Antimicrobial Activity of Silver and Gold Nanoparticles Prepared by Photoreduction Process with Leaves and Fruit Extracts of Plinia cauliflora and Punica granatum.

The increased number of resistant microbes generates a search for new antibiotic methods. Metallic nanoparticles have emerged as a new platform against several microorganisms. The nanoparticles can damage the bacteria membrane and DNA by oxidative stress. The photoreduction process is a clean and low-cost method for obtaining silver and gold nanoparticles. This work describes two original insights: (1) the use of extracts of leaves and fruits from a Brazilian plant Plinia cauliflora, compared with a well know plant Punica granatum, and (2) the use of phytochemicals as stabilizing agents in the photoreduction process. The prepared nanoparticles were characterized by UV-vis, FTIR, transmission electron microscopy, and Zeta potential. The antimicrobial activity of nanoparticles was obtained with Gram-negative and Gram-positive bacteria, particularly the pathogens Staphylococcus aureus ATCC 25923; Bacillus subtilis ATCC 6633; clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis; Escherichia coli ATCC 25922; Escherichia coli O44:H18 EAEC042 (clinical isolate); Klebsiella pneumoniae ATCC 700603, Salmonella Thiphymurium ATCC 10231; Pseudomonas aeruginosa ATCC 27853; and Candida albicans ATCC 10231. Excellent synthesis results were obtained. The AgNPs exhibited antimicrobial activities against Gram-negative and Gram-positive bacteria and yeast (80-100%), better than AuNPs (0-87.92%), and may have the potential to be used as antimicrobial agents.

Antimicrobial activity of silver and gold nanoparticles prepared by photoreduction process with leaves and fruit extracts of Plinia cauliflora and Punica granatum

The increased number of resistant microbes generates a search for new antibiotic methods. Metallic nanoparticles have emerged as a new platform against several microorganisms. The nanoparticles can damage the bacteria membrane and DNA by oxidative stress. The photoreduction process is a clean and low-cost method for obtaining silver and gold nanoparticles. This work describes two original insights: (1) the use of extracts of leaves and fruits from a Brazilian plant Plinia cauliflora, compared with a well know plant Punica granatum, and (2) the use of phytochemicals as stabilizing agents in the photoreduction process. The prepared nanoparticles were characterized by UV-vis, FTIR, transmission electron microscopy, and Zeta potential. The antimicrobial activity of nanoparticles was obtained with Gram-negative and Gram-positive bacteria, particularly the pathogens Staphylococcus aureus ATCC 25923; Bacillus subtilis ATCC 6633; clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Enterococcus faecalis; Escherichia coli ATCC 25922; Escherichia coli O44:H18 EAEC042 (clinical isolate); Klebsiella pneumoniae ATCC 700603, Salmonella Thiphymurium ATCC 10231; seudomonas aeruginosa ATCC 27853; and Candida albicans ATCC 10231. Excellent synthesis results were obtained. The AgNPs exhibited antimicrobial activities against Gram-negative and Gram-positive bacteria and yeast (80–100%), better than AuNPs (0–87.92%), and may have the potential to be used as antimicrobial agents.

Antibacterial and antitumoral activities of the spider acylpolyamine mygalin silver nanoparticles

Mygalin is a synthetic analog of polyamine spermidine isolated from spider hemocytes. Polyamines show potential therapeutic activity against a wide range of human diseases such as cancer and microbial infections. In this work, we analyzed the antibacterial and antitumoral activities of Mygalin silver nanoparticles synthesized by the photoreduction method. The formation and distribution of MygAgNPs were confirmed by UV-visible spectroscopy, zeta potential, and transmission electron microscopy. The obtained nanoparticles were mostly spherical with a particle size distribution in the range of ~ 10–60 nm. We have demonstrated that MygAgNPs increased the effectiveness of the native Mygalin by approximately 6400-fold. Cytotoxicity tests were performed, and it was possible to reach a concentration that was not toxic to healthy cells (NHI-3T3) and at the same time toxic to the tumor cell line (MCF-7). The obtained results suggest that this system shows potential enhanced antibacterial activity against Escherichia coli, DH5a and anticancer activity against MCF-7 cell line

Antibacterial and antitumoral activities of the spider acylpolyamine mygalin silver nanoparticles

Mygalin is a synthetic analog of polyamine spermidine isolated from spider hemocytes. Polyamines show potential therapeutic activity against a wide range of human diseases such as cancer and microbial infections. In this work, we analyzed the antibacterial and antitumoral activities of Mygalin silver nanoparticles synthesized by the photoreduction method. The formation and distribution of MygAgNPs were confirmed by UV-visible spectroscopy, zeta potential, and transmission electron microscopy. The obtained nanoparticles were mostly spherical with a particle size distribution in the range of ~ 10–60 nm. We have demonstrated that MygAgNPs increased the effectiveness of the native Mygalin by approximately 6400-fold. Cytotoxicity tests were performed, and it was possible to reach a concentration that was not toxic to healthy cells (NHI-3T3) and at the same time toxic to the tumor cell line (MCF-7). The obtained results suggest that this system shows potential enhanced antibacterial activity against Escherichia coli, DH5a and anticancer activity against MCF-7 cell line

Tryptophan Silver Nanoparticles Synthesized by Photoreduction Method: Characterization and Determination of Bactericidal and Anti-Biofilm Activities on Resistant and Susceptible Bacteria.

The high rates of antibiotics use in hospitals have resulted in a condition where multidrug-resistant pathogens have become a severe threat to the human health worldwide. Therefore, there is an increasing necessity to identify new antimicrobial agents that can inhibit the multidrug-resistant bacteria and biofilm formation. In this study, antibacterial and anti-biofilm activities of tryptophan silver nanoparticles (TrpAgNP) were investigated. The TrpAgNPs were synthesized by photoreduction method, and the influence of irradiation time and concentration of reagents were analyzed. The nanoparticles were characterized by transmission electron microscopy, Zeta Potential and (UV)-absorption spectra. The antibacterial activity of TrpAgNPs was tested for antibiotic-resistant and susceptible pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Salmonella typhimurium, and Pseudomonas aeruginosa, evaluating the influence of photoreduction parameters in bactericidal effect. The results have shown that TrpAgNPs solutions with lower tryptophan/silver nitrate (AgNO3) ratio and higher AgNO3 concentration have higher bactericidal action against bacteria with inhibition of ~100% in almost all studied bacterial strains. The antimicrobial activity of TrpAgNPs within biofilms generated under static conditions of antibiotic-resistant and susceptible strains of S. aureus, S. epidermidis, E. coli, K. pneumoniae, C. freundii, and P. aeruginosa was also investigated. The results showed that TrpAgNPs have an inhibitory effect against biofilm formation, exceeding 50% in the case of Gram-negative bacteria (E. coli, K. pneumoniae, C. freundii, and P. aeruginosa-54.8% to 98.8%). For Gram-positive species, an inhibition of biofilm formation of 68.7% to 72.2 % was observed for S. aureus and 20.0% to 40.2% for S. epidermidis.

Tryptophan silver nanoparticles synthesized by photoreduction method: characterization and determination of bactericidal and anti-biofilm activities on resistant and susceptible bacteria

The high rates of antibiotics use in hospitals have resulted in a condition where multidrug-resistant pathogens have become a severe threat to the human health worldwide. Therefore, there is an increasing necessity to identify new antimicrobial agents that can inhibit the multidrug-resistant bacteria and biofilm formation. In this study, antibacterial and anti-biofilm activities of tryptophan silver nanoparticles (TrpAgNP) were investigated. The TrpAgNPs were synthesized by photoreduction method, and the influence of irradiation time and concentration of reagents were analyzed. The nanoparticles were characterized by transmission electron microscopy, Zeta Potential and (UV)-absorption spectra. The antibacterial activity of TrpAgNPs was tested for antibiotic-resistant and susceptible pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Salmonella typhimurium, and Pseudomonas aeruginosa, evaluating the influence of photoreduction parameters in bactericidal effect. The results have shown that TrpAgNPs solutions with lower tryptophan/silver nitrate (AgNO3) ratio and higher AgNO3 concentration have higher bactericidal action against bacteria with inhibition of ~100% in almost all studied bacterial strains. The antimicrobial activity of TrpAgNPs within biofilms generated under static conditions of antibiotic-resistant and susceptible strains of S. aureus, S. epidermidis, E. coli, K. pneumoniae, C. freundii, and P. aeruginosa was also investigated. The results showed that TrpAgNPs have an inhibitory effect against biofilm formation, exceeding 50% in the case of Gram-negative bacteria (E. coli, K. pneumoniae, C. freundii, and P. aeruginosa—54.8% to 98.8%). For Gram-positive species, an inhibition of biofilm formation of 68.7% to 72.2 % was observed for S. aureus and 20.0% to 40.2% for S. epidermidis.

Tryptophan silver nanoparticles synthesized by photoreduction method: characterization and determination of bactericidal and anti-biofilm activities on resistant and susceptible bacteria

The high rates of antibiotics use in hospitals have resulted in a condition where multidrug-resistant pathogens have become a severe threat to the human health worldwide. Therefore, there is an increasing necessity to identify new antimicrobial agents that can inhibit the multidrug-resistant bacteria and biofilm formation. In this study, antibacterial and anti-biofilm activities of tryptophan silver nanoparticles (TrpAgNP) were investigated. The TrpAgNPs were synthesized by photoreduction method, and the influence of irradiation time and concentration of reagents were analyzed. The nanoparticles were characterized by transmission electron microscopy, Zeta Potential and (UV)-absorption spectra. The antibacterial activity of TrpAgNPs was tested for antibiotic-resistant and susceptible pathogens, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Citrobacter freundii, Klebsiella pneumoniae, Salmonella typhimurium, and Pseudomonas aeruginosa, evaluating the influence of photoreduction parameters in bactericidal effect. The results have shown that TrpAgNPs solutions with lower tryptophan/silver nitrate (AgNO3) ratio and higher AgNO3 concentration have higher bactericidal action against bacteria with inhibition of ~100% in almost all studied bacterial strains. The antimicrobial activity of TrpAgNPs within biofilms generated under static conditions of antibiotic-resistant and susceptible strains of S. aureus, S. epidermidis, E. coli, K. pneumoniae, C. freundii, and P. aeruginosa was also investigated. The results showed that TrpAgNPs have an inhibitory effect against biofilm formation, exceeding 50% in the case of Gram-negative bacteria (E. coli, K. pneumoniae, C. freundii, and P. aeruginosa—54.8% to 98.8%). For Gram-positive species, an inhibition of biofilm formation of 68.7% to 72.2 % was observed for S. aureus and 20.0% to 40.2% for S. epidermidis.KeywoRDS: tryptophan, silver nanoparticles, photoreduction, antimicrobial activity, anti-biofilmReCeIV eD: December 20, 2018. ACCePTeD: January 20, 2019.TyPe: Original ResearchFuNDINg: The authors are grateful to the FAPESP (2014/06960-9) and CNPq, Brazilian funding agencies, for their financial support.DeClARATIoN oF C oNFlICTINg INTeReSTS: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.CoRReSPoNDINg AuTHoR: Lilia Coronato Courrol, Laboratório de Lasers e Óptica Biomédica Aplicada and Departamento de Física, Universidade Federal de São Paulo, Diadema SP 09972-270, Brazil. Email: lccourrol@gmail.com831677TRY0010.1177/1178646919831677International Journal of Tryptophan ResearchCourrol et alresearch-article2019

Enhancement of blood porphyrin emission intensity with aminolevulinic acid administration: a new concept for photodynamic diagnosis of early prostate cancer.

BACKGROUND: The objective of this paper was to verify if the oral administration of δ-aminolevulinic acid (ALA) in animals with prostate tumor can increase the sensitivity of cancer diagnosis by protoporphyrin IX blood autofluorescence. In this study, the autofluorescence of blood porphyrin was analyzed using fluorescence spectroscopy on healthy male NUDE mice and in those with prostate cancer induced by the inoculation of DU145 cells. METHODS: A total of 18 male NUDE mice, ∼8 weeks old on arrival were divided into 3 groups: Control, Tumor and ALA Tumor. The autofluorescence of blood porphyrin of the groups was analyzed using fluorescence spectroscopy at different days after tumor induction, to monitor the tumor progression. Emission spectra were obtained by exciting the samples at 405 nm. The animals inoculated had their blood collected with and without oral ALA solution administration to compare PPIX endogenous (Tumor group) and exogenous (ALA Tumor group) signal intensity and to establish a method to diagnosis early prostate cancer. RESULTS: Significant differences were observed in autofluorescence intensities measured in the 575-725 nm spectral regions for the studied groups. CONCLUSIONS: The results showed an enhancement of almost 100% in blood PPIX fluorescence, using the oral administration of δ-aminolevulinic acid on male NUDE mice with prostate cancer, making fluorescence measurements more accurate and sensitive since the first week after tumor induction.

Erythrocyte protoporphyrin fluorescence as a potential marker of diabetes.

Protoporphyrin (PpIX), a porphyrin derivative, is the intermediate metabolic precursor of the heme molecule. Abnormal metabolism of total erythrocyte PpIX has been observed in diseases such as cancer, lead poisoning, psoriasis, iron deficiency anemia and acute porphyries. Diabetes mellitus (DM) is a complex metabolic syndrome in which hyperglycemia is the primary clinical manifestation and contributes to the diabetic complications. The aim of this study was to evaluate the utility of fluorescence spectroscopy of erythrocyte PpIX for monitoring the early stages of diabetes. A total of 14 male C 57BL mice, 6 weeks old, were divided into two groups: diabetic and non-diabetic. Diabetes was induced by intraperitoneal injection of streptozotocin (SZT). Blood cells were cultured with standard and 50 mM supplemented RPMI medium. Blood smears were prepared and stained for qualitative morphology analysis under optical microscopy. Blood porphyrin autofluorescence was analyzed by fluorescence spectroscopy. Characteristic PpIX emission spectra were obtained by exciting the samples at 405 nm. Average blood glucose was lower in the control group than in the diabetic group (156.50 +/- 8.11 mg/dL vs. 371.10 +/- 14.43 mg/dL, P < 0.05). Both diabetic and glucose-cultured erythroblasts showed a significant decrease (around 30.5% and 40%, respectively) in the emission band intensity at 635 nm. Our results indicate that the erythrocyte PpIX profile could be used as a biological monitor for diabetes.

Enhancement of europium emission band of europium tetracycline complex in the presence of cholesterol.

We report here the observation, for the first time, of the enhancement of Europium-Tetracycline complex emission in cholesterol solutions. This enhancement was initially observed with the addition of the enzyme cholesterol oxidase, which produces H(2)O(2), the agent driver of the Europium tetracycline complex, to the solution. However, it was found that the enzyme is not needed to enhance the luminescence. A calibration curve was determined, resulting in a simple method to measure the cholesterol quantity in a solution. This method shows that the complex can be used as a sensor to determine cholesterol in biological systems.