Understanding the mechanism of action of protease inhibitors in controlling the growth of the Candida Genus: potential candidates for development of new antifungal molecules.

There is a growing imperative for research into alternative compounds for the treatment of the fungal infections. Thus, many studies have focused on the analysis of antifungal proteins and peptides from different plant sources. Among these molecules are protease inhibitors (PIs). Previously, PIs present in the peptide-rich fractions called PEF1, PEF2 and PEF3 were identified from Capsicum chinense seeds, which have strong activity against phytopathogenic fungi. The aim of this study was to evaluate the mechanism of action and antimicrobial activity of PIs from PEF2 and PEF3 on the growth of yeasts of the genus Candida. In this work, analyses of their antimicrobial activity and cell viability were carried out. Subsequently, the mechanism of action by which the PIs cause the death of the yeasts was evaluated. Cytotoxicity was assessed in vitro by erythrocytes lysis and in vivo in Galleria mellonella larvae. PEF2 and PEF3 caused 100% of the growth inhibition of C. tropicalis and C. buinensis. For C. albicans inhibition was approximately 60% for both fractions. The PEF2 and PEF3 caused a reduction in mitochondrial functionality of 54% and 46% for C. albicans, 26% and 30% for C. tropicalis, and 71% and 68% for C. buinensis, respectively. These fractions induced morphological alterations, led to membrane permeabilization, elevated ROS levels, and resulted in necrotic cell death in C. tropicalis, whilst demonstrating low toxicity toward host cells. From the results obtained here, we intend to contribute to the understanding of the action of PIs in the control of fungal diseases of medical importance.

Mechanisms of antifungal resistance and developments in alternative strategies to combat Candida albicans infection.

Candida albicans is a commensal fungus that infects the humans and becomes an opportunistic pathogen particularly in immuno-compromised patients. Among the Candida genus, yeast C. albicans is the most frequently incriminated species and is responsible for nearly 50-90% of human candidiasis, with vulvovaginal candidiasis alone, affecting about 75% of the women worldwide. One of the significant virulence traits in C. albicans is its tendency to alternate between the yeast and hyphae morphotypes, accounting for the development of multi-drug resistance in them. Thus, a thorough comprehension of the decision points and genes controlling this transition is necessary, to understand the pathogenicity of this, naturally occurring, pernicious fungus. Additionally, the formation of C. albicans biofilm is yet another pathogenesis trait and a paramount cause of invasive candidiasis. Since 1980 and in 90 s, wide spread use of immune-suppressing therapies and over prescription of fluconazole, a drug used to treat chronic fungal infections, triggered the emergence of novel anti-fungal drug development. Thus, this review thoroughly elucidates the diseases associated with C. albicans infection as well as the anti-fungal resistance mechanism associated with them and identifies the emerging therapeutic agents, along with a rigorous discussion regarding the future strategies that can possibly be adopted for the cure of this deleterious pathogen.

Identification and characterization of a novel decalin derivative with anti-Candida activity from Streptomyces chrestomyceticus strain ADP4.

A novel decalin derivative, trans-1-oxo-2,4-diacetylaminodecalin (1) with anti-Candida activity, had been isolated from Streptomyces chrestomyceticus strain ADP4. The structure of the compound was determined from the analysis of spectral data (LCMS/MS, UV, FTIR, 1D- and 2D-NMR). The anti-Candida activity of 1 was specific to Candida albicans and Candida auris. Further, it displayed inhibition of the early-stage biofilm of C. albicans. In-silico analysis of the compound revealed its drug likeness properties without any violations and PAINS alert when investigated for ADME properties. Along with the overall bioavailability, compound 1 did not show any predicted bioaccumulation and mutagenicity in the analysis by TEST software. Non-cytotoxic property was further confirmed by in-vitro assay on the HepG2 cell line.

A novel diterpenic derivative produced by Streptomyces chrestomyceticus ADP4 is a potent inhibitor of biofilm and virulence factors in Candida albicans and C. auris.

AIM: Isolation, identification, structural and functional characterization of potent anti-Candida compound with specific antagonistic activities against significant human pathogens, Candida albicans and C. auris. METHODS AND RESULTS: The compound (55B3) was purified from the metabolites produced by Streptomyces chrestomyceticus ADP4 by employing column chromatography. The structure of 55B3 was determined from the analyses of spectral data that included LCMS, nuclear magnetic resonance, FTIR, and UV spectroscopies. It was identified as a novel derivative of diterpenic aromatic acid, 3-(dictyotin-11'-oate-15'α, 19'ß-olide)-4-(dictyotin-11'-oate-15″α, 19″ß-olide)-protocatechoic acid. The compound displayed potent antifungal and anti-biofilm activities against C. albicans ATCC 10231 (Minimum Inhibitory Concentration, MIC90:14.94 ± 0.17 µgmL-1 and MBIC90: 16.03 ± 1.1 µgmL-1) and against C. auris CBS 12372 (MIC90: 21.75 ± 1.5 µgmL-1 and Minimum Biofilm Inhibitory Concentration, MBIC90: 18.38 ± 1.78 µgmL-1). Further, pronounced inhibition of important virulence attributes of Candida spp., e.g. yeast-to-hyphae transition, secretory aspartyl proteinase and phospholipase B by 55B3 was noted at subinhibitory concentrations. A plausible mechanism of anti-Candida action of the compound appeared to be the inhibition of ergosterol biosynthesis, which was inhibited by 64 ± 3% at the MIC90 value. The non-cytotoxic attribute of the compound was noted in the liver cell line (HepG2 cells). CONCLUSION: The present work led to the discovery of a novel diterpenic derivative produced by S. chrestomyceticus ADP4. The compound displayed potent anti-Candida activity, particularly against the two most significant human pathogens, C. albicans and C. auris, which underlined its significance as a potential drug candidate for infections involving these pathogens.

Dereplication of Lantana trifolia L. leaves and fruits by UFLC-DAD-(+)-ESI-MS/MS and its antifungal and cytotoxic activities.

INTRODUCTION: Lantana trifolia L. (Verbenaceae) is a shrubby plant. In folk medicine, its leaves are used in the form of infusions and syrups to treat angina, coughs, and colds; they are also applied as tranquilizer. Previous studies have reported the antimicrobial potential of the compounds present in L. trifolia leaves. OBJECTIVES: To report the anti-Candida activities of the fractions obtained from the fruits and leaves of two L. trifolia specimens. METHODS: The L. trifolia fractions were submitted to UFLC-DAD-(+)-ESI-MS/MS, and the data were analyzed by using multivariate statistical tools (PCA, PLS-DA) and spectral similarity analyses based on molecular networking, which aided dereplication of the bioactive compounds. Additionally, NMR analyses were performed to confirm the chemical structure of some of the major compounds in the fractions. RESULTS: The ethyl acetate fractions presented MIC values lower than 100 µg mL-1 against the three Candida strains evaluated herein (C. albicans, C. tropicalis, and C. glabrata). Fractions FrPo AcOEt, FrPe AcOEt, and FrPe nBut had MIC values of 1.46, 2.93, and 2.93 µg mL-1 against C. glabrata, respectively. These values resembled the MIC value of amphotericin B, the positive control (0.5-1.0 µg mL-1), against this same strain. Cytotoxicity was measured and used to calculate the selectivity index. CONCLUSION: On the basis of our data, the most active fractions in the antifungal assay were more selective against C. glabrata than against non-infected cells. The analytical approach adopted here allowed us to annotate 29 compounds, nine of which were bioactive (PLS-DA results) and belong to the class of phenolic compounds.

Yeasts originating from fermented foods, their potential as probiotics and therapeutic implication for human health and disease.

Yeasts derived from fermented foods have historically been known for their organoleptic properties, enriching nutritional values, and producing bioactive metabolites with therapeutic potential. In this review, we discuss the yeast flora in fermented foods, their functional aspects in fermentation, as well as their probiotic and biotherapeutic properties. These yeasts have numerous physical and biochemical characteristics, such as larger cells as compared to bacteria, a rigid cell wall composed primarily of glucans and mannans, natural resistance to antibiotics, and the secretion of secondary metabolites that are both pleasing to the consumer and beneficial to the host's health and well-being. The review also focused on therapeutic applications of probiotic yeasts derived from fermented foods on infections associated with Candida species. These potential probiotic yeasts present an additional avenue to treat dysbiosis of the gut microbiota and prevent health complications that arise from opportunistic fungal colonization, especially drug-resistant superbugs, which are highlighted in this review.

Anti-Candida attributes and in-silico drug-likeness properties of phenyl 2'ß, 6'ß-trimethyl cyclohexyl ketone and phenyl nonanyl ether produced by Streptomyces chrestomyceticus ADP4.

AIM: To isolate and characterize anti-Candida compounds from soil actinobacterium Streptomyces chrestomyceticus ADP4 and to assess their drug likeness. METHODS AND RESULTS: Two anti-Candida compounds, Phenyl 2'α, 2'ß, 6'ß-trimethyl cyclohexyl ketone (1PB1) and Phenyl nonanyl ether (1PB2), were isolated from the metabolites produced by Streptomyces chrestomyceticus ADP4. Their structures were deduced by extensive analyses of spectral data obtained from liquid chromatography with tandem mass spectrometry (LCMS/MS), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR) and ultraviolet (UV) spectroscopies. While both the compounds inhibited growth of the Candida spp., 1PB2 was effective in inhibiting biofilm formed by Candida albicans ATCC 10231. The compounds did not show any cytotoxicity against HepG2 cells and were found to be safe when predicted theoretically on rat model, bioaccumulation and mutagenicity by using the software: toxicity estimation software tool (TEST). The compounds displayed drug-like properties when analyzed by using SwissADME software. CONCLUSIONS: 1PB1 and 1PB2 are being reported for the first time from any natural source along with their anti-Candida properties. In-silico studies revealed their druggability and suitability to take up further work on the compounds for their possible application in treating Candida-associated infections. SIGNIFICANCE AND IMPACT OF THE STUDY: The increasing prevalence of Candidiasis associated with drug-resistant strains of Candida spp. highlighted the urgent need for discovery of new compounds with anti-Candida properties that could hold promise as potential drug candidate.

Anti-Candida and Anti-Leishmanial Activities of Encapsulated Cinnamomum verum Essential Oil in Chitosan Nanoparticles.

Nanoencapsulation is widely considered as a highly effective strategy to enhance essential oils' (EO) stability by protecting them from oxidative deterioration and evaporation. The present study aims to optimize and characterize an efficient technique for encapsulating Cinnamomum (C.) verum essential oil into chitosan nanoparticles using response surface methodology (RSM). Moreover, the optimized C. verum EO nanoparticle was investigated for its antibacterial (against Gram-positive and Gram-negative bacteria), antifungal (against Candida albicans), and antiparasitic activity (against Leishmania parasites). Five parameters were investigated using a Plackett-Burman and Box-Behnken statistical design: the chitosan molecular weight, TPP concentration, C. verum EO/chitosan ratio, mixing method, and the duration of the reaction. Encapsulation efficiency and anti-candida activity were considered as responses. The antibacterial, anticandidal, and anti-leishmanial activities were also assessed using a standard micro-broth dilution assay and the cytotoxicity assay was assessed against the macrophage cell line RAW 264.7. The optimized nanoparticles were characterized using Fourier transform infrared spectroscopy, Zeta potential, and scanning electron microscopy. The study results indicated that under optimal conditions, the nanoencapsulation of C. verum EO into chitosan nanoparticles resulted in an encapsulation efficiency of 92.58%, with a regular distribution, a nanoparticle size of 480 ± 14.55 nm, and a favorable Zeta potential of 35.64 ± 1.37 mV. The optimized C. verum EO/chitosan nanoparticles showed strong antifungal activity against C. albicans pathogens (CMI = 125 µg mL-1), notable antibacterial activity against both Gram-positive and Gram-negative bacteria (ranging from 125 to 250 µg mL-1), high leishmanicidal potential against the promastigotes form of L. tropica and L. major (IC50 = 10.47 and 15.09 µg mL-1, respectively), and a four-fold cytotoxicity reduction compared to non-encapsulated essential oil. These results suggest that C. verum EO-loaded chitosan nanoparticles could be a promising delivery system for the treatment of cutaneous Candida albicans infections.

Chemical Composition and Anti-Candida Activity of Mentha suaveolens Ehrh. Essential Oils Obtained by Different Distillation Processes.

A comparative study on essential oils extracted from Mentha suaveolens Ehrh. from Italy is reported. Two extraction procedures were investigated: hydrodistillation and steam distillation, carried out as a continuous and fractionated procedure. Fresh and dried plant material from two harvests was used. The hydrodistillation method yielded a higher amount of essential oil. The dried plant was significantly richer in essential oil per kg of starting plant material. Gas chromatography-mass spectrometry analysis of 112 samples showed that the essential oils belong to the piperitenone oxide-rich chemotype. In addition, piperitenone, p-cymen-8-ol, and limonene were among the most abundant compounds in the different samples. A higher amount of piperitenone oxide was obtained by hydrodistillation, while steam distillation gave a higher percentage of piperitenone and limonene. The essential oils were characterized for their anti-Candida albicans activity; higher potency was observed for the samples rich in piperitenone oxide, with MIC values ranging from 0.39 to 0.78 mg·mL-1 (0.039% and 0.078% p/v). The results of this work provide a deep insight into the methodology of essential oil extraction and the associated chemical variability of M. suaveolens Ehrh. Some of the essential oils are potent against C. albicans and could be considered for potential use in therapy.

Phenyl Pentyl Ketone and m-isobutyl Methoxy Benzoate Produced by Streptomyces Chrestomyceticus ADP4 are Potent Antimicrobial Agents Displaying Broad Spectrum Activities.

Isolation and identification of two antimicrobial compounds, a phenyl pentyl ketone (CP1) and m-isobutyl methoxy benzoate (CP2), from Streptomyces chrestomyceticus ADP4 have been reported. Structure of the compounds were elucidated from analyses of spectral data that included LCMS/MS, NMR, FTIR and UV spectroscopies. Both the compounds displayed significant inhibition of albicans and non-albicans species of Candida (NAC) pathogens including C. auris, which is currently a pathogen of global concern. Also, the compounds showed potent antagonistic activity against Staphylococcus aureus, another significant human pathogen. No in-vitro cytotoxicity against HePG2 cells was observed with either of the compounds. Both displayed favourable drug likeness properties as determined by in-silico ADME and toxicological studies. Also, this is the first report on production of these anti-microbial compounds by an actinobacterium. Supplementary Information: The online version contains supplementary material available at 10.1007/s12088-023-01068-7.

Monoclonal Antibodies Targeting Surface-Exposed Epitopes of Candida albicans Cell Wall Proteins Confer In Vivo Protection in an Infection Model.

Monoclonal antibody (mAb)-based immunotherapies targeting systemic and deep-seated fungal infections are still in their early stages of development, with no licensed antifungal mAbs currently being available for patients at risk. The cell wall glycoproteins of Candida albicans are of particular interest as potential targets for therapeutic antibody generation due to their extracellular location and key involvement in fungal pathogenesis. Here, we describe the generation of recombinant human antibodies specifically targeting two key cell wall proteins (CWPs) in C. albicans: Utr2 and Pga31. These antibodies were isolated from a phage display antibody library using peptide antigens representing the surface-exposed regions of CWPs expressed at elevated levels during in vivo infection. Reformatted human-mouse chimeric mAbs preferentially recognized C. albicans hyphal forms compared to yeast cells, and increased binding was observed when the cells were grown in the presence of the antifungal agent caspofungin. In J774.1 macrophage interaction assays, mAb pretreatment resulted in the faster engulfment of C. albicans cells, suggesting a role of the CWP antibodies as opsonizing agents during phagocyte recruitment. Finally, in a series of clinically predictive mouse models of systemic candidiasis, our lead mAb achieved improved survival (83%) and a several-log reduction of the fungal burden in the kidneys, similar to the levels achieved for the fungicidal drug caspofungin and superior to the therapeutic efficacy of any anti-Candida mAb reported to date.

Production of More Potent Anti-Candida Labdane Diterpenes by Biotransformation Using Cunninghamella elegans.

Candida species are responsible for causing invasive candidiasis with high mortality rate and their resistance to available antifungal drugs is a major clinical challenge. Biotransformation process of the labdane diterpene ent-labd-8(17)-en-15,18-dioic acid (1) carried out with Cunninghamella elegans afforded five new derivatives (compounds 2-6). Unusual regioselective hydroxylation of the methyl group at the C-20 position of labdane-type diterpene was achieved and all compounds were subjected to cytotoxicity and antifungal evaluations. Compound 1 and its derivatives were not cytotoxic to normal (MCF-10A) and tumor (MCF-7) cell lines. Compounds 2 and 3 exhibited fungistatic activity against all tested Candida strains at lower concentrations than fluconazole. Both compounds also showed the strongest fungicidal activity against C. albicans, which is the most prevalent fungal agent involved in candidemia.

Antifungal Activity of Mexican Propolis on Clinical Isolates of Candida Species.

Infections caused by micro-organisms of the genus Candida are becoming a growing health problem worldwide. These fungi are opportunistic commensals that can produce infections-clinically known as candidiasis-in immunocompromised individuals. The indiscriminate use of different anti-fungal treatments has triggered the resistance of Candida species to currently used therapies. In this sense, propolis has been shown to have potent antimicrobial properties and thus can be used as an approach for the inhibition of Candida species. Therefore, this work aims to evaluate the anti-Candida effects of a propolis extract obtained from the north of Mexico on clinical isolates of Candida species. Candida species were specifically identified from oral lesions, and both the qualitative and quantitative anti-Candida effects of the Mexican propolis were evaluated, as well as its inhibitory effect on C. albicans isolate's germ tube growth and chemical composition. Three Candida species were identified, and our results indicated that the inhibition halos of the propolis ranged from 7.6 to 21.43 mm, while that of the MFC and FC50 ranged from 0.312 to 1.25 and 0.014 to 0.244 mg/mL, respectively. Moreover, the propolis was found to inhibit germ tube formation (IC50 ranging from 0.030 to 1.291 mg/mL). Chemical composition analysis indicated the presence of flavonoids, including pinocembrin, baicalein, pinobanksin chalcone, rhamnetin, and biochanin A, in the Mexican propolis extract. In summary, our work shows that Mexican propolis presents significant anti-Candida effects related to its chemical composition, and also inhibits germ tube growth. Other Candida species virulence factors should be investigated in future research in order to determine the mechanisms associated with antifungal effects against them.

Antagonist activities and phylogenetic relationships of actinomycetes isolated from an Artemisia habitat.

Diverse habitats have been screened for novel antimicrobial actinomycetes, while others remain unexplored. In this study, we analyzed the bioactivities of actinomycetes cultured from rhizosphere soils of the desert plant Artemisia tridentata and the nearby bulk soils. Actinomycetes were screened for antifungal and antibacterial activities toward a panel of plant pathogens; all comparisons were between activities of rhizosphere soil isolates toward those of its counterpart bulk soil. A selected group of the strongest antifungal isolates were also tested against two antifungal-drug resistant strains of Candida albicans. 16S rDNA partial sequences and phylogenetic analysis of isolates that showed broad-spectrum antifungal activities were performed. Forty-two out of 200 and two soil isolated actinomycetes were selected for their strong antifungal activities. The highest proportion of isolates (p<0.05) from rhizosphere soil of an old plant showed antagonism against gram-positive bacteria (0.483 and 0.224 proportions against Bacillus subtilis and Rathayibacter tritici, respectively), and phytopathogenic fungi (0.259, 0.431, and 0.345 proportions against Fusarium oxysporum, Rhizoctonia solani and Pythium ultimum, respectively), while the highest antagonism against the gram-negative bacteria predominated in isolates from the bulk soils. Isolates from a rhizosphere soil of a young plant were characterized for strong antagonist activities against Fusarium oxysporum (0.333 proportion, p<0.05). Phylogenetic analysis of 16S rDNA sequences showed that isolates that exhibited strong antifungal activity were genetically similar. We conclude that the rhizosphere soil of A. tridentata is an excellent source for discovery of actinomycetes with potentially novel antifungal compounds.

Phytochemical characterization and inhibition of Candida sp. by the essential oil of Baccharis trimera (Less.) DC.

This study aimed to investigate the chemical composition and antifungal potential of the essential oil of Baccharis trimera (Less.) DC. against Candida strains. The half maximal inhibitory concentration (IC50) was assessed by the microdilution method using the essential oil at a concentration range of 8192 to 8 µg/mL. The minimum fungicide concentration (MFC) was determined by subculture in solid medium. The ability of the essential oil to modulate the activity of antifungals was determined in wells treated simultaneously with the oil at a subinhibitory concentration (MFC/16) and fluconazole (FCZ). The fungal morphology was analyzed by microscopy. Gas chromatography coupled with mass spectrometry (GC/MS) was used to identify the chemical composition. The essential oil presented an CI50 of 11.24 and 1.45 µg/mL, which was found to potentiate the effect of FCZ against Candida albicans. On the other hand, this combined treatment resulted in antagonism against Candida tropicalis and no evident modulation against Candida krusei was observed. The essential oil significantly inhibited hyphae growth. However, with a MFC ≥ 16,384 µg/mL, it is assumed that it has a fungistatic action. The antifungal properties demonstrated in this study might be related to the presence of sesquiterpenes and monoterpenes, and the interaction between them. In conclusion, Baccharis trimera showed promising anti-Candida effects, in addition to potentiating the activity of FCZ against Candida albicans, affecting its morphological transition. Therefore, this species constitutes a source of chemical compounds with the potential to be used in the combat of fungal infections.

Health Potential of Clery Strawberries: Enzymatic Inhibition and Anti-Candida Activity Evaluation.

Strawberries, belonging to cultivar Clery (Fragaria × ananassa Duchesne ex Weston) and to a graft obtained by crossing Clery and Fragaria vesca L., were chosen for a study on their health potential, with regard to the prevention of chronic and degenerative diseases. Selected samples, coming from fresh and defrosted berries, submitted to different homogenization techniques combined with thermal and microwave treatments, had been previously analyzed in their polyphenolic content and antioxidant capacity. In the present work, these homogenates were evaluated in relation to their enzymatic inhibition activity towards acetylcholinesterase and butyrylcholinesterase, α-amylase, α-glucosidase and tyrosinase. All these enzymes, involved in the onset of diabetes, and neurodegenerative and other chronic diseases, were modulated by the tested samples. The inhibitory effect on tyrosinase and cholinesterase was the most valuable. Antifungal activity against Candida albicans, recently shown to play a crucial role in human gut diseases as well as diabetes, rheumatoid arthritis and Alzheimer's disease, was also shown in vitro and confirmed by the in vivo text on Galleria mellonella. Overall, the obtained results confirm once again the health potential of strawberries; however, the efficacy is dependent on high quality products submitted to correct processing flow charts.

Biosurfactant from vaginal Lactobacillus crispatus BC1 as a promising agent to interfere with Candida adhesion.

BACKGROUND: Lactobacillus spp. dominating the vaginal microbiota of healthy women contribute to the prevention of urogenital and sexually transmitted infections. Their protective role in the vagina can be mediated by Lactobacillus cells themselves, metabolites or bacterial components, able to interfere with pathogen adhesion and infectivity. Vulvovaginal candidiasis (VVC) is a common genital infection, caused by the overgrowth of opportunistic Candida spp. including C. albicans, C. glabrata, C. krusei and C. tropicalis. Azole antifungal drugs are not always efficient in resolving VVC and preventing recurrent infections, thus alternative anti-Candida agents based on vaginal probiotics have gained more importance. The present work aims to chemically characterize the biosurfactant (BS) isolated from a vaginal Lactobacillus crispatus strain, L. crispatus BC1, and to investigate its safety and antiadhesive/antimicrobial activity against Candida spp., employing in vitro and in vivo assays. RESULTS: BS isolated from vaginal L. crispatus BC1 was characterised as non-homogeneous lipopeptide molecules with a critical micellar concentration value of 2 mg/mL, and good emulsification and mucoadhesive properties. At 1.25 mg/mL, the BS was not cytotoxic and reduced Candida strains' ability to adhere to human cervical epithelial cells, mainly by exclusion mechanism. Moreover, intravaginal (i.va.) inoculation of BS in a murine experimental model was safe and did not perturb vaginal cytology, histology and cultivable vaginal microbiota. In the case of i.va. challenge of mice with C. albicans, BS was able to reduce leukocyte influx. CONCLUSIONS: These results indicate that BS from vaginal L. crispatus BC1 is able to interfere with Candida adhesion in vitro and in vivo, and suggest its potential as a preventive agent to reduce mucosal damage occasioned by Candida during VVC.

Novel 2,4-Disubstituted-1,3-Thiazole Derivatives: Synthesis, Anti-Candida Activity Evaluation and Interaction with Bovine Serum Albumine.

Herein we report the synthesis of two novel series of 1,3-thiazole derivatives having a lipophilic C4-substituent on account of the increasing need for novel and versatile antifungal drugs for the treatment of resistant Candida sp.-based infections. Following their structural characterization, the anti-Candida activity was evaluated in vitro while using the broth microdilution method. Three compounds exhibited lower Minimum Inhibitory Concentration (MIC) values when compared to fluconazole, being used as the reference antifungal drug. An in silico molecular docking study was subsequently carried out in order to gain more insight into the antifungal mechanism of action, while using lanosterol-C14α-demethylase as the target enzyme. Fluorescence microscopy was employed to further investigate the cellular target of the most promising molecule, with the obtained results confirming its damaging effect towards the fungal cell membrane integrity. Finally, the distribution and the pharmacological potential in vivo of the novel thiazole derivatives was investigated through the study of their binding interaction with bovine serum albumin, while using fluorescence spectroscopy.

The effect of benzyl isothiocyanate on Candida albicans growth, cell size, morphogenesis, and ultrastructure.

Candida albicans is a commensal yeast that may become pathogenic and even lethal to the host. Over the last few decades, antifungal resistance has increased, promoting screening of the antifungal potential of old and new substances. This study investigates the antifungal potential of isothiocyanates (ITCs) against C. albicans oral isolates. A preliminary susceptibility disk diffusion test (DD) was performed using allyl isothiocyanate (AITC), benzyl isothiocynanate (BITC) and phenyl ethyl isothiocyanate (PEITC) at a fixed concentration range (0.001-0.1 M). Because C. albicans isolates were more susceptible to BITC and PEITC, their effect on cell size and on germ tube formation (GTF) were tested. The most promising molecule, BITC, was further tested for effects on cell viability, oxidative stress and for ultrastructure. ITCs, especially the aromatic ones, had a significant type-, dose- and isolate-dependent anti-Candida activity. Although BITC and PEITC had similar activity against the yeast cells, BITC had a more pronounced effect on cell size and GTF. Furthermore, BITC appears to induce oxidative stress and promote changes in the cell ultrastructure, interfering with cell wall structure. Our work showed that aromatic ITCs have the potential to effect C. albicans cells in multiple ways, including size, shape and GTF (BITC and PEITC), oxidative stress, and ultrastructure (BITC). Overall, our results suggest that BITC may be effectively used against C. albicans to modulate its growth, and control or suppress its invasive potential.

The use of nanoparticles as alternative therapeutic agents against Candida infections: an up-to-date overview and future perspectives.

Candida spp. are opportunistic fungi that can cause severe infections especially in immunocompromised patients. Candidiasis is currently the most frequent fungal disease affecting humans globally. This rise is attributed to the vast increase in resistance to antifungal agents. In recent years, the epidemiological and clinical relevance of fungal infections caused by Candida species have attracted a lot of interest with increasing reports of intrinsic and acquired resistance among Candida species. Thus, the formulation of novel, and efficient therapy for Candida infection persists as a critical challenge in modern medicine. The use of nanoparticle as a potential biomaterial to achieve this feat has gained global attention. Nanoparticles have shown promising antifungal activity, and thus, could be seen as the next generation antifungal agents. This review concisely discussed Candida infection with emphasis on anti-candida resistance mechanisms and the use of nanoparticles as potential therapeutic agents against Candida species. Moreover, the mechanisms of activity of nanoparticles against Candida species, recent findings on the anti-candida potentials of nanoparticles and future perspectives are also presented.