Natural antimicrobial agents

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Incorporation of natural antimicrobial agents into starch-based material for food packaging

Incorporation of natural antimicrobial agents into starch-based material for food packaging

I would like to express my sincere gratitude to everyone who directly and/or indirectly supported me during my studies, particularly my principal supervisor Professor Stephen Bigger and co-supervisors Dr. Marlene Cran, Associate Professor Kees Sonneveld and Professor Joesph Miltz for their guidance, advice, support and the encouragement they have provided me during the course of my project. Your attention to detail and constructive feedbacks help me maintain focus and direction throughout the research process. Particularly thanks to Dr. Marlene Cran for her valuable assistance in proof reading and formatting of all the papers published. Furthermore, many thanks to staff of National Measurement Institute whom I had privelige of working with them especially Dr. Saman Buddhadasa, Shyman Kumara, Tim Stobaus, Katherine Stockham and Mahdi Codi for their advice and support. I would like to Dr. Rohani Paimin, Associate Professor Todor Vasiljevic for their valuable advice and support. I owe many thanks to Liyana Arachchige Rupika Herath for her helpful advice during the preparation of the antimicrobial films.
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APPLICATION OF LYSOZYME AND DEXTRAN CONJUGATED LYSOZYME AS NATURAL ANTIMICROBIAL AGENTS IN THE TREATMENT OF EXPERIMENTAL SKIN WOUND IN MICE

APPLICATION OF LYSOZYME AND DEXTRAN CONJUGATED LYSOZYME AS NATURAL ANTIMICROBIAL AGENTS IN THE TREATMENT OF EXPERIMENTAL SKIN WOUND IN MICE

DISCUSSION: This study was undertaken to prepare and apply a modified form of lysozyme as a novel antimicrobial agent. Modification was performed by conjugation of lysozyme with dextran under mild conditions. Dextran is a complex, branched polysaccharide made of many glucose molecules, composed of chains of varying lengths (from 3 to 2000 kilodaltons). It is used medicinally as an antithrombotic to reduce blood viscosity and as a volume expander in anemia. It is also used in some eye drops as a lubricant, and in certain intravenous fluids to solubilize other factors, e.g. iron (=iron dextran such as Cosmofer)
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Development of Multi-layer Films Containing Natural Antimicrobial Agents

Development of Multi-layer Films Containing Natural Antimicrobial Agents

Limjaroen et al. (2003) studied an AM coating material produced by a casting method. Saran® F-310 resin (a copolymer of vinylidene chloride) was dissolved in methyl ethyl ketone at a concentration of 18% w/v and AM agents nisin, lactoferrin, sodium diacetate, sorbic acid or potassium sorbate were added at different concentrations. Lactic acid and 2 M NaOH were used to adjust the pH of the coating solution to 5.2. The coating material was applied to a glass plate, dried and removed from the plate then tested for AM activity by the agar diffusion method. All films except those containing lactoferrin or sodium diacetate showed positive inhibitory effects against L. monocytogenes. Furthermore, increasing the concentration of AM agent promoted the inhibitory effectiveness of the produced films. It was claimed that the coating material containing 3% w/v sorbic acid without pH adjustment demonstrated the best AM activity due to the greatest solubility and more homogeneous distribution of the AM agent in the polymer structure.
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Optimisation of β-cyclodextrin inclusion complexes with natural antimicrobial agents: thymol, carvacrol and linalool

Optimisation of β-cyclodextrin inclusion complexes with natural antimicrobial agents: thymol, carvacrol and linalool

Beta-cyclodextrin complexes encapsulating thymol as well as carvacrol and linalool were each prepared under the optimised conditions as determined from the previous experiments. In these cases, β-CD (3.8352 g, 3.33 mmol) was reacted with the AM agents: thymol, carvacrol, and linalool in a 1:1 mole ratio in each case. The β-CD was dissolved in 60 mL of water at 55°C to which the appropriate mass of AM agent was added and the reaction mixture vigorously stirred. The solutions were covered and maintained at 55°C for 4 h with continuous stirring after which the heating was discontinued and the mixture was continuously stirred for a further 4-5 h until the temperature decreased to 26 ± 1°C. The mixture was then cooled to 4°C, maintained at this temperature for 24 h and the precipitated complexes were recovered by vacuum filtration. The complexes were dried in a vacuum desiccator for 1 h after which the vacuum was removed. The complexes remained in the desiccator for a further 12 h to remove any residual water and until constant masses were attained. The yield, IE, absorbed AM agent on the surface of the β-CD, and amount of un-complexed agent were determined in accordance with the methods described above.
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Ecofriendly antimicrobial finishing of textiles using bioactive agents based on natural products

Ecofriendly antimicrobial finishing of textiles using bioactive agents based on natural products

broad spectrum inhibitory activity is also to be looked in. The mechanism of bactericidal action of the different natural antimicrobial agents is still unknown. The dissolution of the agents for textile application is also a major challenge because most of the products are not soluble in water. The attachment of the bioactive substances to the different types of complex textile substrates for longer durability of the antimicrobial activity is also a new avenue of research. Although a little research has been done for the development of natural agents encapsulated products (such as microencapsulated neem oil), the design of bioactive textiles with slow release mechanism for longer activity will be a good area of innovations in the world of biotextiles. Some natural products have very stringent and bitter smell which may cause mental illness of the wearer is also to be considered before putting those substances onto textile substrates. The physical and other performance properties of the treated textiles also need to be unaltered too much during making it antibacterial. For example, air permeability of the fabric which ultimately affects the comfort of the wearers is reduced after coating the textile surface with chitosan and so on. The antimicrobial finishing should not alter the other important functional and physical properties, such as bending rigidity and bending modulus which directly affect the fabric stiffness and drape characteristics. The blocking of the active functional groups (which may be responsible for their antimicrobial activity) during their textile attachment may also loose their bioactivity on textile substrates.
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SUSTAINABLE ANTIMICROBIAL FINISHING OF FABRICS USING NATURAL BIOACTIVE AGENTS - A REVIEW

SUSTAINABLE ANTIMICROBIAL FINISHING OF FABRICS USING NATURAL BIOACTIVE AGENTS - A REVIEW

Antimicrobial textiles have gained much attention and popularity in the market and in day- to- day life during the last two decades. The textile industries continue to introduce different methods in their production to enhance the quality of their products and to satisfy their customers. Increased competition in the industry has lead to the development of different synthetic antimicrobial agents. Though these synthetic agents are used widely, they pose a threat to both the users and the environment. Taking into consideration these threatening issues, several environmental bodies have implemented rules in the use of synthetic agents. On the contrary, the natural antimicrobial agents which have less adverse effect on humans and are eco friendly, are gaining much attention. Several natural agents such as basil (active agent is eugenol), neem (active limnoids like azadirachtin, nimbinin), turmeric (curcumin), clove oil, chitosan, sercin, onion, aloevera and pomegranate have antimicrobial properties. This review paper highlights the different natural antimicrobial sources, their effect on public and the possibilities of using these agents in textiles to impart antimicrobial properties and to develop different products.
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Thiazole: A Remarkable Antimicrobial And Antioxidant Agents

Thiazole: A Remarkable Antimicrobial And Antioxidant Agents

antibacterial compounds. Mehta and Patel 10 synthesized thiazole with thiazolidinone and azetidinone as Antibacterial compounds. Shakeel AS and coworkers 11 Synthesized Thiazole Schiff bases as Antibacterial agent. Kopnarr M and coworkers 12 synthesized New 2-Amino-4-[3-methyl-3-(5,6,7,8-tetrahydro-2- naphthyl)cyclobutyl]thiazole Derivatives as Antifungal agent. Logu and coworkers 13 reported In vitro Antifungal activity of 2-cyclohexylidenhydrazo-4-phenyl-thiazole against clinically isolated Candida albicans spp. Capan and Coworkers 14 synthesized 6-Phenylimidazo[2,1-b]thiazole Derivatives as Antifungal agents.
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Antimicrobial Agents Used in Endodontic Treatment

Antimicrobial Agents Used in Endodontic Treatment

The mechanism of action of antimicrobial agents is va- ried as they have multiple sites of action except for antibio- tics, which have very specific sites of action. The nature of the organism, antimicrobial agent and the concentration determine the response of the microorganisms to the anti- microbials. Furthermore, with the involvement of multiple cell structures causing primary and secondary effect and cell lysis, it is difficult to determine the precise mode of ac- tion of these antimicrobial agents. The cell wall, cytoplas- mic membrane and ribosomes of vegetative cells, the coat and cortex of bacterial spores, envelope and capsid of viru- ses and proteins (structural proteins, enzymes), nucleic acids and polysaccharides are some of the sites of action of antimicrobial agents. These antimicrobial actions eventual- ly result in the loss of important cell functions like protein synthesis and metabolism, replication, transcription and de- struction of cell membranes with leakage of cell contents (103).
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Synthesis of Fluoroquinolones Derivatives as Antimicrobial Agents

Synthesis of Fluoroquinolones Derivatives as Antimicrobial Agents

In our previous work, we have described various modifications to the main structure of fluoroquinolone, including the introduction of different substituent’s at position 1 and 7 (Fig. 1) and in continuation for obtaining a new fluoroquinolone derivatives with excellent antibacterial activity, our team reported synthon C (1, 2, 3 and 4) as a potent antibacterial agents.

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NATURAL PRODUCTS AS PROMISING ANTIMICROBIAL AGENTS: A REVIEW

NATURAL PRODUCTS AS PROMISING ANTIMICROBIAL AGENTS: A REVIEW

individuals are frequently found suffering from skin infections that are difficult to cure. A novel compound with difference in mode of activity of antibiotics against microbes is an attractive alternative against multidrug resistant bacteria. 5 The drugs already in use to treat infectious disease are of concern also because drug safety remains an enormous global issue. Most of the synthetic drugs cause side effects. To alleviate this problem, antimicrobial compounds from potential plants should be explored. These drugs from plants are less toxic; side effects are scanty and also cost effective. They are effective in the treatment of infectious diseases while simultaneously mitigating many of the side effects that are often associated with synthetic antimicrobials. 1 Topical drug administration is a localized drug delivery system anywhere in the body through ophthalmic, rectal, vaginal, and skin as topical routes. Skin is one of the most accessible organ of human body for topical administration and main route of topical drug delivery system. Number of medicated products is applied to the skin or mucous membrane that either enhances or restores a fundamental function of a skin or pharmacologically alters an action in the underlined tissues. Such products are referred as topical or dermatological products. At the skin surface, drug molecules come in contact with cellular debris, microorganisms, and other materials, which effect permeation. The applied medicinal substance has three pathways to the viable tissue- 1) through hair follicles, 2) via sweat ducts and 3) across continuous stratum corneum between the appendages (hair follicles, sebaceous glands, eccrine, apocrine glands and nails). This route of drug delivery has gained popularity because it avoids first-pass effect, gastrointestinal irritation and metabolic degradation associated with oral administration. The topical route of administration has been utilized either to produce local effect for treating skin disorder or to produce systemic drug effects. 7
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Topical antimicrobial agents for pediatric burns

Topical antimicrobial agents for pediatric burns

Silver physiology Silver has been known for centuries to have antimicrobial properties, and it is the foundation of established topical antibacterial agents for the burn wound such as silver nitrate solution, silver sulfadiazine cream, and silver-releasing dressings. Metallic silver (Ag 0 ) is biologically inert and has no antimicrobial activ- ity, but the silver cation (Ag + ) is highly reactive and strongly bactericidal, at relatively low concentrations. Silver may also exist in two highly reactive and unstable oxidation states: Ag ++ and Ag +++ [18]. Silver ions are toxic to bacteria, yeasts, and fungi through several mechanisms. These include inhibition of enzymes neces- sary for metabolism and respiration of the microorgan- ism, disruption of the cell membrane or cell wall of the microbe, and interference with DNA and RNA prevent- ing replication of the microorganism [18–20]. Microbial killing is strongly correlated with the concentration of free silver ions [18]. However, free Ag + is rapidly bound and depleted by proteins and compounds on the wound surface and in the wound fluid. This hinders the main- tenance of adequate Ag + levels necessary for microbe killing on the wound bed. Resistance to silver is uncom- mon, presumably because silver acts by multiple mecha- nisms, but there is some evidence that suggests that chronic exposure to very low concentrations of ionic sil- ver can induce resistance. Thus, it is recommended that dressings or agents that release high levels of ionic silver are preferable, from the standpoint of avoiding develop- ment of silver resistance [4].
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NATURAL ANTI-PLATELET AGENTS

NATURAL ANTI-PLATELET AGENTS

The evidence on the inhibition of platelet aggregation in diabetic patients support the possible utility of this drug to decrease the platelet hyperreactivity associated to Diabetes mellitus. The effects of this natural drug on two different platelet activation pathways (23-24) were assessed in this assay. ADP but not collagen-induced aggregation was affected, thus, suggesting that Policosanol selectively inhibits ADP- induced platelet activation pathway and that, perhaps, higher doses of the drug would be needed to inhibit collagen-induced platelet aggregation.

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Agents used for antimicrobial treatment for textiles a review

Agents used for antimicrobial treatment for textiles a review

Bacteria, each unhealthful and odour inflicting, act with fibres in many phases together, however, these fibers encourage the holding of stale perspiration within the interstices, whereby the microbes multiply readily(Wooding N et. al. 1970) Foot infection, as an example, has been found to be additional pronounced for artificial fibre socks than fibre socks. Yau and Merry (Yau Lo et al., 1986) found that the adherence of bacterium to the materials accumulated because the content of polyester within the materials accumulated. Synthetic fibres conjointly become prone to microbic degradation, if there square measure finishing agents, like polythene and polysiloxane emulsions, on these fibres. These additives enable the microorganisms to degrade the compound into ‘chewable bites’ by utilizing the acidic or basic by-products of their metabolism, so initiating the cycle of reaction. During this means, even the powerful polyurethanes are often countermined. Plastic, nylon and polyester fibres have all been seen to be subject to microbic attack beneath contributory conditions (Yau, 1988). A matter of larger concern, however, is that the textiles not solely act as substrates for microbic growth however they'll act as active agents in propagation of microbes. a minimum of 2 viruses of public health importance, specifically acute anterior poliomyelitis and Vaccinia, are shown to persist on cotton and wool materials for decent periods of your time (Isquith et al., 1972) Viruses will persist on materials like cotton cloth, bath towel, washable wool suit, polyester / cotton fabric and nylon jersey for up to sixteen hour. Artificial fibres enable larger degree of infectious agent persistence and transfer than cotton. Once subjected to washing, the virus gets physically far from the material however isn't inactivated, because it was found to be gift in extracted water. Detergents that scale back the physical phenomenon assist this physical removal. Thus, virus transfer will occur simply throughout traditional cold washing method. Also, some bacteriumcontinue to really survive on laundered material also (Vigo et al., 1981).
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Antimicrobial agents – optimising the ecological balance

Antimicrobial agents – optimising the ecological balance

Drug discovery and development is conventionally driven by financial motivation. For the private industry, aligning to an antimicrobial programme has more risk than other pharmacological fields. Taking new drugs to market requires considerable testing for safety and efficacy in each indication sought. Once resistance ensues, the clinical, and therefore commercial, value of the product falls. In the medical profession, physicians try to limit a new antibiotic’s utilisation to maintain its clinical value; however, paradoxically, this affects sales, in effect creating another disincentive to drug discovery. When these new drugs are used in infectious disease management they have a short-term curative application as opposed to drugs used in the treatment of chronic diseases. It is no wonder that this “antibiotic pipeline” is weak and requires support from government and non-government sectors.
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Carbon Dots as Potent Antimicrobial Agents

Carbon Dots as Potent Antimicrobial Agents

Among popular photosensitizers have been dye molecules such as porphyrins, phenothiazines, phthalocyanines, bacteriochlorins, and their various derivatives [7, 8]. In more recent development, nanoscale materials have emerged as excellent alternative antimicrobial agents by serving not only as vehicles to improve the selective delivery and dispersion of photosensitizers in targeted cells, but also as photosensitizers themselves to enhance the effectiveness of PDI. While nanoscale metal particles and semiconductors have been widely explored for such a purpose, carbon nanomaterials for their broad optical spectral coverage and other advantageous materials characteristics have also attracted much recent attention in PDI related applications [12-15]. Beyond the excitements associated with the famous nanoscale carbon allotropes (fullerenes, nanotubes, and graphenes), the recent recognition of carbon nanoparticles as a distinct zero-dimensional carbon allotrope, versus fullerenes as “zero-dimensional all carbon molecules” of defined chemical stoichiometry and structures, has created new opportunities in the continuing fight against pathogens and MDR. By exploiting and enhancing the intrinsic optical properties and photoinduced redox characteristics of carbon nanoparticles, carbon dots (CDots) [16-26], which are generally defined as small carbon nanoparticles of various surface passivation schemes (Figure 1) [17-19], have emerged to represent a new platform for visible/natural light-activated antimicrobial agents [12-15]. In this regard, CDots are essentially unique visible photosensitizers for effective PDI, with additional benefits due to their advantageous properties including the nontoxic nature [18, 19, 27-29], photostability, versatility in surface functionality for desired microbial adhesion and interactions, and their production from abundant
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Utilization pattern, safety profile and cost analysis of antimicrobials prescribed in an intensive care unit of a teaching hospital

Utilization pattern, safety profile and cost analysis of antimicrobials prescribed in an intensive care unit of a teaching hospital

Initial therapy for infection is often empiric and guided by the clinical presentation. Therefore, a common approach is to use broad spectrum antimicrobial agents as initial empiric therapy with the intent to cover multiple possible pathogens commonly associated with the specific clinical syndrome. Once laboratory results of microbiology tests are available with identification of pathogen along with antimicrobial susceptibility data, every attempt should be made to narrow the antibiotic spectrum. This is a critically helpful and integral component of antimicrobial therapy because it can reduce cost and toxicity and significantly delay the emergence of antimicrobial resistance in the community. Antimicrobial agents with a narrower spectrum should be directed at the most likely pathogens for the duration of therapy for infections such as community-acquired pneumonia, urinary tract infections, soft tissue infections etc. in an OPD setting because specific microbiological tests are not routinely performed or available or affordable
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Laboratory confirmed puerperal sepsis in a national referral hospital in Tanzania: etiological agents and their susceptibility to commonly prescribed antibiotics

Laboratory confirmed puerperal sepsis in a national referral hospital in Tanzania: etiological agents and their susceptibility to commonly prescribed antibiotics

Methods: Hospital based cross-sectional study conducted at tertiary hospital from December 2017 to April 2018. The study recruited post-delivery women suspected with puerperal sepsis. Socio- demographic, clinical and obstetric information were collected using structured questionnaire. Blood and endocervical swab samples were collected for aerobic culture. Blood culture bottles were incubated in BACTEC FX40 (Becton – Dickinson, Sparks, MD, USA). Positive blood cultures and cervical swabs were inoculated onto sheep blood agar, MacConkey agar, chocolate agar and Sabouraud ’ s dextrose agar, incubated aerobically at 37 °C for 18 – 24 h. Antimicrobial susceptibility was determined by Kirby-Bauer disc diffusion method.
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Biocidal polymers: synthesis and antimicrobial properties of benzaldehyde derivatives immobilized onto amine-terminated polyacrylonitrile

Biocidal polymers: synthesis and antimicrobial properties of benzaldehyde derivatives immobilized onto amine-terminated polyacrylonitrile

chemical structure of the prepared polymers was con- firmed by FTIR Spectra, and TGA. The antimicrobial ac- tivity of the prepared polymers against different types of microorganisms including Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Pseudo- monas aeruginosa; Escherichia coli; and Salmonella typhi) as well as fungi (Aspergillus flavus, Aspergillus niger, Can- dida albicans, Cryptpcoccus neoformans) were explored by the cut plug method and viable cell counting methods. The prepared biocidal polymers are water-insoluble; therefore, they can be used safely in sterilizing drinking water and many other applications, such as disinfecting water supplies, swimming pools, hot-tubs, industrial water systems, and other applications where a sanitized water supply is required.
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Aloe vera plant products as antimicrobial agents

Aloe vera plant products as antimicrobial agents

Traditionally medicinal plants are considered as medicinal backbone. According to estimation around 80% of citizens still rely primarily on traditional medicine system for the treatment of diseases (Narayana, 1987). Aloe Vera is native to Africa, belongs to “liliaceae” family with approximately “200” species. This medicinal plant is commonly used in the treatment of various diseases of skin. Powerfully reduces abrasion, irritation and inflammation. Widely used in aromatic compounds, toiletry industry, and cosmetics production. Mostly used in the manufacturing of Ointments, creams, soaps, cleansing facials, lotions, shampoos, tablets, capsules and gel preparations (Eshun, 2004). In the food manufacturing it is used as a resource of well-organized foods as well as in new food products it is used as an ingredient. As food it improves circulation blood, recover the damaged cells and tissues. Aloe Vera is well- known as natural healer its juice allows the body its self to heal up the internal body damages and get better digestive and immune systems (Vogler 1999). The fresh Aloe Vera gel shows pharmacological activities (antioxidant, anti inflammatory, anti fungal, anti bacterial, anti diabetic, anti viral etc) that are naturally curative Talmadge 2004. Chemical properties (anthraquinones, vitamins, enzymes, sugars, minerals etc) from different parts of Aloe are extensively used in various disease treatments (Dagne, 2000). Phytochemicals i.e. saponins, lectins flavanoids, tannins, steroids etc are also extracted from Aloe Vera thatplays a structural role in the body by increasing growth hormones (Moreira et al., 2008).
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Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries

Distribution of serotypes and patterns of antimicrobial resistance among commensal Streptococcus pneumoniae in nine European countries

agents in primary health care in Europe with respect to antimicrobial resistance’ (APRES) study as described by van Bijnen et al. [10]. Briefly, general practitioners (GP) from Austria, Belgium, Croatia, France Hungary, Spain, Sweden, the Netherlands and the United Kingdom (9 countries, 20 GPs per country), were each asked to pro- vide nasal swabs from 200 healthy persons (with no his- tory of antibiotic therapy or hospitalization in the previous three months), older than 4 years (except for UK, where for ethical reasons patients were older than 18 years). Within 48 h after collection swabs were trans- ported to each national laboratory for further processing, with the exception of samples collected in France that were all sent to the Dutch national laboratory at Maas- tricht University Medical Centre (MUMC). On arrival to diagnostic labs, samples were cultured for S. pneumoniae using a standardized protocol [10]. Putative S. pneumo- niae isolates from all participating countries were sent to the MUMC in skimmed milk at -80 °C for further analysis.
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