methanol extract revealed positive results for flavonoids, coumarins and tannins. Terpenoids and anthraquinones were detected only in the methanol extract. The extract of Ferula communis showed an antibacterial effect on both gram-negative and gram-positive bacteria in a concentration-dependent manner. The average zone of inhibition for gram-positive bacteria was 11 mm, whereas for gram-negative bacteria, it was 9 mm. The MIC and MBC values also varied with the type of bacteria. In all bacterial species tested, the mean MBC value was similar to the MIC. CONCLUSION: Different phytochemicals were detected in extracts of the root bark of F. communis and extracts showed antibacterial effects in a concentration-dependent manner. Therefore, further purification and evaluation of the extracts and antioxidant activity of the plant should be investigated.

Quinone Pool, a Key Target of Plant Flavonoids Inhibiting Gram-Positive Bacteria.

Plant flavonoids have attracted increasing attention as new antimicrobial agents or adjuvants. In our previous work, it was confirmed that the cell membrane is the major site of plant flavonoids acting on the Gram-positive bacteria, which likely involves the inhibition of the respiratory chain. Inspired by the similar structural and antioxidant characters of plant flavonoids to hydro-menaquinone (MKH2), we deduced that the quinone pool is probably a key target of plant flavonoids inhibiting Gram-positive bacteria. To verify this, twelve plant flavonoids with six structural subtypes were preliminarily selected, and their minimum inhibitory concentrations (MICs) against Gram-positive bacteria were predicted from the antimicrobial quantitative relationship of plant flavonoids to Gram-positive bacteria. The results showed they have different antimicrobial activities. After their MICs against Staphylococcus aureus were determined using the broth microdilution method, nine compounds with MICs ranging from 2 to 4096 µg/mL or more than 1024 µg/mL were eventually selected, and then their MICs against S. aureus were determined interfered with different concentrations of menaquinone-4 (MK-4) and the MKs extracted from S. aureus. The results showed that the greater the antibacterial activities of plant flavonoids were, the more greatly their antibacterial activities decreased along with the increase in the interfering concentrations of MK-4 (from 2 to 256 µg/mL) and the MK extract (from 4 to 512 µg/mL), while those with the MICs equal to or more than 512 µg/mL decreased a little or remained unchanged. In particular, under the interference of MK-4 (256 µg/mL) and the MK extract (512 µg/mL), the MICs of α-mangostin, a compound with the greatest inhibitory activity to S. aureus out of these twelve plant flavonoids, increased by 16 times and 8 to 16 times, respectively. Based on the above, it was proposed that the quinone pool is a key target of plant flavonoids inhibiting Gram-positive bacteria, and which likely involves multiple mechanisms including some enzyme and non-enzyme inhibitions.

The synergy of tea tree oil nano-emulsion and antibiotics against multidrug-resistant bacteria.

AIMS: We determined the synergistic effects of tea tree essential oil nano-emulsion (nanoTTO) and antibiotics against multidrug-resistant (MDR) bacteria in vitro and in vivo. Then, the underlying mechanism of action of nanoTTO was investigated. METHODS AND RESULTS: Minimum inhibitory concentrations and fractional inhibitory concentration index (FICI) were determined. The transepithelial electrical resistance (TEER) and the expression of tight junction (TJ) protein of IPEC-J2 cells were measured to determine the in vitro efficacy of nanoTTO in combination with antibiotics. A mouse intestinal infection model evaluated the in vivo synergistic efficacy. Proteome, adhesion assays, quantitative real-time PCR, and scanning electron microscopy were used to explore the underlying mechanisms. Results showed that nanoTTO was synergistic (FICI ≤ 0.5) or partial synergistic (0.5 < FICI < 1) with antibiotics against MDR Gram-positive and Gram-negative bacteria strains. Moreover, combinations increased the TEER values and the TJ protein expression of IPEC-J2 cells infected with MDR Escherichia coli. The in vivo study showed that the combination of nanoTTO and amoxicillin improved the relative weight gain and maintained the structural integrity of intestinal barriers. Proteome showed that type 1 fimbriae d-mannose specific adhesin of E. coli was downregulated by nanoTTO. Then, nanoTTO reduced bacterial adhesion and invasion and inhibited the mRNA expression of fimC, fimG, and fliC, and disrupted bacterial membranes.

Improvement of the optical, photocatalytic and antibacterial properties of ZnO semiconductor nanoparticles using different pepper aqueous extracts.

Peppers are fruits that grow on plants of the genus Capsicum and are popular for their use in gastronomy as a condiment and for their anti-inflammatory and anti-cancer properties due to their phytocompounds such as flavonoids, polyphenols, or alkaloids. Semiconductor zinc oxide (ZnO) nanoparticles (NPs) were synthesized using a green approach employing natural aqueous extracts of several varieties of peppers (jalapeño, morita, and ghost). The obtained NPs were characterized by different techniques, and their photocatalytic and antibacterial activity was studied. The signal at 620 cm-1 in the FTIR spectra belonging to the Zn-O bond, the appearance of the main peaks of a hexagonal wurtzite structure in the XRD pattern, and the characteristic signals in the UV-Vis spectra confirm the correct formation of ZnO NPs. The photocatalytic activity was analyzed against Methylene Blue (MB), Rhodamine B (RB), and Methyl Orange (MO) under UV and sunlight. All syntheses were able to degrade more than 93% of the pollutants under UV light. Antibacterial assays were performed against gram-positive and gram-negative bacteria. All syntheses exhibited antibacterial activity against all bacteria and maximum growth inhibition against Bacillus subtilis. The prominent results demonstrate that natural aqueous extracts obtained from peppers can be used to synthesize ZnO NPs with photocatalytic and biomedical applications.

An osteogenic, antibacterial, and anti-inflammatory nanocomposite hydrogel platform to accelerate bone reconstruction.

Fabricating an organic-inorganic nanocomposite hydrogel platform with antibacterial, anti-inflammatory, and osteoinductive properties that mimic bone extracellular matrix composition is decisive for guiding bone development in orthopedic practice. Despite significant progress in developing hydrogels for tissue repair, little attention has been paid to replicating the natural bone ECM microenvironments and addressing the importance of anti-inflammatory agents during osteogenesis. Herein, we developed ciprofloxacin and dexamethasone loaded strontium (Sr) and/or iron (Fe) substituted hydroxyapatite (HAp) nanomaterials precipitated in collagen (Col) to construct a multifunctional bioactive nanocomposite hydrogel platform to prevent inflammation and bacterial adhesion, leading to augmenting bone development in the defect site. The fabricated nanocomposite hydrogels (Sr:HAp-Col, Fe:HAp-Col, and Sr/Fe:HAp-Col) were physicochemically characterized and demonstrated high loading and prolonged drug release, and excellent antibacterial activity against Gram-positive and Gram-negative bacteria. In in vitro experiments, the Sr/Fe:HAp-Col sample exhibited enhanced bioactivity against the preosteoblast MC3T3-E1 cell line, with high alkaline phosphatase and bone-like inorganic calcium deposition, as well as increased gene expression of osteogenesis-related differentiation markers, including OPN, OCN, and RUNX2. Furthermore, in vivo experiments revealed that the Sr/Fe:HAp-Col matrix degraded over time by controlling the release of ions into the body, without causing acute inflammation at the implanted site or in the blood serum, or in the internal organs, including the heart, lungs, liver, and kidney of the Sprague-Dawley rat model. The micro-CT scan and histological examination showed high bone mineral density and more mature bone formation at the nanocomposite hydrogel implanted site associated with the ColMA hydrogel in the femur defect of the rat model. The strategy of applying collagen hydrogel supplemented with HAp to bone regeneration is promising due to its ability to mimic the natural bone ECM. Overall, the developed bioactive nanocomposite hydrogel may have great potential not only in bone regeneration but also in repairing nonunion-infected defects of other tissues.