Bioactive substances produced by Burkholderia sp. with antifungal action in Candida spp

Yeasts of the genus Candida are commensals, colonizing the gastrointestinal and genital tract. Accounting for 15% of hospital acquired infections, they are considered a pathogen of clinical importance. The emergence of fungal infections and the occurrence of intrinsic and acquired resistance have reflected in the increased search for new antimicrobials. The objective of this study was to evaluate the antifungal activity of extracellular substances produced by Burkholderia sp. strain RV7S3, for yeast control of the genus Candida. The substance responsible for the antifungal activity was identified and characterized biochemically, its activity was evaluated by agar diffusion tests, minimum inhibitory concentration (MIC), action effect on biofilm formation, and hemolytic activity. The data suggested that the antifungal substance is a hydrolase that exhibits lipolytic activity. The lowest concentration of this enzyme, capable of inhibiting 90% of fungal growth, was 0.38 µg.mL-1. The agar diffusion test showed inhibition halo formation of fungal growth with a diameter of 10 mm or greater, presenting 17.5 ± 0.5 mm. The substance showed low hemolytic activity and reduced biofilm cell viability, demonstrating its potential as an antifungal agent.

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The Impact of Gelatin on the Pharmaceutical Characteristics of Fucoidan Microspheres with Posaconazole

Materials ◽

10.3390/ma14154087 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4087

Author(s):

Marta Szekalska ◽

Aleksandra Citkowska ◽

Magdalena Wróblewska ◽

Katarzyna Winnicka

Keyword(s):

Antifungal Activity ◽

Drug Release ◽

Spray Drying ◽

Fungal Infections ◽

Drug Loading ◽

High Surface ◽

Vaginal Fluid ◽

Sustained Drug Release ◽

Candida Spp ◽

The Impact

Fungal infections and invasive mycoses, despite the continuous medicine progress, are an important globally therapeutic problem. Multicompartment dosage formulations (e.g., microparticles) ensure a short drug diffusion way and high surface area of drug release, which as a consequence can provide improvement of therapeutic efficiency compared to the traditional drug dosage forms. As fucoidan is promising component with wide biological activity per se, the aim of this study was to prepare fucospheres (fucoidan microparticles) and fucoidan/gelatin microparticles with posaconazole using the one-step spray-drying technique. Pharmaceutical properties of designed fucospheres and the impact of the gelatin addition on their characteristics were evaluated. An important stage of this research was in vitro evaluation of antifungal activity of developed microparticles using different Candida species. It was observed that gelatin presence in microparticles significantly improved swelling capacity and mucoadhesiveness, and provided a sustained POS release. Furthermore, it was shown that gelatin addition enhanced antifungal activity of microparticles against tested Candida spp. strains. Microparticles formulation GF6, prepared by the spray drying of 20% fucoidan, 5% gelatin and 10% Posaconazole, were characterized by optimal mucoadhesive properties, high drug loading and the most sustained drug release (after 8 h 65.34 ± 4.10% and 33.81 ± 5.58% of posaconazole was dissolved in simulated vaginal fluid pH 4.2 or 0.1 M HCl pH 1.2, respectively).

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Biodirected Synthesis of Silver Nanoparticles Using Aqueous Honey Solutions and Evaluation of Their Antifungal Activity against Pathogenic Candida Spp.

International Journal of Molecular Sciences ◽

10.3390/ijms22147715 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7715

Author(s):

Grzegorz Czernel ◽

Dominika Bloch ◽

Arkadiusz Matwijczuk ◽

Jolanta Cieśla ◽

Monika Kędzierska-Matysek ◽

...

Keyword(s):

Silver Nanoparticles ◽

Antifungal Activity ◽

Fungal Pathogens ◽

Fungal Growth ◽

Disc Diffusion ◽

Candida Spp ◽

Antifungal Effect ◽

Synthesis Of Nanoparticles ◽

Honey Solution ◽

Diffusion Assay

Silver nanoparticles (AgNPs) were synthesized using aqueous honey solutions with a concentration of 2%, 10%, and 20%—AgNPs-H2, AgNPs-H10, and AgNPs-H20. The reaction was conducted at 35 °C and 70 °C. Additionally, nanoparticles obtained with the citrate method (AgNPs-C), while amphotericin B (AmB) and fluconazole were used as controls. The presence and physicochemical properties of AgNPs was affirmed by analyzing the sample with ultraviolet–visible (UV–Vis) and fluorescence spectroscopy, scanning electron microscopy (SEM), and dynamic light scattering (DLS). The 20% honey solution caused an inhibition of the synthesis of nanoparticles at 35 °C. The antifungal activity of the AgNPs was evaluated using opportunistic human fungal pathogens Candida albicans and Candida parapsilosis. The antifungal effect was determined by the minimum inhibitory concentration (MIC) and disc diffusion assay. The highest activity in the MIC tests was observed in the AgNPs-H2 variant. AgNPs-H10 and AgNPs-H20 showed no activity or even stimulated fungal growth. The results of the Kirby–Bauer disc diffusion susceptibility test for C. parapsilosis strains indicated stronger antifungal activity of AgNPs-H than fluconazole. The study demonstrated that the antifungal activity of AgNPs is closely related to the concentration of honey used for the synthesis thereof.

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The killer yeast Wickerhamomyces anomalus Cf20 exerts a broad anti-Candida activity through the production of killer toxins and volatile compounds

Medical Mycology ◽

10.1093/mmy/myaa011 ◽

2020 ◽

Vol 58 (8) ◽

pp. 1102-1113 ◽

Cited By ~ 1

Author(s):

Miguel Fernández de Ullivarri ◽

Gabriela A Bulacios ◽

Silvia A Navarro ◽

Lucía Lanza ◽

Lucia M Mendoza ◽

...

Keyword(s):

Antifungal Activity ◽

Volatile Compounds ◽

Opportunistic Infections ◽

Killer Toxin ◽

Fungal Growth ◽

Candida Spp ◽

Killer Yeast ◽

Wickerhamomyces Anomalus ◽

Fungistatic Activity ◽

Killer Toxins

Abstract Candidiasis is a group of opportunistic infections caused by yeast of the genus Candida. The appearance of drug resistance and the adverse effects of current antifungal therapies require the search for new, more efficient therapeutic alternatives. Killer yeasts have aroused as suitable candidates for mining new antifungal compounds. Killer strains secrete antimicrobial proteins named killer toxins, with promissory antifungal activity. Here we found that the killer yeast Wickerhamomyces anomalus Cf20 and its cell-free supernatant (CFS) inhibited six pathogenic strains and one collection strain of Candida spp. The inhibition is mainly mediated by secreted killer toxins and, to a lesser extent, by volatile compounds such as acetic acid and ethyl acetate. A new large killer toxin (>180 kDa) was purified, which exerted 70–74% of the total CFS anti-Candida activity, and the previously described glucanase KTCf20 was inhibitory in a lesser extent as well. In addition, we demonstrated that Cf20 possesses the genes encoding for the β-1,3-glucanases WaExg1 and WaExg2, proteins with extensively studied antifungal activity, particularly WaExg2. Finally, the 10-fold concentrated CFS exerted a high candidacidal effect at 37°C, completely inhibiting the fungal growth, although the nonconcentrated CFS (RCF 1) had very limited fungistatic activity at this temperature. In conclusion, W. anomalus Cf20 produces different low and high molecular weight compounds with anti-Candida activity that could be used to design new therapies for candidiasis and as a source for novel antimicrobial compounds as well.

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Increased itraconazole antifungal activity by agar diffusion test

Journal of Microbiological Methods ◽

10.1016/0167-7012(94)90063-9 ◽

1994 ◽

Vol 20 (1) ◽

pp. 47-54 ◽

Cited By ~ 5

Author(s):

F.D. D'Auria ◽

N. Simonetti ◽

V. Strippoli

Keyword(s):

Antifungal Activity ◽

Diffusion Test ◽

Agar Diffusion ◽

Agar Diffusion Test

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Antifungal Activity of N-(4-Halobenzyl)amides against Candida spp. and Molecular Modeling Studies

International Journal of Molecular Sciences ◽

10.3390/ijms23010419 ◽

2021 ◽

Vol 23 (1) ◽

pp. 419

Author(s):

Yunierkis Perez-Castillo ◽

Ricardo Carneiro Montes ◽

Cecília Rocha da Silva ◽

João Batista de Andrade Neto ◽

Celidarque da Silva Dias ◽

...

Keyword(s):

Antifungal Activity ◽

Benzoic Acid ◽

Mechanism Of Action ◽

Fungal Infections ◽

Redox Balance ◽

Inhibitory Effect ◽

Candida Spp ◽

Cellular Processes ◽

Antifungal Action ◽

Dynamics Simulations

Fungal infections remain a high-incidence worldwide health problem that is aggravated by limited therapeutic options and the emergence of drug-resistant strains. Cinnamic and benzoic acid amides have previously shown bioactivity against different species belonging to the Candida genus. Here, 20 cinnamic and benzoic acid amides were synthesized and tested for inhibition of C. krusei ATCC 14243 and C. parapsilosis ATCC 22019. Five compounds inhibited the Candida strains tested, with compound 16 (MIC = 7.8 µg/mL) producing stronger antifungal activity than fluconazole (MIC = 16 µg/mL) against C. krusei ATCC 14243. It was also tested against eight Candida strains, including five clinical strains resistant to fluconazole, and showed an inhibitory effect against all strains tested (MIC = 85.3–341.3 µg/mL). The MIC value against C. krusei ATCC 6258 was 85.3 mcg/mL, while against C. krusei ATCC 14243, it was 10.9 times smaller. This strain had greater sensitivity to the antifungal action of compound 16. The inhibition of C. krusei ATCC 14243 and C. parapsilosis ATCC 22019 was also achieved by compounds 2, 9, 12, 14 and 15. Computational experiments combining target fishing, molecular docking and molecular dynamics simulations were performed to study the potential mechanism of action of compound 16 against C. krusei. From these, a multi-target mechanism of action is proposed for this compound that involves proteins related to critical cellular processes such as the redox balance, kinases-mediated signaling, protein folding and cell wall synthesis. The modeling results might guide future experiments focusing on the wet-lab investigation of the mechanism of action of this series of compounds, as well as on the optimization of their inhibitory potency.

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Berberine Antifungal Activity in Fluconazole-Resistant Pathogenic Yeasts: Action Mechanism Evaluated by Flow Cytometry and Biofilm Growth Inhibition in Candida spp.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01846-15 ◽

2016 ◽

Vol 60 (6) ◽

pp. 3551-3557 ◽

Cited By ~ 41

Author(s):

Anderson Ramos da Silva ◽

João Batista de Andrade Neto ◽

Cecília Rocha da Silva ◽

Rosana de Sousa Campos ◽

Rose Anny Costa Silva ◽

...

Keyword(s):

Flow Cytometry ◽

Antifungal Activity ◽

Cryptococcus Neoformans ◽

Fungal Infections ◽

Cell Activity ◽

Candida Spp ◽

Antifungal Effect ◽

Content Type ◽

Broth Microdilution Method ◽

Fluconazole Resistant

The incidence of fungal infections and, in particular, the incidence of fungal antibiotic resistance, which is associated with biofilm formation, have significantly increased, contributing to morbidity and mortality. Thus, new therapeutic strategies need to be developed. In this context, natural products have emerged as a major source of possible antifungal agents. Berberine is a protoberberine-type isoquinoline alkaloid isolated from the roots, rhizomes, and stem bark of natural herbs, such asBerberis aquifolium,Berberis vulgaris,Berberis aristata, andHydrastis canadensis, and ofPhellodendron amurense. Berberine has been proven to have broad antibacterial and antifungal activity. In the present study, the potential antifungal effect of berberine against fluconazole-resistantCandidaandCryptococcus neoformansstrains, as well as against the biofilm form ofCandidaspp., was assessed. The antifungal effect of berberine was determined by a broth microdilution method (the M27-A3 method of the Clinical and Laboratory Standards Institute) and flow cytometry techniques, in which the probable mechanism of action of the compound was also assessed. For biofilm assessment, a colorimetric 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to determine the susceptibility of sessile cells. The isolates used in the study belonged to the Laboratory of Bioprospection and Experiments in Yeast (LABEL) of the Federal University of Ceará. After 24 and 72 h, fluconazole-resistantCandidaandCryptococcus neoformansstrains showed berberine MICs equal to 8 μg/ml and 16 μg/ml, respectively. Cytometric analysis showed that treatment with berberine caused alterations to the integrity of the plasma and mitochondrial membranes and DNA damage, which led to cell death, probably by apoptosis. Assessment of biofilm-forming isolates after treatment showed statistically significant reductions in biofilm cell activity (P< 0.001).

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Ocotea glomerata (Nees) Mez Extract and Fractions: Chemical Characterization, Anti-Candida Activity and Related Mechanism of Action

Antibiotics ◽

10.3390/antibiotics9070394 ◽

2020 ◽

Vol 9 (7) ◽

pp. 394

Author(s):

Mayara Nunes Vitor Anjos ◽

Luiz Nascimento de Araújo-Neto ◽

Maria Daniela Silva Buonafina ◽

Rejane Pereira Neves ◽

Edson Rubhens de Souza ◽

...

Keyword(s):

Antifungal Activity ◽

Cell Viability ◽

Mechanism Of Action ◽

Methanol Extract ◽

Fungal Infections ◽

Synergistic Effects ◽

Chemical Characterization ◽

Ros Generation ◽

Candida Spp ◽

Minimal Inhibitory Concentrations

Background: Opportunistic fungal infections are increasingly common, with Candida albicans being the most common etiological agent; however, in recent years, episodes of candidiasis caused by non-albicans Candida species have emerged. Plants belonging to the Lauraceae family have shown remarkable antifungal effects. This study assessed the anti-Candida activity of Ocotea glomerata extracts and fractions, time of death and the synergistic effects with conventional antifungals. The possible mechanism of action was also addressed. Methods: Minimal inhibitory concentrations (MIC) were determined by broth microdilution technique, and the mechanism of action was assessed by ergosterol, sorbitol, cell viability, reactive oxygen species (ROS) generation and phosphatidylserine externalization tests. Results: All the tested extracts evidenced antifungal activity, but the methanol extract was revealed to be the most effective (MIC = 3.12 μg/mL) on C. krusei. The combination of methanol extract with ketoconazole and fluconazole revealed a synergistic effect for C. krusei and C. albicans, respectively. Fractions 1 and 5 obtained from the methanol extract had fungicidal activity, mainly against C. krusei. Methanol extract did not reveal effects by ergosterol and sorbitol assays; however, it led to an increase in intracellular ROS levels, decreased cell viability, and consequently, cell death. Conclusion: O. glomerata methanol extract may be viewed as a rich source of biomolecules with antifungal activity against Candida spp.

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Antifungal Activity of Natural Compounds vs. Candida spp.: A Mixture of Cinnamaldehyde and Eugenol Shows Promising In Vitro Results

Antibiotics ◽

10.3390/antibiotics11010073 ◽

2022 ◽

Vol 11 (1) ◽

pp. 73

Author(s):

Ilaria Maria Saracino ◽

Claudio Foschi ◽

Matteo Pavoni ◽

Renato Spigarelli ◽

Maria Chiara Valerii ◽

...

Keyword(s):

Gastrointestinal Tract ◽

Antifungal Activity ◽

Synergistic Effect ◽

Fungal Infections ◽

Natural Compounds ◽

Vulvovaginal Candidiasis ◽

Total Loss ◽

Diffusion Method ◽

Candida Spp

Candida spp. are commensal organisms of the skin, mucous membranes, gastrointestinal tract, blood, and vagina of animals and humans. In recent decades, the incidence of human fungal infections has increased, with Candida spp. (mainly C. albicans) infections being the most frequent, and the treatment of fungal infections is still a clinical challenge. Colonization of the human gastrointestinal tract by Candida spp. is significant because infections (e.g., candidemia and vulvovaginal candidiasis) frequently arise from commensal microorganisms. The aim of this study was to test in vitro the antifungal activity and the eventual synergistic effect of five pure components of essential oils: cinnamaldehyde, α-pinene, limonene, eucalyptol, and eugenol. These compounds were tested on 18 Candida strains (15 C. albicans, 2 C. glabrata, and 1 C. lusitaniae) derived from a culture collection of vaginal clinical strains. Methods: Fungistatic activity was evaluated using the disk diffusion method. For fungicidal activity, microdilution and time–kill curve protocols were set up. The checkerboard method was chosen to evaluate a possible synergistic effect of these compounds when mixed. Results: Cinnamaldehyde and eugenol gave the best results, inhibiting all the Candida strains and showing a highly additive effect (FICI 0.625). The cinnamaldehyde inhibition zone (IZ), MIC, and MFC means were 69 mm, 50.05 mg/L, and 109.26 mg/L respectively. Cinnamaldehyde led to the total loss of viable Candida cells within 4 h. Eugenol IZ, MIC, and MFC means were 35.2 mm, 455.42 mg/L, and 690.09 mg/L, respectively. Eugenol led to the total loss of viable fungal cells within 1 h. Treatment with α-pinene inhibited 88.9% of Candida strains, with an IZ mean of 21.2 mm, a MIC mean of 195.41 mg/L, and a MFC mean of 251.27 mg/L; this compound led to the total loss of viable fungal cells only after 24 h. Limonene inhibited only 33.3% of the tested strains and eucalyptol did not produce an inhibition halo, so these compounds were not tested further. Conclusions: These characteristics, together with the well-known safety of cinnamaldehyde and eugenol for human use, make these two natural compounds the perfect candidates for the treatment of candidiasis. This was a pilot study, the purpose of which was to evaluate the best composition of a mixture to be used against intestinal and vulvovaginal candidiasis; in vivo studies are needed to confirm these very encouraging results.

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REFRACTORY FUNGAL VAGINITIS TREATED BY TOPICAL AMPHOTERICIN B. Review

Medical Science of Ukraine (MSU) ◽

10.32345/2664-4738.2.2020.10 ◽

2020 ◽

Vol 16 (2) ◽

pp. 55-58

Author(s):

Falah Hasan Obayes AL-Khikani

Keyword(s):

Antifungal Activity ◽

Side Effects ◽

Amphotericin B ◽

Intravenous Injection ◽

Fungal Infections ◽

Wide Spectrum ◽

Candida Spp

Vaginitis is a common problem for women regarding a worldwide health challenge with many side effects. Vaginitis is among the most visiting to gynecology clinics. About 75% of all reproductive women had at least one fungal vaginitis infection in their life, and more than 40% will have two or more than two. Candida spp is the most prevalent in fungal vaginitis, while reports for unusual fungi were observed as mucor spp. Amphotericin B (AmB) belongs to the polyene group has a wide spectrum in vitro and in vivo antifungal activity. All of the known available formulas of AmB are administrated via intravenous injection to treat severe systemic fungal infections, while the development of the topical formula of AmB is still under preliminary development including topical vaginal AmB. Due to the revealing of antimicrobial-resistant fungi in recent years, this study explains the role of topical AmB in treating refractory fungi vaginitis that may not a response to other drugs reported in many cases that may help researchers to develop new effective formula of AmB regarding fungal vaginitis.

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Synthesis of 5-amino-1-aryl-3-methyl-1H-pyrazole-4-carbonitriles, Antifungal Activity and In Silico Analysis

Letters in Organic Chemistry ◽

10.2174/1570178617666200210105246 ◽

2020 ◽

Vol 17 (10) ◽

pp. 779-787

Author(s):

Luciana Terra ◽

Daiane de Jesus Viegas ◽

Alice Maria Rolim Bernardino ◽

Jéssica Venância Faria ◽

Percilene Fazolin Vegi ◽

...

Keyword(s):

Antifungal Activity ◽

Fungal Infections ◽

In Silico Analysis ◽

Single Step ◽

Antifungal Drugs ◽

Candida Spp ◽

Disk Diffusion Test ◽

Chemical Structures ◽

Microdilution Method ◽

Drug Classes

Serious fungal infections are increasing worldwide and have become a great concern in the medical field since antifungal drugs are restricted to a few drug classes. This work aims to evaluate the antifungal activity of a series of 5-amino-1-aryl-3-methyl-1H-pyrazole-4-carbonitriles (1a-g) and to establish a structure-activity relationship (SAR). The synthesis of these compounds was carried out in a single step followed by cyclization in good to excellent yields i.e. 73-94%. The chemical structures were confirmed by melting point, IR, 1H-NMR, 13C-NMR, and HRMS. These seven compounds were submitted to the disk diffusion test against Candida spp. and the active compound was evaluated by means of the microdilution method to determine the minimum inhibitory concentration (MIC). In addition, the stereo electronic descriptors were evaluated and pharmacokinetic and toxicological properties were calculated to predict the potential of these compounds as a drug. All the compounds presented good theoretical physicochemical parameters and one of them showed reasonably good antifungal activity.

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