Fungicidal activity of human antimicrobial peptides and their synergistic interaction with common antifungals against multidrug-resistant Candida auris.

Emergence of Candida auris, a multidrug-resistant yeast, demonstrates the urgent need for novel antifungal agents. Human antimicrobial peptides (AMPs) are naturally occurring molecules with wide spectrum antimicrobial activity, particularly against a variety of fungi. Therefore, this study examined the antifungal activity of seven different human AMPs against C. auris following the CLSI guidelines. The antifungal activity was further assessed using time kill curve and cell viability assays. For combination interaction, effectiveness of these peptides with three antifungals, fluconazole, amphotericin B, and caspofungin was done following standard protocols. To elucidate the antifungal mechanism, the effects of peptides on membrane permeability were investigated using propidium iodide staining method and confocal imaging. Antifungal susceptibility results showed that all the examined peptides possessed fungicidal effect against C. auris at different levels, with human ß-defensin-3 being the most potent antifungal with MIC values ranging from 3.125 to 12.5 µg/ml. Time kill curves further confirmed the killing effect of all the tested peptides. Viability assay showed a significant decrease in the percentage of viable cells exposed to different inhibitory and fungicidal concentrations of each peptide (p < 0.01). Furthermore, peptides showed mostly synergistic interaction when combined with conventional antifungal drugs, with caspofungin showing 100% synergy when combined with different AMPs. As antifungal mechanism, peptides disrupted the membrane permeability at concentrations that correlated with the inhibition of growth. Overall, the findings of this study point towards the application of the tested peptides as a monotherapy or as a combination therapy with antifungal drugs to treat multidrug-resistant C. auris infections.

Click synthesis of pyrrolidine-based 1,2,3-triazole derivatives as antifungal agents causing cell cycle arrest and apoptosis in Candida auris.

The emergence of multidrug-resistant fungal pathogens such as Candida auris is one of the major reasons WHO has declared fungal infections as a public health threat. Multidrug resistance, high mortality rates, frequent misidentification, and involvement in hospital outbreaks of this fungus demand the development of novel therapeutic drugs. In this direction, we report the synthesis of novel pyrrolidine-based 1,2,3-triazole derivatives using Click Chemistry (CC) and evaluation of their antifungal susceptibility against C. auris following Clinical and Laboratory Standards Institute (CLSI) guidelines. The fungicidal activity of the most potent derivative (P6) was further quantitatively confirmed by the MUSE cell viability assay. For insight mechanisms, the effect of the most active derivative on cell cycle arrest was studied using MuseTM Cell Analyzer and apoptotic mode of cell death was determined by studying phosphatidylserine externalization and mitochondrial depolarization. In vitro susceptibility testing and viability assays showed that all the newly synthesized compounds have antifungal activity with P6 being the most potent derivative. Cell cycle analysis revealed that P6 arrested the cells in S-phase in a concentration dependent manner and the apoptotic mode of cell death was confirmed by the movement of cytochrome c from mitochondria to cytosol with membrane depolarization. The hemolytic assay confirmed the safe use of P6 for further in vivo studies.

Unique roles of aminophospholipid translocase Drs2p in governing efflux pump activity, ergosterol level, virulence traits, and host-pathogen interaction in Candida albicans.

Infections caused by Candida albicans are rising due to increment in drug resistance and a limited arsenal of conventional antifungal drugs. Thus, elucidating the novel antifungal targets still represent an alternative that could overcome the problem of multidrug resistance (MDR). In this study, we have uncovered the distinctive effect of aminophospholipid translocase (Drs2p) deletion on major MDR mechanisms of C. albicans. We determined that efflux activity was diminished in Δdrs2 mutant as revealed by extracellular rhodamine 6G (R6G) efflux and flow cytometry. Moreover, we further unveiled that Δdrs2 mutant displayed decreased ergosterol content and increased membrane fluidity. Furthermore, Drs2p deletion affects the virulence attributes and led to inhibited hyphal growth and reduced biofilm formation. Additionally, THP-1 cell lines' mediated host-pathogen interaction studies revealed that Δdrs2 mutant displayed enhanced phagocytosis and altered cytokine production leading to increased IL-6 and decreased IL-10 production. Taken together, the present study demonstrates the relevance of Drs2p in C. albicans and consequently disrupting pathways known for mediating drug resistance and immune recognition. Comprehensive studies are further required to authenticate Drs2p as a novel antifungal drug target.

Modulation of key antioxidant enzymes and cell cycle arrest as a possible antifungal mode of action of cinnamaldehyde based azole derivative.

Although Candida auris was only identified in the year 2009, it has rapidly spread in more than a dozen countries and is proving more deadly and notorious. In our previous studies, we reported on the tremendous antifungal potential of a series of cinnamaldehyde based azole derivatives against fluconazole susceptible and resistant clinical isolates of Candida albicans and identified a promising lead molecule (6f). In this study, the effect of this compound on the viability and physiology of cell death in C. auris was assessed. The impact of compound 6f on cell cycle, oxidative stress enzymes and transcriptional profile of genes encoding these oxidative stress enzymes was also analysed. The results confirmed that compound 6f possessed the minimum inhibitory concentration of 0.98 µg/mL and prevented the growth and caused death in yeast cells. Furthermore, the compound at subinhibitory and inhibitory concentrations blocked the cell cycle in C. auris at S phase and G2/M phase and inhibited expression as well as activity of antioxidant enzymes that resulted in production of reactive oxygen species. Altogether, compound 6f showed potential antifungal activity against a virulent strain of C. auris and was able to induce oxidative stress and arrested cell cycle in C. auris and therefore, it can be considered as a strong candidate for antifungal drug development against C. auris.

Differential expression of miRNA in histological subtype of Wilms tumor.

INTRODUCTION: Wilms tumor is the most common renal malignancy in children and difficult to differentiate from other paediatric abdominal tumors radiologically, necessitating an invasive procedure for diagnosis. Previous studies have shown the potential role of miRNA as biomarkers for diagnosis, histological subtyping and prognosis. In this study, we are exploring the role of miRNA in the histological subtyping of Wilms tumor in the Indian population. MATERIALS AND METHODS: A total of 15 cases of Wilms tumor were evaluated for global miRNA expression analysis by microarray. Total RNA was extracted from fresh frozen tumor and miRNA expression analysis was performed using Agilent platform. Unsupervised clustering was done to analyse the data. RESULTS: Using unpaired student T test, top 10 significantly differentially expressed miRNA were selected which could differentiate among different histological subtypes by unsupervised hierarchical clustering and principal component analysis. The presence of necrosis, heterologous differentiation led to change in miRNA expression profile and led to a distinct cluster formation. CONCLUSIONS: A panel of 5 miRNAs (miR1, 133b, 299-3p, 499a-5p, 491-3p) could differentiate among different histological subtypes of Wilms tumor, thus avoiding an invasive procedure in children, however, further confirmation using real time PCR analysis will be needed.

Modulation of antioxidant defence system in response to berberine in Candida albicans.

Emergence of multidrug resistant species of Candida is evolving, which advocates an urgent need for the development of new therapeutic strategies and antifungal drugs. Activation of antioxidant defence system in Candida albicans is known as forefront mechanism to escape drug toxicity. This study evaluated the role of antioxidant defence genes in the susceptibility to fluconazole in C. albicans and also determined the effect of berberine on growth, antioxidant enzymes and the expression of their genes in C. albicans isolates. Expression of major antioxidant genes was significantly increased in fluconazole-resistant isolates in comparison with the susceptible group. Antifungal susceptibility against berberine showed MIC values ranging from 125 to 500 µg/ml. Berberine treatment caused upregulation of mRNA expression and enzymatic activities of the targeted major antioxidants. Interestingly, C. albicans exhibited efficient antioxidant response at lower concentrations but could not sufficiently alleviate berberine-induced oxidative stress occurring at concentrations greater than 250 µg/ml. Therefore, berberine could serve as a potent Reactive Oxygen Species (ROS)-inducing agent, disrupting the antioxidant system especially in fluconazole-resistant C. albicans to overcome antifungal drug resistance. TAKE AWAYS: Evaluated the role of antioxidant enzymes in FLC resistance in C. albicans Studied the effect of berberine on growth of different C. albicans isolates Investigated the modulation of antioxidant enzymes by berberine in C. albicans Studied the effect of berberine on antioxidant gene expression in C. albicans.

Citral and its derivatives inhibit quorum sensing and biofilm formation in Chromobacterium violaceum.

With an upsurge in multidrug resistant bacteria backed by biofilm defence armours, there is a desperate need of new antibiotics with a non-traditional mechanism of action. Targeting bacteria by misguiding them or halting their communication is a new approach that could offer a new way to combat the multidrug resistance problem. Quorum sensing is considered to be the achilles heel of bacteria that has a lot to offer. Since, both quorum sensing and biofilm formation have been related to drug resistance and pathogenicity, in this study we synthesised new derivatives of citral with antiquorum sensing and biofilm disrupting properties. We previously reported antimicrobial and antiquorum sensing activity of citral and herein we report the synthesis and evaluation of citral and its derivatives (CD1-CD3) for antibacterial, antibiofilm and antiquorum sensing potential against Chromobacterium violaceum using standard methods. Preliminary results revealed that CD1 is the most active of all the derivatives. Qualitative and quantitative evaluation of antiquorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for CD1 followed by CD2, CD3 and citral. These compounds also inhibit biofilm formation at subinhibitory concentrations without causing any bacterial growth inhibition. These results were replicated by RT-qPCR with down regulation of the quorum sensing genes when C. violaceum was treated with these test compounds. Overall, the results are quite encouraging, revealing that biofilm and quorum sensing are interrelated processes and also indicating the potential of these derivatives to impede bacterial communication and biofilm formation.

Citral derivative activates cell cycle arrest and apoptosis signaling pathways in Candida albicans by generating oxidative stress.

For combating life-threatening infections caused by Candida albicans there is an urgent requirement of new antifungal agents with a targeted activity and low host cytotoxicity. Manipulating the mechanistic basis of cell death decision in yeast may provide an alternative approach for future antifungal therapeutics. Herein, the effect of an active citral derivative (Cd1) over the physiology of cell death in C. albicans was assessed. The viability of C. albicans SC5314 cells was determined by broth microdilution assay. The crucial morphological changes and apoptotic markers in Cd1-exposed yeast cells were analyzed. Subsequently the results confirmed that Cd1 arrested growth and caused death in yeast cells. Furthermore, this molecule inhibited antioxidant enzymes that resulted in production of reactive oxygen species. DNA fragmentation and condensation, phosphatidylserine exposure at the outer leaflet of cell membrane, mitochondrial disintegration as well as accumulation of cells at G2/M phase of the cell cycle were recorded. Altogether, this derivative induced apoptotic-type cell death in C. albicans SC5314.

Inhibition of ergosterol synthesis in Candida albicans by novel eugenol tosylate congeners targeting sterol 14α-demethylase (CYP51) enzyme.

This study is a continuation and extension of our previous study in which we synthesized seven novel eugenol tosylate congeners (ETC-1 to ETC-7) from a natural compound eugenol and checked their antifungal activity against different isolates of Candida albicans. All these ETCs showed potent antifungal activity to varying degrees. In this study, the aim is to evaluate the effect of most active compounds (ETC-5, ETC-6 and ETC-7) on ergosterol biosynthesis pathway and cellular viability in C. albicans by applying combined approach of in silico and in vitro methodologies. In silico studies were done through all atom molecular mechanics approach and free binding energy estimations, and in vitro study was done by estimating total intracellular sterol content and effect on expression of ERG11 gene. Furthermore, effect on cell viability by these compounds was also tested. Our results demonstrated that these ETCs target ergosterol biosynthesis pathway in C. albicans by inhibiting the lanosterol 14-α demethylase enzyme and also downregulates expression of its related gene ERG11. Furthermore, these ETCs exhibit potent fungicidal effect in cell viability assay, thus overall results advocating the claim that these tosylates have potential to be taken to next level of antifungal drug development.

S-benzyldithiocarbazate imine coordinated metal complexes kill Candida albicans by causing cellular apoptosis and necrosis.

Development of new chemotherapeutic agents and strategies are urgently needed to curb and halt the growing menace caused by hard-to-treat microbes. Coordination of metals to bioactive organic ligands is now considered to be an efficient strategy for delivering bioactive compounds inside the microbial cell membranes. Metal complexes have been effectively used to treat many dreadful diseases were other treatment modalities had failed. Use of metal complexes to treat microbial infections is now conceived to be an alternative and efficient strategy. Towards this, some new homoleptic transition metal complexes, obtained by coordination of metal ions to bioactive S-benzyldithiocarbazate Schiff-base ligands were evaluated for their anti-Candida activity and their potential to disrupt the membrane architecture. The complexes displayed remarkable antifungal activity against a wide spectrum of fluconazole susceptible and resistant Candida albicans isolates, with Ni complex (dtc3) being highly active with minimum inhibitory concentration (MIC) values ranging from 1 to 32 µg/mL. Cell viability assay confirmed the fungicidal activity of these metal complexes, especially the complex dtc3. These metal complexes kill Candida albicans by inducing cellular apoptosis and necrosis thereby causing phosphatidylserine externalization as revealed by Annexin V-FITC and propidium iodide staining assays.

Lactobacillus rhamnosus cell-free extract targets virulence and antifungal drug resistance in Candida albicans.

Candidiasis caused by multidrug-resistant Candida species continues to be difficult to eradicate. The use of live probiotic bacteria has gained a lot of interest in the treatment of candidiasis; however, whole-cell probiotic use can often be associated with a high risk of sepsis. Strategies manipulating cell-free methods using probiotic strains could lead to the development of novel antifungal solutions. Therefore, we evaluated the effect of three probiotic cell-free extracts (CFEs) on the growth, virulence traits, and drug efflux pumps in C. albicans. On the basis of its minimum inhibitory concentration, Lactobacillus rhamnosus was selected and assessed against various virulence traits and drug resistance mechanisms. The results showed that L. rhamnosus CFE significantly inhibited hyphae formation and reduced secretion of proteinases and phospholipases. Moreover, L. rhamnosus inhibited the drug efflux proteins in resistant C. albicans strains thus reversing drug resistance. Gene expression data confirmed downregulation of genes associated with microbial virulence and drug resistance following treatment of C. albicans with L. rhamnosus CFE. Through gas chromatography - mass spectrometry chemical characterization, high contents of oleic acid (24.82%) and myristic acid (13.11%) were observed in this CFE. Collectively, our findings indicate that L. rhamnosus may potentially be used for therapeutic purposes to inhibit C. albicans infections.

Candida auris-the growing menace to global health.

A paradigm shift of candidiasis from Candida albicans to non-albicans Candida species has fundamentally increased with the advent of C. auris. C. auris, despite being a newly emerged multidrug-resistant fungal pathogen, is associated with severe invasive infections and outbreaks with high mortality rates. Initially reported from Japan in 2009, C. auris have now been found in different countries on all the continents except Antarctica. Due to its capability of nosocomial transmission and forming adherent biofilms on clinically important substrates, a high number of related hospital outbreaks have been reported worldwide. As C. auris is a multidrug-resistant pathogen and is prone to misidentification by available conventional methods, it becomes difficult to detect and manage C. auris infection and also limits the therapeutic options against this deadly pathogen. The emergence of multidrug-resistant C. auris advocates and amplifies the vigilance of early diagnosis and appropriate treatment of fungal infections. In this review, we discussed the nine-year-old history of C. auris-its trends in global emergence, epidemiological relatedness, isolation, mortality, associated risk factors, virulence factors, drug resistance and susceptibility testing, diagnostic challenges, microbiological characteristics, therapeutic options and infection prevention and control associated with this pathogen.

Flucytosine analogues obtained through Biginelli reaction as efficient combinative antifungal agents.

Invasive fungal infection is a problem that continues to challenge the healthcare sector. New antifungals and new therapeutic strategies are needed to address this challenge. We previously reported that the combination of a synthetic compound with a drug with known mechanism of action is a good strategy to treat aggressive and resistant fungi. Here we revisited our approach and synthesized structural analogues of flucytosine, which is a synthetic antifungal and is being studied for its use in combination therapy with other antifungal drugs. Pyrimidin-one and -thione (often known as DHPM's) as flucytosine analogues were obtained through a Biginelli reaction of corresponding aldehydes, ethylacetoacetate and urea/thiourea. Structure was confirmed by FTIR, 1HNMR, 13CNMR, COSY and MS (ESI+) analysis. All the newly synthesized derivatives were evaluated for the antifungal activity alone and in combination of two most commonly used antifungal drugs, amphotericin B and fluconazole against different clinically isolated Candida albicans strains. Minimum inhibitory concentration results confirmed that BG4 possess high antifungal activity against all the tested strains (MIC = 1-32 µg/ml). For all the combinations with amphotericin B and fluconazole, 37% were synergistic followed by 30% additive and 24% indifferent interactions. Interestingly, 9% antagonistic interaction was observed when BG1 and BG3 were combined with fluconazole, however, no antagonistic interaction was observed with amphotericin B. In-depth studies of all the synergies were done by constructing isobolograms with nine different ratio combinations. These results warrant the use of DHPM derivatives as chemosensitising agents which could lower down the dosages of the antifungal drugs to treat invasive fungal diseases.

Effect of two monoterpene phenols on antioxidant defense system in Candida albicans.

Thymol and carvacrol from the class of monoterpene phenols are one of the most potent plant essential oil components possessing antimicrobial effects. Known for their wide bioactive spectrum, these positional isomers of isopropyl cresol deplete ergosterol content, compromise membrane permeability, block efflux pumps and restore antifungal susceptibility to fluconazole in resistant Candida strains. Exposure to these natural compounds induces a cascade of stress responses, which are important to comprehend their microbicidal mechanisms. This study evaluates the antioxidant defense response to lower concentrations of thymol and carvacrol in Candida albicans. The antioxidant defense responses in C. albicans are important for developmental mechanisms pertaining to resistance against the immune system, infection establishment and drug resistance. In this view, primary and secondary antioxidant defense enzymes, and oxidative stress markers including glutathione and lipid peroxidation were determined in C. albicans cells exposed to lower concentrations of thymol and carvacrol. These compounds were found to induce oxidative stress and compromised the antioxidant defense system in C. albicans at lower concentrations. This study helps in understanding the 'in cell' antifungal mechanisms of natural monoterpene phenols originating from oxidative stress. Thymol and carvacrol induced membrane deterioration reported earlier, is further explained as a result of a toxic radical cascade mediated by lipid peroxidation. Findings reinforce the observed toxic oxidizing effects of these compounds as a consequence of direct damage to antioxidant components and not to their genetic manipulations.

Imidazole clubbed 1,3,4-oxadiazole derivatives as potential antifungal agents.

A series of compounds in which 2-(4-ethyl-2-pyridyl)-1H-imidazole was clubbed with substituted 1,3,4-oxadiazole was synthesized and subjected to antifungal activity evaluation. In vitro assays indicated that several clubbed derivatives had excellent antifungal activity against different strains of laboratory and clinically isolated Candida species. Structural Activity Relationship (SAR) studies revealed that the presence and position of substituents on the phenyl ring of the 1,3,4-oxadiazole unit, guides the antifungal potential of the compounds, where compound 4b, 4c and 4g were found to be active against all the tested fungal strains. Impairment of ergosterol biosynthesis upon the concomitant treatment of 4b, 4c and 4g, revealed the possible mechanisms of antifungal action of these compounds. Inhibitors snugly fitting the active site of the target enzyme, as revealed by molecular docking studies, may well explain their excellent inhibitory activity.

Unravelling the complex antimicrobial interactions of essential oils--the case of Thymus vulgaris (thyme).

Thymus vulgaris has gained tremendous popularity as an ornamental, culinary herb and its use in phytotherapy is well established and supported in the literature. The objective of this study was to explore possible interactions between selected molecules within Thymus vulgaris essential oil (TvEO) to gain a better understanding of how this complex essential oil exerts its antimicrobial activity. Evaluation of the antimicrobial efficacy and interactions were assessed on the essential oil and volatile constituents against various pathogens. Interactions between molecules at various ratios were graphically observed through the construction of isobolograms. Gas chromatography-mass spectrometry (GC-MS) analysis revealed 22 compounds which collectively represent >95% of the oil composition. Based on their minimum inhibitory concentration (MIC) values, they were categorised into weak (≥4 mg mL⁻¹), moderate (2-4 mg mL⁻¹) and noteworthy active (≤2 mg mL⁻¹) compounds. For the combination study, 21% synergistic, 42% additive, 36% indifferent and 1% antagonistic interactions were observed. Most of the interactions were observed between the weak and highly active molecules, and interestingly, no synergistic interaction was observed between the highly active compounds. Synergistic and additive interactions between the strong and weaker antimicrobial constituents present in TvEO enhance the antimicrobial efficacy of this commercially important essential oil.

Yeast-Based Screening of Anti-Viral Molecules.

Viruses are minuscule infectious agents that reproduce exclusively within the living cells of an organism and are present in almost every ecosystem. Their continuous interaction with humans poses a significant threat to the survival and well-being of everyone. Apart from the common cold or seasonal influenza, viruses are also responsible for several important diseases such as polio, rabies, smallpox, and most recently COVID-19. Besides the loss of life and long-term health-related issues, clinical viral infections have significant economic and social impacts. Viral enzymes, especially proteases which are essential for viral multiplication, represent attractive drug targets. As a result, screening of viral protease inhibitors has gained a lot of interest in the development of anti-viral drugs. Despite the availability of anti-viral therapeutics, there is a clear need to develop novel curative agents that can be used against a given virus or group of related viruses. This review highlights the importance of yeasts as an in vivo model for screening viral enzyme inhibitors. We also discuss the advantages of yeast-based screening platforms over traditional assays. Therefore, in the present article, we discuss why yeast is emerging as a model of choice for in vivo screening of anti-viral molecules and why yeast-based screening will become more relevant in the future for screening anti-viral and other molecules of clinical importance.

Antifungal activity of human antimicrobial peptides targeting apoptosis in Candida auris.

Introduction. Innovative antifungal therapies are of crucial importance to combat the potentially life-threatening infections linked to the multidrug-resistant fungal pathogen Candida auris. Induction of regulated cell death, apoptosis, could provide an outline for future therapeutics. Human antimicrobial peptides (AMPs), well-known antifungal compounds, have shown the ability to induce apoptosis in pathogenic fungi.Hypothesis/Gap Statement . Although it is known that AMPs possess antifungal activity against C. auris, their ability to induce apoptosis requires further investigations.Aim. This study evaluated the effects of AMPs on the induction of apoptosis in C. auris.Methods. Human neutrophil peptide-1 (HNP-1), human ß-Defensins-3 (hBD-3) and human salivary histatin 5 (His 5) were assessed against two clinical C. auris isolates. Apoptosis hallmarks were examined using FITC-Annexin V/PI double labelling assay and terminal deoxynucleotidyl transferase deoxynucleotidyl transferase nick-end labelling (TUNEL) to detect phosphatidylserine externalization and DNA fragmentation, respectively. Then, several intracellular triggers were studied using JC-10 staining, spectrophotometric assay and 2',7'-dichlorofluorescin diacetate staining to measure the mitochondrial membrane potential, cytochrome-c release and reactive oxygen species (ROS) production, respectively.Results and conclusion. FITC-Annexin V/PI staining and TUNEL analysis revealed that exposure of C. auris cells to HNP-1 and hBD-3 triggered both early and late apoptosis, while His 5 caused significant necrosis. Furthermore, HNP-1 and hBD-3 induced significant mitochondrial membrane depolarization, which resulted in substantial cytochrome c release. In contrast to His 5, which showed minimal mitochondrial depolarization and no cytochrome c release. At last, all peptides significantly increased ROS production, which is related to both types of cell death. Therefore, these peptides represent promising and effective antifungal agents for treating invasive infections caused by multidrug-resistant C. auris.

Heteroleptic cobalt complex augments antifungal activity with fluconazole and causes membrane disruption in Candida albicans.

Heteroleptic metal complexes containing CuII, CoII, and ZnII, incorporating curcumin and a Schiff base ligand (L), were synthesized and characterized, and their antifungal activity was evaluated. Their antifungal activities were investigated individually and in combination with fluconazole. Utilizing various analytical techniques such as UV-Vis, FT-IR, NMR, ESI-MS, TGA-DTG, elemental analyses, conductance, and magnetic susceptibility measurements, complex C1 ([Cu(Cur)LCl(H2O)]) was assigned a distorted octahedral geometry, while complexes C2 ([Co(Cur)LCl(H2O)]) and C3 ([Zn(Cur)LCl(H2O)]) were assigned octahedral geometries. Among these complexes, C2 exhibited the highest inhibitory activity against both FLC-susceptible and resistant strains of Candida albicans. Furthermore, C2 demonstrated candidicidal activity and synergistic interactions with fluconazole, effectively inhibiting the growth and survival of both FLC-resistant and FLC-sensitive C. albicans strains. The complex displayed a dose-dependent inhibition of drug efflux pumps in FLC-resistant C. albicans strains, indicating its potential to disrupt the cell membrane of these strains. The significant role of membrane efflux transporters in the development of antifungal drug resistance within Candida species has been extensively documented and our findings indicate that complex C2 specifically targets this crucial factor, thereby playing a pivotal role in mitigating drug resistance in C. albicans.

Multifunctional chitosan-cross linked- curcumin-tannic acid biocomposites disrupt quorum sensing and biofilm formation in pathogenic bacteria.

Natural products have a long history of success in treating bacterial infections, making them a promising source for novel antibacterial medications. Curcumin, an essential component of turmeric, has shown potential in treating bacterial infections and in this study, we covalently immobilized curcumin (Cur) onto chitosan (CS) using glutaraldehyde and tannic acid (TA), resulting in the fabrication of novel biocomposites with varying CS/Cur/TA ratios. Comprehensive characterization of these ternary biocomposites was conducted using FTIR, SEM, XPS, and XRD to assess their morphology, functional groups, and chemical structures. The inhibitory efficacy of these novel biocomposites (n = 4) against the growth and viability of Pseudomonas aeruginosa (ATCC27853) and Chromobacterium violaceum (ATCC12472) was evaluated and the most promising composite (C3) was investigated for its impact on quorum sensing (QS) and biofilm formation in these bacteria. Remarkably, this biocomposite significantly disrupted QS circuits and effectively curtailed biofilm formation in the tested pathogens without inducing appreciable toxicity. These findings underscore its potential for future in vivo studies, positioning it as a promising candidate for the development of biofilm disrupting antibacterial agents.