scholarly journals Standardization of resazurin use in susceptibility testing of natural products against yeasts in planktonic cells and in biofilms formation

2021 ◽  
Vol 43 ◽  
pp. e55700
Author(s):  
Isabella Letícia Esteves Barros ◽  
Flávia Franco Veiga ◽  
Jakeline Luiz Corrêa ◽  
Isabele Carrilho Jarros ◽  
Melyssa Negri ◽  
...  
Keyword(s):  
Natural Products ◽  
Inhibitory Concentration ◽  
Physicochemical Characteristics ◽  
Yeast Cells ◽  
In Vitro Tests ◽  
Candida Spp ◽  
Propolis Extract ◽  
Nail Diseases ◽  
High Concentrations

Natural products, such as the ethanolic propolis extract (PE), have been shown to be a safe and effective therapeutic alternative for the treatment of fungal skin and nail diseases. However, the presence of the resin and the physicochemical characteristics of the extract sometimes difficult the reading and determination of breakpoints of the in vitro tests, evidencing the need for alternatives that facilitate the reading. The present study aimed to standardize the use of resazurin in tests of susceptibility of PE with planktonic yeast cells and biofilm forms. The antifungal activity of PE was determined by minimum inhibitory concentration (MIC) and we observed that, for all Candida spp. tested, the most reproducible MIC results were obtained when resazurin was placed after 24 hours of incubation and remained more 24 hours with yeasts plus PE. For encapsulated yeasts, there was no dye reduction and color transition. Resazurin was also used for the evaluation of minimal biofilm inhibitory concentration and minimal biofilm eradication concentration and it was metabolized and reproduced the action of PE on Candida biofilms. In addition, microdilution checkerboard plates were made with the dye, which assisted reading the result of the interaction between PE and nystatin. We observed that the resin, the color and the turbidity of the PE slightly changed the color of the resazurin in high concentrations of the extract and did not impair the reading. Therefore, the resazurin standardization tests were proven to be efficient and grounds that it should be used as an auxiliary methodology for reading and interpretation of the susceptibility tests for non-encapsulated yeasts with natural products, which form turbidity or precipitation, such as propolis.

scholarly journals THE EFFECT OF PROPOLIS EXTRACT AND PROPOLIS CANDIES ON THE GROWTH OF AGGREGATIBACTER ACTINOMYCETEMCOMITANS ATCC 43718

2017 ◽  
Vol 10 (17) ◽  
pp. 26
Author(s):  
Khodijah Khodijah ◽  
Ratna Farida ◽  
Nurtami Soedarsono
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Minimum Bactericidal Concentration ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Spectrophotometric Analysis ◽  
Propolis Extract ◽  
Post Exposure ◽  
Colony Forming Units

Objective: This experiment aimed to analyze the effect of propolis extract and propolis containing candies on the growth of Aggregatibacter actinomycetemcomitans using spectrophotometric analysis and colony-forming units (CFU) counts.Methods: After A. actinomycetemcomitans were exposed to propolis extract and candies, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined with spectrophotometry and post-exposure colony counting.Results: The MIC of propolis extract against A. actinomycetemcomitans was determined to be 10%, and the MBC was 20%. A decrease in the total CFU count of A. actinomycetemcomitans was observed after propolis extract and candy exposure.Conclusions: Propolis extract and propolis candies were effective in inhibiting the growth of A. actinomycetemcomitans ATCC 43718 in vitro.

Activity of myxin against Ceratocystis ulmi

1969 ◽  
Vol 15 (1) ◽  
pp. 133-135 ◽  
Author(s):  
E. A. Peterson
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Liquid Culture ◽  
Inhibitory Concentration ◽  
In Vitro Tests ◽  
Strong Inhibition ◽  
Solid Media ◽  
Highly Sensitive ◽  
Paper Disc ◽  
Disc Assay

Eight strains of Ceratocystis ulmi originating from different locations and host species were found to be highly sensitive to the antibiotic myxin in in vitro tests. By paper disc assay, amounts as low as 0.5–1.0 μg caused strong inhibition of the fungus on solid media. The minimum inhibitory concentration in liquid culture was 0.2 μg/ml and levels of antibiotic above this concentration proved to be fungicidal.

Freeze-thaw injury in erythrocytes of the freeze-tolerant wood frog, Rana sylvatica

1991 ◽  
Vol 261 (6) ◽  
pp. R1346-R1350 ◽  
Author(s):  
J. P. Costanzo ◽  
R. E. Lee
Keyword(s):  
Cell Injury ◽  
Osmotic Fragility ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Wood Frog ◽  
In Vitro Tests ◽  
Freezing And Thawing ◽  
Freeze Tolerant ◽  
High Concentrations

Erythrocytes from the freeze-tolerant wood frog (Rana sylvatica) were subjected to in vitro tests of freeze tolerance, cryoprotection, and osmotic fragility. The responses of cells from frogs acclimated to 4 or 15 degrees C were similar. Erythrocytes that were frozen in saline hemolyzed at -4 degrees C or lower. The addition of high concentrations (150 and 1,500 mM) of glucose or glycerol, cryoprotectants produced naturally by freeze-tolerant frogs, significantly reduced cell injury at -8 degrees C, but concentrations of 1.5 or 15 mM were ineffective. Hemolysis was reduced by 94% with 1,500 mM glycerol and by 84% with 1,500 mM glucose; thus glycerol was the more effective cryoprotectant. Mean fragility values for frog erythrocytes incubated in hypertonic and hypotonic saline were 1,938 and 49 mosM, respectively. Survival in freeze tolerance and cryoprotection experiments was comparable for erythrocytes from frogs and humans, suggesting that these cells may respond similarly to freezing-related stresses. However, the breadth of osmotic tolerance, standardized for differences in isotonicity, was greater for frog erythrocytes than for human erythrocytes. Our data suggest that erythrocytes from R. sylvatica are adequately protected by glucose under natural conditions of freezing and thawing.

Toxic Effects of Chromium Acetate Hydroxide on Cells Cultivated In Vitro

2001 ◽  
Vol 29 (2) ◽  
pp. 163-177 ◽  
Author(s):  
Emil Rudolf ◽  
Jan Peychl ◽  
Miroslav Červinka
Keyword(s):  
Dna Analysis ◽  
Cell Damage ◽  
Toxic Waste ◽  
Toxic Effects ◽  
Waste Materials ◽  
In Vitro Tests ◽  
High Concentrations ◽  
Discrete Manner ◽  
Chromium Acetate

Many human activities, particularly industrial ones, result in an ever-growing production of toxic waste materials. The dynamics of the toxic effects of chromium acetate hydroxide, which is found in high concentrations in a waste sediment produced in the Czech Republic, were assessed by using a battery of in vitro tests carried out on two cell lines: L-929 (mouse fibroblasts) and Hep 2 (human laryngeal cells). Various markers of cell damage were assessed by phase-contrast, video and fluorescence microscopy, fluorometry, and DNA analysis. Chromium acetate hydroxide, over a concentration range of 1–0.02mol/l induced immediate cell death by fixation, whereas, at 0.002mol/l, the treated cells died in a much slower, more discrete manner. All the detected markers of cell damage, whether immediate or slow, clearly demonstrated that the cells died by necrosis. On the other hand, test concentration of 0.001mol/l appeared to constitute a threshold at which no pathological changes of Hep 2 cells were observed over 96 hours. We conclude that chromium acetate hydroxide has a high toxic potential in vitro, which should be considered when studying the toxicity of waste materials containing it.

Cytotoxic Activity of tropane alkaloides of Species of Erythroxylum

2021 ◽  
Vol 21 ◽  
Author(s):  
José Fernando Araújo Neto ◽  
Erika Maria de Oliveira Ribeiro ◽  
Ademir Evangelista do Vale ◽  
Jorge Maurício David ◽  
Juceni Pereira de Lima David
Keyword(s):  
Natural Products ◽  
Cytotoxic Activity ◽  
Screening Program ◽  
Evaluation Studies ◽  
Tropane Alkaloids ◽  
Chemotherapeutic Agents ◽  
In Vitro Tests ◽  
Cytotoxic Activities ◽  
Cytotoxic Potential

: Erythroxylaceae is a family composed of four genera being Erythroxylum the only one represented in the Neotropical region. Chemical studies indicate the presence of alkaloids, terpenes, flavonoids and phenolic compounds as main compounds. The incorporation of cytotoxic activity assays of natural products using cell cultures assists in the selection of potential chemotherapeutic agents. In this work we describe a revision of the cytotoxicity evaluation studies performed with extracts and/or pure substances obtained from Erythroxylum species through an integrative review. We have found studies that evaluated the cytotoxic activity of 21 species of Erythroxylum against 45 different cell lines, the analysis of the chemical composition of these species shows that the metabolites present in each species influence the cytotoxic potential of them, especially the presence of disubstituted tropane alkaloids species with the highest cytotoxic potential. MTT and Sulforrodamine B assays were the main in vitro tests used for the evaluation of the cytotoxic activities. From the total of species, less than 10% of the Erythroxylum species have already been evaluated for the cytotoxic activity, four of them showed high cytotoxic activity according to with the criteria of the NCI plant screening program. Thus, this genus represents a potential source of natural products with antitumor activity.

scholarly journals Antiprotozoal Activity Against Entamoeba histolytica of Flavonoids Isolated from Lippia graveolens Kunth

Molecules ◽  
2020 ◽  
Vol 25 (11) ◽  
pp. 2464
Author(s):  
Ramiro Quintanilla-Licea ◽  
Javier Vargas-Villarreal ◽  
María Julia Verde-Star ◽  
Verónica Mayela Rivas-Galindo ◽  
Ángel David Torres-Hernández
Keyword(s):  
Entamoeba Histolytica ◽  
Inhibitory Concentration ◽  
Public Health Problem ◽  
In Vitro Tests ◽  
Antiprotozoal Activity ◽  
Subsequent Work ◽  
Antiamoebic Activity ◽  
Work Up ◽  
First Time

Amebiasis caused by Entamoeba histolytica is nowadays a serious public health problem worldwide, especially in developing countries. Annually, up to 100,000 deaths occur across the world. Due to the resistance that pathogenic protozoa exhibit against commercial antiprotozoal drugs, a growing emphasis has been placed on plants used in traditional medicine to discover new antiparasitics. Previously, we reported the in vitro antiamoebic activity of a methanolic extract of Lippia graveolens Kunth (Mexican oregano). In this study, we outline the isolation and structure elucidation of antiamoebic compounds occurring in this plant. The subsequent work-up of this methanol extract by bioguided isolation using several chromatographic techniques yielded the flavonoids pinocembrin (1), sakuranetin (2), cirsimaritin (3), and naringenin (4). Structural elucidation of the isolated compounds was achieved by spectroscopic/spectrometric analyses and comparing literature data. These compounds revealed significant antiprotozoal activity against E. histolytica trophozoites using in vitro tests, showing a 50% inhibitory concentration (IC50) ranging from 28 to 154 µg/mL. Amebicide activity of sakuranetin and cirsimaritin is reported for the first time in this study. These research data may help to corroborate the use of this plant in traditional Mexican medicine for the treatment of dyspepsia.

scholarly journals Dalbavancin, Vancomycin and Daptomycin Alone and in Combination with Cefazolin against Resistant Phenotypes of Staphylococcus aureus in a Pharmacokinetic/Pharmacodynamic Model

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 696 ◽  
Author(s):  
Jacinda C. Abdul-Mutakabbir ◽  
Razieh Kebriaei ◽  
Kyle C. Stamper ◽  
Zain Sheikh ◽  
Philip T. Maassen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Inhibitory Concentration ◽  
Pharmacodynamic Model ◽  
In Vitro Tests ◽  
Beta Lactam ◽  
Fold Reduction ◽  
The One ◽  
Time Kill

The most efficacious antimicrobial therapy to aid in the successful elimination of resistant S. aureus infections is unknown. In this study, we evaluated varying phenotypes of S. aureus against dalbavancin (DAL), vancomycin (VAN), and daptomycin (DAP) alone and in combination with cefazolin (CFZ). The objective of this study was to observe whether there was a therapeutic improvement in adding a beta-lactam to a glycopeptide, lipopeptide, or a lipoglycopeptide. We completed a series of in vitro tests including minimum inhibitory concentration testing (MIC) of the antimicrobials in combination, time-kill analysis (TKA), and a 168 h (7-day) one-compartment pharmacokinetic/pharmacodynamic (PK/PD) model on two daptomycin non-susceptible (DNS), vancomycin intermediate S. aureus strains (VISA), D712 and 6913. Results from our MIC testing demonstrated a minimum 2-fold and a maximum 32-fold reduction in MIC values for DAL, VAN, and DAP in combination with CFZ, in contrast to either agent used alone. The TKAs completed on four strains paralleled the enhanced activity demonstrated via the combination MICs. In the one-compartment PK/PD models, the combination of DAP plus CFZ or VAN plus CFZ resulted in a significant (p < 0.001) improvement in bactericidal activity and overall reduction in CFU/ml over the 7-day period. While the addition of CFZ to DAL improved time to bactericidal activity, DAL alone demonstrated equal and more sustained overall activity compared to all other treatments. The use of DAL alone, with or without CFZ and the combinations of VAN or DAP with CFZ appear to result in increased bactericidal activity against various recalcitrant S. aureus phenotypes.

scholarly journals The Inhibitory Effect of Clindamycin onLactobacillus in vitro

2001 ◽  
Vol 9 (4) ◽  
pp. 239-244 ◽  
Author(s):  
Alla Aroutcheva ◽  
Jose A. Simoes ◽  
Susan Shott ◽  
Sebastian Faro
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Inhibitory Effect ◽  
Bacteriostatic Effect ◽  
The Mean ◽  
High Concentrations ◽  
Effect On Growth

Objective:To evaluate thein vitroeffect of varying concentrations of clindamycin onLactobacillusspp.Methods: Concentrations of clindamycin ranging from 1.95–20 000 mg/ml were studied for their effect on the growth of six strains ofLactobacillus.Results:Clindamycin concentrations between 1.95–31.25 mg/ml had no statistically significant effect on growth of lactobacilli (p> 0.05). Concentrations 125 and 250 mg/ml had a bacteriostatic effect. The mean minimum inhibitory concentration (MIC) for studiedLactobacillusstrains was determined as 1000 mg/ml.Conclusion:High concentrations of clindamycin achieved in the vagina by intravaginal application might be inhibitory forLactobacillus.

scholarly journals Antibiofilm Potential of Medicinal Plants against Candida spp. Oral Biofilms: A Review

Antibiotics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1142
Author(s):  
Rafaela Guimarães ◽  
Catarina Milho ◽  
Ângela Liberal ◽  
Jani Silva ◽  
Carmélia Fonseca ◽  
...  
Keyword(s):  
Natural Products ◽  
Medicinal Plants ◽  
Oral Cavity ◽  
Plant Extracts ◽  
Fungal Infections ◽  
High Capacity ◽  
Biologically Active ◽  
Antibiofilm Activity ◽  
Candida Spp

The use of natural products to promote health is as old as human civilization. In recent years, the perception of natural products derived from plants as abundant sources of biologically active compounds has driven their exploitation towards the search for new chemical products that can lead to further pharmaceutical formulations. Candida fungi, being opportunistic pathogens, increase their virulence by acquiring resistance to conventional antimicrobials, triggering diseases, especially in immunosuppressed hosts. They are also pointed to as the main pathogens responsible for most fungal infections of the oral cavity. This increased resistance to conventional synthetic antimicrobials has driven the search for new molecules present in plant extracts, which have been widely explored as alternative agents in the prevention and treatment of infections. This review aims to provide a critical view and scope of the in vitro antimicrobial and antibiofilm activity of several medicinal plants, revealing species with inhibition/reduction effects on the biofilm formed by Candida spp. in the oral cavity. The most promising plant extracts in fighting oral biofilm, given their high capacity to reduce it to low concentrations were the essential oils extracted from Allium sativum L., Cinnamomum zeylanicum Blume. and Cymbopogon citratus (DC) Stapf.

scholarly journals Synthesis and in vitro Antibacterial Activity of Quaternization 10-Methoxycanthin-6-one Derivatives

2019 ◽  
Author(s):  
Na Li ◽  
Jiang-Kun Dai ◽  
Dan Liu ◽  
Jin-Yi Wang ◽  
Jun-Ru Wang
Keyword(s):  
Antibacterial Activity ◽  
Natural Products ◽  
Minimum Inhibitory Concentration ◽  
Pathogenic Bacteria ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
In Vitro Antibacterial Activity

Natural products are an important source of antibacterial agents. Canthin-6-one alkaloids have displayed potential antibacterial activity based on our previous work. In order to improve the activity, twenty-two new 3-N-benzylated 10-methoxy canthin-6-ones were designed and synthesized through quaternization reaction. The in vitro antibacterial activity against three bacteria was evaluated by double dilution method. Four compounds (6f, 6i, 6p and 6t) displayed 2-fold superiority (minimum inhibitory concentration (MIC) = 3.91 &micro;g/mL) against agricultural pathogenic bacteria R. solanacearum and P. syringae than agrochemical propineb. Moreover, the structure&ndash;activity relationships (SARs) were also carefully summarized in order to guide the development of antibacterial canthin-6-one agents.

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