Significant Antibacterial Activity Research Articles

Metallic Gallium Droplets Exhibit Poor Antibacterial Properties.

The rise of antibiotic resistance in pathogenic bacteria requires new therapeutics to be developed. Several metallic nanoparticles such as those made from silver, copper, and zinc have shown significant antibacterial activity, in part due to metal ion leaching. Ga3+ containing compounds have also been shown to have antibacterial properties. Accordingly, it is estimated that metallic Ga droplets may be antibacterial, and some studies to date have confirmed this. Here, multiple concentrations of Ga droplets were tested against the antibiotic resistant Gram-positive bacteria methicillin-resistantStaphylococcus aureus (MRSA) and the Gram-negative bacteria Pseudomonas aeruginosa (P. aeruginosa) Despite a high concentration (2 mg/mL), Ga droplets had only modest antibacterial activity against both bacteria after 24 h of interaction. Finally, we demonstrated that Ga droplets were easily functionalized through a galvanic replacement reaction to develop antibacterial particles with copper and silver demonstrating a total detectable reduction of MRSA and >96% reduction ofP. aeruginosa. Altogether, these results contradict previous literature and show that Ga droplets demonstrate no antibacterial activity at concentrations comparable to those of conventional antibiotics and well-established antibacterial nanomaterials and only modest antibacterial activity at very high concentrations. However, we demonstrate that their antibacterial activity can be easily enhanced by functionalization.

Nanocrystal engineering: Unraveling bioactivities and augmented photocatalytic degradation of ZnO and Cr-doped ZnO via green and chemical synthesis routes

Herein, we focused on the combined investigation of physicochemical traits and multifunctional bioactivity of ZnO and Cr-doped ZnO NPs synthesized by chemical and green synthesis methods. The green synthesis was accomplished by utilizing Azadirachta Indica leaf extracts which include the phytochemicals azadirachtin and nimbolide function as prominent therapeutic agents in diagnosis. The XRD and TEM analysis evidences all the prepared NPs exhibit hexagonal wurtzite structure, and the change in crystallinity of ZnO NPs with Cr substitution has been examined. The optical properties show that Cr inclusion effectively changes the optical band gap of pure ZnO NPs, confirming the quantum confinement effect. The synthesized NPs were employed to investigate photocatalytic degradation of Rhodamine B (Rh B) dye in an aqueous environment under UV irradiation. The Rh-B dye effectively degraded within 180 min in the presence of synthesized nano catalyst at room temperature. Further, the synthesized NPs were subjected to investigate their bio-potency for microbicidal and cytotoxicity properties. The biosynthesized Cr-ZnO NPs exhibit significant cytotoxicity against A-549 lung cancer cells with the lowest IC50 value (21.79 µg/ml) and also demonstrate good antioxidant activity with the highest percentage of inhibition 81.23 % as measured by the DPPH scavenging assay in contrast to other NPs. In addition, the chemically synthesized Cr-ZnO NPs found the highest inhibition activity (90.78 %) for antidiabetic efficiency of Alpha-amylase enzyme assay and also shows significant antibacterial activities with a higher zone of inhibition (17 mm) against gram-positive Bacillus cereus over other samples. Thus, this study highlights ZnO NPs versatile attributes, paving the way for promising biomedical and environmental uses.

Green synthesis of silver nitrate (AgNO) mediated herbal antimicrobial aqueous extracts of Ocimum basilicum (Basil Leaves)

Green antimicrobial herbal preparations have emerged as cost effective, non-toxic and sustainable approach that involves the use of eco-friendly and non-toxic plant herbs and spices extracts. Green synthesis of silver-treated herbal extracts of Ocimum basilicum (basil leaves extracts) is well known for its safe and cost-effective approach due to having antimicrobial activity to treat various influenza like symptoms, antistress and antidepressant properties. Herbal plant leaf extracts have also been reported to contain an active reducing agent that can reduce metal ions to synthesize biogenic metal nanoparticles. Silver itself, is well reported for their bactericidal properties and also enhance antimicrobial properties when used to prepare biogenic silver nanoparticles from herbal and other biological sources. Hence, we prepared silver nitrate (AgNO) mediated herbal formulations of (basil extracts) that showed significant antibacterial activity against gram-negative bacteria, Escherichia coli BL21 strain. Moreover, this green approach can be more promising to prepare antimicrobial of silver-treated formulations using Ocimum basilicum extracts. It might be safe and cost effective herbal based preparations including nanosuspensions that can further proposed for clinical practices to treat various microbial pathogenesis.

Growth, Optical, Thermal, Antibacterial Activity and Computational Study of Highly Efficient Organic NLO Crystal: 2‐Amino‐1‐methyl‐4‐oxo‐4, 5‐dihydro‐1H‐imidazol‐3‐ium 4‐methyl‐benzene‐sulfonate

AbstractA good organic single crystal of 2‐Amino‐1‐methyl‐4‐oxo‐4, 5‐di‐hydro‐1H‐imidazol‐3‐ium 4‐methyl‐benzene‐sulfonate (2ADPTS) is grown by slow evaporation technique, and the orthorhombic system with noncentrosymmetric space group (P212121) is corroborated by single‐crystal X‐ray diffraction analysis. The structural parameters of the 2ADPTS crystal are investigated and weighted up with the theoretical interpretation. The Hydrogen–Hydrogen interaction with (43.6%) in 2ADPTS promotes crystal structure packing stabilization. The presence of various functional groups and chemical composition of the 2ADPTS compound is identified by FTIR and FT‐Raman spectroscopy. The natural bond orbital evaluation interprets all the possible hydrogen bonding interactions and charge delocalizations in the crystal structure. Thermal analysis confirmed the thermal stability of the 2ADPTS crystal. The absorption spectrum of the 2ADPTS crystal is recorded using UV–Vis spectroscopy. The third‐order nonlinear property of the 2ADPTS crystal is confirmed by using the Z‐scan technique. The higher significant antibacterial activity of 2ADPTS is carried out by the standard Kirby‐Bauer test against four pathogenic bacteria commonly called the agar well diffusion process.

Pitsubcosides M−S: Novel antibacterial cadinane sesquiterpenoid glycoside esters from Pittosporum subulisepalum

A previous study on Pittosporum subulisepalum led to twelve novel, antibacterial eudesmane sesquiterpenoid glycoside esters (ESGEs). To continue the work on P. subulisepalum, this study focused on the exploration of cadinane sesquiterpenoid glycoside esters (CSGEs) with antibacterial activities and their mechanism of actions. Chemical exploration of the ethyl acetate (EtOAc) soluble phase of the leaves and stems of P. subulisepalum resulted in seven previously unreported cadinane sesquiterpenoid glycosides (CSGs), pitsubcosides M-S (1 −7), along with three known analogs. Based on one- and two-dimensional NMR (1D and 2D NMR), HRESIMS, and experimental/calculated electronic circular dichroism (ECD) spectroscopic analyses, the structures of the isolated compounds were elucidated. The novelty of these sesquiterpenoid glycosides was characterized by the highly esterified glycoside moieties. Compounds 1 − 5 exhibited marked inhibitory effects on Bacillus subtilis, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Bacillus cereus, Erwinia carotovora, and Pseudomonas syringae pv. actinidiae with the minimum inhibitory concentration (MIC) values of 3.13 μM− 50 μM. Of these, compounds 1 − 2 displayed significant antibacterial activity against B. subtilis (MIC = 3.13 and 6.25 μM). The live masses and the biofilms of B. subtilis were quantified after being treated with compounds 1 and 2. The preliminary antibacterial mechanism was revealed as to prevent bacterial biofilm formation or to destroy the formed cell membranes. These results indicated that CSGEs from P. subulisepalum are potential antibacterial lead agents.

Chemical compositions and antimicrobial activities of three lemon odor essential oils of Cupressus macrocarpa, Cymbopogon citratus. and Citrus limon

ABSTRACT Infectious diseases caused by bacteria, fungi and viruses are globally of major concern. Plant essential oils produced by various differentiated structures possess varied properties as significant antiseptic, antibacterial, antifungal, antiviral, antioxidant, anti-parasitic and insecticidal activities. The essential oil of three lemon odor plants; Cupressus macrocarpa, Cymbopogon citratus and Citrus limon were isolated and evaluated for their antimicrobial activities. The analysis of essential oil components of C. macrocarpa by GC-MS revealed D-limonene (38.00%) as the major component followed by citral (9.72%), carveol (6.86%) and citronellal (5.35%). Analyses of the essential oil of C. citratus resulted in the identification of pseudolimonene (19.2%) as the most abundant component followed by D-limonene (12.34%), Ɣ-terpinene (10.89%), citronellol (9.58%), sabinene hydrate (9.24%), (+)-2-bornanone (8.29%) and α-terpinolene (5.53%). Also, GC-MS detected neral dimethyl acetal (41.56%) was the main component of C. limon EO with carveol (12.39%) and citral (11.21%). A study of the antimicrobial activity of the three essential oils against E. coli, Proteus mirabilis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus. and Candida albicans has been evaluated and revealed that C. citratus EO had antibacterial activity against gram-positive organisms and C. limon EO exhibited the strongest antifungal activity against Candida albicans.

Antibacterial and photocatalytic potential of bioactive compounds extracted from freshwater microalgae species (Spirogyra and Ocillatoria): A comparative analysis

Water pollution by pathogenic bacteria and organic dyes poses potential health hazards for human and aquatic life. This study aims to explore the potential of bioactive compounds extracted from two microalgae species (Spirogyra and Ocillatoria) for water pollution control. The optimization of the extraction process for bioactive compounds resulted in the highest yield at 25 min for Spirogyra and 30 min for Ocillatotia species. Further, the extracted bioactive compounds were analyzed using Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectroscopy (GC–MS). The bioactive compounds exhibited significant antibacterial activity against gram-positive and gram-negative bacteria. Notably, Spirogyra species exhibited a higher zone of inhibition (19.5–20.7 mm) than Ocillatoria species (17.0–18.0 mm) against both gram-positive and gram-negative bacterial strains. Furthermore, the photocatalytic potential of these bioactive compounds was examined by assessing the photodegradation of methylene blue (MB) and crystal violet (CV) dyes under different light sources. The findings revealed that Spirogyra species exhibited better photocatalytic activity than Ocillatoria species for MB and CV. For MB, 89.75 %, 77.82 % and 63.54 % were photodegraded when exposed to UV light, sunlight and visible light using Spirogyra extract, compared to 84.90 %, 74.70 % and 58.30 % by Ocillatoria extract. Regarding CV, Spirogyra extract achieved photodegradation efficiency of 88.94 %, 76.59 % and 64.50 % under UV light, sunlight and visible light, higher than 83.60 %, 73.60 % and 57.70 % by Ocillatoria extract. Both Spirogyra and Ocillatoria species demonstrated the best performance for dye photodegradation under UV irradiation, demonstrating great potential for nature-based water treatment.

New Insights into Bioactive Compounds of Wild-Growing Medicinal Plants

Plants contain bioactive substances and secondary metabolites that have a variety of functions, including antibacterial, antioxidant, anti-inflammatory, and anticancer activities. In this study, the content of bioactive compounds in five medicinal plants was determined, i.e., Plantago major L., Armoracia rusticana, Hypericum perforatum L., Rumex acetosa L., and Urtica dioica L., from 38 locations. Additionally, the antimicrobial effect of extracts of bioactive compounds from the above-mentioned plants was checked. The experiment used an original method of extracting bioactive compounds. Purpose of the research: the assessment of antimicrobial activity and chemical characterization of extracts obtained using our own method of isolating bioactive compounds from green parts of medical plants in Poland. Based on the research, the presence of bioactive compounds, i.e., phenolic acids and flavonoids, was found in the tested plant extracts. The results of this study suggest that the geographic parameters of the locations where these plants grow have different effects on their biochemical composition and biological activity. The results showed that all tested plants had significant antibacterial activities. Rumex acetose L. showed the highest antimicrobial activity against Escherichia coli and Salmonella enteritidis. These studies supplement the existing literature on the subject with information about the antimicrobial properties of the tested plant extracts that can be used in herbal medicine. The results have significant implications for the pharmaceutical, nutraceutical, and cosmetic sectors, establishing a foundation for future research in this area.

Two New Compounds from the Endophytic Fungi of Dryopteris crassirhizoma and Their Antimicrobial Activities.

Two endophytic fungi Trichoderma afroharzianum (HP-3) and Alternaria alstroemeriae (HP-7) were isolated and purified from the fresh root of Dryopteris crassirhizoma. Chemical investigation of the two fungi resulted in the isolation of two new phenols 2,4-dihydroxy-3-farnesyl-5-methoxy benzoic acid (1) and 2-hydroxyphenethyl 2-phenylacetate (2), together with 22 known compounds. Their structures were elucidated by NMR, UV, IR, HRESIMS, and comparison to the literature data. Compounds 15 and 16 showed significant antibacterial activity against Micrococcus lysodeikticus with MIC value of 6.25 μg/mL, while 8 and 14 displayed moderate inhibitory activities against several plant pathogenic fungi and clinically important bacterial strains. This is the first study to report the isolation, identification, and antimicrobial properties of metabolites from endophytic fungi of D. crassirhizoma. Our findings may provide lead compounds for the development of new antibacterial agents.

Antimicrobial Activity of Stilbenes from Bletilla striata against Cutibacterium acnes and Its Effect on Cell Membrane.

The abnormal proliferation of Cutibacterium acnes is the main cause of acne vulgaris. Natural antibacterial plant extracts have gained great interest due to the efficacy and safety of their use in skin care products. Bletilla striata is a common externally used traditional Chinese medicine, and several of its isolated stilbenes were reported to exhibit good antibacterial activity. In this study, the antimicrobial activity of stilbenes from B. striata (BSS) against C. acnes and its potential effect on cell membrane were elucidated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), bacterial growth curve, adenosine triphosphate (ATP) levels, membrane potential (MP), and the expression of genes related to fatty acid biosynthesis in the cell membrane. In addition, the morphological changes in C. acnes by BSS were observed using transmission electron microscopy (TEM). Experimentally, we verified that BSS possessed significant antibacterial activity against C. acnes, with an MIC and MBC of 15.62 μg/mL and 62.5 μg/mL, respectively. The growth curve indicated that BSS at 2 MIC, MIC, 1/2 MIC, and 1/4 MIC concentrations inhibited the growth of C. acnes. TEM images demonstrated that BSS at an MIC concentration disrupted the morphological structure and cell membrane in C. acnes. Furthermore, the BSS at the 2 MIC, MIC, and 1/2 MIC concentrations caused a decrease in the intracellular ATP levels and the depolarization of the cell membrane as well as BSS at an MIC concentration inhibited the expression of fatty acid biosynthesis-associated genes. In conclusion, BSS could exert good antimicrobial activity by interfering with cell membrane in C. acnes, which have the potential to be developed as a natural antiacne additive.

A new starch based wound dressing modified by graphene oxide/silver nanowire nanoparticles

Considering the special effect of wound treatment in the field of medicine, antibacterial wound dressings preparation is one of the main challenges in successful wound healing. In this research, a starch (St)/polyvinyl alcohol (PVA) nanofiberous mat modified with graphene oxide (GO)-silver nanowire (AgNW) hybrid was fabricated. Initially, silver nanowires were synthesized by the polyol method, then GO-AgNW nanoparticle was prepared as a biocompatible and antibacterial biofilm. Reducing the diameter of nanofibers due to the addition of starch and GO-AgNW nanoparticles leads to fibroblast proliferation, increased collagen secretion, reduced inflammation and wound closure. Nanofibrous mats showed significant antibacterial activity against Staphylococcus aureus and Escherichia coli microorganisms. The largest zone of bacterial inhibition was obtained for Starch/PVA nanofibers containing 8% GO-AgNWs hybrid (27.11 and 24.62 mm). The use of GO-AgNW nanoparticles without drugs is an important point due to the strong antibacterial property of silver nanowire. The measured contact angle of nanofibrous mats was in the range of 57.8° as a desirable level of hydrophilicity for wound dressings. The degree of swelling obtained about 491.12%, and the water vapor transmission rate of 2549 ± 36 (g/m2.day) as a proof for accelerating wound healing. Finally, the results indicated that St/PVA/GO-AgNWs composite electrospun fibers could be a suitable candidate for the treatment of infectious wounds, surgical wounds, minor burns, etc.

Evaluation of antimicrobial and antioxidant activity of zinc oxide nanoparticles biosynthesized with Ziziphus spina-christi leaf extracts

Background: Due to their simplicity, eco-friendliness, availability and non-toxicity, the greener fabrication of metal and metal oxide nanoparticles has been a highly attractive research area over the last decade. Aim: This study aimed to assess the antioxidant and antimicrobial activities of the green synthesized zinc oxide nanoparticles (ZnO-NPs) using an aqueous leaf extract of Ziziphus spina-christi. Method: The antioxidant property of ZnO-NPs was analyzed by the α, α-diphenyl-β-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). Additionally, the diffusion agar method assessed the antimicrobial activities against bacteria and fungi. Results: ZnO-NPs synthesized by Z. spina-christi had shown promising H2O2 and DPPH free radical scavenging actions compared to vitamin C. The ZnO-NPs exhibited significant antibacterial activity against the tested bacteria with various susceptibility as a concentration-dependent effect. The largest zone of inhibition for Staphylococcus aureus (S. aureus) was observed (36 ± 2 mm) compared to Escherichia coli (E. coli) (15 ± 2 mm) by the same concentration of ZnO-NPs. The ZnO-NPs showed remarkable antifungal activity against Aspergillus niger. Conclusion: It can be concluded that, ZnO-NP have been imposed as suitable antimicrobial agent being able to combat both S. aureus and E. coli in vitro.

Chemical Processing and Various Applications of Starch Extracted from Avocado Seeds: A Step towards Sustainable Food Waste Management

AbstractA sustainable food waste management methodology has been proposed for the discarded seeds of avocados (Persia Americana mill) where starch is extracted from the seeds through a microwave assisted heating process using only water, and this starch is modified through chemical treatment into acrylamide starch and carboxymethylated starch. Native as well as modified variants of starch are characterized using fourier transform infrared spectroscopy (FTIR), which confirms the extraction of native starch and its chemical modification. The extracted and modified variants are then analyzed for their antioxidant properties against oxidative stress by checking their scavenging activity against DPPH (2,2‐diphenyl‐1‐picrylhydrazyl). Moreover, the three variants of starch are tested for hemolytic activity in order to determine whether they are harmful to human blood, finally these three variants are checked for their activity against Escherichia coli and Staphylococcus bacteria, the root cause in most cases of bacterial infection in humans. The starch variants are found to be excellent antioxidants and all three starch variants indicate a very low hemolytic activity and significant antibacterial activity in comparison to widely used antibiotic Ciproflaxin. All these results indicate that avocado seeds waste can be an excellent non‐conventional source of starch that can be used for sustainable applications in food and pharmaceutical industries.

In-situ green synthesis of copper tannic acid framework in the presence of graphene quantum dots: Improved colloidal and antibacterial properties

This work reports the preparation of a copper tannic acid MOF (CuTA) and graphene quantum dot (GQD) nanocomposite, GQD/CuTA, by a simple, environmentally friendly, and inexpensive method with exceptionally enhanced antibacterial properties. To end this, GQDs were first fabricated from citric acid using a neoteric, simple and straightforward hydrolysis approach and followed by they effectively anchor MOF nanoparticles (CuTA) by a green hydrothermal in situ synthesizing method. The constructed GQD/CuTA nanomaterials were characterized and validated using XRD, FT-IR, TEM, DLS, UV–vis, and PL techniques. Significant antibacterial activity against E. coli bacteria for both CuTA and GQD/CuTA (0 CFU/mL) and S. aureus bacteria for CuTA and GQD/CuTA (300 and 40 CFU/mL) was observed for the GQD/CuTA nanocomposite. The MTT assay showed good cytocompatibility for the GQD/CuTA nanocomposite against human dermal fibroblast cells (HFF-2). The result suggests that the synthesized GQD/CuTA nanocomposite with improved colloidal and antibacterial properties has the potential to be used as a safe photoluminescent nanoplatform with strong antimicrobial activity.

The potential of Spirulina platensis to substitute antibiotics in Japanese quail diets: impacts on growth, carcass traits, antioxidant status, blood biochemical parameters, and cecal microorganisms

The development of antibiotic-resistant microorganisms prompted the investigation of possible antibiotic substitutes. As a result, the purpose of the current study is to assess the effect of dietary Spirulina platensis extract as an antibiotic alternative on Japanese quail (Coturnix japonica) growth, antioxidant status, blood parameters, and cecal microorganisms. There was a total of 150 Japanese quails used in this study, divided equally among 5 experimental groups (10 birds per group with 3 replicates): group 1 (G1) received a basal diet without any S. platensis extract, group 2 (G2) received a basal diet supplemented with 1 mL S. platensis extract/kg, group 3 (G3) received a basal diet supplemented with 2 mL S. platensis extract/kg, group 4 (G4) received a basal diet supplemented with 3 mL S. platensis extract/kg, and group 5 (G5) received a basal diet supplemented with 4 mL S. platensis extract/kg from d 7 until d 35. The results showed that compared to the control birds in G1, Japanese quail supplemented with 4 mL of S. platensis extract/kg of diet (G5) had significantly better live body weight, body weight gain, feed intake, feed conversion ratio, digestive enzymes, blood parameters, liver and kidney functions, lipid profile, antioxidant profile, immunological parameters, and cecal microorganism's count. There were no significant changes in the percentage of carcasses, liver, and total giblets among all the 5 groups. Only gizzard percentage showed a significant increase in G2 compared to birds in G1. In addition, intestinal pH showed a significant drop in G2 and G5 compared to birds in G1. After cooking the quail meat, the juiciness and tenderness increased as S. platensis extract levels increased, whereas aroma and taste declined slightly as S. platensis extract levels increased. Furthermore, when a high concentration of S. platensis extract was used, the lightness of the meat reduced while its redness and yellowness increased. The disk diffusion assay showed that S. platensis extract had significant antibacterial activity against Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, and Salmonella typhi, with inhibition zones ranging from 16 to 42 mm. This activity may be attributable to the volatile chemicals in S. platensis extract, of which Geosmin and 2-methylisoborneol are the primary components. In the diet of Japanese quails, it is possible to draw the conclusion that the extract of S. platensis can be utilized as a feed additive and as an alternative to antibiotics.

Anti-infective Efficacy of Duloxetine against Catheter-Associated Urinary Tract Infections Caused by Gram-Positive Bacteria.

Catheter-associated urinary tract infections (CAUTIs) frequently occur following the insertion of catheters in hospitalized patients, often leading to severe clinical complications. These complications are exacerbated by biofilm-forming organisms such as Staphylococcus aureus, contributing to the emergence of multidrug-resistant (MDR) strains, which complicates treatment strategies. This study aims to investigate the antibacterial, antibiofilm, and antiadhesive properties of duloxetine against S. aureus in the context of CAUTI. Our findings demonstrate that duloxetine exhibits significant antibacterial activity, as evidenced by the agar diffusion method. A minimal inhibitory concentration (MIC) of 37.5 μg/mL was established using the microdilution method. Notably, duloxetine displayed inhibitory effects against biofilm formation on polystyrene surfaces up to its MIC level, as demonstrated by the crystal violet method. Intriguingly, the study also revealed that duloxetine could prevent biofilm formation at lower concentrations and reduce mature biofilms, as confirmed by scanning electron microscopy (SEM) and quantitative biofilm assays. Furthermore, duloxetine-coated silicone catheter tubes exhibited antibacterial properties against S. aureus in a bladder model, visualized by confocal laser scanning microscopy (CLSM) and corroborated through FDA and PI staining, highlighting noticeable morphological changes in S. aureus post-treatment. In conclusion, this study presents duloxetine as a promising alternative agent with antibacterial and antiadhesive properties against S. aureus in the prevention and management of CAUTI, warranting further exploration in the clinical setting.

Span 60/Cholesterol Niosomal Formulation as a Suitable Vehicle for Gallic Acid Delivery with Potent In Vitro Antibacterial, Antimelanoma, and Anti-Tyrosinase Activity.

Natural compounds such as gallic acid (GA) have attracted more attention in cosmetic and pharmaceutical skin care products. However, the low solubility and poor stability of GA have limited its application. This study aimed to synthesize and characterize the GA niosomal dispersion (GAN) and investigate the potential of an optimal formulation as a skin drug delivery system for GA. For this purpose, GAN formulations were synthesized using the thin layer evaporation method with different molar ratios of Tween 60/Span 60, along with a constant molar ratio of polyethylene glycol 4000 (PEG-4000) and cholesterol in a methanol and chloroform solvent (1:4 v/v). The physicochemical properties of nanosystems in terms of size, zeta potential, drug entrapment, drug release, morphology, and system-drug interaction were characterized using different methods. In addition, in vitro cytotoxicity, anti-tyrosinase activity, and antibacterial activity were evaluated by MTT assay, the spectrophotometric method, and micro-well dilution assay. All formulations revealed a size of 80-276 nm, polydispersity index (PDI) values below 0.35, and zeta potential values below-9.7 mV. F2 was selected as the optimal formulation due to its smaller size and high stability. The optimal formulation of GAN (F2) was as follows: a 1:1 molar ratio of Span 60 to cholesterol and 1.5 mM GA. The release of the F2 drug showed a biphasic pattern, which was fast in the first 12 h until 58% was released. Our results showed the high antibacterial activity of GAN against Escherichia coli and Pseudomonas aeruginosa. The MTT assay showed that GA encapsulation increased its effect on B6F10 cancer cells. The F2 formulation exhibited potent anti-tyrosinase activity and inhibited melanin synthesis. These findings suggest that it can be used in dermatological skin care products in the cosmetic and pharmaceutical industries due to its significant antibacterial, anti-melanoma, and anti-tyrosinase activity.

Bioinspired total synthesis and biological activity of Pegaharine A.

Phytopathogens cause various diseases by parasitizing crops, reducing crop yield and resulting in substantial economic losses in agricultural production. A novel type isolated from the perennial herbaceous Peganum harmala L. seeds, β-carboline alkaloids pegaharine A (PA), has become a hot topic in developing plant-originated green pesticides owing to their significant physiological activities. A scalable bioinspired total synthesis of PA is accomplished in the present work. The systematical biological assay study showed that PA exhibited moderate inhibitory activity against nine tested plant pathogenic fungi and showed significant inhibitory activity in vitro against the three tested plant pathogenic bacteria. Most noteworthy is the inhibitory rates of PA on Xanthomonas oryzae pv. oryzae (Xoo), X. oryzae pv. oryzicola (Xoc) and X. axonopodis pv. citri (Xac) of 93.6%, 92.1% and 86.1%, respectively, which are better than the control drug, bismerthiazol (63.4%, 61.2% and 53.7% at 100 μg mL-1 concentration). Furthermore, the EC50 value of PA against Xoo, Xoc and Xac was 52.2, 60.0 and 65.1 μg mL-1 , respectively, superior to 72.9, 64.2 and 70.1 μg mL-1 of the control drug. Moreover, the anti-Xoo mechanistic studies revealed that PA exerted its antibacterial effects by increasing the permeability of the bacterial membrane, reducing the extracellular polysaccharide content and inducing morphological changes in bacterial cells. A novel β-carboline alkaloid, PA, was prepared by biomimetic total synthesis. Its significant antibacterial activity was closely related to the permeation of bacterial cell membranes, which was confirmed by anti-Xoo mechanistic studies. More importantly, the structure could be regarded as a model for developing novel bactericides. © 2023 Society of Chemical Industry.

Upscaling of Electrospinning Technology and the Application of Functionalized PVDF-HFP@TiO2 Electrospun Nanofibers for the Rapid Photocatalytic Deactivation of Bacteria on Advanced Face Masks.

In recent years, Electrospinning (ES) has been revealed to be a straightforward and innovative approach to manufacture functionalized nanofiber-based membranes with high filtering performance against fine Particulate Matter (PM) and proper bioactive properties. These qualities are useful for tackling current issues from bacterial contamination on Personal Protective Equipment (PPE) surfaces to the reusability of both disposable single-use face masks and respirator filters. Despite the fact that the conventional ES process can be upscaled to promote a high-rate nanofiber production, the number of research works on the design of hybrid materials embedded in electrospun membranes for face mask application is still low and has mainly been carried out at the laboratory scale. In this work, a multi-needle ES was employed in a continuous processing for the manufacturing of both pristine Poly (Vinylidene Fluoride-co-Hexafluoropropylene) (PVDF-HFP) nanofibers and functionalized membrane ones embedded with TiO2 Nanoparticles (NPs) (PVDF-HFP@TiO2). The nanofibers were collected on Polyethylene Terephthalate (PET) nonwoven spunbond fabric and characterized by using Scanning Electron Microscopy and Energy Dispersive X-ray (SEM-EDX), Raman spectroscopy, and Atomic Force Microscopy (AFM) analysis. The photocatalytic study performed on the electrospun membranes proved that the PVDF-HFP@TiO2 nanofibers provide a significant antibacterial activity for both Staphylococcus aureus (~94%) and Pseudomonas aeruginosa (~85%), after only 5 min of exposure to a UV-A light source. In addition, the PVDF-HFP@TiO2 nanofibers exhibit high filtration efficiency against submicron particles (~99%) and a low pressure drop (~3 mbar), in accordance with the standard required for Filtering Face Piece masks (FFPs). Therefore, these results aim to provide a real perspective on producing electrospun polymer-based nanotextiles with self-sterilizing properties for the implementation of advanced face masks on a large scale.

Synthesis of Silver Nanoparticles in <i>Psidium Guajava</i> (Guava) Leaf Extract for Antibacterial Textiles

Textiles, an integral part of everyday clothing, are exposed to varied sources of dirt, leading to bacterial accumulation and cross-contamination. As such, antibacterial textile has become a widespread research interest. One method to create antibacterial textiles is the incorporation of silver nanoparticles (NPs) due to their efficacy in stopping multi-drug resistant (MDR) bacteria. However, most synthesis techniques in producing silver NPs are complex and expensive. Guava leaf extracts (GE) have a high quantity of metabolites and carbohydrates that can reduce and stabilize silver (Ag) ions. Guava leaves also have an innate antimicrobial property, making them highly compatible with biomedical applications. This study synthesized Ag NPs using Ag nitrate and Ag acetate as Ag precursors and guava leaves extract as reducing agents to create an antimicrobial fabric. The green synthesis successfully produced spherical Ag NPs with mean diameters around 24 nm. Energy-dispersive X-ray spectroscopy (EDX) analysis confirmed the formation of Ag NPs after the reaction. The Ag NPs were deposited on cotton fabrics, which showed significant antibacterial activity even after 5 washings. Generally, the Ag NPs synthesized with larger amounts of guava leaves extract showed larger clearing zones, indicating better antimicrobial activity.