scholarly journals Plasmon-Enhanced Antibacterial Activity of Chiral Gold Nanoparticles and In Vivo Therapeutic Effect

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1621
Author(s):  
Yuelong Xu ◽  
Hongxia Wang ◽  
Min Zhang ◽  
Jianhao Zhang ◽  
Wenjing Yan

d-cysteine (d-cys) has been demonstrated to possess an extraordinary antibacterial activity because of its unique steric configuration. However, inefficient antibacterial properties seriously hinder its wide applications. Here, cysteine-functionalized gold nanoparticles (d-/l-Au NPs) were prepared by loading d-/l-cysteine on the surface of gold nanoparticles for the effective inhibition of Escherichia coli (E. coli) in vitro and in vivo, and the effects on the intestinal microflora in mice were explored during the treatment of E. coli infection in the gut. We found that the antibacterial activity of d-/l-Au NPs was more than 2–3 times higher than pure d-cysteine, l-cysteine and Au NPs. Compared with l-Au NPs, d-Au NPs showed the stronger antibacterial activity, which was related to its unique steric configuration. Chiral Au NPs showed stronger destructive effects on cell membrane compared to other groups, which further leads to the leakage of the cytoplasm and bacterial cell death. The in vivo antibacterial experiment illustrated that d-Au NPs displayed impressive antibacterial activity in the treatment of E. coli-infected mice comparable to kanamycin, whereas they could not affect the balance of intestinal microflora. This work is of great significance in the development of an effective chiral antibacterial agent.

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.


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.


Author(s):  
Ruvanthika Pn ◽  
Manikandan S

Objective: The objective of the study was to evaluate whether ethanolic extracts of Nelumbo nucifera (EENN) seedpod and quercetin (active component of NN) possess antibacterial proprieties against Gram (-) bacteria such as Escherichia coli and Pseudomonas aeruginosa and Gram (+) bacteria such as Staphylococcus aureus. Methods: Antibacterial activities of EENN seedpod and quercetin were investigated using disc diffusion method, minimum inhibitory concentration against E. coli and P. aeruginosa and Gram (+) bacteria such as S. aureus. Results: The antibacterial activity of both EENN seedpod and quercetin was found to be increased in dose-dependent manner. The maximum zone of inhibition was exhibited by both EENN seedpod and quercetin against E. coli (14 mm and 15 mm) and P. aeruginosa (13 mm and 15 mm). Gram-negative bacteria were more susceptible to the EENN seedpod extract and quercetin than Gram-positive bacteria.Conclusion: The results of the present study suggested that the effect of EENN seedpod and quercetin against the tested bacteria in vitro may contribute to the in vivo activities of the EENN seedpod and quercetin.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Adel S. Al-Zubairi ◽  
Ahmad Bustamam Abdul ◽  
Siddig Ibrahim Abdelwahab ◽  
Chew Yuan Peng ◽  
Syam Mohan ◽  
...  

The use of evidence-based complementary and alternative medicine is increasing rapidly.Eleucine indica(EI) is traditionally used in ailments associated with liver and kidneys. The therapeutic benefit of the medicinal plants is often attributed to their antioxidant properties. Therefore, the aim of this study was to screen the hexane, dicholoromethane, ethyl acetate (EA) and methanol extracts (MeTH) of EI for their antioxidant, antibacterial and anti-cancer effects using total phenolic contents (TPCs) and DPPH, disc diffusion method and MTT cytotoxicity assays, respectively. The MeTH was showed to have the highest TPC and scavenging activity (77.7%) on DPPH assay, followed by EA (64.5%), hexane (47.19%) and DCM (40.83%) extracts, whereas the MeTH showed no inhibitory effect on all tested bacteria strains. However, the EA extract exhibited a broad spectrum antibacterial activity against all tested bacteria exceptBacillus subtilis, in which this bacterium was found to be resistant to all EI extracts. Meanwhile, hexane extract was demonstrated to have a remarkable antibacterial activity against methicillin resistantStaphylococcus aureus(MRSA) andPseudomonas aeruginosa, while the dicholoromethane extract did not exhibit significant activity againstP. aeruginosa. None of the extracts showed significant cytotoxic activity towards MCF-7, HT-29 and CEM-SS human cancer cell lines after 72 h incubation time (IC50> 30 μg/ml). These results demonstrate that the extract prepared from the EI possesses antioxidant activityin vitroin addition to antibacterial properties. Further investigations are needed to verify the antioxidant effectsin vitroandin vivo.


2018 ◽  
Vol 34 (4) ◽  
pp. 2026-2030 ◽  
Author(s):  
Sarrah Sattar Jabbar

In search of novel antibacterial agent, a series of new isatin derivatives (3a-d) have been synthesized by condensation isatin (2,3-indolinendione) with piperidine (hexahydropyridine), hydrazine hydrate and Boc-amino acids respectively. Compounds synthesized have been characterized by IR spectroscopy and elemental analysis. In addition, the in vitro antibacterial properties have been tested against E. coli, P. aeruginosa, and Bacillus cereus, S. aureus by employing the well diffusion technique. A majority of the synthesized compounds were showing good antibacterial activity and from comparisons of the compounds, compound 3d has been determined to be the most active compound.


1990 ◽  
Vol 70 (2) ◽  
pp. 647-654 ◽  
Author(s):  
M. D. DREW ◽  
I. M. BEVANDICK ◽  
B. D. OWEN

Two iron chelators, ethylene diamine-di-orthohydroxyphenyl acetic acid (EDDHA) and N,N′-Bis(o-hydroxybenzyl)-ethylenediamine diacetic acid (HBED), were investigated as possible substitutes for lactoferrin in sow milk replacers. The antibacterial properties of lactoferrin, EDDHA and HBED, with and without porcine immunoglobulins, were compared in vitro using E. coli 0 157 K88. Lactoferrin and EDDHA inhibited the growth of E. coli over a 12-h incubation period, while HBED had no effect on bacterial growth. Porcine immunoglobulins inhibited the growth of E. coli after 6, but not after 12 h of incubation. Ethylene diamine-di-orthohydroxyphenyl acetic acid and HBED were further compared as substitutes for lactoferrin in sow milk replacers fed to colostrum-deprived piglets. All piglets received porcine immunoglobulins for 24 h following birth. They then received EDDHA, HBED or no chelator with or without porcine immunoglobulins on days 2–14. Piglets that received HBED had lower survival rates and weight gains than piglets that received EDDHA or no chelator. Weight gains were equal for piglets receiving either EDDHA or immunoglobulins alone and there was no additive effect on piglet weight gains when EDDHA and immunoglobulins were fed together. Ethylene diamine-di-orthohydroxyphenyl acetic acid may be a practical substitute for lactoferrin in sow milk replacers. Key words: Immunoglobulins, piglet, lactoferrin, iron chelators, E. coli


Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1099
Author(s):  
Domenico Franco ◽  
Giovanna Calabrese ◽  
Salvatore Petralia ◽  
Giulia Neri ◽  
Carmelo Corsaro ◽  
...  

Hydroxyapatite (HA) is the main inorganic mineral that constitutes bone matrix and represents the most used biomaterial for bone regeneration. Over the years, it has been demonstrated that HA exhibits good biocompatibility, osteoconductivity, and osteoinductivity both in vitro and in vivo, and can be prepared by synthetic and natural sources via easy fabrication strategies. However, its low antibacterial property and its fragile nature restricts its usage for bone graft applications. In this study we functionalized a MgHA scaffold with gold nanorods (AuNRs) and evaluated its antibacterial effect against S. aureus and E. coli in both suspension and adhesion and its cytotoxicity over time (1 to 24 days). Results show that the AuNRs nano-functionalization improves the antibacterial activity with 100% bacterial reduction after 24 h. The toxicity study, however, indicates a 4.38-fold cell number decrease at 24 days. Although further optimization on nano-functionalization process are needed for cytotoxicity, these data indicated that Au-NRs nano-functionalization is a very promising method for improving the antibacterial properties of HA.


2018 ◽  
pp. 31-38

Actividad antibacteriana de extractos vegetales frente a cepas intrahospitalarias, Iquitos-Perú Antibacterial activity of plant extracts against nosocomial strains, Iquitos-Peru Ricardo E. Abadie, Ronald Medina O., Lastenia Ruiz, Alvaro Tresierra-Ayala Laboratorio de Microbiología. Centro de Investigación de Recursos Naturales de la Universidad Nacional de la Amazonía Peruana (CIRNA-UNAP). Psje. Los Paujiles S/N, San Lorenzo, distrito de San Juan Bautista, Iquitos-Perú DOI: https://doi.org/10.33017/RevECIPeru2014.0005/  Resumen La región amazónica es una de las áreas que posee la mayor biodiversidad del mundo, albergando varios miles de especies de plantas, muchas de las cuales son utilizadas por sus pobladores como plantas medicinales. Durante los últimos años, el empleo de estos recursos vegetales o de sus productos viene incrementándose de manera importante, lo cual podría deberse a una serie de factores, entre los que destacan el conocimiento de su composición química, y al hecho que en la actualidad se han realizado numerosos ensayos farmacológicos tanto in vivo como in vitro. La aparición de cepas resistentes a los antibióticos comerciales en los últimos tiempos, está creando la necesidad de buscar otras estrategias o alternativas para controlarlas, tal es el caso del uso de las plantas (medicina tradicional), debido a los principios activos que poseen. Se pretende con este trabajo, determinar probables alternativas para combatir infecciones bacterianas de aquellos agentes drogoresistentes, este problema reviste importancia crítica particular en los países en desarrollo, donde quizás no se dispone de antibióticos de segunda línea más costosos o, si los hay, su precio es inasequible. El estudio se realizó en la ciudad de Iquitos, Provincia de Maynas, Departamento de Loreto. Los ensayos microbiológicos se realizaron en el Laboratorio de Microbiología del Centro de Investigación de Recursos Naturales de la Amazonia (CIRNA) de la Universidad Nacional de la Amazonia  Peruana (UNAP). Se determinó la actividad antibacteriana de 6 extractos vegetales (Alchornea triplinervia, Annona muricata, Averrhoa carambola, Brunfelsia grandiflora, Caraipa grandifolia y Cedrela odorata) mediante la técnica de difusión en disco, y a aquellos que presentaron actividad se les determinó la Concentración Inhibitoria Mínima y la Concentración Bactericida Mínima mediante la técnica de macrodilución en caldo. Ninguno de los extractos tuvieron actividad frente a las cepas de E. coli; cuatro extractos tuvieron actividad frente a las cepas de P. aeruginosa, siendo los extractos de Cedrela odorata y Alchornea triplinervia los que tuvieron mayor actividad frente a esta bacteria, con CIM = 15.62 y 62.5 mg/ml, respectivamente; todos los extractos tuvieron actividad frente a las cepas de S. aureus, siendo los extracto de C. odorata, A. triplinervia y Caraipa grandiflora, los de mayor actividad con una CIM = 3.91 mg/ml para cada uno.  Se obtuvieron prometedores resultados de actividad antibacteriana de los extractos en estudio frente a cepas intrahospitalarias, mayormente contra S. aureus. Descriptores: Actividad antibacteriana, extractos vegetales, cepas intrahospitalarias Abstract The Amazon region is one of the areas with the largest biodiversity in the world, hosting several thousand species of plants, many of which are used by its people as medicinal plants. In recent years, the use of these plant resources or products has been increasing significantly, which could be due to a number of factors, among them the knowledge of their chemical composition, and the fact that at present there have been numerous pharmacological tests both in vivo and in vitro. The emergence of antibiotic-resistant strains in recent years, is creating a need for other strategies or ways to control them, as in the case of the use of plants (traditional medicine), because the active ingredients bearing. This work is intended to determine probable alternatives to combat bacterial infections of those agents antibiotic-resistant, this problem is particularly critical in developing countries, where perhaps there are no antibiotics or expensive second line, if any, price is unavailable. The study was conducted in Iquitos city, Province of Maynas, Department of Loreto. Microbiological tests were performed at Microbiology Laboratory of Research Center of Natural Resources of the Amazon (CIRNA) of the National University of the Peruvian Amazon (UNAP). The antibacterial activity of six plant extracts (Alchornea triplinervia, Annona muricata, Averrhoa carambola, Brunfelsia grandiflora, Caraipa grandifolia y Cedrela odorata) by the disk diffusion method was determined, and those that showed activity were determined Minimum Inhibitory Concentration and Minimum Bactericidal Concentration by macrodilution technique. None of the extracts were active against strains of E. coli; four extracts had activity against strains of P. aeruginosa, with Cedrela odorata and Alchornea triplinervia extracts which had greater activity against these bacteria, with MIC = 15.62 and 62.5 mg/ml, respectively; all extracts were active against strains of S. aureus, with the extract of C. odorata, A. triplinervia and Caraipa grandiflora, the most active with an MIC = 3.91 mg/ml for each. Was obtained Promising results of antibacterial activity of the extracts in study against nosocomial strains, mostly against S. aureus. Keywords: Antibacterial activity, plant extracts, nosocomial strains


2019 ◽  
pp. 96-104
Author(s):  
N. Hrynchuk ◽  
N. Vrynchanu

The emergence and spread of antibiotic-resistant strains of microorganisms reduces the effectiveness of antibiotic therapy and requires finding solutions to problems, one of which is the study of antimicrobial properties in drugs of various pharmacological groups. The purpose of the work was to summarize the data on the antibacterial activity of thioridazine and its derivatives to determine the feasibility and prospects of creating new antibacterial drugs on their basis. The paper presents literature data on the effects of thioridazine on the causative agent of tuberculosis, antistaphylococcal activity, susceptibility of plasmodium and trypanosoma. The antibacterial activity of the drug was established within in vitro studies with the determination of MIC towards gram-positive and gram-negative microorganisms, ex vivo using macrophage lines, as well as within in vivo experiments on mice. It is established that the neuroleptic thioridazine is characterized by pronounced anti-tuberculosis activity, the mechanism of action is associated with the impact on the cell membrane of M. tuberculosis, inactivation by calmodulin and inhibition of specific NADH-dehydrogenase type II. The literature data indicate that thioridazine is able to increase the activity of isoniazid against the strains of mycobacteria that are susceptible and resistant to its action. It has been established that resistance to thioridazine in antibiotic-resistant M. tuberculosis strains is not formed. The drug is characterized by its ability to inhibit the growth and reproduction of both methicylin-sensitive (MSSA) and methicilin-resistant (MRSA) strains of Staphylococcus aureus, which has been proven within in vitro experiments. The effectiveness of thioridazine has been proven within in vivo experiments in case of skin infection and sepsis caused by S. aureus. Antimicrobial effect of the drug is also observed towards to plasmodium (P. falciparum) and trypanosomes (Trypanosoma spp.). Currently, the synthesis of thioridazine derivatives is carried out to identify compounds with a pronounced antibacterial effect. Some of the first synthesized compounds are not inferior or superior to thioridazine by the inhibitory effect. Thus, these data suggest that drugs of different pharmacological groups, including drugs that affect the nervous system - thioridazine and its derivatives, can be a source of replenishment of the arsenal of antimicrobial drugs to control such threatening infections as tuberculosis and diseases caused by polyresistant strains of microorganisms.


2016 ◽  
Vol 64 (3) ◽  
Author(s):  
Nelson Méndez Álvarez ◽  
Alberto Angulo Ortíz ◽  
Orfa Contreras Martínez

Bacterial resistance is a growing health problem worldwide that has serious economic and social impacts, compromising public health, and the therapeutic action of current antibiotics. Therefore, the search for new compounds with antimicrobial properties is relevant in modern studies, particularly against bacteria of clinical interest. In the present study, in vitro antibacterial activity of the ethanol extract and essential oil of Curcuma longa (Zingiberaceae) was evaluated against nosocomial bacteria, using the microdilution method. Escherichia coli strains, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus sp. were used, Salmonella sp. and Bacillus sp., isolated from nosocomial infections in a hospital in the city of Monteria and reference strains of S. aureus ATCC 43300, S. aureus ATCC 29213, S. aureus ATCC 25923, P. aeruginosa ATCC 27853, E. coli ATCC 25922 and K. pneumonia ATCC 700603. The ethanol extract antibacterial profile was more efficient at higher concentrations (1 000 ppm), obtaining significant percentages of reduction of more than 50 % against K. pneumoniae ATCC 700603 and a clinical isolate of E. coli; while compared to Bacillus clinical isolate, was more active than the essential oil. For the rest of microorganisms, the reduction percentages obtained at a concentration of 1 000 ppm varied between 17 and 42 % with ethanolic extract, and 8 to 43 % with essential oil. At concentrations of 100 and 500 ppm antibacterial activity of the extracts was lower. The results indicated that the ethanolic extract and essential oil of C. longa rhizomes have active compounds with antibacterial properties that could be used in future research as a therapeutic alternative for the treatment of infections caused by nosocomial pathogens.


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