Potent Antimicrobial Effects Research Articles

Antibacterial and Anti-Inflammatory Activities of Thymus vulgaris Essential Oil Nanoemulsion on Acne Vulgaris.

Antibiotics are frequently used in acne treatment and their prolonged use has led to an emergence of resistance. This study aimed to investigate the use of natural antimicrobials as an alternative therapy. The antimicrobial and anti-inflammatory activities of five commonly used essential oils (EOs) (tea tree, clove, thyme, mentha and basil EOs), and their possible mechanisms of action against Cutibacterium acnes and Staphylococcus epidermidis, were explored. The effect of the most potent EO on membrane permeability was elucidated and its anti-inflammatory action, when formulated as nanoemulsion, was tested in an in vivo acne model. The in vitro studies showed that thyme EO had the most potent antimicrobial and antibiofilm activity, with phenolics and terpenoids as main antimicrobial constituents of EO. Thyme EO affected cell membrane permeability of both bacterial species, evident by the detection of the leakage of intracellular ions and membrane integrity by the leakage of nucleic acids. Morphological alteration in bacterial cells was confirmed by transmission electron microscopy. Thyme EO nanoemulsion led to the suppression of an inflammatory response in acne animal models along with a bacterial load decrease and positive histopathological changes. Collectively, thyme EO nanoemulsion showed potent antimicrobial and anti-inflammatory effects compared to the reference antibiotics, suggesting its effectiveness as a natural alternative in acne treatment.

Antimicrobial Activity of Fruits and Vegetables Peels on Human Enteric Pathogen: A Review

Fruits and vegetables are widely employed in food production in India. Depending on their nature and cooking procedure, these products are consumed uncooked, half-cooked, or fully cooked, with or without peels. If these peel remnants are not further handled, they become garbage. But different studies conducted on peels revealed the presence of important metabolites, using the polar and carbohydrates, carotenoids, proteins, steroids, flavonoids, alkaloids, tannins, saponins, triterpenoids, and phlobatannin, coumarin, and other nonpolar solvent systems. These extracts are also having potent antimicrobial effects on enteric human pathogens. Various phytochemical elements have antibacterial, antioxidant, antiproliferative, and anti-inflammatory properties. etc. The current study examines the medicinal potential of Indian regional fruits and vegetable peels.

GC- MS analysis of Volatile Flavour Compounds from Cardamom Flavoured peanut milk and their Biological Activities

Peanut milk was prepared by roasting method (roasting for 5 mins followed by soaking for 3 hrs) in CO 6 peanut variety. In the present study volatile bioactive compounds in control and cardamom flavoured peanut milk were identified by GC – MS analysis and identified the rapeutical bioactive compounds present in cardamom flavoured peanut milk. Good quality peanut was weighed and roasted for 5 mins followed by soaking for 3 hrs. Then it was grinded with kernel and water ratio 3:1 and filtered. Palm sugar, cardamom flavour, antioxidant, stabilizer was added and homogenized. The developed flavoured peanut milk was double pasteurized at 85º C for 30 mins. The prepared samples were freeze dried and used for the analysis of volatile compounds. Volatile compounds in the samples were analyzed by GC –MS analysis with suitable solvent. From the results it could be inferred that, compared to control cardamom flavoured peanut milk had linoleic acid ethyl ester, squalene, isoxazole, 5-chloro-4-(2-phenylethyl)-, 9-Octadecenoic acid bioactive compounds. The identified compounds had potent antioxidant, antimicrobial, anticancer and anti-flammatory effects.

Antimicrobial Potential of Grape Seed Extract and MTA: A Comparative Experimental Study

AIM: This study aims to evaluate and compare the antibacterial potential of mineral trioxide aggregate (MTA) and grape seed extract (GSE) against Streptococcus mutans, Enterococcus faecalis, Staph aureus, Candida albicans, Lactobacillus spp., and Streptococcus sobrinus. HYPOTHESIS: We hypothesized that GSE could have potent antimicrobial effect against oral pathogens when compared to MTA. MATERIALS AND METHODS: MTA and GSE were utilized to determine the antibacterial effectiveness against S. mutans, E. faecalis, S. aureus, C. albicans, Lactobacillus spp. and S. sobrinus using the agar well diffusion test. The tested materials were used according to the manufacturer’s instructions and put into the prepared wells of agar plates; diluted inocula (105 and 106 CFU/ml) of the tested microorganism strains were also used. For bacteria, all plates were incubated at 37°C in anaerobic conditions, and for C. albicans, at 30°C. The inhibitory zones were determined after 3 days. A digital caliper was used to measure the diameter of bacterial inhibition zones surrounding each well to the nearest size in mm. RESULTS: GSE-created inhibition zones against all tested microorganisms except C. albicans, zones were significantly larger than MTA-created zones (p < 0.05). CONCLUSION: Both MTA and GSE showed antimicrobial effect against all tested microorganisms except C. albicans, which will pave the route to use GSE as a natural herbal substitute of MTA.

GC-MS-employed phytochemical characterization, synergistic antioxidant, and cytotoxic potential of Triphala methanol extract at non-equivalent ratios of its constituents

Triphala is a famous triherbal drug, comprising three herb fruits, including Terminalia chebula (Haritaki), Terminalia bellirica (Bibhitaki), and Phyllanthus emblica (Amalaki). It is enriched with vitamin C, polyphenols, flavonoids, sterols, saponins, etc., and is well-documented for its potent antioxidant, anticancer, chemoprotective, antimicrobial, and anti-inflammatory effects. This research was conducted to evaluate the synergistic antioxidative and cytotoxic potential of mixtures of the individual constituents of Triphala at their nonequivalent ratios along with the chemical characterization of individual constituents of Triphala to identify and quantify individual compounds. The antioxidative potential was measured using total antioxidant capacity (TAC), DPPH free radical scavenging assay, and total phenolic content (TPC) tests. The cytotoxic potential was assessed on brain cancer cells (N4X4) using MTT assay, and phytochemical characterization was performed by GS-MS analysis. Nonequivalent ratios of Triphala constituents exhibited significantly higher synergistic antioxidant and cytotoxic potential than the equivalent ratios of them. Moreover, the nonequivalent ratio where the quantity of Amalaki was doubled than the other two constituents showed the highest synergistic antioxidant and cytotoxic effect. GC-MS analysis of individual constituents of Triphala identified and quantified the presence of a wide array of compounds, and fatty acid, fatty acid ester, triterpene, and aminoglycoside remained the predominant class of compounds. Thus, it can be inferred that the observed bioactivities can be attributed to the phytocompounds characterized and extracts at the nonequivalent ratio of Triphala constituents where Amalaki is doubled can be more effective in treating oxidative degenerative diseases and glioblastoma.

The development of a novel ultrashort antimicrobial peptide nanoparticles with potent antimicrobial effect

Conventional antibiotics are facing significant microbial resistance, which has recently reached previously unnoticed critical levels. As a result of this situation, a large proportion of antimicrobial agents currently used in the clinic have significantly reduced therapeutic potential. Antimicrobial peptides (AMPs) may offer the medical community an alternative strategy to traditional antibiotics in the fight against microbial resistance. Current research efforts are focused on developing technologies that may reduce AMP toxicity while retaining their potent antimicrobial activity and possibly improving their delivery. The ionotropic gelation method was used to encapsulate a novel in-house designed potent ultrashort antimicrobial peptide (USAMP) into chitosan-based nanoparticles (CS-NPs) in this study. WRWRWR -CS-NPs were tested for antibacterial kinetics against two strains of Staphylococcus aureus for four days, and the developed WRWRWR -CS-NPs showed a 3-log decrease in the number of colonies when compared to CS-NP and a 5-log decrease when compared to control bacteria. Loaded WRWRWR into CS-NPs could represent an innovative approach to develop delivery systems based on NPs technology for achieving potent antimicrobial effects against multi-drug resistant and biofilm forming bacteria with negligible systemic toxicity and reduced synthetic costs that are obstructing the clinical development of AMPs generally.

Antibacterial activities of two potential peptides extracted from Polistes wattii Cameron, 1900 (Vespidae: Polistinae) wasp venom collected at Eastern Province, Saudi Arabia.

Alternatives of conventional antibiotics have become an urgent need to control drug-resistant bacteria. Therefore, search for new antibacterial agents has become a trend in several microbiological and pharmaceutical scientific works. Insects, one of the most successful and evolved species on earth is known to be an effective natural source of several medically useful chemicals including antibacterial agents. There is considerable evidence of using wasp venom against medical ailments in several parts of the world. In this work venom from Polistes wattii Cameron, 1900 collected from Eastern Province, Saudi Arabia was evaluated for its antibacterial activities. Such activity was tested against four pathogenic bacteria: two-gram positive Staphylococcus aureus (ATCC 25923) and Streptococcus mutans (RCMB 017(1) ATCC 25175) and two gram-negative (Salmonella typhimurium NCTC 12023 ATCC 14028 and Enterobacter cloacae (RCMB 001(1) ATCC 23355). Also, chemical characterization of wasp venom was done using HPLC and two isolated peptides were sequenced. The result indicates the potent anti-microbial effect of the venom against the four tested bacteria. The most sensitive bacteria were Staphylococcus aureus (ATCC 25923) and Streptococcus mutans (RCMB 017(1) ATCC 25175). The sequence of the two purified peptides indicates that they belong to mastoparan. The study results may pave way to use this wasp venom in future antibiotics especially in controlling skin infection by Staphylococcus aureus.

Improvement of the microbial quality, antioxidant activity, phenolic and flavonoid contents, and shelf life of smoked herring (Clupea harengus) during frozen storage by using chitosan edible coating

Smoked herring is a very popular traditional fish product widely consumed in Egypt. Nonetheless, rapid mould growth and lipid oxidation, with consequent short shelf life and loss of the essential characteristics, including the smoking color and flavor, are emerged as adverse problems during storage of this product. This study was aimed to improve the quality and lipid stability of smoked herring using chitosan coating. To achieve this goal, smoked herrings were collected from local producers and divided into 5 groups, including two controls (water-dipped and 0.5% lactic acid-dipped samples) and three treated groups (2%, 3% and 4% chitosan-coated samples) followed by storage at −18 °C for 3 months during which microbiological, physicochemical, and sensorial analyses, besides determination of phenolics, flavonoids, and the antioxidant activity were carried out. The results revealed that chitosan-coated (3% and 4%) samples exhibited more than 4 log 10 CFU/g reduction in aerobic plate count, along with complete suppression of psychrotrophic, Enterobacteriaceae, yeast and mould counts, which were all under the detectable levels (2 log 10 CFU/g). Chitosan improved and maintained the phenolic and flavonoid compounds along with the free radical scavenging activity in chitosan-coated smoked fish during frozen storage. Moreover, chitosan coating induced significant improvement of the physiochemical quality including; pH, total volatile base nitrogen, trimethylamine, thiobarbituric acid values, free fatty acid %, acid number, together with the sensory attributes, compared to control uncoated ones. The study concluded that chitosan coating can be a good choice for fish industry to overcome the problems that arise in smoked fish. • The first study determined phenolics and flavonoids in chitosan-coated smoked fish. • Chitosan improved and maintained phenolics and flavonoids in stored smoked herring. • Chitosan has a potent antimicrobial effect in smoked herring during frozen storage. • Chitosan exerted a strong antioxidant activities in frozen-stored smoked herring. • Chitosan improved the chemical & sensory quality of smoked herrings during storage.

Nanoreinforced biodegradable gelatin based active food packaging film for the enhancement of shelf life of tomatoes (Solanum lycopersicum L.)

The major chunk of fresh farm produce in world is wasted due to improper packaging and handling. The current study focuses on tailoring of properties of copper oxide (CuO) nanoparticles to make them fit in active food packaging applications. A facile customized co-precipitation approach was used for synthesis of gelatin stabilized Titanium (Ti)-doped CuO nanoparticles., Their physico-chemical properties, confirmed the reduction in size of nanoparticles after doping from 92 to 94 nm for pure CuO nanoparticles to 10–13 nm for Ti-doped CuO nanoparticles with better antimicrobial activity and lower cytotoxicity against animal cells. Furthermore, Ti-doped CuO nanoparticles were found to be cream of the crop to be incorporated into gelatin based active food packaging films to achieve desired functionality, with complete decomposition into natural soil (9 days). The shelf life of tomatoes ( Solanum lycopersicum L.) was greatly enhanced (up to 18 days at 40 ± 3 °C) with the use of nanoreinforced active food packaging films. • Ti-Doped CuO nanoparticles were synthesized via customized precipitation approach. • These nanoparticles showed potent antimicrobial effect with lower cytotoxicity. • Nanoreinforced active food packaging film was prepared with enhanced functionality. • The shelf life of tomatoes was greatly enhanced with the use of active package.

A new antimicrobial nor-friedelane-type triterpenoid and other constituents from Plectranthus glandulosus Hook. f. (Lamiaceae)

Chemical investigation of the ethanol extract from the whole plant of Plectranthus glandulosus led to the isolation of a new nor-triterpenoid (1) along with seventeen known compounds (2–18) including seven triterpenoids, nine flavonoids and one steroid. Their structures were established on the basis of 1D- and 2D-NMR, IR, and MS experiments, and by comparison of their spectroscopic data with those of similar compounds reported in the literature. The EtOH extract and some isolated triterpenoids (1–4 and 13) were subjected to in vitro antimicrobial assays against a panel of pathogenic microorganisms, including Gram-positive and Gram-negative bacteria, and fungi using broth microdilution method. The EtOH extract displayed moderate activity (MIC = 512 µg/mL) against Staphylococcus aureus MSSA1, Shigella flexneri SDINT and Cryptococcus neoformans H99. Compounds 1, 4 and 13 showed the most potent antimicrobial effect with MICs of 32–256 µg/mL.

Ozonated Sunflower Oil Exerted Protective Effect for Embryo and Cell Survival via Potent Reduction Power and Antioxidant Activity in HDL with Strong Antimicrobial Activity.

Ozonated sunflower oil (OSO) has potent antimicrobial effects, making it useful for topical applications to treat various skin diseases. On the other hand, regarding mechanistic insight, the antioxidant activity and cytoprotective effects of OSO are relatively less known. The current study compared the antioxidant ability and protective ability of OSO on cells and embryos against oxidative stress, such as H2O2 and oxidized low-density lipoproteins (oxLDL), to investigate its potential applications for wound-healing and anti-infection. OSO showed potent radical scavenging activity and ferric ion reduction ability that was up to 35% and 42% stronger than sunflower oil (SO) as a control in a dose-dependent manner. Measurement of the wavelength-maximum fluorescence (WMF) of high-density lipoproteins (HDL) revealed different behavior between OSO and SO treatment (final 1–16%). The OSO treatment caused a 12 nm red shift of Trp movement from 345 nm (at 0%) to 357 nm (at 16%), while SO caused a 12 nm blue shift of Trp movement from 345 nm (at 0%) to 333 nm (at 16%). The fluorescence intensity of HDL3 was diminished remarkably by the OSO treatment by up to 80% from the initial level, while SO-treated HDL did not. OSO-treated HDL3 showed slower electromobility with stronger band intensity and bigger HDL particle sizes than those of SO-treated HDL3. The paraoxonase-1 (PON-1) activity of HDL3 was enhanced by a co-treatment of OSO that was up to 2.3 times higher than HDL3 alone in a dose-dependent manner, whereas the co-treatment of SO even inhibited the PON activity. The cell viability of RAW264.7 by the OSO treatment was 3.3 times higher than the SO treatment at a high dose range (from 10% to 50%, final). The OSO also exhibited more cytoprotective effects than SO in brain microglial cells in the presence of H2O2 (final 0.03%); treatment with OSO impeded apoptosis and reduced ROS production more than an SO treatment did. In the presence of H2O2 alone, 86 ± 5% of the embryos were killed by cell explosion after 24 h, but a co-treatment of OSO (final 4%) resulted in almost no embryo death (98% survivability). Injection of oxLDL (15 ng of protein) into zebrafish embryos caused acute death, while the co-injection of OSO (final 2%) resulted in 2.8 times higher survivability than oxLDL alone. These results suggest new effects of ozonated oil, such as enhanced antioxidant activity, more cytoprotective ability, and higher embryo protection against oxidative stress. These results may be useful in developing new methods for the quality control of ozonated oil and an assessment of its efficacy.

Mesenchymal Stromal Cells: an Antimicrobial and Host-Directed Therapy for Complex Infectious Diseases.

There is an urgent need for new antimicrobial strategies for treating complex infections and emerging pathogens. Human mesenchymal stromal cells (MSCs) are adult multipotent cells with antimicrobial properties, mediated through direct bactericidal activity and modulation of host innate and adaptive immune cells. More than 30 in vivo studies have reported on the use of human MSCs for the treatment of infectious diseases, with many more studies of animal MSCs in same-species models of infection. MSCs demonstrate potent antimicrobial effects against the major classes of human pathogens (bacteria, viruses, fungi, and parasites) across a wide range of infection models. Mechanistic studies have yielded important insight into their immunomodulatory and bactericidal activity, which can be enhanced through various forms of preconditioning. MSCs are being investigated in over 80 clinical trials for difficult-to-treat infectious diseases, including sepsis and pulmonary, intra-abdominal, cutaneous, and viral infections. Completed trials consistently report MSCs to be safe and well tolerated, with signals of efficacy against some infectious diseases. Although significant obstacles must be overcome to produce a standardized, affordable, clinical-grade cell therapy, these studies suggest that MSCs may have particular potential as an adjunct therapy in complex or resistant infections.

Photocatalytic nanoparticles – From membrane interactions to antimicrobial and antiviral effects

As a result of increasing resistance among pathogens against antibiotics and anti-viral therapeutics, nanomaterials are attracting current interest as antimicrobial agents. Such materials offer triggered functionalities to combat challenging infections, based on either direct membrane action, effects of released ions, thermal shock induced by either light or magnetic fields, or oxidative photocatalysis. In the present overview, we focus on photocatalytic antimicrobial effects, in which light exposure triggers generation of reactive oxygen species. These, in turn, cause oxidative damage to key components in bacteria and viruses, including lipid membranes, lipopolysaccharides, proteins, and DNA/RNA. While an increasing body of studies demonstrate that potent antimicrobial effects can be achieved by photocatalytic nanomaterials, understanding of the mechanistic foundation underlying such effects is still in its infancy. Addressing this, we here provide an overview of the current understanding of the interaction of photocatalytic nanomaterials with pathogen membranes and membrane components, and how this translates into antibacterial and antiviral effects.

Facile synthesis of MnO2/ZnO coated on cotton fabric for boosted antimicrobial, self-cleaning and photocatalytic activities under sunlight

MnO2 nanosheet/ZnO microflower (MnO2/ZnO) coated on cotton fabric was synthesized using a reflux-thermal deposition combined method. Myriad spectroscopic methods were utilized to scrutinize the catalyst as well as the created composite fabric. The composite fabric displayed a potent antimicrobial effect against Escherichia Coli bacteria and Aspergillus Niger fungi. Importantly, the fabric was proved to possess excellent self-cleaning activity and photodegradation of methyl green aqueous solution under direct sunlight. The high photoactivity of composite fabric was ascribed to not only the pronounced capability in harnessing photon energies from visible region, but also the accelerated charge separation boosted by the MnO2 nanosheet distributed on the ZnO microflower. The promising performance shown in this work enable the scalable production of composite fabric for multifarious applications.

Chemical compositions, antibacterial, antifungal and cytotoxic effects of Alhagi mannifera five extracts.

Plants were used as medicines thousands of years ago. Conventional medicine use is increasing and many of the currently used drugs are extracted from herbal sources. In Palestinian traditional medicine, the Alhagi mannifera plant is used for the treatment of cancer. Our study aimed to extract this plant using five solvent fractions, identifying their chemical compositions, and evaluating their antimicrobial and cytotoxic effects. The successive technique was used to extract five solvent fractions of A.mannifera. While the spectral analysis was used to characterize quantitatively and qualitatively the chemical components of these extracts. The antimicrobial activity of plant extracts was evaluated against seven microbial strains using a broth micro-dilution assay. The cytotoxic activity was assessed using a 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay against cervical cancer cell line (HeLa). A total of 165 compounds were identified in A.mannifera different extracts. In the petroleum etherextract were found a total of 55 compounds. The major compounds were 2,5-cyclooctadien-1-ol (9.42%), 3-chloropropionic acid, heptyl ester (9.42%), carbonic acid, ethyl nonyl ester (9.42%) and chloroacetic acid. In methylene chloride extract a total of 11 compounds were found, and the major compounds were m-ainobenzenesulfonyl fluoride (14.35%), dodecane,2,6,10-trimethyl- (14.35%) and propanoic acid,2,2-dimethyl-,2-ethylexyl ester (14.35%). In chloroform extract, a total of 23 compounds were found. The major compounds were 5-ethyl-1-nonene (21.28%), and decanedioic acid, bis(2-ethylhexyl) ester (21.28%). In acetone extract were found a total of 47 compounds and the major compound was phenol,2,4-bis(1,1-dimethylethyl)- (5.22%). In methanol extract a total of 29 compounds were found and the major compounds were 3-o-methyl-d-glucose (10.79%), myo-inositol, 2-c-methyl- (10.79%), myo-inositol, 4-c-methyl- (10.79%), and scyllo-inositol,1C-methyl- (10.79%). All extracts showed antimicrobial activity. However, the petroleum ether extract showed the most potent antimicrobial effect against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia, MRSA, and Candida albicans with minimal inhibitory concentration (MIC) values of 1.25, 1.25, 6.25, 0.325, 6.25, and 1.56μg/mL, respectively. De facto, chloroform extract followed by ether extract displayed potential cytotoxic activity with IC50 values of 0.2 and 1.2mg/mL, respectively. A.mannifera was found to contain a variety of phytochemicals and its chloroform extract showed a potent cytotoxic effect on HeLa cancer cells. In addition, petroleum ether showed potent antimicrobial agents and these extracts look promising as drug candidates. Further in vivo investigations should be conducted to provide the basis for developing new cancer and microbial infections treatments.

Novel bile acid biosynthetic pathways are enriched in the microbiome of centenarians.

Centenarians have a decreased susceptibility to ageing-associated illnesses, chronic inflammation and infectious diseases1-3. Here we show that centenarians have a distinct gut microbiome that is enriched in microorganisms that are capable of generating unique secondary bile acids, including various isoforms of lithocholic acid (LCA): iso-, 3-oxo-, allo-, 3-oxoallo- and isoallolithocholic acid. Among these bile acids, the biosynthetic pathway for isoalloLCA had not been described previously. By screening 68 bacterial isolates from the faecal microbiota of a centenarian, we identified Odoribacteraceae strains as effective producers of isoalloLCA both in vitro and in vivo. Furthermore, we found that the enzymes 5α-reductase (5AR) and 3β-hydroxysteroid dehydrogenase (3β-HSDH) were responsible for the production of isoalloLCA. IsoalloLCA exerted potent antimicrobial effects against Gram-positive (but not Gram-negative) multidrug-resistant pathogens, including Clostridioides difficile and Enterococcus faecium. These findings suggest that the metabolism of specific bile acids may be involved in reducing the risk of infection with pathobionts, thereby potentially contributing to the maintenance of intestinal homeostasis.

Bactericidal and Virucidal Activities of Biogenic Metal-Based Nanoparticles: Advances and Perspectives.

Much progress has been achieved in the preparation and application of engineered nanoparticles (NPs) in the field of medicine, mainly for antibacterial and antiviral applications. In the war against bacteria and viruses, besides traditional antibiotics and antiviral drugs, metal-based nanoparticles, such as silver (AgNPs), copper (CuNPs), copper oxides (CuO-NPs), iron oxide (FeO-NPs), zinc oxide (ZnO-NPs), and titanium oxide (TiO2-NPs) have been used as potent antimicrobial agents. These nanoparticles can be synthesized by traditional methods, such as chemical and physical routes, or more recently by biogenic processes. A great variety of macro and microorganisms can be successfully used as reducing agents of metal salt precursors in the biogenic synthesis of metal-based NPs for antimicrobial activity. Depending on the nature of the biological agent, NPs with different sizes, aggregation states, morphology, surface coatings and charges can be obtained, leading to different antimicrobial effects. Considering the drug resistance to traditional therapies, the development of versatile nanomaterials with potent antimicrobial effects is under intensive investigation. In this sense, this review presents and discusses the recent progress in the preparation and application of metal-based nanoparticles biogenically synthesized for antibacterial and antivirus applications. The strength and limitations are critically discussed.

Development of a Potent Antimicrobial Peptide With Photodynamic Activity.

The emergence of antibiotic-resistant bacteria poses a serious challenge to medical practice worldwide. A small peptide with sequence RWRWRW was previously identified as a core antimicrobial peptide with limited antimicrobial spectrum to bacteria, especially Gram-positive bacteria. By conjugating this peptide and its analogs with lipophilic phthalocyanine (Pc), we identified a new antibiotic peptide [PcG3K5(RW)3]. The peptide demonstrates increased antimicrobial effect to both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. In addition, Pc also provides added and potent antimicrobial effect upon red light illumination. The inhibitory efficacy of PcG3K5(RW)3 was increased by ~140-fold to nanomolar range upon illumination. Moreover, PcG3K5(RW)3 was safe for mammalian cell and promoted wound healing in the mouse infection model. Our work provides a new direction to optimize antimicrobial peptides to enhance antimicrobial efficacy.

Selenization of cotton products with NaHSe endowing the antibacterial activities

Selenization reaction with the in situ prepared NaHSe has been successfully developed to occur in aqueous solution. The technique affords a method to upload the bioactive Se element on cotton products in semi-industrial scale. The antibacterial tests revealed that the selenized cotton possessed a potent and prolonged antimicrobial effect against both Gram-positive S. aureus and Gram-negative E. coli bacteria. This work discloses a practical method for preparing the selenium-containing antibacterial materials concisely and directly with industrial application potential.

Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite.

Conducting polymer based nanocomposites are known to be effective against pathogens. Herein,we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii). The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells. These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications. •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.