Ultrasmall silver nanoclusters: Highly efficient antibacterial activity and their mechanisms

2017 ◽  
Vol 5 (2) ◽  
pp. 247-257 ◽  
Author(s):  
Jian-Cheng Jin ◽  
Xiao-Juan Wu ◽  
Juan Xu ◽  
Bei-Bei Wang ◽  
Feng-Lei Jiang ◽  
...  

We study the antibacterial activities of bifunctional fluorescent DHLA-AgNCs against three types of bacteria, and the antibacterial mechanisms against differentE. colistrains are different.

Author(s):  
Olufunmiso O. Olajuyigbe ◽  
Morenike O. Adeoye-Isijola ◽  
Otunola Adedayo

Background: Black soap is a medicinal product that could be harnessed for economic purpose if properly packaged, and misconception about its traditional use by herbalists is thrown overboard.Aims: To promote the relevance of these soaps for economic development, this study compared the antibacterial activity of black soaps with medicated soaps widely used against bacterial infections.Methods: The antibacterial activities of these soap samples were determined by agar diffusion and macrobroth dilution methods.Results: In this study, the statistical analysis of the inhibition zones showed that black soaps were significantly (p < 0.05) more active than medicated soaps used against the test bacterial isolates. The black soaps inhibited and killed the isolates better than the medicated soaps at the different concentrations used. The minimum inhibitory concentration for Klebsiella pneumoniae and Enterococcus faecalis ranged between 0.125 mg/mL and 2 mg/mL, Staphylococcus aureus (0.25–4) mg/mL, Escherichia coli (0.125–4) mg/mL and Pseudomonas aeruginosa (1–4) mg/mL. The result showed that K. pneumoniae and E. faecalis were the most susceptible, followed by E. faecalis > E. coli > S. aureus > P. aeruginosa.Conclusion: As a valuable medicinal output derivable from organic waste product that could be converted to wealth, African black soap production, utilisation and commercialisation have tremendous economic potentials. These soaps showed significant antibacterial activity greater than those of the medicated soaps. Hence, their use could be a better option in place of commercially available medicated and antiseptic soaps because of the degree of antibacterial activities they exhibited.


RSC Advances ◽  
2019 ◽  
Vol 9 (23) ◽  
pp. 13275-13282 ◽  
Author(s):  
Xizhe Li ◽  
Tao Fu ◽  
Bingyu Li ◽  
Peng Yan ◽  
Yayan Wu

Riboflavin acted as a surface coating to synthesize ultrasmall silver nanoclusters and RF@AgNCs possessed highly efficient antibacterial activity and good biocompatibility.


2021 ◽  
Vol 21 (3) ◽  
pp. 1430-1438
Author(s):  
Hongyang Yu ◽  
Runxuan Chu ◽  
Xue Li ◽  
Bing Wang ◽  
Wei Chen ◽  
...  

Graphene oxide (GO) sheets attracted great attention as effectively antibacterial agents in water treatment and environmental remediation applications. In the study, the interaction of humic acid (HA) as the model of natural organic matter (NOM) with GO and their antibacterial activities against Escherichia coli (E. coli) was investigated. The interaction between GO and HA molecules was analyzed by isothermal titration calorimetry (ITC) and fluorescence spectroscopy analysis. The study demonstrated that GO reaction with HA was a spontaneously exothermic process, which enabled formation of stable and well dispersed GO-HA complex in aqueous solution. Both GO and GO-HA could significantly inhibit the growth of E. coli and present dose-dependent bactericidal property. GO and GO-HA showed more obvious antibacterial activity in saline solution than in LB broth. We suggest the surface wrinkles of GO and GO-HA could contribute to the firm wrapping of E. coli, which is the principle factor for the antibacterial activity of GO and GO-HA. Especially, GO-HA exhibit less surface wrinkles in comparison with GO, corresponding to its reduced antibacterial activity in saline solution.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Thanh Dung Ngo ◽  
Thi My Hanh Le ◽  
The Huu Nguyen ◽  
Thien Vuong Nguyen ◽  
Tuan Anh Nguyen ◽  
...  

For the vulcanized natural rubber (NR), incorporation of silver nanoparticles (AgNPs) into the NR matrix did not exhibit the bactericidal property against Escherichia coli (E. coli). However, incorporation of AgNPs into polyethylene (PE) matrix showed good antibacterial activities to both Gram-negative and Gram-positive bacteria. In the present work, NR/PE (85/15) blends have been prepared by melt blending with presence of compatibilizer in an internal mixer. To possess antibacterial property, AgNPs (5–10 nm) or Fe3O4–Ag hybrid nanoparticles (FAgNPs, 8 nm/16 nm) were added into PE matrix before its blending with NR component. The tensile test indicated that the presence of compatibilizer in NR/PE blend significantly enhanced the tensile strength and elongation at break (up to 35% and 38% increases, resp.). The antibacterial activity test was performed by monitoring of the bacterial lag-log growth phases with the presence of nanocomposites in the E. coli cell culture reactor. The antibacterial test showed that the presence of FAgNPs in NR/PE blend had a better antibacterial activity than that obtained with the lone AgNPs. Two similar reasons were proposed: (i) the faster Ag+ release rate from the Fe3O4–Ag hybrid nanoparticles due to the electron transfer from AgNP to Fe3O4 nanoparticle and (ii) the fact that the ionization of AgNPs in hybrid nanostructure might be accelerated by Fe3+ ions.


2021 ◽  
pp. e304
Author(s):  
Candy GERGES ◽  
Mohamad HADLA ◽  
Michele ELIALI ◽  
Martine RICHA ◽  
Nour Mammari ◽  
...  

Background: Thousands of people are dying as a result of infections caused by bacteria. Among the main routes of germ transmission are the hands, making hand hygiene very important in preventing the spread of pathogens and bacterial infection. Hand washing with soap and water is considered to be a simple and effective measure. Old soap manufacturers have long had traditional uses in the Lebanese community. Methods: The purpose of this study is to compare the antibacterial activity of oil-based soaps with commercial soap sold in the Lebanese market. Different types of herbal soap and antiseptics have been used in this study. Four bacterial strains were used: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli and Enterobacter Spp. The antibacterial activities of these soaps were determined by the diffusion method of disks in agar medium. Results and Discussion: Statistical analysis of zones of inhibition showed that S. epidermidis, P. aeruginosa and Enterobacter Spp. were sensitive only to traditional oil-based soaps, which are Sage, Rose Mary and Cedar. In addition, S. aureus showed sensitivity to soaps comprised of essential oils as well as antibacterial synthetic soap, Dettol and Lifebuoy. On the other hand, E. coli showed resistance to all soaps. Soaps comprised of natural essential oils have shown antibacterial activity superior to so-called “Antibacterial” soaps. Conclusion: Based on this study, we can say that the use of soaps with essential oils might be the best option due to their organic origin as well as their antibacterial proved activities.


MEDULA ◽  
2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Nur Illiyyin Akib ◽  
Mariani Triwatami ◽  
Andi Eka Purnama Putri

Background: Eucheuma spinosum seaweed contain flavonoid, triterpenoid, alkaloids and polyphenol which has been widely used in antibacterial activity. Purpose(s):The aim of the research are to determine antibacterial activities of metanol extracts of E. spinosum against Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922; to formulate hand wash of seaweed of methanol extract E. spinosum that has antibacterial activity and has physical and chemical stability. Methods: Seaweed E.spinosum methanol extract was derived by maceration method. Antibacterial activities of the extract were tested by liquid dilution and solid dilution method. Hand wash was formulated by mechanical dissolved methods. Antibacterial activity of hand wash were tested by liquid dilution and solid dilution method. Physical and chemical stabilities were conducted by cycling test. Results:. These were showed through minimum inhibitory concentration (MIC) of ethanol extracts of E. spinosum against S. aureus ATCC 25923 at concentrations of 6% and E. coli ATCC 25922 at concentrations of 6%. The minimum bactericidal concentration (MBC) of ethanol extracts of E. spinosum against S. aureus ATCC 25923 at concentrations of 8% and E. coli ATCC 25922 at concentrations of 8%. Formulation of hand wash seaweed E. spinosum methanol extract at concentrations of 8% and 10%. The test of stabilities results of hand wash changes were organoleptic, viscosity, pH, and foaming ability were accordance to qualified standard. The antibacterial activity of hand wash contains seaweed E. spinosum methanol extract at concentration of  8% and 10% have bactericidal activity againts S. aureus ATCC 25923 and E. coli ATCC 25922. Conclusion: Overall, these results suggested that formula of hand wash contains E. spinosum metanol extracts have antibacterial properties against S. aureus ATCC 25923 and E. coli ATCC 25922.Keywords: antibacterial, Eucheuma spinosum, hand wash, physical and chemical stability Latar Belakang: Rumput laut Eucheuma spinosum mengandung flavonoid, triterpenoid, alkaloid, dan polifenol yang memiliki aktivitas antibakteri. Tujuan: Penelitian ini bertujuan mengetahui aktivitas antibakteri ekstrak metanol E. spinosum terhadap Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922; membuat sediaan sabun cuci tangan dari ekstrak metanol E. spinosum yang memiliki aktivitas antibakteri dan stabil secara fisika dan kimia. Metode: Ekstrak metanol E. spinosum diperoleh dengan metode maserasi. Uji aktivitas antibakteri ekstrak dilakukan dengan metode dilusi cair dan dilusi padat. Sabun cuci tangan diformulasi dengan metode pencampuran mekanik. Uji aktivitas antibakteri sabun cuci tangan dilakukan dengan metode dilusi cair dan dilusi padat. Uji stabilitas fisika kimia dilakukan dengan metodecycling test. Hasil: Konsentrsi Hambat Minimum (KHM) ekstrak metanol E. spinosum terhadap S. aureus ATCC 25923 adalah 6% dan terhadap E. coli ATCC 25922 adalah 8%. Ekstrak metanol E. spinosum dapat diformulasi menjadi sabun cuci tangan dengan konsentrasi 8% dan 10%. Uji stabilitas menunjukkan bahwa perubahan organoleptik, viskositas, pH, dan kemampuan membentuk busa masih berada dalam nilai yang dipersyaratkan. Uji aktivitas antibakteri sabun cuci tangan yang mengandung ekstrak metanol E. spinosum dengan konsentrasi 8% dan 10% memiliki aktivitas antibakteri terhadap ATCC 25923 and E. coli ATCC 25922. Simpulan: Formula sabu cuci tangan yang mengandung ekstrak metanol E. spinosum memiliki aktivitas antibakteri terhadap ATCC 25923 and E. coli ATCC 25922.Kata kunci: antibakteri, Eucheuma spinosum, sabun cuci tangan, stabilitas fisika kimia


2021 ◽  
Vol 2 (2) ◽  
pp. 16-24
Author(s):  
Sara Hajib ◽  
Mohamed Hssaini ◽  
Anouar Alami ◽  
Hicham Bekkari ◽  
Najoua Benchemsi ◽  
...  

Bacterial resistance to antibiotics and disinfectants has become a real concern. The hospital presents a favorable environment for the colonization and development of bacteria resistant to antibiotics and disinfectants. The search for new antimicrobial compounds is essential to combat this phenomenon. Tetrazole derivatives may represent a solution due to their interesting antibacterial activity. In this work, two tetrazole derivatives; thiophene-2-carbaldehyde (T2C) and 5-(thiophen-2-yl)-1H-tetrazole (5TPh-1HT), were evaluated for their antibacterial activities against a set of reference strains and strains isolated from the hospital environment. The antibacterial effect was studied by the disc diffusion method and by determination of MIC and MBC. The 5-(thiophen-2-yl)-1H-tetrazole (5TPh-1HT) has a broader spectrum of activity than its oxime derivative (T2C). The latter has bactericidal activity only on gram-negative Escherichia coli, Pseudomonas aeruginosa with MICs ranging from 0.62 mg/ml to 2.5 mg/ml, while 5TPh-1HT has a bactericidal effect on all strains with MICs ranging from 0.62 mg/ml to 1.25 mg/ml. Both products have a significant inhibitory activity on the strains tested in particular E. coli H, S. aureus H, P. aeruginosa and Streptococcus spp A. It was found that these activities vary depending on the microbial strain tested and the product applied.


Author(s):  
Kaur M. ◽  
Sharma S. ◽  
Garg S. ◽  
Arora M.

This study describes the antibacterial activities of three different solvent extracts of leaves of Chenopodium album. Methanol, acetone and chloroform extracts of C. album were prepared. The antibacterial activity was assessed using well plate method and were examined for the size of zone of inhibition. Different extracts were investigated against the test organisms namely Lactobacillus, Bacillus subtilis and Escherichia coli. The maximum activity was observed at 100% concentration of different extracts of leaves. The maximum zone of inhibition for 100% concentration were observed as E. coli (19 mm) and Lactobacillus (19 mm) in diameter respectively. C. album did not show any antibacterial activity against B. subtilis. Antibacterial activity was compared with standard Amoxicillin and it was found to be 23 mm diameter for Lactobacillus and 25 mm for both E. coli and B. subtilis in terms of zone of inhibition.


2021 ◽  
Vol 5 (1) ◽  
pp. 436-444
Author(s):  
Sabiu Shitu ◽  
M. Attahiru ◽  
F. A. Iliya

The antibacterial activity of Tokar sha; a local traditional medication widely used by many people in North-west zone of Nigeria especially Sokoto, Kebbi and Zamfara against enteric infections were examined against some clinical isolates of pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Bacillus cereus and Salmonella typhi) using agar well diffusion method. The pattern of inhibition varied with the tokar sha concentrations and the organisms tested. The tokar sha was more effective on E. coli with a maximum zone of growth inhibition of 25mm at 35mg/ml followed by B. cereus (20mm). However, S. aureus and S. typhi were resistant to tokar sha at all concentrations tested. The minimum inhibitory concentrations (MIC) were found to be 35mg/ml for both E. coli and B. cereus. The antibacterial activities exhibited by tokar sha in this study could be attributed to the presence of its constituents which signifies the potential of the tokar sha as a therapeutic agent. These findings may justify the ethnomedicinal use of tokar sha as an antibacterial agent against enterobacteria


2021 ◽  
Vol 6 (3) ◽  
pp. 189-195
Author(s):  
Hary Widjajanti ◽  
Christina Vivid Handayani ◽  
Elisa Nurnawati

The antibiotic resistance of phatogenic bacteria has become a serious health problem and has encouraged the search for novel and effective antimicrobial metabolites. Meanwhile, endophytic fungi have great potential as a natural source for antimicrobial agents. The endophytic fungi that live in plant tissue produces secondary metabolites which potentially act as an antibacterial compound. The isolation of fungi for antibacterial sources reduces the large amount of plant as a source of antibacterial agents. Hence, this study aims to obtain endophytic fungi isolates from Paederia foetida L. that are capable of producing secondary metabolites as antibacterial, carry out in vitro tests to verify the antibacterial properties of secondary metabolites of the Paederia foetida L. endophytic fungi, and identify the potential of Paederia foetida L. endophytic fungi in producing antibacterial compounds. The antibacterial activity was tested against Escherichia coli ATCC8739 and Staphylococcus aureus ATCC6538 while seven isolates of endophytic fungi that potentially produced antibacterial were obtained from Sembukan (P. foetida L.). The results showed that antibacterial activities of SL1, SL4 and SL6 secondary metabolites against S. aureus ATCC6538 and E. coli ATCC8739 were moderate to strong activities. Furthermore, the Minimum Inhibition Concentration (MIC) of secondary metabolites extract of SL1 against S. aureus ATCC6538 value was 250 ????g/mL while the values of MIC extract of SL4 against S. aureus ATCC6538 and E. coli ATCC8739 were 125 ????g/mL and 250 ????g/mL respectively and MIC extract of SL6 against E. coli ATCC8739 value was 125 ????g/mL. The secondary metabolites extract of SL1 isolate were alkaloid and tannin, SL4 were phenolic and alkaloid while SL6 isolate were alkaloid and terpenoid. Hence, endophytic fungi SL1 isolate was identified as Fusarium sp., SL4 as Dematophora sp., and SL6 isolate as Acremonium sp.


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