Hydroxytyrosol (HT) analogues act as potent antifungals by direct disruption of the fungal cell membrane

Fungal infections constitute an emerging threat and a prevalent health problem due to increasing number of immunocompromised people and pharmacological or other treatments aiming at viral infections, cancer or allergies. Currently used antifungals suffer from inefficiency, toxic side effects and developing drug-resistance. Additionally, over the last two decades no new classes of antifungals have been approved, emphasizing the urgent need for developing a novel generation of antifungals. Here we investigate the antifungal activity of a series of chemically synthesized Hydroxytyrosol (HT) analogues. HT is one of the major phenolic compounds in olive oil, shown to possess radical-scavenging antioxidant, antiproliferative, proapoptotic and anti-inflammatory activities. No previous report has studied HT analogues as antifungals. We show that specific analogues have broad and strong antifungal activity, significantly stronger than the parent compound HT. Using A. nidulans as an in vivo cellular model system, we show that antifungal HT analogues have an unprecedented efficiency in fungal plasma membrane destruction. Importantly, antifungal HT analogues did not show toxicity in a mammalian cell line, whereas no resistance to HT analogues was obtained by standard mutagenesis. Our results open the way for the development of a novel, efficient and safer class of antifungals.

Download Full-text

A second generation fungerp analog SCY-247, shows potent in vitro activity against Candida auris and other clinically relevant fungal isolates

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01988-20 ◽

2020 ◽

pp. AAC.01988-20

Author(s):

Sherman Chu ◽

Lisa Long ◽

Rania Sherif ◽

Thomas S. McCormick ◽

Katyna Borroto-Esoda ◽

...

Keyword(s):

Antifungal Activity ◽

Second Generation ◽

Fungal Infections ◽

Parent Compound ◽

Fungal Species ◽

Antifungal Compound ◽

Candida Auris ◽

Fungal Cell ◽

Antifungal Properties

Due to the increase of antifungal drug resistance and difficulties associated with drug administration, new antifungal agents for invasive fungal infections are needed. SCY-247 is a second-generation fungerp antifungal compound that interferes with the synthesis of the fungal cell wall polymer ß-(1,3)-D-glucan. We conducted an extensive antifungal screen of SCY-247 against yeast and mold strains compared with the parent compound ibrexafungerp (IBX, formerly SCY-078) to evaluate the in vitro antifungal properties of SCY-247. SCY-247 demonstrated similar activity to IBX against all of the organisms tested. Moreover, SCY-247 showed a higher percentage of fungicidal activity against the panel of yeast and mold isolates compared to IBX. Notably, SCY-247 showed considerable antifungal properties against numerous strains of Candida auris. Additionally, SCY-247 retained its antifungal activity when evaluated in the presence of synthetic urine, indicating that SCY-247 maintains activity and structural stability under environments with decreased pH levels. Finally, a time-kill study showed SCY-247 has potent anti-Candida, Aspergillus, and Scedosporium activity. In summary, SCY-247 has potent antifungal activity against various fungal species, indicating that further studies on this fungerp analog are warranted.

Download Full-text

Poly-ε-caprolactone Nanoparticles Loaded with 4-Nerolidylcatechol (4-NC) for Growth Inhibition of Microsporum canis

Antibiotics ◽

10.3390/antibiotics9120894 ◽

2020 ◽

Vol 9 (12) ◽

pp. 894

Author(s):

Vanessa Raquel Greatti ◽

Fernando Oda ◽

Rodrigo Sorrechia ◽

Bárbara Regina Kapp ◽

Carolina Manzato Seraphim ◽

...

Keyword(s):

Antifungal Activity ◽

Growth Inhibition ◽

Fungal Infections ◽

Polymeric Nanoparticles ◽

Weight Ratio ◽

Microsporum Canis ◽

Nanostructured Systems ◽

The Stability

Dermatophyte fungal infections are difficult to treat because they need long-term treatments. 4-Nerolidylcatechol (4-NC) is a compound found in Piper umbellatum that has been reported to demonstrate significant antifungal activity, but is easily oxidizable. Due to this characteristic, the incorporation in nanostructured systems represents a strategy to guarantee the compound’s stability compared to the isolated form and the possibility of improving antifungal activity. The objective of this study was to incorporate 4-NC into polymeric nanoparticles to evaluate, in vitro and in vivo, the growth inhibition of Microsporum canis. 4-NC was isolated from fresh leaves of P. umbellatum, and polymer nanoparticles of polycaprolactone were developed by nanoprecipitation using a 1:5 weight ratio (drug:polymer). Nanoparticles exhibited excellent encapsulation efficiency, and the antifungal activity was observed in nanoparticles with 4-NC incorporated. Polymeric nanoparticles can be a strategy employed for decreased cytotoxicity, increasing the stability and solubility of substances, as well as improving the efficacy of 4-NC.

Download Full-text

Antifungal activity of the clove essential oil from Syzygium aromaticum on Candida, Aspergillus and dermatophyte species

Journal of Medical Microbiology ◽

10.1099/jmm.0.010538-0 ◽

2009 ◽

Vol 58 (11) ◽

pp. 1454-1462 ◽

Cited By ~ 226

Author(s):

Eugénia Pinto ◽

Luís Vale-Silva ◽

Carlos Cavaleiro ◽

Lígia Salgueiro

Keyword(s):

Antifungal Activity ◽

Essential Oil ◽

Cell Membrane ◽

Fungal Infections ◽

Yeast Cells ◽

Syzygium Aromaticum ◽

Clove Oil ◽

Fungal Cell ◽

Minimum Fungicidal Concentration ◽

Clove Essential Oil

The composition and antifungal activity of clove essential oil (EO), obtained from Syzygium aromaticum, were studied. Clove oil was obtained commercially and analysed by GC and GC-MS. The EO analysed showed a high content of eugenol (85.3 %). MICs, determined according to Clinical and Laboratory Standards Institute protocols, and minimum fungicidal concentration were used to evaluate the antifungal activity of the clove oil and its main component, eugenol, against Candida, Aspergillus and dermatophyte clinical and American Type Culture Collection strains. The EO and eugenol showed inhibitory activity against all the tested strains. To clarify its mechanism of action on yeasts and filamentous fungi, flow cytometric and inhibition of ergosterol synthesis studies were performed. Propidium iodide rapidly penetrated the majority of the yeast cells when the cells were treated with concentrations just over the MICs, meaning that the fungicidal effect resulted from an extensive lesion of the cell membrane. Clove oil and eugenol also caused a considerable reduction in the quantity of ergosterol, a specific fungal cell membrane component. Germ tube formation by Candida albicans was completely or almost completely inhibited by oil and eugenol concentrations below the MIC values. The present study indicates that clove oil and eugenol have considerable antifungal activity against clinically relevant fungi, including fluconazole-resistant strains, deserving further investigation for clinical application in the treatment of fungal infections.

Download Full-text

Identification of a New Class of Antifungals Targeting the Synthesis of Fungal Sphingolipids

mBio ◽

10.1128/mbio.00647-15 ◽

2015 ◽

Vol 6 (3) ◽

Cited By ~ 64

Author(s):

Visesato Mor ◽

Antonella Rella ◽

Amir M. Farnoud ◽

Ashutosh Singh ◽

Mansa Munshi ◽

...

Keyword(s):

Cell Cycle Progression ◽

Fungal Infections ◽

Pathogenic Fungi ◽

Antifungal Drugs ◽

Sequencing Analysis ◽

Fungal Cell ◽

New Class ◽

Narrow Spectrum

ABSTRACT Recent estimates suggest that >300 million people are afflicted by serious fungal infections worldwide. Current antifungal drugs are static and toxic and/or have a narrow spectrum of activity. Thus, there is an urgent need for the development of new antifungal drugs. The fungal sphingolipid glucosylceramide (GlcCer) is critical in promoting virulence of a variety of human-pathogenic fungi. In this study, we screened a synthetic drug library for compounds that target the synthesis of fungal, but not mammalian, GlcCer and found two compounds [N′-(3-bromo-4-hydroxybenzylidene)-2-methylbenzohydrazide (BHBM) and its derivative, 3-bromo-N′-(3-bromo-4-hydroxybenzylidene) benzohydrazide (D0)] that were highly effective in vitro and in vivo against several pathogenic fungi. BHBM and D0 were well tolerated in animals and are highly synergistic or additive to current antifungals. BHBM and D0 significantly affected fungal cell morphology and resulted in the accumulation of intracellular vesicles. Deep-sequencing analysis of drug-resistant mutants revealed that four protein products, encoded by genes APL5, COS111, MKK1, and STE2, which are involved in vesicular transport and cell cycle progression, are targeted by BHBM. IMPORTANCE Fungal infections are a significant cause of morbidity and mortality worldwide. Current antifungal drugs suffer from various drawbacks, including toxicity, drug resistance, and narrow spectrum of activity. In this study, we have demonstrated that pharmaceutical inhibition of fungal glucosylceramide presents a new opportunity to treat cryptococcosis and various other fungal infections. In addition to being effective against pathogenic fungi, the compounds discovered in this study were well tolerated by animals and additive to current antifungals. These findings suggest that these drugs might pave the way for the development of a new class of antifungals.

Download Full-text

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

10.26434/chemrxiv.12736505 ◽

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>

Download Full-text

Evaluation of Antifungal Activity of Chitosan Nanoparticles Against Fusarium Solani Phytopathogenic Fungi in in Vitro and in Vivo Assays

10.21203/rs.3.rs-362614/v1 ◽

2021 ◽

Author(s):

Pamela R. Avila ◽

Graciela Juez Castillo ◽

Carel E. Carvajal

Keyword(s):

Antifungal Activity ◽

Fusarium Solani ◽

Plant Root ◽

Chitosan Nanoparticles ◽

Fungal Growth ◽

Fungal Cell ◽

Tomato Root ◽

Root Cells

Abstract Fungal diseases are a current problem in agriculture causing significant losses in several crops whereby its prevention and treatment is of utmost importance. The Chitosan nanoparticles (ChNPs) were evaluated for their antimicrobial activity against the phytopathogen Fusarium solani. The chitosan concentration in nanoparticles that showed antifungal activity was 2.0 µg/mL. ChNPs showed to be a potential antifungal candidate with applications in phytosanitary control. Transmission electron microscopy (TEM) results showed damage to the fungal cell wall and membrane caused by the nanoparticles interaction with these structures affecting fungal growth and development in in vitro as in in vivo assay where microscopy demonstrated the internalization of nanoparticles aggregates within plant root cells cytoplasm up to 45 days. Therefore ChNPs nanoparticles could be an alternative method for diseases caused by Fusarium solani instead of chemical fungicides commonly used for treating tomato root rot.

Download Full-text

Natural Killer Cells and Antifungal Host Response

Clinical and Vaccine Immunology ◽

10.1128/cvi.00606-12 ◽

2013 ◽

Vol 20 (4) ◽

pp. 452-458 ◽

Cited By ~ 33

Author(s):

Stanislaw Schmidt ◽

Stefanie-Yvonne Zimmermann ◽

Lars Tramsen ◽

Ulrike Koehl ◽

Thomas Lehrnbecher

Keyword(s):

Antifungal Activity ◽

Nk Cells ◽

Natural Killer ◽

Host Response ◽

Fungal Infections ◽

Treatment Strategies ◽

Cytotoxic Molecules ◽

Insight Into

ABSTRACTAs a result of improved experimental methodologies and a better understanding of the immune system, there is increasing insight into the antifungal activity of natural killer (NK) cells. Murine and human NK cells are able to damage fungi of different genera and speciesin vitro, and they exert both direct and indirect antifungal activity through cytotoxic molecules such as perforin and through cytokines and interferons, respectively. On the other hand, recent data suggest that fungi exhibit immunosuppressive effects on NK cells. Whereas clearin vivodata are lacking in humans, the importance of NK cells in the host response against fungi has been demonstrated in animal models. Further knowledge of the interaction of NK cells with fungi might help to better understand the pathogenesis of invasive fungal infections and to improve treatment strategies.

Download Full-text

Pharmacokinetics-Driven Evaluation of the Antioxidant Activity of Curcuminoids and Their Major Reduced Metabolites—A Medicinal Chemistry Approach

Molecules ◽

10.3390/molecules26123542 ◽

2021 ◽

Vol 26 (12) ◽

pp. 3542

Author(s):

Gábor Girst ◽

Sándor B. Ötvös ◽

Ferenc Fülöp ◽

György T. Balogh ◽

Attila Hunyadi

Keyword(s):

Chemical Stability ◽

Medicinal Chemistry ◽

Water Solubility ◽

Parent Compound ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Liver Microsomes ◽

Metabolic Stability ◽

Pharmacokinetic Parameters

Curcuminoids are the main bioactive components of the well-known Asian spice and traditional medicine turmeric. Curcuminoids have poor chemical stability and bioavailability; in vivo they are rapidly metabolized to a set of bioreduced derivatives and/or glucuronide and sulfate conjugates. The reduced curcuminoid metabolites were also reported to exert various bioactivities in vitro and in vivo. In this work, we aimed to perform a comparative evaluation of curcuminoids and their hydrogenated metabolites from a medicinal chemistry point of view, by determining a set of key pharmacokinetic parameters and evaluating antioxidant potential in relation to such properties.Reduced metabolites were prepared from curcumin and demethoxycurcumin through continuous-flow hydrogenation. As selected pharmacokinetic parameters, kinetic solubility, chemical stability, metabolic stability in human liver microsomes, and parallel artificial membrane permeability assay (PAMPA)-based gastrointestinal and blood-brain barrier permeability were determined. Experimentally determined logP for hydrocurcumins in octanol-water and toluene-water systems provided valuable data on the tendency for intramolecular hydrogen bonding by these compounds. Drug likeness of the compounds were further evaluated by a in silico calculations. Antioxidant properties in diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and oxygen radical absorbance capacity (ORAC) assays were comparatively evaluated through the determination of ligand lipophilic efficiency (LLE). Our results showed dramatically increased water solubility and chemical stability for the reduced metabolites as compared to their corresponding parent compound. Hexahydrocurcumin was found the best candidate for drug development based on a complex pharmacokinetical comparison and high LLE values for its antioxidant properties. Development of tetrahydrocurcumin and tetrahydro-demethoxycurcumin would be limited by their very poor metabolic stability, therefore such an effort would rely on formulations bypassing first-pass metabolism.

Download Full-text

Isolation, Characterization and Mode of Action of a Plant-Derived Antifungal Peptide, Cc-AFP1 Against Aspergillus Fumigatus

10.21203/rs.3.rs-571433/v1 ◽

2021 ◽

Author(s):

Sima Sadat Seyedjavadi ◽

Soghra Khani ◽

Mehdi Goudarzi ◽

Hadi Zare-Zardini ◽

Masoomeh Shams-Ghahfarokhi ◽

...

Keyword(s):

Antifungal Activity ◽

Structure Prediction ◽

Fungal Pathogens ◽

Tertiary Structure ◽

Fungal Infections ◽

Cell Membrane Permeability ◽

Random Coil ◽

Iodide Uptake ◽

Fungal Cell ◽

Human Red Blood Cells

Abstract Among novel molecules with therapeutic efficacy, antifungal peptides (AFPs) have recently been attracted due to their unique ability to evade fungal pathogens. In this study, a novel AFP, Cc-AFP1 (MW ~ 3.759 kDa) isolated from Carum carvi L. was purified by precipitation and chromatography techniques. Sequence analysis by Edman degradation revealed a fragment of 36 amino acid residues as RVCFRPVATYLGVCGVSGACRDHCVKLGSCVYKGPG. The tertiary structure prediction using the I-TASSER showed α-helix and random coil structure. Cc-AFP1 had a net charge of +4 and hydrophobicity ratio of 44%. The antifungal activity of Cc-AFP1 was confirmed against Aspergillus species with MIC values in the range of 8-16 µg/mL. Cc-AFP1 had less than 5% hemolytic activity at 8-16 µg/mL on human red blood cells, while it was nontoxic for HEK293 cell lines. Stability analysis showed that Cc-AFP1 activity was maintained at different temperatures (20 to 80ºC) and pH (8 to 10). The results of a propidium iodide uptake and transmission electron microscopy showed that the antifungal activity of Cc-AFP1 could be attributed to altering the fungal cell membrane permeability. Taken together, these results indicate that Cc-AFP1 may be an attractive molecule to develop as a novel antifungal agent combating fungal infections cause by Aspergillus species.

Download Full-text

Carvacrol essential oil stimulates growth performance, immune response, and tolerance of Nile tilapia to Cryptococcus uniguttulatus infection

Diseases of Aquatic Organisms ◽

10.3354/dao03506 ◽

2020 ◽

Vol 141 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

HH Mahboub ◽

YH Tartor

Keyword(s):

Antifungal Activity ◽

Growth Performance ◽

Nile Tilapia ◽

Fungal Infections ◽

Antifungal Drugs ◽

Fish Growth ◽

Immunological Parameters ◽

Species Production

This study investigated the antifungal activity of 5 essential oils (EOs) towards yeasts recovered from diseased fishes; and focused on the efficacy of one EO (carvacrol) on growth performance, non-specific immunity, and disease resistance of Nile tilapia Oreochromis niloticus against Cryptococcus uniguttulatus challenge. Thymoquinone, thymol, carvacrol, eugenol, and cinnamon were first tested in vitro against 20 clinical yeast strains in comparison with antifungal drugs (fluconazole, ketoconazole, itraconazole, amphotericin B, nystatin, and clotrimazole) using disc diffusion and broth microdilution methods. For the in vivo challenge, fish (n = 150) were divided into 5 groups (carvacrol prophylaxis, carvacrol treatment, itraconazole treatment, unchallenged control, and positive control; 30 fish group-1) with 3 replicates. Phagocytic activity, reactive oxygen species production, reactive nitrogen species production, myeloperoxidase, lysozyme activity, and total immunoglobulins were tested before and after challenge. Relative percent survival (RPS) and mortality percent were determined as indicators for functional immunity. EOs displayed divergent degrees of antifungal activity, and carvacrol was the most effective against the tested yeasts. The dietary additive of carvacrol significantly enhanced growth performance, all immunological parameters, and the RPS values (90%) compared to other treatments. This unique experimental model indicates that carvacrol seems promising not only for enhancing immunity and promoting fish growth, but also for controlling emerging fungal infections. Future studies should investigate different concentrations of carvacrol as well as its antifungal activity in different fish species.

Download Full-text