Antifungal Potential Research Articles

Molecular identification and antifungal potentials of lactic acid bacteria isolated from soil

Molecular identification and antifungal potentials of lactic acid bacteria isolated from soil

Design, Synthesis, and Evaluation of Quinoline‐1,2,3‐Triazole Hybrids as CYP51 Inhibitors: In Silico Study and In Vitro Antimicrobial Assessment

AbstractNovel Quinoline‐triazole hybrid derivatives (9 a–9 l) were designed and synthesized via click reaction methodology to develop lead compounds with good antibacterial and antifungal potency. Synthetic compounds have been characterized using 1H NMR, 13C NMR, and mass spectrum analysis. In‐vitro antibacterial activity against two gram‐positive and two gram‐negative strains and in‐vitro antifungal activity against three different strains were performed for the synthesized compounds. Compounds 9 a, 9 d, and 9 i exhibited potent inhibition activity against S. aureus ranging from MIC=12.5–50 μg/mL, and compounds 9 a, 9 c, 9 d, 9 e, 9 f, 9 j, and 9 l exhibited potent inhibition activity against C. albicans fungal strains ranging from MFC=250–500 μg/mL. Molecular docking study of C. albicans Sterol 14α‐demethylase (CYP51) protein (PDB ID:5TZ1) and S. aureus tyrosyl‐tRNA synthetase (PDB ID: 1JIJ) was performed to understand the mechanism of action through which these derivatives work. In silico studies of Hybrid 9 d demonstrated strong hydrogen bonding and π–π interactions with Tyr64, Phe233, and Phe228 in line with the co‐crystals SB‐239629 and VT1161 exhibiting favorable interactions that inhibits both bacterial and fungal strains.

In vitro anti-fungal potential of selected plant extracts against Fusarium oxysporum

In vitro anti-fungal potential of selected plant extracts against Fusarium oxysporum

Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

Antifungal Potential of Selected Plant Extracts on Pathogenic Post-Harvest Fungi Causing Tuber Rot in Ipomoea batatas (L.) Lam. (Sweet Potato)

Caprylic Acid From Vitex mollis Pulp Alters Colletotrichum gloeosporioides Plasma Membrane and Reduces Anthracnose Development on Papaya Fruit

ABSTRACTSynthetic fungicides are used to control anthracnose caused by Colletotrichum gloeosporioides; however, their frequent application increases the risk of pathogen resistance, environmental damage, and health concerns. It has been reported that caprylic acid (CA) inhibits the in vitro development of C. gloeosporioides; however, its antifungal mechanism and in vivo antifungal potential are still unknown. Therefore, the present work aims to analyse the effect of a CA‐enriched sub‐fraction (CAES) extracted from Vitex mollis fruit on the fungal microstructure by confocal fluorescence microscopy and morphometric analysis. Moreover, the effect of CAES on anthracnose development and quality parameters in papaya fruit was evaluated. The confocal microscopy images confirmed that CAES damaged the cell wall of conidia, given their decreased width. The increased fluorescence intensity in the CAES and CA‐treated mycelium suggested they were attached to the plasma membrane. These treatments produced structural alterations of the vacuoles and septa in mycelium, while in the fungicide thiabendazole (TBZ) treatment, apoptotic bodies appeared. CAES at 1.0 g L−1 had the best effect against anthracnose incidence and severity in papaya fruit, whereas TBZ was only effective on anthracnose severity. None of the applied treatments affected the fruit quality parameters. Therefore, CAES may be develop as an effective option to suppress anthracnose on papaya fruit.

Assessment of Antifungal Potentials of Ethanol Extract of Cleistocalyx operculatus Roxb Against Cercospora nicotianae for Pesticidal Applicability: In Vitro and In Silico Screening

Assessment of Antifungal Potentials of Ethanol Extract of Cleistocalyx operculatus Roxb Against Cercospora nicotianae for Pesticidal Applicability: In Vitro and In Silico Screening

Preparation, Characterization, DFT Calculations, biological evaluations and Molecular docking studies of benzimidazolium-based N-heterocyclic carbenes and selenium-adducts

This study involves designing through DFT, synthesis, and characterization of three benzimidazolium salts (AL1-AL3) and their corresponding selenium adducts (AC1-AC3). The compounds were characterized theoretically as well as experimentally through FT-IR and 1H &13C NMR. Theoretical calculations were performed using the B3LYP/6–31 G (d, p) levels of theory to determine various optical and chemical properties of the designed molecules. The HOMO/LUMO energies and their energy gaps were also calculated to assess the structure–activity relationships. In vitro testing against the Human breast Adenocarcinoma cell line (MCF-7) was conducted using the MTT assay and 5-Fluorouracil (standard) was used for the comparison of results. The ligand AL3 showed maximum inhibitory potential (66.51 ± 0.82) even approaching the standard 5FU while the complex AC3 showed maximum viability with the least inhibition value as (21.7 ± 0.73) against MCF7 cell line. The antioxidant potential for scavenging DPPH radicals was also assessed, revealing that AL1 has the greatest potential, with a value of 62.01 ± 0.9. The interactions of the complexes with various proteins were also assessed via molecular docking studies, revealing strong binding energies and ligand affinities towards angiogenic factors such as VEGF-A, EGF, HIF, and COX-1. This suggests that the anticancer activities of the complexes AC1-AC3 may be attributed to their potent anti-angiogenic effects. Moreover, selenium-NHC adducts exhibited more significant anticancer potential as compared to their ligands. Furthermore, the antibacterial and antifungal potential of compounds AC1-AC3 was assessed. Notably, the ligand AL2 exhibited significant antibacterial activity against E. coli, as evidenced by a zone of inhibition (ZI) value of 17.5 ± 0.29 mm, whereas AL3 demonstrated the highest activity against P. multocida showing the ZOI value of 18.5 ± 0.38. Among all the synthesized compounds, AL1 displayed the most significant antifungal activity against F. avenaceum (27 ± 0.51 mm), surpassing even the standard drug gentamycin (13 ± 0.23 mm), which was tested under the same conditions. However, its corresponding Se-NHC, AC1, adduct was found to be inactive. Overall, AL3 and its corresponding Se-NHC adduct (AC3), demonstrated superior biological potential against the majority of the tested strains.

Assessment of Antifungal Potential of Rhizospheric Bacterial Isolates of Daucus carota against Rhizoctonia solani

Rhizoctonia solani is an important plant pathogen which is responsible for causing a number of plant diseases in a variety of cropping plants. The current studies were carried out to explore antifungal potential of bacteria isolated from rhizospheric region of Daucus carota against Rhizoctonia. Of the total 21 bacterial isolates isolated, only 3 isolates namely CVO-3, CVO-4 and CRY-O-2 were shown antifungal potential against Rhizoctonia. Besides having antifungal potential these isolates also have some plant growth promoting attributes that will be an extra benefit of using these isolates as a biofungicides against R. solani. Thus, these isolates could be used as biofungicides against Rhizoctonia to prevent a variety of plant diseases like sheath blight in Oryza sativa, stem canker and black scurf in Solanum tuberosum and seedling diseases in Brassica napus. The isolates CVO-3, CVO-4 and CRY-O-2 were also characterized biochemical level by using methods based on Determinative Bacteriology given in Bergey’s manual and at molecular level using 16S rRNA sequencing and sequences of 16S rDNA segment were submitted to NCBI in GenBank database with the accession numbers OR775574 (Lysinibacillus boronitolerans ss3cvo3), OR775575 (Lysinibacillus boronitolerans ss4cvo4) and OR708523 (Shouchella rhizosphaerae ss1cryo2). The present investigation is an approach towards the use of these bacterial isolates from carrot rhizosphere to control the activities in the rhizosphere of other cropping plants.

Exploring the anticandidal potential: Evaluating leaf extract efficacy and GC–MS metabolite profiling of Chenopodium album var. album L.

IntroductionChenopodium album var. album L., renowned as lamb's quarters, is a versatile medicinal plant, revealing its efficacy in treating various ailments. This study evaluated the in vitro antifungal activity of ethyl acetate extract of C. album var. album L. MethodsChenopodium album leaf extract demonstrated antifungal potential via the Agar well-diffusion and Broth-dilution method. Active fractions, obtained through column chromatography, were rigorously tested against Candida spp. The most potent fraction underwent detailed analysis with High-Performance Thin-Layer Chromatography (HPTLC), Gas Chromatography Mass Spectrometry (GC–MS), and Fourier-Transform Infrared Spectroscopy (FT-IR), for comprehensive characterization. ResultsThe ethyl acetate extract (EAE) exhibited significant antifungal activity, with Candida albicans being the most susceptible (inhibition zone of 14.67 ± 0.58a). Fractionation of the EAE yielded a highly active F2 fraction, which showed a remarkable zone of inhibition against C. albicans (17.50 ± 1.00a). Comprehensive examinations, including HPTLC, GC–MS, and FT-IR, identified 12 compounds in the F2 fraction, and the major compounds were Furo [2,3-c] pyridine, 2,3-dihydro-2,7-dimethyl, Bis (2-ethylhexyl) phthalate, and 2,3,4,4-Tretrapropyl-1-(trimethylsilyl)-1-(trimethylsilyloxy)-1,3-diaza-2,4-diborabutane. This study marks the first report of these 12 compounds identified from the F2 fraction of C. album. ConclusionThe present study highlights the antifungal activity of EAE and its fractions from C. album var. album that could be further explored for the selection of leads that may contribute to novel drug development.

Chiral Fluorescent Antifungal Azole Probes Detect Resistance, Uptake Dynamics, and Subcellular Distribution in Candida Species.

Azoles are essential for fungal infection treatment, yet the increasing resistance highlights the need for innovative diagnostic tools and strategies to revitalize this class of antifungals. We developed two enantiomers of a fluorescent antifungal azole probe (1 S and 1 R ), analyzing 60 Candida strains via live-cell microscopy. A database of azole distribution images in strains of Candida albicans, Candida glabrata, and Candida parapsilosis, among the most important pathogenic Candida species, was established and analyzed. This analysis revealed distinct populations of yeast cells based on the correlation between fluorescent probe uptake and cell diameter. Varied uptake levels and subcellular distribution patterns were observed in C. albicans, C. glabrata, and C. parapsilosis, with the latter displaying increased localization to lipid droplets. Comparison of the more potent fluorescent antifungal azole probe enantiomer 1 S with the moderately potent enantiomer 1 R highlighted time-dependent differences in the uptake profiles. The former displayed a marked elevation in uptake after approximately 150 min, indicating the time required for significant cell permeabilization to occur and its association with the azole's antifungal activity potency. Divergent uptake levels between susceptible and high efflux-based azole-resistant strains were detected, offering a rapid diagnostic approach for identifying azole resistance. This study highlights unique insights achievable through fluorescent antifungal azole probes, unraveling the complexities of azole resistance, subcellular dynamics, and uptake within fungal pathogens.

Genomics, Proteomics, and Antifungal Activity of Chitinase from the Antarctic Marine Bacterium Curtobacterium sp. CBMAI 2942.

This study aimed to evaluate the genomic profile of the Antarctic marine Curtobacterium sp. CBMAI 2942, as well as to optimize the conditions for chitinase production and antifungal potential for biological control. Assembly and annotation of the genome confirmed the genomic potential for chitinase synthesis, revealing two ChBDs of chitin binding (Chi C). The optimization enzyme production using an experimental design resulted in a 3.7-fold increase in chitinase production. The chitinase enzyme was identified by SDS-PAGE and confirmed through mass spectrometry analysis. The enzymatic extract obtained using acetone showed antifungal activity against the phytopathogenic fungus Aspergillus sp. series Nigri CBMAI 1846. The genetic capability of Curtobacterium sp. CBMAI 2942 for chitin degradation was confirmed through genomic analysis. The basal culture medium was adjusted, and the chitinase produced by this isolate from Antarctica showed significant inhibition against Aspergillus sp. Nigri series CBMAI 1846, which is a tomato phytopathogenic fungus. This suggests that this marine bacterium could potentially be used as a biological control of agricultural pests.

Evaluation of antifungal activities of some Indian dietary spices against pathogenic Rhizopus arrhizus and Rhizopus stolonifer

Rhizopus arrhizus and Rhizopus stolonifer are pathogenic fungi responsible for causing ‘soft rot’ disease in fruits and vegetables, as well as life-threatening ‘mucormycosis’ in animals and humans, especially immunocompromised hosts. The use of synthetic fungicides and chemical preservatives to inhibit microbes is being challenged due to their toxic effects on human health and the environment. This has prompted researchers to investigate novel antimicrobials that are natural and safe. Current study aimed to evaluate the antifungal activities of essential oils (EOs), powdered (PWD) forms, and water extracts (WEs) of ten Indian dietary spices (Allium sativum (Als), Brassica nigra (Brn), Cinnamomum zeylanicum (Ciz), Cuminum cyminum (Cuc), Curcuma longa (Cul), Mentha piperita (Mep), Ocimum sanctum (Ocs), Syzygium aromaticum (Sya), Trigonella foenum-graecum (Trf), and Zingiber officinale (Zio)) against R. arrhizus (NCIM877) and R. stolonifer (NCIM1139). Spice agar method was used for investigating antifungal potential of PWD spices. Impregnated paper disc method and broth dilution technique were followed for screening the antifungal activities of EOs and WEs. Results revealed that EOs of six spices (Als, Brn, Ciz, Cuc, Mep, Sya), and PWD forms of four spices (Brn, Ciz, Cuc, Sya) inhibited the growth of both fungi in culture media, effectively. WEs of all ten spices remained ineffective in arresting the growth of tested fungal strains. R. stolonifer was found more sensitive compared to R. arrhizus towards tested substances. Based on these findings, further in vivo studies on PWD forms of Ccb, Ccm, and Sya and EOs of Als, Brn, Ccb, Ccm, Mep, Ocs and Sya may establish spices as ‘botanical antimicrobials’ to prolong the shelf life of valuable horticultural crops by arresting the growth of R. arrhizus and R. stolonifer.

Antarctic Streptomyces: Promising biocontrol agents for combating Fusarium oxysporum f. sp. cubense

Fusarium wilt of Banana (FWB) caused by Fusarium oxysporum f. sp. cubense (Foc) poses a significant threat to the banana industry, with current inadequate control measures. This study evaluated the antifungal potential of nine Streptomyces strains isolated from Antarctic soil samples, using Casein-Starch media to stimulate the production of antifungal compounds. The inhibition spectrum against Foc was assessed under laboratory conditions using the well diffusion on Mueller-Hinton agar, with antifungal activity measured in arbitrary units (AU/mL) and minimum inhibitory concentration (MIC) tested using ethyl acetate extracts. Among the nine isolates, K6 and E7 were closely related to Streptomyces polyrhachis and Streptomyces fildesensis, exhibited significant antifungal activity, with K6 and E7 showing 320 and 80 AU/mL, and MIC values of 250 and >500 ppm, respectively. These findings highlight K6 and E7 as potential biocontrol agents against Foc, offering new avenues for sustainable Fusarium wilt management in banana cultivation.

Mechanistic insights into antifungal potential of Alexidine dihydrochloride and hexachlorophene in Candida albicans: a drug repurposing approach.

Candida albicans has been listed in the critical priority group by the WHO in 2022 depending upon its contribution in invasive candidiasis and increased resistance to conventional drugs. Drug repurposing offers an efficient, rapid, and cost-effective solution to develop alternative therapeutics against pathogenic microbes. Alexidine dihydrochloride (AXD) and hexachlorophene (HCP) are FDA approved anti-cancer and anti-septic drugs, respectively. In this study, we have shown antifungal properties of AXD and HCP against the wild type (reference strain) and clinical isolates of C. albicans. The minimum inhibitory concentrations (MIC50) of AXD and HCP against C. albicans ranged between 0.34 and 0.69 µM and 19.66-24.58 µM, respectively. The biofilm inhibitory and eradication concentration of AXD was reported comparatively lower than that of HCP for the strains used in the study. Further investigations were performed to understand the antifungal mode of action of AXD and HCP by studying virulence features like cell surface hydrophobicity, adhesion, and yeast to hyphae transition, were also reduced upon exposure to both the drugs. Ergosterol content in cell membrane of the wild type strain was upregulated on exposure to AXD and HCP both. Biochemical analyses of the exposed biofilm indicated reduced contents of carbohydrate, protein, and e-DNA in the extracellular matrix of the biofilm when compared to the untreated control biofilm. AXD exposure downregulated activity of tissue invading enzyme, phospholipase in the reference strain. In wild type strain, ROS level, and activities of antioxidant enzymes were found elevated upon exposure to both drugs. FESEM analysis of the drug treated biofilms revealed degraded biofilm. This study has indicated mode of action of antifungal potential of alexidine dihydrochloride and hexachlorophene in C. albicans.

Hybrid de novo whole genome assembly of lipopeptide producing novel Bacillus thuringiensis strain NBAIR BtAr exhibiting antagonistic activity against Sclerotium rolfsii

Bacillus thuringiensis Berliner is recognized as a predominant bioinsecticide but its antifungal potential has been relatively underexplored. A novel B. thuringiensis strain NBAIR BtAr was isolated and morphologically characterized using light and scanning electron microscopy, revealing presence of bipyramidal, cuboidal, and spherical parasporal crystals. The crude form of lipopeptides was extracted from NBAIR BtAr and assessed for its antagonistic activity in vitro, and demonstrated 100 % inhibition of Sclerotium rolfsii Sacc. at a minimum inhibitory concentration of 50 μL of the crude lipopeptide extract per mL of potato dextrose agar. To identify the antagonistic genes responsible, we performed whole genome sequencing of NBAIR BtAr, revealing the presence of circular chromosome of 5,379,913 bp and 175,362 bp plasmid with 36.06 % guanine-cytosine content and 5814 protein-coding sequences. Average nucleotide identity and whole genome phylogenetic analysis delineated the NBAIR BtAr strain as konkukian serovar. Gene ontology analysis revealed associations of 1474, 1323, and 1833 genes with biological processes, molecular function, and cellular components, respectively. Antibiotics & secondary metabolite analysis shell analysis of the whole genome yielded secondary metabolites biosynthetic gene clusters with 100 %, 85 %, 40 %, and 35 % similarity for petrobactin, bacillibactin, fengycin, and paenilamicin, respectively. Also, novel biosynthetic gene clusters, along with antimicrobial genes, including zwittermicin A, chitinase, and phenazines, were identified. Moreover, the presence of eight bacteriophage sequences, 18 genomic islands, insertion sequences, and one CRISPR region indicated prior occurrences of genetic exchange and thus improved competitive fitness of the strain. Overall, the whole genome sequence of NBAIR BtAr is presented, with its taxonomic classification and critical genetic attributes that contribute to its strong antagonistic activity against S. rolfsii.

Investigation of antibacterial and antifungal properties of benzene sulfonamide derivatives by experimental and computational studies

This study investigates the antibacterial and antifungal properties of eight benzene sulfonamide derivatives synthesized and reported in our previous study using a combination of experimental and computational methods. In antimicrobial activity, the MIC values of all the eight tested compounds were approximately 125.00 μg/mL against eight bacterial and three fungal strains. However, the compound 8 was found to exhibit remarkable activity (MIC=31.25 μg/mL) against E. faecalis (bacteria) and C. parapsilosis (fungi) compared to the MIC values of rest of the compounds. Results of in-silico drug-likeness and pharmacokinetic (ADMET) assessment reveal that all the title compounds met the compliance of criteria of drug-likeness rules and exhibited zero violations across. Results of docking study demonstrates that the compound 8 showed the highest binding affinity (-8.7 kcal/mol) among the compounds against S. aureus TyrRS, whereas against S. aureus DHFR, compound 2 exhibited the highest binding afinity of -8.5 kcal/mol. Among the compounds docked against C. albicans DHFR and C. albicans N-myristoyl transferase, compound 8 demonstrated the highest binding affinity of -8 kcal/mol and -8.9 kcal/mol, respectively. The results of antibacterial and antifungal experiments substantiate the predictions made by computational studies and provide empirical evidence of antibacterial and antifungal potential of the reported benzene sulfonamide derivatives.

Antifungal potentials of ten selected plants against fungi associated with postharvest spoilage of fruits

Antifungal potentials of ten selected plants against fungi associated with postharvest spoilage of fruits

Ru-terpyridine complexes containing clotrimazole as potent photoactivatable selective antifungal agents

The overuse of antimicrobial agents in medical and veterinary applications has led to the development of antimicrobial resistance in some microorganisms and this is now one of the major concerns in modern society. In this context, the use of transition metal complexes with photoactivatable properties, which can act as drug delivery systems triggered by light, could become a potent strategy to overcome the problem of resistance. In this work several Ru complexes with terpyridine ligands and the clotrimazole fragment, which is a potent antimycotic drug, were synthesized. The main goal was to explore the potential photoactivated activity of the complexes as antifungal agents and evaluate the effect of introducing different substituents on the terpyridine ligand. The complexes were capable of delivering the clotrimazole unit upon irradiation with visible light in a short period of time. The influence of the substituents on the photodissociation rate was explained by means of TD-DFT calculations. The complexes were tested against three different yeasts, which were selected based on their prevalence in fungal infections. The complex in which a carboxybenzene unit was attached to the terpyridine ligand showed the best activity against the three species under light, with minimal inhibitory concentration values of 0.88 μM and a phototoxicity index of 50 achieved. The activity of this complex was markedly higher than that of free clotrimazole, especially upon irradiation with visible light (141 times higher). The complexes were more active on yeast species than on cancer cell lines.

Synthesis, antioxidant, antimicrobial activities and molecular modeling analysis of some 5-Nitro-N-phenyl-3-(phenylamino)-1H-indazole-1-carboxamide derivatives: Docking, SAR, toxicity and molecular dynamics analysis

This study reports the synthesis and characterization of a novel series of 5-nitro-N-phenyl-3-(phenylamino)-1H-indazole-1-carboxamide derivatives (5a-5v) obtained through the reaction of 3-chloro-5-nitro-N-phenyl-1H-indazole-1-carboxamide (4) with diverse aniline derivatives in isopropanol. The compounds underwent thorough biological evaluation encompassing antibacterial, antifungal, and in addition to antioxidant potential assessed through DPPH (IC50 = 0.105-0.513 μmol/mL) and ABTS assays (IC50 = 0.124-0.538 μmol/mL). Remarkably, compound 5b displayed exceptional antibacterial efficacy, while compounds 5k, 5p, and 5q exhibited noteworthy antifungal potential. Compound 5k showed the most significant antioxidant activity. Molecular docking studies unveiled robust binding interactions with target enzymes (PDB ID: 3SRG), and molecular dynamics simulations indicated the stability of the most active compound at the binding site. Additionally, favourable drug-likeness and ADMET properties underscore the promising therapeutic potential of these derivatives, urging further investigations for potential clinical applications. The multifaceted activities, including antibacterial, antifungal, and antioxidant properties, make these derivatives compelling candidates for in-depth exploration in the pursuit of novel therapeutic agents.

Antifungal Tetrahydrocarbazole Compound CAR-8 Induces Endoplasmic Reticulum Stress in Candida albicans.

The development of new effective antifungal agents is essential to combat fungal infections. Tetrahydrocarbazole has been exploited as a promising skeleton against various pathogenic microorganisms and is used to search for novel active antifungal compounds. In this study, a library composed of small tetrahydrocarbazole compounds was screened, and a potent antifungal agent, CAR-8, was identified with a minimum inhibitory concentration of 2-4 μg/mL against Candida albicans. CAR-8 showed strong fungicidal activities and killed almost all C. albicans within 3 h at a concentration of 16 μg/mL. At concentrations of 2 and 8 μg/mL, CAR-8 significantly inhibited the formation of hyphae and biofilms. Moreover, CAR-8 at 10 and 20 mg/kg reduced the fungal load and improved the survival in the C. albicans infection model in the invertebrate Galleria mellonella. Transcriptome analysis revealed significant changes in the expression of genes associated with protein processing in the endoplasmic reticulum (ER), ER-associated degradation, and unfolded protein response (UPR), which suggested that CAR-8 treatment induced ER stress. Moreover, CAR-8 treatment resulted in various phenotypes similar to tunicamycin, a classical ER stress inducer. These included nonconventional splicing of HAC1 mRNA, the fragmented morphology of ER, the distribution changes of GFP-Snc1 in Saccharomyces cerevisiae, and cell apoptosis probably caused by ER stress. More importantly, the disruption of IRE1 or HAC1 increased the sensitivity of C. albicans to CAR-8, confirming that the UPR signaling pathway was critical for CAR-8 resistance. Overall, our study identifies a potent ER stress-induced antifungal compound that will help the discovery of new antifungal drugs.