Enhanced Spontaneous Antibacterial Activity of δ-MnO2 by Alkali Metals Doping

Recently, the widespread use of antibiotics is becoming a serious worldwide public health challenge, which causes antimicrobial resistance and the occurrence of superbugs. In this context, MnO2 has been proposed as an alternative approach to achieve target antibacterial properties on Streptococcus mutans (S. mutans). This requires a further understanding on how to control and optimize antibacterial properties in these systems. We address this challenge by synthesizing δ-MnO2 nanoflowers doped by magnesium (Mg), sodium (Na), and potassium (K) ions, thus displaying different bandgaps, to evaluate the effect of doping on the bacterial viability of S. mutans. All these samples demonstrated antibacterial activity from the spontaneous generation of reactive oxygen species (ROS) without external illumination, where doped MnO2 can provide free electrons to induce the production of ROS, resulting in the antibacterial activity. Furthermore, it was observed that δ-MnO2 with narrower bandgap displayed a superior ability to inhibit bacteria. The enhancement is mainly attributed to the higher doping levels, which provided more free electrons to generate ROS for antibacterial effects. Moreover, we found that δ-MnO2 was attractive for in vivo applications, because it could nearly be degraded into Mn ions completely following the gradual addition of vitamin C. We believe that our results may provide meaningful insights for the design of inorganic antibacterial nanomaterials.

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An Evaluation of the Antibacterial Properties of Tormentic Acid Congener and Extracts From Callistemon viminalis on Selected ESKAPE Pathogens and Effects on Biofilm Formation

Advances in Pharmacological and Pharmaceutical Sciences ◽

10.1155/2020/8848606 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Tafadzwa Chipenzi ◽

Genuine Baloyi ◽

Tatenda Mudondo ◽

Simbarashe Sithole ◽

Godloves Fru Chi ◽

...

Keyword(s):

Antibacterial Activity ◽

Biofilm Formation ◽

Antibacterial Properties ◽

Extracellular Dna ◽

Dilution Method ◽

Antibacterial Drug ◽

Antibacterial Effects ◽

Callistemon Viminalis ◽

Eskape Pathogens ◽

Tormentic Acid

ESKAPE pathogens, namely, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species, are responsible for a majority of all healthcare-acquired infections (HAI). The bacteria cause nosocomial infections in immunocompromised patients. Extracts from Callistemon viminalis have been shown to have antibacterial, antifungal, and anti-inflammatory activities. Tormentic acid congener, a pentacyclic triterpene saponin, was isolated from C. viminalis leaves. This study aimed to investigate the antibacterial effects of tormentic acid congener and leaf extracts on biofilm formation by A. baumannii, S. aureus, S. pyogenes, and P. aeruginosa. The antibacterial effects were determined by the microbroth dilution method, and ciprofloxacin was used as the standard antibacterial drug. Biofilm formation and detachment assays were performed using crystal violet staining. Production of extracellular polymeric DNA and polysaccharides from biofilms was also determined. Tormentic acid congener showed time-dependent antibacterial activity against P. aeruginosa with a MIC of 100 µg/ml and caused significant protein leakage. Antibacterial activity was found when tormentic acid congener was tested against both S. aureus and P. aeruginosa. The MICs were found to be 25 µg/ml and 12.5 µg/ml for P. aeruginosa and S. aureus cells, respectively. S. pyogenes was found to be susceptible to tormentic acid congener and the hydroethanolic extract with an MIC of 100 µg/ml and 25 µg/ml, respectively. A. baumannii was found not to be susceptible to the compound or the extracts. The compound and the extracts caused a significant decrease in the biofilm extracellular polysaccharide content of S. pyogenes. The extracts and tormentic acid congener caused detachment of biofilms and decreased the release of extracellular DNA and capsular polysaccharides from biofilms of P. aeruginosa and S. aureus. Tormentic acid congener and extracts, thus, have significant antibacterial and antibiofilm activities on these selected ESKAPE bacteria and can act as source lead compounds for the development of antibacterial triterpenoids.

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Interaction of Silver Nanoparticles with Serum Proteins Affects Their Antimicrobial ActivityIn Vivo

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00152-13 ◽

2013 ◽

Vol 57 (10) ◽

pp. 4945-4955 ◽

Cited By ~ 87

Author(s):

Divya Prakash Gnanadhas ◽

Midhun Ben Thomas ◽

Rony Thomas ◽

Ashok M. Raichur ◽

Dipshikha Chakravortty

Keyword(s):

Silver Nanoparticles ◽

Antibacterial Activity ◽

Serum Albumin ◽

Serum Proteins ◽

Antibacterial Properties ◽

Antibacterial Activities ◽

Resistant Bacteria ◽

Human Society ◽

Vis Spectroscopy

ABSTRACTThe emergence of multidrug-resistant bacteria is a global threat for human society. There exist recorded data that silver was used as an antimicrobial agent by the ancient Greeks and Romans during the 8th century. Silver nanoparticles (AgNPs) are of potential interest because of their effective antibacterial and antiviral activities, with minimal cytotoxic effects on the cells. However, very few reports have shown the usage of AgNPs for antibacterial therapyin vivo. In this study, we deciphered the importance of the chosen methods for synthesis and capping of AgNPs for their improved activityin vivo. The interaction of AgNPs with serum albumin has a significant effect on their antibacterial activity. It was observed that uncapped AgNPs exhibited no antibacterial activity in the presence of serum proteins, due to the interaction with bovine serum albumin (BSA), which was confirmed by UV-Vis spectroscopy. However, capped AgNPs [with citrate or poly(vinylpyrrolidone)] exhibited antibacterial properties due to minimized interactions with serum proteins. The damage in the bacterial membrane was assessed by flow cytometry, which also showed that only capped AgNPs exhibited antibacterial properties, even in the presence of BSA. In order to understand thein vivorelevance of the antibacterial activities of different AgNPs, a murine salmonellosis model was used. It was conclusively proved that AgNPs capped with citrate or PVP exhibited significant antibacterial activitiesin vivoagainstSalmonellainfection compared to uncapped AgNPs. These results clearly demonstrate the importance of capping agents and the synthesis method for AgNPs in their use as antimicrobial agents for therapeutic purposes.

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A high-throughput metabolic microarray assay reveals antibacterial effects of black and red raspberries and blackberries against Helicobacter pylori infection

10.1101/2020.12.14.422663 ◽

2020 ◽

Author(s):

Candace Goodman ◽

Katrina Lyon ◽

Aitana Scotto ◽

Mandi M. Roe ◽

Farimah Moghimpour ◽

...

Keyword(s):

Helicobacter Pylori ◽

High Throughput ◽

Severe Disease ◽

Antibacterial Properties ◽

Black Raspberry ◽

Antibacterial Effects ◽

Ulcer Disease ◽

H Pylori

AbstractHelicobacter pylori is an important bacterial pathogen that causes chronic infection of the human stomach, leading to gastritis, peptic ulcer disease and gastric cancer. Treatment with appropriate antibiotics can eliminate H. pylori infection and reduce the risk for severe disease outcomes. However, since H. pylori is becoming increasingly resistant to standard antibiotic regimens, novel treatment strategies are needed. Previous studies have demonstrated that black and red berries may have antibacterial properties. Therefore, we analyzed organic extracts and powders from black and red raspberries and blackberries and determined their antibacterial effects on multiple H. pylori strains. We used high-performance liquid chromatography to measure berry anthocyanins, which are considered the major active ingredients. To monitor antibiotic effects of the berry preparations on H. pylori, we developed a high-throughput metabolic growth assay based on the OmniLog™ system. All berry preparations tested had significant bactericidal effects in vitro, with MIC90 values ranging from 0.49 to 4.17%. We next used human gastric epithelial organoids to evaluate biocompatibility of the berry preparations and showed that black raspberry extract, which had the strongest antimicrobial activity, was non-toxic at the concentration required for complete bacterial growth inhibition. To determine whether dietary black raspberry application could eliminate H. pylori infection in vivo, mice were infected with H. pylori and then were placed on a diet containing 10% black raspberry powder. However, this treatment did not significantly impact bacterial infection rates or gastric pathology. In summary, our data indicate that black and red raspberry and blackberry products have potential applications in the treatment and prevention of H. pylori infection, because of their antibacterial effects and good biocompatibility. However, delivery and formulation of berry compounds needs to be optimized to achieve significant antibacterial effects in vivo.

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In Vivo Study of the Antibacterial Chitosan/Polyvinyl Alcohol Loaded with Silver Nanoparticle Hydrogel for Wound Healing Applications

International Journal of Polymer Science ◽

10.1155/2019/7382717 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 5

Author(s):

Tan Dat Nguyen ◽

Thanh Truc Nguyen ◽

Khanh Loan Ly ◽

Anh Hien Tran ◽

Thi Thanh Ngoc Nguyen ◽

...

Keyword(s):

Wound Healing ◽

Silver Nanoparticles ◽

Antibacterial Activity ◽

Polyvinyl Alcohol ◽

Healing Rate ◽

Antibacterial Effects ◽

Topical Gel ◽

Significant Difference

Silver nanoparticles have attracted great interests widely in medicine due to its great characteristics of antibacterial activity. In this research, the antibacterial activity and biocompatibility of a topical gel synthesized from polyvinyl alcohol, chitosan, and silver nanoparticles were studied. Hydrogels with different concentrations of silver nanoparticles (15 ppm, 30 ppm, and 60 ppm) were evaluated to compare their antibacterial activity, nanoparticles’ sizes, and in vivo behaviors. The resulted silver nanoparticles in the hydrogel were characterized by TEM showing the nanoparticles’ sizes less than 22 nm. The in vitro results prove that the antibacterial effects of all of the samples are satisfied. However, the in vivo results demonstrate the significant difference among different hydrogels in wound healing, where hydrogel with 30 ppm shows the best healing rate.

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MXene-based hybrid system exhibits excellent synergistic antibiosis

Nanotechnology ◽

10.1088/1361-6528/ac385d ◽

2021 ◽

Author(s):

P S Lv ◽

Bo Song ◽

Fengqi Han ◽

Zhanrong Li ◽

Bingbing Fan ◽

...

Keyword(s):

Antibacterial Activity ◽

Hybrid System ◽

Hydrophilic Polymers ◽

Ros Production ◽

Oxygen Species ◽

Antibacterial Effects ◽

Ag Nps ◽

Low Cytotoxicity ◽

Poor Stability ◽

Synergistic Antibacterial Activity

Abstract MXene are a group of inorganic two-dimensional (2D) nanomaterial, and have raised significant interests in biomedical areas. Ti3C2Tx, as an important member of MXene family, is widely studied because of its biodegradability and low-cytotoxicity. However, their single antibacterial mechanism and poor stability in aqueous solution need to be improved, especially for the antimicrobial applications. In this work, a MXene-based hybrid antibacterial system (M-HAS) was developed and its synergistic antibacterial activity was investigated. In the M-HAS, 2D few-layer Ti3C2Tx (FL-Ti3C2Tx) was modified with hydrophilic polymers and thereby used as carriers for silver nanoparticles (Ag NPs). By assembling these two substrates, photodynamic performance of the prepared system is significantly improved with a large amount of reactive oxygen species (ROS) production under 660 nm laser. Antibacterial effects of the M-HAS are enhanced by over 4 times with irradiation. In another word, the developed hybrid system displays excellent photodynamic antibacterial synergistic properties. This work takes full advantage of the photodynamic properties of every component in the MAS to achieve efficient antibacterial activity and proposes an innovative approach to develop the 2D FL-Ti3C2Tx-based antibacterial platform.

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Eleucine indicaPossesses Antioxidant, Antibacterial and Cytotoxic Properties

Evidence-based Complementary and Alternative Medicine ◽

10.1093/ecam/nep091 ◽

2011 ◽

Vol 2011 ◽

pp. 1-6 ◽

Cited By ~ 10

Author(s):

Adel S. Al-Zubairi ◽

Ahmad Bustamam Abdul ◽

Siddig Ibrahim Abdelwahab ◽

Chew Yuan Peng ◽

Syam Mohan ◽

...

Keyword(s):

Antibacterial Activity ◽

Human Cancer ◽

Antioxidant Properties ◽

Antibacterial Properties ◽

Diffusion Method ◽

Total Phenolic ◽

Significant Activity ◽

Human Cancer Cell Lines

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.

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

Nanomaterials ◽

10.3390/nano11061621 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1621

Author(s):

Yuelong Xu ◽

Hongxia Wang ◽

Min Zhang ◽

Jianhao Zhang ◽

Wenjing Yan

Keyword(s):

Gold Nanoparticles ◽

Antibacterial Activity ◽

Intestinal Microflora ◽

Antibacterial Properties ◽

Au Nps ◽

E Coli ◽

Bacterial Cell Death ◽

Steric Configuration

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.

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Antibacterial properties of thioridazine

Farmatsevtychnyi zhurnal ◽

10.32352/0367-3057.4.19.11 ◽

2019 ◽

pp. 96-104

Author(s):

N. Hrynchuk ◽

N. Vrynchanu

Keyword(s):

Antibacterial Activity ◽

Ex Vivo ◽

Antibacterial Properties ◽

Antimicrobial Properties ◽

Antibiotic Resistant ◽

In Vivo Experiments ◽

Antistaphylococcal Activity ◽

The Impact

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.

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In Vitro Antibacterial Activity, Preliminary Phytochemical Screening Profile, and In Vivo Toxicity of Seven Traditional Medicinal Plants in Ethiopia

Traditional and Integrative Medicine ◽

10.18502/tim.v6i4.8273 ◽

2022 ◽

Author(s):

Eyerus Mekuriaw ◽

Enat Mengistu ◽

Ayana Erdedo ◽

Hassen Mamo

Keyword(s):

Antibacterial Activity ◽

Medicinal Plants ◽

Ethyl Acetate ◽

Antibacterial Properties ◽

Ethanol Extract ◽

Diffusion Method ◽

Phytochemical Screening ◽

Phytochemical Content

The threat of antibiotic-resistance calls for novel antibacterial agents. This study was aimed at screening medicinal plants for their antibacterial properties, phytochemical content and safety. Leaves of Allophylus abyssinicus (Hochst.) Radlk., Dicliptera laxata C.B.Clarke, Ligustrum vulgare L., Solanecio gigas (Vatke) c. Jeffrey and Gymnanthemum myrianthum (Hook.f.) H.Rob.; leaf and stem-bark of Olinia rochetiana A. Juss. and the seed of Cucurbita pepo L. were used. Chloroform and ethanol were used to extract G. myrianthum, D. laxata and O. rochetiana; ethyl acetate and methanol for the rest, and water for all. The extracts were tested against clinical/standard strains of Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and Staphylococcus aureus by the agar-diffusion method. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined. Acute toxicity to mice was checked and preliminary phytochemical screening was done. Thirteen extracts, out of 24, were active (inhibition zone >7 mm) at differing levels (9.67±0.33-25.66±0.57 mm) against at least one bacterial strain. The MICs and MBCs were 1.95-15.6 mg/mL and 7.8-125 mg/mL respectively. The aqueous extract of S. gigas, methanol extracts of L. vulgare and A. abyssinicus, and ethanol extract of O. rochetiana leaf were the most active (MIC 1.95mg/ml) against S. aureus. Ethyl acetate extracts of A. abyssinicus, L. vulgare and S. gigas; aqueous of C. pepo, O. rochetiana and G. myrianthum; and all D. laxata had no antibacterial activity. P. aeruginosa was the least susceptible to any extract, although the methanol and aqueous extracts of S. gigas performed better against it. Preliminary phytochemical screening of selected extracts for phenols, flavonoids, tannins, steroids, terpenoids, steroidal glycosides, alkaloids, saponins, resins and glycosides showed positivity at least for four of these phytochemicals with glycoside and terpenoids in nearly all extracts and resin in none. The plants were not toxic to mice at 2000 mg/kg. Further consideration of S. gigas, L. vulgare, A. abyssinicus and O. rochetiana is recommended in light of their promising potential and safety.

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SCREENING ANTIBACTERIAL EFFECTS OF VIETNAMESE PLANT EXTRACTS AGAINST PATHOGENS CAUSED ACUTE HEPATOPANCREATIC NECROSIS DISEASE IN SHRIMPS

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2018.v11i5.23618 ◽

2018 ◽

Vol 11 (5) ◽

pp. 77 ◽

Cited By ~ 1

Author(s):

Hai Thanh Nguyen ◽

Lua Thi Dang ◽

Hanh Thi Nguyen ◽

Hai Ha Hoang ◽

Ha Thi Ngoc Lai ◽

...

Keyword(s):

High Performance ◽

Pathogenic Bacteria ◽

Survival Rates ◽

Antibacterial Properties ◽

Piper Betle ◽

Antibacterial Effects ◽

Plant Materials ◽

Acute Hepatopancreatic Necrosis Disease

Objectives: The objectives are aimed to investigate the antibacterial properties of five Vietnamese medicinal plants against acute hepatopancreatic necrosis disease (AHPND)-caused bacterial pathogens, to verify their potentials to apply as a new treatment therapy.Methods: Extracts from plants, such as Psidium guajava leaf, Piper betle L. leaf, Phyllanthus amarus leaf, Rhodomyrtus tomentosa seed, and Allium sativum bulb, were tested against three AHPND-caused bacteria. Agar infusion and broth dilution methods were employed to evaluate extract in vitro antibacterial effects, while experiments with cultured whiteleg shrimps were applied to access their safety when applied in vivo. High-performance liquid chromatography (HPLC) analysis was applied to identify components in the extracts.Results: P. amanus and R. tomentosa extracts exerted the strongest inhibition on tested bacteria. Other extracts, including P. betel and P. guajava, were less effective, while A. sativum showed no effects against bacteria. In safety assessment experiments, we observed that only crude extracts of R. tomentosa and A. satium were safe, while others significantly reduced their survival rates. HPLC showed that extracts of high antibacterial properties had rich phenol constituents. In addition, the phenolic profile of R. tomentosa showed the presence of piceatannol.Conclusion: Considering both of antibacterial effects and safety properties altogether, we concluded that among the five examined plant materials of this study, R. tomentosa had the highest potential to apply in AHPND treatment, as only this plant showed the high effects on pathogenic bacteria while were still safe for host aquatic shrimps.

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