scholarly journals Novel Antifungal Activity of Q-Griffithsin, a Broad-Spectrum Antiviral Lectin

2021 ◽  
Author(s):  
Henry W. Nabeta ◽  
Joseph C. Kouokam ◽  
Amanda B. Lasnik ◽  
Joshua L. Fuqua ◽  
Kenneth E. Palmer
Keyword(s):  
Antifungal Activity ◽  
Broad Spectrum ◽  
Fungal Infections ◽  
Morbidity And Mortality ◽  
New Agents ◽  
Drug Regimens

Fungal infections contribute to morbidity and mortality annually, and the number of organisms that are nonresponsive to the current available drug regimens are on the rise. There is a need to develop new agents to counter these infections and to add to the limited arsenal available to treat fungal infections.

Antifúngicos poliénicos. Mecanismo de acción y aplicaciones

2020 ◽  
Vol 63 (2) ◽  
pp. 7-17
Author(s):  
Evelyn Rivera-Toledo ◽  
Alan Uriel Jiménez-Delgadillo ◽  
Patricia Manzano-Gayosso
Keyword(s):  
Antifungal Activity ◽  
Key Words ◽  
Secondary Metabolism ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Variable Number ◽  
Therapeutic Failure ◽  
Morbidity And Mortality ◽  
Clinical Use

The first compounds with specific antifungal activity were identified in the middle of the last century as a product of the secondary metabolism of bacteria of the order Actinomycetales, and their clinical use significantly diminished the morbidity and mortality associated with severe fungal infections. Many of such biosynthetic compounds are characterized by a chemical polygenic structure, with a variable number of carbon-carbon double bonds. Currently, besides polygenic antimycotics, there are other antifungal agents, such as the azole compounds, that have less toxicity in patients; however, cases of therapeutic failure with such compounds have been documented, therefore, the use of polygenics is still the best alternative in such cases. This review presents data about the properties and applications of antifungal-polygenic compounds using amphotericin B as a model. Key words: Amphotericin B; antifungal polyenes; ergosterol

scholarly journals Non-toxic Cobalt(III) Schiff Base Complexes with Broad Spectrum Antifungal Activity

2020 ◽  
Author(s):  
Angelo Frei ◽  
A. Paden King ◽  
Gabrielle J. Lowe ◽  
Amy K. Cain ◽  
Francesca L. Short ◽  
...  
Keyword(s):  
Schiff Base ◽  
Antifungal Activity ◽  
Broad Spectrum ◽  
Bacterial Infections ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
New Drugs ◽  
Schiff Base Complexes ◽  
In Vivo Studies

Resistance to currently available antifungal drugs has quietly been on the rise but overshadowed by the alarming spread of antibacterial resistance. There is a striking lack of attention to the threat of drug resistant fungal infections, with only a handful of new drugs currently in development. Given that metal complexes have proven to be useful new chemotypes in the fight against diseases such as cancer, malaria, and bacterial infections, it stands to reason to explore their possible utility in treating fungal infections. Herein we report a series of cobalt(III) Schiff base complexes with broad spectrum antifungal activity. Some of these complexes (1-3) show minimum inhibitory concentrations (MIC) in the low micro- to nanomolar range against a series of Candida and Cryptococcus yeasts. Additionally, we demonstrate that these compounds show no cytotoxicity against both bacterial and human cells. Finally, we report first in vivo toxicity data on these compounds in Galleria mellonella, showing that doses as high as 266 mg/kg are tolerated without adverse effects, paving the way for further in vivo studies of these complexes. <br>

A Combination approach using Areca nut and Ketoconazole for Treating Cutaneous Candidiasis

2021 ◽  
pp. 3074-3076
Author(s):  
Manoj M Wagle ◽  
Kiran Noel Lobo ◽  
Rajath Kanchan R ◽  
Adithya Chandrashekar ◽  
Subrahmanyam VM
Keyword(s):  
Candida Albicans ◽  
Antifungal Activity ◽  
Antifungal Agent ◽  
Fungal Infections ◽  
Morbidity And Mortality ◽  
Areca Nut ◽  
Topical Formulations ◽  
Areca Catechu ◽  
Cutaneous Candidiasis ◽  
Combination Approach

Fungal infections caused by Candida are often associated with increasing rates of morbidity and mortality. It is a serious concern for patients with immunocompromised system. The resistance to Ketoconazole, a known antifungal agent is increasing at an alarming rate and a number of such cases have been reported in the recent years. In order to circumvent this problem, a study was carried out using ketoconazole-areca nut (Areca catechu L.) combination. When this combination was tested against Candida albicans, there was an increase in the antifungal activity of ketoconazole. The study can be explored further for the design of suitable topical formulations containing the above combination in the treatment of cutaneous candidiasis.

scholarly journals Toxoflavin Produced byBurkholderia gladiolifromLycoris aureaIs a New Broad-Spectrum Fungicide

2019 ◽  
Vol 85 (9) ◽  
Author(s):  
Xiaodan Li ◽  
Yikui Li ◽  
Ren Wang ◽  
Qizhi Wang ◽  
Ling Lu
Keyword(s):  
Antifungal Activity ◽  
Broad Spectrum ◽  
Fungal Pathogens ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Endophytic Bacterium ◽  
Content Type ◽  
Burkholderia Gladioli ◽  
Lycoris Aurea ◽  
Resistant Mutants

ABSTRACTFungal infections not only cause extensive agricultural damage but also result in serious diseases in the immunodeficient populations of human beings. Moreover, the increasing emergence of drug resistance has led to a decrease in the efficacy of current antifungals. Thus, screening of new antifungal agents is imperative in the fight against antifungal drug resistance. In this study, we show that an endophytic bacterium,Burkholderia gladioliHDXY-02, isolated from the medicinal plantLycoris aurea, showed broad-spectrum antifungal activity against plant and human fungal pathogens. An antifungal ability assay indicated that the bioactive component was produced from strain HDXY-02 having an extracellular secreted component with a molecular weight lower than 1,000 Da. In addition, we found that this new antifungal could be produced effectively by liquid fermentation of HDXY-02. Furthermore, the purified component contributing to the antifungal activity was identified to be toxoflavin, a yellow compound possessing a pyrimido[5,4-e][1,2,4]triazine ring.In vitrobioactivity studies demonstrated that purified toxoflavin fromB. gladioliHDXY-02 cultures had a significant antifungal activity against the human fungal pathogenAspergillus fumigatus, resulting in abolished germination of conidia. More importantly, the growth inhibition by toxoflavin was observed in both wild-type and drug-resistant mutants (cyp51Aand non-cyp51A) ofA. fumigatus. Finally, an optimized protocol for the large-scale production of toxoflavin (1,533 mg/liter) has been developed. Taken together, our findings provide a promising biosynthetic resource for producing a new antifungal reagent, toxoflavin, from isolates of the endophytic bacteriumB. gladioli.IMPORTANCEHuman fungal infections are a growing problem associated with increased morbidity and mortality. Moreover, a growing number of antifungal-resistant fungal isolates have been reported over the past decade. Thus, the need for novel antifungal agents is imperative. In this study, we show that an endophytic bacterium,Burkholderia gladioli, isolated from the medicinal plantLycoris aurea, is able to abundantly secrete a compound, toxoflavin, which has a strong fungicidal activity not only against plant fungal pathogens but also against human fungal pathogensAspergillus fumigatusandCandida albicans,Cryptococcus neoformans, and the model filamentous fungusAspergillus nidulans. More importantly, toxoflavin also displays an efficacious inhibitory effect against azole antifungal-resistant mutants ofA. fumigatus. Consequently, our findings provide a promising approach to abundantly produce toxoflavin, which has novel broad-spectrum antifungal activity, especially against those currently problematic drug-resistant isolates.

scholarly journals Antifungal In Vitro Activity of Pilosulin- and Ponericin-Like Peptides from the Giant Ant Dinoponera quadriceps and Synergistic Effects with Antimycotic Drugs

Antibiotics ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 354 ◽  
Author(s):  
Hilania Valéria Dodou Lima ◽  
Carolina Sidrim de Paula Cavalcante ◽  
Gandhi Rádis-Baptista
Keyword(s):  
Antifungal Activity ◽  
Antimicrobial Peptides ◽  
Broad Spectrum ◽  
Culture Medium ◽  
Fungal Infections ◽  
Synergistic Effects ◽  
Antifungal Drugs ◽  
Clinical Strain ◽  
Onset Of Action

Venoms from ants comprise a rich source of bioactive peptides, including antimicrobial peptides. From the proteome and peptidome of the giant ant Dinoponera quadriceps venom, members of five known classes of antimicrobial peptides were disclosed (e.g., dermaseptin-, defensin-, ICK-, pilosulin- and ponericin-like types). Based on comparative analysis, these family members have structural determinants that indicate they could display antimicrobial activities. In previous works, pilosulin- and ponericin-like peptides were demonstrated to be active against bacteria, fungi, and parasites. Herein, the antifungal activity of ponericin- and pilosulin-like peptides were assessed, aiming at the expansion of the knowledge about AMPs in predatory ants and the development of new microbicide strategies to deal with difficult-to-treat fungal infections. Synthetic pilosulin- (Dq-2562, Dq-1503, and Dq-1319) and ponericin-like (Dq-3162) peptides were evaluated for their fungicide and fungistatic activities against different species of Candida, including a drug-resistant clinical strain. The MICs and MLCs were determined for all peptides individually and in combination with general antifungal drugs by the microdilution method. The time-kill kinetic curves were set up by means of a luminescent reagent, of which the light signal is proportional to the number of viable cells. The candicidal synergism observed by the combination of subinhibitory concentrations of peptides and general antimycotic drugs were quantified by the checkerboard test and fluorescent dye permeation assay. The influence of ergosterol on the antifungal activity was verified by supplementation of culture medium. The pilosulin- (Dq-2562 and Dq-1503) and ponericin-like (Dq-3162) were the most active peptides, displaying a broad spectrum of antifungal activity in vitro, with MICs in the range of 0.625 to 10 µM. The combination of peptides and conventional antimycotic drugs displayed a synergistic reduction in the MIC values of individual peptides and drugs, while soluble ergosterol in the culture medium increased the MICs. The fungicide and fungistatic activity of the individual peptides and peptides in combination with antimycotics were time-dependent with a rapid onset of action and long-lasting effect, which involved membrane disruption as an underlying mechanism of their action. Altogether, pilosulin- and ponericin-like peptides from the giant ant D. quadriceps venom display a broad-spectrum of candicidal activity, what allows their inclusion in the row of the antifungal peptides and gives support for further studies on the development of strategies to fight candidiasis.

scholarly journals Crystal Structure of the New Investigational Drug Candidate VT-1598 in Complex with Aspergillus fumigatus Sterol 14α-Demethylase Provides Insights into Its Broad-Spectrum Antifungal Activity

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Tatiana Y. Hargrove ◽  
Edward P. Garvey ◽  
William J. Hoekstra ◽  
Christopher M. Yates ◽  
Zdzislaw Wawrzak ◽  
...  
Keyword(s):  
Antifungal Activity ◽  
Aspergillus Fumigatus ◽  
Broad Spectrum ◽  
Fungal Infections ◽  
Enzymatic Reaction ◽  
Heme Iron ◽  
Antifungal Drugs ◽  
Drug Candidate ◽  
Investigational Drug ◽  
Content Type

ABSTRACT Within the past few decades, the incidence and complexity of human fungal infections have increased, and therefore, the need for safer and more efficient, broad-spectrum antifungal agents is high. In the study described here, we characterized the new tetrazole-based drug candidate VT-1598 as an inhibitor of sterol 14α-demethylase (CYP51B) from the filamentous fungus Aspergillus fumigatus. VT-1598 displayed a high affinity of binding to the enzyme in solution (dissociation constant, 13 ± 1 nM) and in the reconstituted enzymatic reaction was revealed to have an inhibitory potency stronger than the potencies of all other simultaneously tested antifungal drugs, including fluconazole, voriconazole, ketoconazole, and posaconazole. The X-ray structure of the VT-1598/A. fumigatus CYP51 complex was determined and depicts the distinctive binding mode of the inhibitor in the enzyme active site, suggesting the molecular basis of the improved drug potency and broad-spectrum antifungal activity. These data show the formation of an optimized hydrogen bond between the phenoxymethyl oxygen of VT-1598 and the imidazole ring nitrogen of His374, the CYP51 residue that is highly conserved across fungal pathogens and fungus specific. Comparative structural analysis of A. fumigatus CYP51/voriconazole and Candida albicans CYP51/VT-1161 complexes supports the role of H bonding in fungal CYP51/inhibitor complexes and emphasizes the importance of an optimal distance between this interaction and the inhibitor-heme iron interaction. Cellular experiments using two A. fumigatus strains (strains 32820 and 1022) displayed a direct correlation between the effects of the drugs on CYP51B activity and fungal growth inhibition, indicating the noteworthy anti-A. fumigatus potency of VT-1598 and confirming its promise as a broad-spectrum antifungal agent.

scholarly journals Derivatives of the antimalarial drug mefloquine are broad spectrum antifungal molecules with activity against drug-resistant clinical isolates

2019 ◽  
Author(s):  
Marhiah C. Montoya ◽  
Sarah Beattie ◽  
Kathryn M. Alden ◽  
Damian J. Krysan
Keyword(s):  
Antifungal Activity ◽  
Mechanism Of Action ◽  
Broad Spectrum ◽  
Fungal Infections ◽  
Clinical Isolates ◽  
In Vitro Toxicity ◽  
Drug Resistant ◽  
Candida Auris ◽  
Recent Emergence ◽  
Derivatives Of

ABSTRACTThe antifungal pharmacopeia is critically small, particularly in light of the recent emergence of multi-drug-resistant pathogens such as Candida auris. Herein, we report that derivatives of the anti-malarial drug mefloquine have broad spectrum antifungal activity against pathogenic yeasts and molds. In addition, the mefloquine derivatives have activity against clinical isolates that are resistant to one or more of the three classes of drugs currently used to treat invasive fungal infections, indicating that they have a novel mechanism of action. Importantly, the in vitro toxicity profiles using human cell lines indicate that the mefloquine derivatives are very similar to the parent mefloquine despite being up to 64-fold more active against fungal cells. In addition to direct antifungal activity, sub-inhibitory concentrations of the mefloquine derivatives inhibit the expression of virulence traits including filamentation in C. albicans and capsule formation/melanization in C. neoformans. Mode/mechanism of action experiments indicate that the mefloquine derivatives interfere with both mitochondrial and vacuolar function as part of a multi-target mechanism of action. The broad-spectrum scope of activity, blood-brain-barrier penetration, and large number of previously synthesized analogs available combine to support the further optimization and development of the antifungal activity of this general class of drug-like molecules.

scholarly journals Derivatives of the Antimalarial Drug Mefloquine Are Broad-Spectrum Antifungal Molecules with Activity against Drug-Resistant Clinical Isolates

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Marhiah C. Montoya ◽  
Sarah Beattie ◽  
Kathryn M. Alden ◽  
Damian J. Krysan
Keyword(s):  
Antifungal Activity ◽  
Mechanism Of Action ◽  
Broad Spectrum ◽  
Antimalarial Drug ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Clinical Isolates ◽  
Content Type ◽  
Recent Emergence ◽  
Derivatives Of

ABSTRACT The antifungal pharmacopeia is critically small, particularly in light of the recent emergence of multidrug-resistant pathogens, such as Candida auris. Here, we report that derivatives of the antimalarial drug mefloquine have broad-spectrum antifungal activity against pathogenic yeasts and molds. In addition, the mefloquine derivatives have activity against clinical isolates that are resistant to one or more of the three classes of antifungal drugs currently used to treat invasive fungal infections, indicating that they have a novel mechanism of action. Importantly, the in vitro toxicity profiles obtained using human cell lines indicated that the toxicity profiles of the mefloquine derivatives are very similar to those of the parent mefloquine, despite being up to 64-fold more active against fungal cells. In addition to direct antifungal activity, subinhibitory concentrations of the mefloquine derivatives inhibited the expression of virulence traits, including filamentation in Candida albicans and capsule formation/melanization in Cryptococcus neoformans. Mode/mechanism-of-action experiments indicated that the mefloquine derivatives interfere with both mitochondrial and vacuolar function as part of a multitarget mechanism of action. The broad-spectrum scope of activity, blood-brain barrier penetration, and large number of previously synthesized analogs available combine to support the further optimization and development of the antifungal activity of this general class of drug-like molecules.

scholarly journals Discovery of Cercosporamide, a Known Antifungal Natural Product, as a Selective Pkc1 Kinase Inhibitor through High-Throughput Screening

2004 ◽  
Vol 3 (4) ◽  
pp. 932-943 ◽  
Author(s):  
Andrea Sussman ◽  
Karen Huss ◽  
Li-Chun Chio ◽  
Steve Heidler ◽  
Margaret Shaw ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antifungal Activity ◽  
High Throughput ◽  
Broad Spectrum ◽  
High Throughput Screening ◽  
Kinase Inhibitor ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
Antifungal Compound ◽  
Glucan Synthase

ABSTRACT The Pkc1-mediated cell wall integrity-signaling pathway is highly conserved in fungi and is essential for fungal growth. We thus explored the potential of targeting the Pkc1 protein kinase for developing broad-spectrum fungicidal antifungal drugs through a Candida albicans Pkc1-based high-throughput screening. We discovered that cercosporamide, a broad-spectrum natural antifungal compound, but previously with an unknown mode of action, is actually a selective and highly potent fungal Pkc1 kinase inhibitor. This finding provides a molecular explanation for previous observations in which Saccharomyces cerevisiae cell wall mutants were found to be highly sensitive to cercosporamide. Indeed, S. cerevisiae mutant cells with reduced Pkc1 kinase activity become hypersensitive to cercosporamide, and this sensitivity can be suppressed under high-osmotic growth conditions. Together, the results demonstrate that cercosporamide acts selectively on Pkc1 kinase and, thus, they provide a molecular mechanism for its antifungal activity. Furthermore, cercosporamide and a β-1,3-glucan synthase inhibitor echinocandin analog, by targeting two different key components of the cell wall biosynthesis pathway, are highly synergistic in their antifungal activities. The synergistic antifungal activity between Pkc1 kinase and β-1,3-glucan synthase inhibitors points to a potential highly effective combination therapy to treat fungal infections.

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