scholarly journals Silver Nanoparticles for Photocatalysis and Biomedical Applications

2021 ◽  
Author(s):  
William Leonardo da Silva ◽  
Daniel Moro Druzian ◽  
Leandro Rodrigues Oviedo ◽  
Pâmela Cristine Ladwig Muraro ◽  
Vinícius Rodrigues Oviedo

The present chapter aims to overview the application of silver nanoparticles (AgNPs) in photocatalysis and biomedical field. Firstly, the relevance of AgNPs will be addressed. Then, the discussion about the photocatalytic activity of the AgNPs (either in suspension or impregnation), and correlation with your properties and its potential application to organic pollutants degradation under UV and visible/solar radiation will be described. Thus, applications of the AgNPs as antimicrobial agents, such as Escherichia coli, Schizophyllum commune, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Haemophilus influenzae, Bacillus subtilis, Bacillus cereus and Enterobactor faecalis, and in the development of biosensors will be discussed. Therefore, the present work will be important to contextualize different scenarios to AgNPs mainly to wastewater treatment and diagnosis/therapeutic applications.

Author(s):  
Powar Priyatama V ◽  
Powar Trupti A

The growing phenomenon of antibiotic resistance, particularly to pathogenic microorganisms, in current medicine, has directed the concern of scientists for finding novel antimicrobial agents from plant origin with negligible side effect. The present study was aimed to phytochemical investigation and antimicrobial activity of seed extract of Datura stramonium in sequentially with different organic solvents. For this, antimicrobial properties were tested against bacteria Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia and Bacillus subtilis by cup plate method. Among the tested bacterial Klebsiella pneumoniae was the most inhibited majorly with the chloroform extract. Datura stramonium chloroform seed extract produced maximum zone of inhibition 26 mm against Klebsiella pneumoniae and 12 mm against Bacillus subtilis and 13 mm against Escherichia coli. Datura Stramonium methanol seed extract produced maximum zone of inhibition 27 mm against Pseudomonas aeruginosa and 15 mm against Bacillus subtilis, 14 mm against Staphylococcus aureus and 19 mm against Escherichia coli. Datura stramonium petroleum ether seed extract produced 16 mm zone of inhibition against Escherichia coli. Datura stramonium aqueous seed extract exhibits 24 mm zone of inhibition against Bacillus subtilis. All the experienced solvent extracts showed potential antimicrobial activity Index against various tested microorganisms. Owning to the results, it can be concluded that the extracts of the Datura stramonium can be used to design different herbal antimicrobial agents.


Author(s):  
Nur Aishah Abdul Wahab ◽  
Hairul Shahril Muhamad ◽  
Nabilah Ahmad Alhadi ◽  
Salina Mat Radzi ◽  
Maryam Mohamed Rehan ◽  
...  

Combination effects between Cymbopogon flexuosus and Cymbopogon nardus essential oils were studied to determine whether the combination could emerge as better and more powerful antimicrobial agents against six selected bacteria includes Bacillus subtilis, Escherichia coli, Salmonella typhimurium, Serratia marcescens, Staphylococcus aureus, and Staphylococcus epidermidis. This combination study exhibited 40.67% additive, 28.67% antagonistic, 16.00% indifferent and 14.66% synergistic effects. C. flexuosus and C. nardus essential oils in combination showed a high inhibitory activity against S. aureus with 16% synergistic, 64% additive and 20% indifferent effects.


2020 ◽  
Vol 39 (03) ◽  
Author(s):  
VĂN HỒNG THIỆN ◽  
LÊ BÍCH TRÂM ◽  
NGUYỄN THANH LAN ◽  
HỒ NGUYỄN HOÀNG YẾN ◽  
LƯU HỒNG TRƯỜNG ◽  
...  

Nghiên cứu này đã xác định được mẫu nghiên cứu thu tại Vườn quốc gia Phú Quốc là loài Homalomena pierreana. Thông qua kỹ thuật sắc ký ghép khối phổ, 10 hợp chất thuộc nhóm sesquiterpene có trong cao chiết ethanol của thân rễ loài H. pierreana đã được xác định. Ngoài ra, cao chiết ethanol từ mẫu nghiên cứu cũng cho thấy khả năng kháng lại 6 chủng vi khuẩn kiểm định là Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis và Salmonella typhimurium.


Author(s):  
LUCIANA HELENA MAIA PORTE ◽  
MARIA HELENA MIGUEZ ROCHA LEÃO ◽  
ALEXANDRE PORTE

Lactoferrina bovina (bLF), proveniente do soro de leite, foimicroencapsulada pela técnica de spray drying. Microcápsulascontendo 20 % de bLF foram produzidas, utilizando-se comomaterial de parede dextrina: amido octenilsuccinato (OSA) emdiferentes proporções: 100:00, 75:25, 50:50, 25:75 e 0:100 %.Foram avaliadas a cor e a estabilidade de cor das microcápsulassob armazenamento em ambientes com diferentes umidadesrelativas e a atividade antimicrobiana da lactoferrina liberadadas microcápsulas. As microcápsulas apresentaram cor clara etenderam a escurecer sob armazenamento em ambiente com altaumidade relativa. Verifi cou-se atividade inibitória das microcápsulasde bLF produzidas para diferentes bactérias Gram positivas(Bacillus subtilis CCT 2576, Staphylococcus aureus CCT 2740,Micrococcus luteus CCT 2692, Enterococcus faecium CCT 5079,Streptococcus faecium ATCC 10541, Rhodococcus equi CCT0541), Gram negativas (Pseudomonas aeruginosa ATCC 13388,Salmonella choleraesius CCT 4296, Escherichia coli CCT 0547) elevedura (Candida albicans ATCC 10231). A concentração inibitóriamínima (MIC) das microcápsulas variou de acordo com o microorganismotestado (MIC entre 2,5-100 mg.mL-1). Com exceção deB. subtilis (MIC entre 50-100 mg.mL-1 para as microcápsulas), aconcentração de bLF contida nas microcápsulas necessária parainibir o crescimento dos micro-organismos foi menor do que a bLFnativa. Esses resultados sugerem efeito de potencialização daatividade antimicrobiana da bLF após o processamento por spraydrying.


2018 ◽  
Vol 13 (4) ◽  
pp. 1934578X1801300
Author(s):  
Daniyar Sadyrbekov ◽  
Timur Saliev ◽  
Yuri Gatilov ◽  
Ivan Kulakov ◽  
Roza Seidakhmetova ◽  
...  

A cyclopropane derivative of limonene, (1 S, 4 S, 6 R)-7,7-dichloro-4-[(1 S)-2,2-dichloro-1-methylcyclopropyl]-1-methylbicyclo [4.1.0] heptane (compound 2), was synthesized and its structure was determined by NMR and X-ray crystallographic methods. In addition, an antimicrobial activity of the compound against Gram-positive ( Staphylococcus aureus, Bacillus subtilis) and Gram-negative ( Escherichia coli, Pseudomonas aeruginosa) bacterial strains was also scrutinized.


2015 ◽  
Vol 10 (6) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Corina Danciu ◽  
Florin Borcan ◽  
Codruta Soica ◽  
Istvan Zupko ◽  
Erzsébet Csányi ◽  
...  

In recent years polyurethane microstructures (PM) have gained increasing attention in the pharmaceutical field due to the importance of their practical application. Since finding that such a formulation with genistein could improve its applications, we have conducted a preliminary study regarding the in vitro antiproliferative (MCF7, MDA-MB-231 and T47D) and antimicrobial ( Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis (D), Bacillus subtilis, B. cereus, and Candida albicans) activity in order to test whether polyurethane micro structuresre present a good option for further modulation of genistein's bioavailability. It was concluded that the polyurethane micro structures are a bad in vitro partner for the isoflavone genistein.


Medicina ◽  
2008 ◽  
Vol 44 (12) ◽  
pp. 977 ◽  
Author(s):  
Alvydas Pavilonis ◽  
Algirdas Baranauskas ◽  
Ligita Puidokaitė ◽  
Žaneta Maželienė ◽  
Arūnas Savickas ◽  
...  

Objective. To evaluate the antimicrobial activity of soft and purified propolis extracts. Study object and methods. Antimicrobial activity of soft and purified propolis extracts was determined with reference cultures of Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 33499, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 12459, Bacillus subtilis ATCC 6633, Bacillus cereus ATCC 8035, and fungus Candida albicans ATCC 60193. Microbiological tests were performed under aseptic conditions. Minimum inhibitory concentration (MIC) – the highest dilution of preparation (the lowest concentration of preparation) that suppresses growth of reference microorganisms – was determined. Results. Concentration of phenolic compounds in soft propolis extract that possesses antimicrobial activity against gram-positive (Staphylococcus aureus, Enterococcus faecalis) and gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis) is 0.587±0.054 mg and 0.587±0.054–0.394±0.022 mg (P>0.05) and in purified propolis extract – 0.427±0.044 mg and 0.256±0.02 mg (P>0.05). Klebsiella pneumoniae is most resistant to soft propolis extract when the concentration of phenolic compounds is 1.119± 0.152 mg and to purified propolis extract when the concentration of phenolic compounds is 1.013±0.189 mg (P>0.05). Spore-forming Bacillus subtilis bacteria are more sensitive to soft and purified propolis extracts when the concentration of phenolic compounds is 0.134±0.002 mg and 0.075±0.025 mg, respectively, and Bacillus cereus – when the concentration is 0.394±0.022 mg and 0.256±0.02 mg (P>0.05). Sensitivity of fungus Candida albicans to soft and purified propolis extracts is the same as Bacillus subtilis. Encapsulated bacterium Klebsiella pneumoniae is most resistant to antimicrobial action of soft and purified propolis extracts as compared with gram-positive Staphylococcus aureus and Enterococcus faecalis bacteria (P<0.05), gram-negative Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis (P<0.05), sporeforming Bacillus subtilis and Bacillus cereus bacteria (P<0.05), and fungus Candida albicans (P<0.05). There is no statistically significant difference between antimicrobial effect of soft propolis extract and purified propolis extract on gram-positive bacteria, gram-negative bacteria, spore-forming bacteria, encapsulated bacteria, and Candida fungus. Conclusions. Soft and purified propolis extracts possess antimicrobial activity. They could be recommended as natural preservatives in the manufacture of pharmaceutical products.


2012 ◽  
Vol 15 (2) ◽  
pp. 78-83
Author(s):  
Reider Vivanco T ◽  
Enrique León S ◽  
Américo Castro L ◽  
Norma J Ramos C

El estudio tuvo como objetivo analizar la composición química del aceite esencial de las hojas de Petroselinum crispum (Mill) Nyman ex A.W. Hill “perejil” y determinar su actividad antibacteriana. El aceite esencial se obtuvo tratando 20 kg de hojas frescas con un equipo de destilación por arrastre con vapor de agua; obteniéndose cuatro mililitros y un rendimiento de 0,02 por ciento v/p. En el análisis cualitativo se analizó su solubilidad en solventes orgánicos; los componentes químicos se determinaron por cromatografía de Gases/ Espectrometría de Masas (CG/EM), lográndose la elucidación de los siguientes compuestos: 1R-α-pineno, β-pineno, β-felandreno, p, α-dimetil estireno, (E)-2-caren-4-ol, 1,3-benzodioxol, 4-metoxi-6-(2-propenil)-, y 1,3-benzodioxol,4,7-dimetoxy-5-(2-propenil)-. La determinación de la actividad antibacteriana in vitro, se realizó por el método de difusión en agar, demostrándose actividad significativa frente a Staphylococcus aureus ATCC 25933 y Staphylococcus epidermidis cepa clínica, a las concentraciones de 100 y 50 por ciento; y para Pseudomonas aeruginosa ATCC 2783 a la concentración de 100 por ciento, teniendo de poca a ninguna actividad frente a Bacillus subtilis y Escherichia coli. Los resultados obtenidos muestran que el aceite esencial de Petroselinum crispum (Mill) Nyman ex A.W. Hill “perejil” presenta actividad antibacteriana.


Author(s):  
E. A. Parashchuk ◽  
N. I. Tkachuk ◽  
S. M. Marchyshyn ◽  
H. R. Kozyr

Мета роботи. Визначення антимікробної активності бедринцю ломикаменевого підземних органів екстракту густого. Матеріали і методи.  Oб’єктoм для дoслідження обрано бедринцю ломикаменевого підземних органів екстракт густий (БЕГ-1, одержаний екстрагуванням 75 % етанолом і БЕГ-2, екстрагент 85 % етанол). В якості тест-культур використовували 5 музейних штамів: грампозитивні мікроорганізми Staphylococcus aureus АТСС 6538, спорову культуру Bacillus subtilis АТСС 6633, грамнегативну культуру Escherichia coli АТСС 25922 та Pseudomonas aeruginosa АТСС 9027. Антифунгальну дію з’ясовували відносно Candida albicans АТСС 885-653. Бактеріостатичні властивoсті дoсліджуваних oб’єктів встанoвлювали за результатами росту еталонних штамів мікроорганізмів у нативному водному розчині бедринцю та в розведені 1:2 та 1:4 в м'ясо-пептонному бульйоні; бактерицидні – за відсутністю росту вмісту пробірок із розведенням екстракту на щільних пoживних середoвищах (м’ясо-пептонний агар – МПА) для грампозитивних мікроорганізмів S. aureus, B. subtilis, для грамнегативної культури E. coli, P. аeruginosa. Агар Сабуро використовували для дріжджеподібних грибів роду Candida (C. аlbicans). Результати й обговорення. Бедринцю ломикаменевого підземних органів екстракт густий має широкий спектр антибактеріальної активності. Нативний екстракт БЕГ-1 по відношенню до тест-штамів S. aureus, B. subtilis, C. аlbicans проявляв бактерицидну дію. Бактеріостатичну дію він проявляв до P. aeruginosa, а по відношенню до E. coli антимікробного ефекту не виявлено. Екстракти в розведені 1:2 та 1:4 проявили бактерицидну дію відносно B. subtilis, бактеріостатичну – до S. aureus, C. albicans і не виявлено протимікробної дії до E. coli та P. aeruginosa. Нативний зразок БЕГ-2 по відношенню до усіх досліджуваних 5 тест–штамів проявив бактерицидну активність; у розведені 1:2 та 1:4 проявляв бактерицидну та бактеріостатичну дію відносно S. aureus, B. subtilis, C. albicans. Антимікробна дія по відношенню до E. coli та P. aeruginosa не виявлена. Антимікрoбну активність нативного бедринцю ломикаменевого екстракту густого також вивчали у дoслідах in vitro методом дифузії в агар –  метод “колодязів”. Штами S. aureus, C. albicans, B. subtilis, P. aeruginosa, E. coli проявили чутливість до нативного бедринцю ломикаменевого підземних органів екстракту густого. Грампозитивні бактеріальні штами S. aureus,а також гриби C. albicans, B. subtilis є найбільш чутливими до  БЕГ-2, а БЕГ-1 проявляв порівняно меншу чутливість. Грамнегативні культури P. aeruginosa та E. coli також проявили помірну чутливість до  БЕГ-1, але значно більшу чутливість до БЕГ-2. Висновки. 1. Експериментально встановлено, що обидва досліджувані зразки бедринцю ломикаменевого підземних органів екстракту густого проявляють антибактеріальну активність. 2. Бедринцю ломикаменевого підземних органів екстракт густий проявляв більш виражену антимікробну активність по відношенню до грампозитивної мікрофлори, тому є перспективним для створення лікарського засобу з антимікробними властивостями.


2016 ◽  
Vol 33 (3) ◽  
pp. 140-145
Author(s):  
Mst Laila Akter Banu ◽  
AKM Bashar ◽  
Md Mujibur Rahman Howlader ◽  
Md Shamsul Alam ◽  
Md Ashraf Hussain

Microorganisms, usually from the dental caries, are the main sources of diseases in dental pulp (root canals) and periapical region. Facultative bacteria and fungi have been identified in therapy resistant persistent endodontic infection. The objectives of this study was to evaluate the antimicrobial efficacy of Mineral Tri Oxide Aggregate (MTA) against therapy resistant endodontic microorganisms. The efficacy of MTA was also compared with that of calcium hydroxide. Six standard bacterial stains were used: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, bacillus subtilis, Candida albicans and Enterococcus faecalis. The agar diffusion method on Muller- Hilton media was employed. The plates containing media were inoculated with the specified bacterial suspensions. Two standard holes were prepared on each microorganism inoculated plate with a copper puncher and one hole was completely filled with MTA & the other with Ca (OH)2 . The plates were then kept at environmental temperature for one hour to ensure prediffusion and then incubated at 370C for 24 hours. After 24 hours, the diameters of inhibition zones were measured. Tests were replicated for thirty times for each sample and mean values were taken. Zone of inhibition as measured for MTA and Ca (OH)2 were statistically analyzed with Student’s t-Test and Post Hoc Games Howell Test and were presented as mean ± SD to compare of efficacy of MTA and calcium hydroxide on different microorganisms. Both MTA and Ca(OH)2 were found to produce zone of inhibition against Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), , Bacillus subtilis (BTCC 17 ), and Candida albicans (BTCC 493). MTA showed highest activity against S. aureus and lowest activity against P. aeruginosa which was similar to the activity range of Ca (OH)2 against the mentioned organisms. But both of them failed to produce any activity against E. coli and. E. faecalis. MTA was found to produce a lower efficacy than Ca (OH)2 while comparing the zone of inhibition between them and statistically it was significant. Mineral Tri Oxide Aggregate (MTA) showed antimicrobial efficacy against some therapy resistant microorganisms but it did not show antimicrobial efficacy against Escherichia coli and Enterococcus faecalis. MTA was found to produce a lower antimicrobial efficacy than Ca (OH)2.J Bangladesh Coll Phys Surg 2015; 33(3): 140-145


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