Chemical Antimicrobial Agents Research Articles

Development of Prangos ferulacea essential oil based nanoemulsions/pickering emulsion and examination of their performance in mayonnaise shelf life

The increasing demand to replace chemical antimicrobial agents with natural compounds leads to the use of some plant extracts and essential oils (EOs) as natural preservatives. Nanoemulsion (NE) with Tween 80 as wall material and Pickering emulsions (PE) stabilized with carbohydrate (Arabic gum (AG)) or protein (sodium caseinate (SC)) wall materials. First of all, the PEO was obtained from two parts of plant: flowers and leave, and characterized by GC-MS and the IC50 index measurement. The Prangos ferulacea essential oil (PEO) extracted from leave was selected for the next tests due to slightly higher antioxidant activity compared to the flower's EO. The leave's PEO was encapsulated in three forms: nanoemulsion (NE) with Tween 80 as wall material and Pickering emulsions (PE) stabilized with carbohydrate (gum Arabic (GA)) or protein (sodium caseinate (SC)) wall materials. The NE had the smallest particle size and the highest antioxidant and antimicrobial (S. aureus and E. coli) activity. AG-stabilized PE recorded the highest encapsulation efficiency (85.37 ± 1.97 %). The occurring of new chemical interactions between PEO and wall materials and uniformly shaped PE microcapsules were approved by FT-IR and FE-SEM tests, respectively. Free and encapsulated PEO were added to the mayonnaise, and the samples were analyzed during storage at 4 °C for 60 days. Peroxide value and TBA index gradually increased for all mayonnaise samples, but this increase was lower for samples containing NE and SC-stabilized PEO capsules. In general, carriers stabilized with the simultaneous application of protein and carbohydrate performed better compared to their single application in sensory tests in mayonnaise.

Comparative Evaluation of Microbial Reduction Using Silver Diamine Fluoride, Azadirachta indica (Neem) and Sodium Hypochlorite as Root Canal Irrigants after Biomechanical Preparation in Uniradicular Canals: An In Vivo Study.

It is difficult to completely eradicate microorganisms from the infected root canal system. Intracanal irrigants seem necessary for eradication of infected tissues and microorganisms in addition to mechanical debridement. Continuous use of chemical antimicrobial agents leads to serious side effects. Therefore, the need arises for alternative agents to overcome the disadvantages of their chemical counterparts. To evaluate and compare the antimicrobial efficacy of three endodontic irrigants against clinically isolated bacteria found in root canals containing necrotic pulp. Preirrigation sample were collected using sterile paper points and sent for microbial count. Chemomechanical preparation was performed, and the root canals were irrigated with 5 mL of test samples. After 3 days, the patient was recalled, and a postirrigation sample was collected and sent for microbial count. Both 3.8% silver diamine fluoride (SDF) and 3% sodium hypochlorite (NaOCl) showed a superior capacity to sterilize the root canals compared to the neem group. The use of SDF as an endodontic irrigant is feasible as it effectively removes the microbes present in the canal. Silver diamine fluoride has not been shown to be cytotoxic or carcinogenic, unlike NaOCl, suggesting it could be used as a potential endodontic irrigant. However, few studies have evaluated the antimicrobial efficacy of SDF as an endodontic irrigant. Raj S, Sharma A, Dhinsa K, et al. Comparative Evaluation of Microbial Reduction Using Silver Diamine Fluoride, Azadirachta indica (Neem) and Sodium Hypochlorite as Root Canal Irrigants after Biomechanical Preparation in Uniradicular Canals: An In Vivo Study. Int J Clin Pediatr Dent 2024;17(6):625-629.

Viability of bacteria associated with root caries after Nd:YAG laser application in combination with various antimicrobial agents: An in vitro study.

The neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has various therapeutic applications in dentistry, including the treatment of dentin hypersensitivity and the bacterial reduction therapy in periodontology. The addition of antimicrobial agents may enhance the impact of the laser on bacterial viability. This in vitro study aimed to assess the effect of Nd:YAG laser application in combination with various chemical antimicrobial agents, including hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl), chlorhexidine (CHX), and sodium fluoride (NaF), on the viability of bacteria implicated in the etiology of root caries. Three oral bacterial species were examined: Streptococcus mutans (S. mutans); Streptococcus sanguinis (S. sanguinis); and Enterococcus faecalis (E. faecalis). The bacteria were grown in broth at 37°C, and then treated with the chemical agents and/or irradiated with an Nd:YAG laser for 30 s. Each treatment modality was repeated 3 times: group 1 - no treatment; group 2 - 0.5% H2O2; group 3 - 0.5% NaOCl; group 4 - 0.12% CHX; group 5 - 2% NaF; group 6 - Nd:YAG laser irradiation; group 7 - laser and 0.5% H2O2; group 8 - laser and 0.5% NaOCl; group 9 - laser and 0.12% CHX; and group 10 - laser and 2% NaF. The viability of the bacteria was determined by plating them, counting viable colonies, converting the data into colony-forming units (CFUs)/mL, and transforming them into the log form. Statistical analysis was performed using the two-tailed paired t test. Irradiation with an Nd:YAG laser alone did not show a statistically significant effect against any of the bacterial species. The only effective antimicrobial used alone was CHX for S. mutans. Chlorhexidine with Nd:YAG resulted in a greater reduction in S. mutans and E. faecalis than either treatment alone. Meanwhile, H2O2 with Nd:YAG also showed an enhanced S. mutans reduction. Treatment with 0.5% NaOCl in conjunction with Nd:YAG brought the most significant reduction in viability for all bacteria in comparison with other treatment modalities. The Nd:YAG laser combined with 0.5% NaOCl resulted in the most substantial reduction in bacterial survival as compared to the antimicrobials or the Nd:YAG laser used alone.

Investigating the Antimicrobial Activity of Different Extracts of Echium on Selected Gram-Positive and Gram-Negative Bacteria

Introduction: Medicinal plants have had a special value and importance in providing health and wellness of communities both in terms of treatment and prevention of diseases. The aim of this research was to investigate the antimicrobial activity of different extracts (aqueous, ethanolic, and methanolic) of two types of Echium (Helioteropium ellipticum and Anchusa strigosa) on Staphylococcus aureus, Bacillus Cereus, Escherichia Coli, Salmonella Typhi and Shigella dysentery bacteria. Material and Methods: Extracts were prepared by soaking method. Antimicrobial activity was determined by two methods: dilution sequence in liquid medium and diffusion from disk in solid medium. The data were analyzed with SPSS24 software. Results: Gram-positive bacteria showed more sensitivity to the extracts than Gram-negative bacteria. Antimicrobial activity of Heliotropium ellipticum was more than Anchusa strigosa. Aqueous extract has the lowest and ethanolic extract has the highest antimicrobial activity. Staphylococcus aureus showed the highest and Escherichia coli the lowest sensitivity to the extracts. Staphylococcus aureus bacteria showed the largest diameter of non-growth aura (20.67 mm) at the concentration of 50 mg/ml of ethanolic extract, and the MIC of Staphylococcus aureus had the highest sensitivity at 312.5 PPM dilution. Conclusion: The two tested species have good antimicrobial activity and they can be used as natural substitutes for chemical antimicrobial agents.

Exploring the impacts of novel cold plasma technology on the volatile profile, flavor, and aroma properties of fruits and vegetables—A review

AbstractCold plasma is a novel nonthermal technology that has recently numerous applications in the food industry. It destroys microorganisms, preserves food, and maintains quality without employing chemical antimicrobial agents. However, food processing by cold plasma (CP) can be associated with food quality challenges, so research on the applications of this technology and its effects on food quality are increasing. This paper reviews the effect of CP on the volatile profile, flavor, and aroma properties of fruits and vegetables. CP induces some chemical modifications in volatile compounds, and these changes vary with the CP operating conditions such as voltage, frequency, and treatment duration parameters and subsequently induces changes in the aroma and flavor of foods. The operating conditions may be properly controlled to avoid any unfavorable effects and provide more accepted food by focusing on the development of favorable flavor and aroma characteristics and reducing the incidence of undesirable ones. Also, more sophisticated techniques for sensory evaluation of processed foods should be developed and commercialized to get standardized outcomes. In conclusion, the data presented in this work highlight the possibility of flavor and aroma modifications and improvement of sensory quality in food products by using CP technology.

Antimicrobial function of yeast against pathogenic and spoilage microorganisms via either antagonism or encapsulation: A review.

Contaminations of pathogenic and spoilage microbes on foods are threatening food safety and quality, highlighting the importance of developing antimicrobial agents. According to different working mechanisms, the antimicrobial activities of yeast-based agents were summarized from two aspects: antagonism and encapsulation. Antagonistic yeasts are usually applied as biocontrol agents for the preservation of fruits and vegetables via inactivating spoilage microbes, usually phytopathogens. This review systematically summarized various species of antagonistic yeasts, potential combinations to improve the antimicrobial efficiency, and the antagonistic mechanisms. The wide applications of the antagonistic yeasts are significantly limited by undesirable antimicrobial efficiency, poor environmental resistance, and a narrow antimicrobial spectrum. Another strategy for achieving effective antimicrobial activity is to encapsulate various chemical antimicrobial agents into a yeast-based carrier that has been previously inactivated. This is accomplished by immersing the dead yeast cells with porous structure in an antimicrobial suspension and applying high vacuum pressure to allow the agents to diffuse inside the yeast cells. Typical antimicrobial agents encapsulated in the yeast carriers have been reviewed, including chlorine-based biocides, antimicrobial essential oils, and photosensitizers. Benefiting from the existence of the inactive yeast carrier, the antimicrobial efficiencies and functional durability of the encapsulated antimicrobial agents, such as chlorine-based agents, essential oils, and photosensitizers, are significantly improved compared with the unencapsulated ones.

The Coexistence of Bacterial Species Restructures Biofilm Architecture and Increases Tolerance to Antimicrobial Agents.

Chronic infections caused by polymicrobial biofilms are often difficult to treat effectively, partially due to the elevated tolerance of polymicrobial biofilms to antimicrobial treatments. It is known that interspecific interactions influence polymicrobial biofilm formation. However, the underlying role of the coexistence of bacterial species in polymicrobial biofilm formation is not fully understood. Here, we investigated the effect of the coexistence of Enterococcus faecalis, Escherichia coli O157:H7, and Salmonella enteritidis on triple-species biofilm formation. Our results demonstrated that the coexistence of these three species enhanced the biofilm biomass and led to restructuring of the biofilm into a tower-like architecture. Furthermore, the proportions of polysaccharides, proteins, and eDNAs in the extracellular matrix (ECM) composition of the triple-species biofilm were significantly changed compared to those in the E. faecalis mono-species biofilm. Finally, we analyzed the transcriptomic profile of E. faecalis in response to coexistence with E. coli and S. enteritidis in the triple-species biofilm. The results suggested that E. faecalis established dominance and restructured the triple-species biofilm by enhancing nutrient transport and biosynthesis of amino acids, upregulating central carbon metabolism, manipulating the microenvironment through "biological weapons," and activating versatile stress response regulators. Together, the results of this pilot study reveal the nature of E. faecalis-harboring triple-species biofilms with a static biofilm model and provide novel insights for further understanding interspecies interactions and the clinical treatment of polymicrobial biofilms. IMPORTANCE Bacterial biofilms possess distinct community properties that affect various aspects of our daily lives. In particular, biofilms exhibit increased tolerance to chemical disinfectants, antimicrobial agents, and host immune responses. Multispecies biofilms are undoubtedly the dominant form of biofilms in nature. Thus, there is a pressing need for more research directed at delineating the nature of multispecies biofilms and the effects of the properties on the development and survival of the biofilm community. Here, we address the effects of the coexistence of Enterococcus faecalis, Escherichia coli, and Salmonella enteritidis on triple-species biofilm formation with a static model. In combination with transcriptomic analyses, this pilot study explores the potential underlying mechanisms that lead to the dominance of E. faecalis in triple-species biofilms. Our findings provide novel insights into the nature of triple-species biofilms and indicate that the composition of multispecies biofilms should be a key consideration when determining antimicrobial treatments.

Fluorescence Intensity of Liposomes and E. coli Attached to Nanopillar Arrays: Implications for Bacterial Death on Nanostructures

Bacterial death on nanostructures has sparked great interest because the principle behind this phenomenon completely differs from that of conventional chemical antimicrobial agents. Physical interactions between the bacterial envelope and nanostructures generate forces that deform the cell membrane. Eventually, the cell envelope breaks, causing the cytoplasm to leak out. However, the events occurring between these stages are unclear. In this work, we used liposomes as pseudocells because they are composed of a lipid bilayer, which is similar to a cytoplasmic membrane. We monitored time-dependent changes in the fluorescence intensities of rhodamine 6G (R6G)-containing liposomes and mCherry-expressing Escherichia coli cells after adhering to Au nanostructure arrays (pitch; height; diameter = 500, 300, 283 nm) and compared the variations in the fluorescence intensities of the pseudo and E. coli cells over time. Electrochemical impedance spectroscopy was then performed to monitor the cell and liposome attachment. Ratio of change in Rct before and after the liposome injection was about 1.7, which means that Rct increased drastically due to the attachment of liposome. Similarly, ratio of change in Rct before and after the E. coli injection was about 1.15 due to the attachment of cell. The fluorescence intensity of mCherry quickly decreased after cell adhesion within 25 min, whereas that of R6G did not even at 60 min. This finding means that the liposomes were not broken down despite their mechanical strength being equal to or weaker than that of E. coli. The time constant (T) of the decrease in fluorescence intensity of E. coli was calculated by fitting the data to an exponential function and found to be −0.13 min–1, which is in good agreement with our previous results. But we could not calculate the T of liposomes. The results indicate that the death of bacteria on nanostructures likely involves an autolytic mechanism.

Efficacy of Antimicrobial Agents in Dentifrices: A Systematic Review.

The aim of this systematic review was to verify if the presence of different antimicrobial agents in dentifrices is effective in reducing the number of microorganisms for disease prevention. This review followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines and was registered with the Open Science Framework (OSF). A search was conducted in the PubMed, Embase, Scopus, and Web of Science databases. Two independent authors reviewed the titles and abstracts according to the inclusion criteria, which comprised in vitro studies published in English that evaluated the efficacy of antimicrobial agents in dentifrices and their antimicrobial activity. A total of 527 articles were found. Of these, 334 were included for reading of the title and abstract, and 69 were selected for reading in full. In the end, 39 articles remained in this review. Triclosan, sodium fluoride, and sodium monofluorophosphate were the most commonly used chemical antimicrobial agents. Among the herbal agents, miswak extract and neem extract were the most commonly used. The presence of antimicrobial agents in dentifrice formulations can promote the reduction of the number of microorganisms involved in oral diseases, but with variations in their effectiveness, depending on the agent used and the microorganism evaluated.

Bibliometric and visual analysis of nephrotoxicity research worldwide.

Background: Nephrotoxicity of drugs contributes to acute kidney injury with high mortality and morbidity, which crucially limits the application and development of drugs. Although many publications on nephrotoxicity have been conducted globally, there needs to be a scientometric study to systematically analyze the intellectual landscape and frontiers research trends in the future. Methods: Publications on nephrotoxicity from 2011 to 2021 were collected to perform bibliometric visualization using VOSviewer, CiteSpace, and Scimago Graphica software based on the Web of Science Core Collection. Results: A total of 9,342 documents were analyzed, which were primarily published in the United States (1,861), China (1,724), and Egypt (701). For institutions, King Saud University (166) had the most publications; Food and Chemical Toxicology, PLOS One, and Antimicrobial Agents and Chemotherapy were productive journals, primarily concentrating on the mechanisms of nephrotoxicity and renoprotective in cisplatin and antibiotics, especially in oxidative stress. Burst detection suggested that cisplatin, piperacillin-tazobactam, vancomycin-induced nephrotoxicity, antioxidants, and new biomaterials are frontiers of research. Conclusion: This study first provides an updated perspective on nephrotoxicity and renoprotective strategies and mechanisms. This perspective may benefit researchers in choosing suitable journals and collaborators and assisting them in the deep understanding of the nephrotoxicity and renoprotective hotspots and frontiers.

Novel antibacterial activity of Sargassum fusiforme extract against coral white band disease

BackgroundCoral diseases are one of the serious threats embroiling in the imbalance of the coral holobiont integrity through disruption of the complex symbiotic relationship between endobiotic alga, coral animal, and a group of microorganisms. Such diseases are usually associated with many bacterial pathogens inflicting gross lesions in corals which show resistance against antibiotics. Therefore, this has led scientists to draw more attention towards the curative compounds from natural resources like herbal plants and seaweeds as substitutes for chemical antimicrobial agents. This study aimed to evaluate the antibacterial activity of the crude extracts (n-hexane, ethyl acetate, and ethanol), alkaloids, and flavonoids from Sargassum fusiforme through Well Diffusion Assay against different isolated bacterial coral pathogens such as (Vibrio owensii, Empedobacter brevis, Providencia vermicola, and Brevibacterium linens) which cause white band disease to coral reef Porites lutea. This study was also validated by bacterial growth kinetics using optical density, dry weight, and plate count method for the isolated coral bacterial pathogens. ResultsThe results indicated that the crude extract with n-hexane and alkaloid extract showed prominent inhibiting activity against the tested bacterial pathogens compared to other extracts. ConclusionsHere we report S. fusiforme extracts as a novel antibacterial agent against four Porites lutea bacterial pathogens and further investigation is recommended against other coral pathogens. Overall, S. fusiforme extracts might be able to improve the health status of commercially important coral species.How to cite: Ahmed N, Mohamed HF, Xu C, et al. Novel antibacterial activity of Sargassum fusiforme extract against coral white band disease. Electron J Biotechnol 2022;57. https://doi.org/10.1016/j.ejbt.2022.03.002.

Issues with Tropical and Temperate Ensilage Protein and Amino Acid Feeds Utilization: A Research Note

Alfalfa protein breakdown was to soluble NPN of oligopeptide-N, AA-N, amide-N, amine-N and NH3-N. Acidity (pH) and moisture (Aw) are critical in determining extent of fermentation and changes in composition. Further changes in digestive flows and post-prandial plasma AA are indicators of protein status. Dual-purpose cropping and tree plant cropping was with ensiling management of the undergrowth. On-farm field-drying and probiotic additives are promising. It is suggested acidity with propionic acid and microbial inoculants together with field-drying and chop length are required to optimize profile qualities in silage. It is proposed use of denaturing with acid and dust cropping with a hypothetical PNA-Auxin repressor to plant protease. Further study with field-drying to follow is needed. Feeding HIS, ARG and LEU AA supplement to change GRH and GH profiles could be used to promote LBM in production. Dual-purpose cropping can expand subsistence to mixed farming with expanded livestock products and services and resources. PNA-Auxin and PNA-ARF penetrates the plant shoot tips to deliver a TF mRNA to boost proteins in residual cell tissues. Ensiled % AA-N delivery per os to per duodenum was higher; yet total AA-N flow was higher in the control. It is suggested that “bulk” flow was less but with a “tighter” conversion on TAA. FAA was 145% higher in the ensiled versus the fresh control indicating the ENU with less PFAA supplied. FAA on the ensiled diet is high inferred to be more soluble and escape lower from the rumen. WSC are less supplied in fermented forage with VFA being lower and presenting the question whether WSC should be supplied for energy and also with EFE through breaking down of polymers of lignocellulose. It was surmised, although not known, that higher dilution rate (% hr-1) was true on the fresh diet compared to the ensiled although end-products may initially detract with feed but that further digestion in the fresh feed may be higher with intake. Plasma AA before and after absorption or feeding are indicators of synthesis and breakdown. No data was available on N status; protein nutrition on neat silage was probably due to net efflux of AA with mobilization before influx with feeding and subsequent insulin action for uptake. Estuarine aquatic plant spp., water hyacinth used in the Philippines and duckweed studies in Australia, and post-harvest treatment with chemical additives and anti-microbial agents to help control potential transfer of diseases. “Greens” as supplements has yet to be established for anti-microbial properties for animal health and welfare. In conclusion, alfalfa silage fed at standard 0.6 cm particle size and wilted led to dramatic changes with AA breakdown, dramatic changes in duodenal AA flows from escape and recapture into microbial cells. Also N status of animals was compromised by lack of adequate “stores”, mobilized, resulting in a net decrease in total plasma AA with insulin-dependent uptake to tissue.

Inhibitory Effect of Cinnamaldehyde on Main Destructive Microorganisms of Nanhai No. 1 Shipwreck

Nanhai No. 1, a shipwreck in the Southern Song Dynasty, China, has a history of more than 800 years. It was salvaged in 2007 and is now on display in the Guangdong Maritime Silk Road Museum. Due to the fact that the hull is a wooden cultural relic and exposed to the air, the biological corrosion and biodegradation caused by microorganisms are key problems of hull protection. At present, the antimicrobial agent Euxyl® K100 (isothiazolinone) has a significant antimicrobial effect in the field, but it has a certain negative impact on the environment and archeologists. In order to reduce the use of chemical antimicrobial agents, we evaluated the inhibitory effects of cinnamaldehyde on the main destructive microorganisms of Nanhai No. 1. Cinnamaldehyde is the main active component of cinnamon, and has broad-spectrum antimicrobial properties. The paper diffusion method, gas diffusion method and minimum inhibitory concentration experiment were used to detect the inhibitory effects of cinnamaldehyde on the main microorganisms of Nanhai No. 1. We found that cinnamaldehyde had significant inhibitory effects on Bacillus tequilensis NK-NH5, Bacillus megaterium NK-NH10, Bacillus velezensis NK-NH11, Bacillus sp. NK-NH15, Bacillus sp. NK-NH16, Bacillus sp. NK-NH17, Fusariumsolani NK-NH1 and Scedosporiumapiospermum NK.W1-3. At the same time, cinnamaldehyde had more inhibitory effects on fungi than bacteria. Finally, we verified that cinnamaldehyde can effectively inhibit the growth of microorganisms in water, for storing the scattered wood blocks of the Nanhai No. 1 hull through laboratory simulation experiments. Cinnamaldehyde, as an environment-friendly antimicrobial agent, is of great significance to protecting water-saturated wooden relics from microbial corrosion and degradation in the future.

Biocide Use in the Antimicrobial Era: A Review.

Biocides are widely used in healthcare and industry to control infections and microbial contamination. Ineffectual disinfection of surfaces and inappropriate use of biocides can result in the survival of microorganisms such as bacteria and viruses on inanimate surfaces, often contributing to the transmission of infectious agents. Biocidal disinfectants employ varying modes of action to kill microorganisms, ranging from oxidization to solubilizing lipids. This review considers the main biocides used within healthcare and industry environments and highlights their modes of action, efficacy and relevance to disinfection of pathogenic bacteria. This information is vital for rational use and development of biocides in an era where microorganisms are becoming resistant to chemical antimicrobial agents.

From Chemistry to Biology: Applications and Advantages of Green, Biosynthesized/Biofabricated Metal- and Carbon-based Nanoparticles

Metal- and carbon-based nanoparticles (MBNPs/CBNPs) with different nanometric dimensions have unique combinations of physical and chemical properties. The physico-chemical properties, morphology, and interactions of nanomaterials with biological systems differ according to the source of synthesis and the extent and type of functionalization involved, which have many advantages for exciting nanotechnological applications in the fields of chemical and biological sciences. The biosynthesis and biofabrication of nanomaterials are achieved in a myriad of ways using plants and microorganisms. Greener synthesis has been conducted using the extracts of plants or other biological entities. This review focuses on the recent insights in the green and biological synthesis of MBNPs based on cadmium, cerium, copper, gold, iron, manganese, nickel, palladium, platinum, selenium, silver, titanium, yttrium, zinc, and zirconium, and CBNPs, such as carbon dots (CDs), as well as their chemical and biological applications, such as chemical catalysis, anticancer, antioxidant, antimicrobial, antibiofilm, antidiabetic, insecticidal, scolicidal, antileshmanial, angiogenesis, and immunostimulant agents, and as tools for bioimaging, biosensing, and drug delivery.

Comparative inhibitory effects of 4-allylpyrocatechol isolated from Piper betle on Streptococcus intermedius, Streptococcus mutans, and Candida albicans

Streptococcus intermedius, Streptococcus mutans, and Candida albicans are harmful oral pathogens and prone to resist chemical antimicrobial agents. Active ingredients from plants are of increasing interest as an alternative. This study aims to compare antimicrobial effects of 4-allylpyrocatechol (APC) extracted from Piper betle on these oral pathogens. Minimum concentration of APC against the tested pathogens was determined using a broth microdilution assay. Killing kinetic study of APC was carried out within 24 h. Morphology of the pathogenic cells was assessed using scanning electron microscopy (SEM). Anti-biofilm was investigated using crystal violet assay and confocal laser scanning microscopy (CLSM). The results showed that the mechanism of inhibition of APC was bactericidal and fungicidal effects. APC at minimum concentration of 400 μg/mL could completely kill Streptococcus and Candida spp., however, the killing rate on S. intermedius and C. albicans was significantly faster than on S. mutans. APC inhibited biofilm formation of C. albicans more efficiently than that of the bacterial cells. Cell morphology from SEM indicated that APC caused bacterial cell membrane destruction and inhibited fungal budding or tubing formation. CLSM images confirmed the killing potential of APC and suggested that bacterial dead cells could be easier washed out than the fungal dead cells. It is concluded that APC potentially inhibits growth and biofilms of oral Streptococcus and Candida spp. in different mechanism of action and killing rate. APC can be considered as a promising agent for preventing and treating dental disorders caused by S. intermedius, S. mutans, and C. albicans.

Role of Photodynamic Therapy in Endodontics―A Review

The irrigants used commonly do not always eradicate the entire microbial flora in infected root canals. Thus in quest other strategies, such as photodynamic therapy (PDT) have been developed. The word photodynamic means the applications of the dynamics of photons of light on the biological molecules. German physician Friedreich Mayer performed the first study, which was first called as photo-radiation therapy with porphyrins (1913) in humans. Photoactivated disinfection is based primarly on the interaction of a photosensitive antibacterial agent and a light source which uses a nontoxic dye named photosensitizer (PS) and lowintensity visible light. In the presence of oxygen, these combine to produce some cytotoxic species. The PS molecules attach to the bacteria membrane. Irradiation with a specific wavelength of the light may result in the production of singlet oxygen, resulting in rupture of the microbial cell wall. There are several applications for PDT in dentistry.. Photodynamic therapy has also been used to disinfect caries dentin before the restoration, disinfecting oral tissues before or during surgical procedures, treating denture stomatitis, and treating oral candidiasis in immunocompromised patients. Photodynamic therapy can also be used in combination with mechanical instrumentation and chemical antimicrobial agents, such as sodium hypochlorite.

Synthesis, antibacterial properties and bioinformatics computational analyses of novel 8-hydroxyquinoline derivatives

New heterocyclic derivatives of 8-hydroxyquinoline were prepared and screened as antimicrobial agents. Chemical structures were elucidated and confirmed using different spectroscopic methods such as elemental analysis data, Infrared, Nuclear Magnetic Resonance Spectroscopy. In order to explore their potential biological activity, the “in vitro” antibacterial activity was investigated against [E. coli (ATCC35218), S. aureus (ATCC29213), V. parahaemolyticus (ATCC17802), and P. aeruginosa (ATCC27853)]. The studied compounds exhibited a remarkable antibacterial activity superior to the standard antibiotic (Penicillin G). These new heterocyclic derivatives of 8-hydroxyquinoline, which proved to be potentially effective, can be used as alternative chemical antimicrobial agents applications. It was very interesting to observe that POM (Petra/Osiris/Molinspiration) bioinformatic analyses of the 8-hydroxyquinoline derivative (5) exhibited more important antibacterial activity (MIC = 10−6 mg/mL against V.p and S.a bacteria) and good drug score (DS = 0.71) when compared with Penicillin (DS = 0.33; MIC = 10−3 mg/mL).

ANTIMICROBIAL ACTIVITY AND PHYTOCHEMICAL STUDY OF PLANT PARTS OF BUTEA MONOSPERMA

ABSTRACT: Since ancient times, plants have been model source of medicines as they are a reservoir of chemical agents with therapeutic properties. The general population is increasingly using herbal medicines as dietary supplements to relieve and treat many different human disorders. All parts of the plant, from root to fruit, consisting of a multitude of secondary metabolites which impart an unprecedented variety of medicinal uses to the plant. Studies have shown the presence of different phytochemical constituents in botanical sample responsible for the antimicrobial activity. These antimicrobial agents should be beneficial to host cells and toxic to pathogenic microbes. Hence, the antibacterial activity was examined from the leaf and flower of Butea monosperma. Sample was collected and its crude extract was obtained by using methanol, acetone and water as the extraction solvent. These extract were tested against some pathogenic microorganisms like Staphylococcus aureus , Bacillus cereusa and B. subtilis. The extract of Butea monosperma showed antibacterial activity against Staphylococcus aureus , Bacillus cereusa and B. subtilis. Bio-chemical test for the presence of phytochemicals have shown positive result and these phytochemicals have ability to fight against microorganisms or inhibit the growth of microorganisms. This approach will be an advanced step in the discovery of some herbal drugs. These plant extracts which was proven to be potentially effective can be used as a natural alternative to the chemical preservatives. It could be an ideal way to avoid health hazards that may occur due to chemical antimicrobial agents.

Advances in nanotechnology for sustainable aquaculture and fisheries

AbstractIn recent years, aquaculture is considered a fastest‐blooming global food industry, playing a crucial role in fulfilling the increased demand for animal protein requirements. However, disease prevalence, chemical contamination, environmental degradation and ineffective feed utilization are the factors that drastically hinder the outcome of this sector in aiding to achieve global food security. In this regard, new avenues have been paved in science and technology to cope with these challenges in aquaculture. Among these, nanotechnology has emerged a tremendous potential to improve aquaculture with novel nanotools. This review critically analyses the advances in the application of nanoparticles and emulsion‐based systems to fish disease prevention, water purification and delivery of nutrients. On the other hand, as the use of antibiotics and other chemical antimicrobial agents, synthetic compounds as growth enhancers not only leads to aquaculture pollution but also consumer's reluctance. Therefore, the importance of ecofriendly, non‐toxic natural strategies to promote sustainable aquaculture has also been highlighted.