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

Machine Learning-Based Approach to Identify Inhibitors of Sterol-14-Alpha Demethylase: A Study on Chagas Disease

Objectives

Chagas Disease, caused by the parasite Trypanosoma cruzi, remains a significant public health concern, particularly in Latin America. The current standard treatment for Chagas Disease, benznidazole, is associated with various side effects, necessitating the search for alternative therapeutic options. In this study, we aimed to identify potential therapeutics for Chagas Disease through a comprehensive computational analysis.

Methods

A library of compounds derived from Cananga odorata was screened using a combination of pharmacophore modeling, structure-based screening, and quantitative structure-activity relationship (QSAR) analysis. The pharmacophore model facilitated the efficient screening of the compound library, while the structure-based screening identified hit compounds with promising inhibitory potential against the target enzyme, sterol-14-alpha demethylase.

Results

The QSAR model predicted the bioactivity of the hit compounds, revealing one compound to exhibit superior activity compared to benznidazole. Evaluation of the physicochemical, pharmacokinetic, toxicity, and medicinal chemistry properties of the hit compounds indicated their drug-like characteristics, oral bioavailability, ease of synthesis, and reduced toxicity profiles.

Conclusion

Overall, our findings present a promising avenue for the discovery of novel therapeutics for Chagas Disease. The identified hit compounds possess favorable drug-like properties and demonstrate potent inhibitory effects against the target enzyme. Further in vitro and in vivo studies are warranted to validate their efficacy and safety profiles.

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'β-olide)-4-(dictyotin-11'-oate-15″α, 19″β-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.

Glycosylated heterocyles emulsified with antifungal fraction of Moringa oleifera for potentiation of mycolytic activity

To enhance the clinical effect of antifungal medications for treating deadly fungal infections there is an increasing demand for novel treatments. Exploration of multiple-drug targeting in antifungal therapeutics is the need of the present era. In this pursuit, we identified potent antifungal compounds that were directed towards the multiple virulent targets in Rhizopus arrhizus. Quinoxaline di-N-oxide and piperazine derivatives were identified to exhibit antifungal activities. 03 bioactive compounds were identified from the docking results and antifungal activity. Furthermore, these compounds which were combined with the alkaline extract of M. olifera to make the aqueous phase, an oil phase containing cinnamon oil or clove oil and a combination of surfactants was made to prepare a bioactive composite emulsion. A significant antimycotic activity was seen for the bioactive composite emulsion when compared with the clinically used antifungal drugs. Our results indicate the synergy and potentiation of antimycotic drugs based on integrative medicine.

Anhydroparthenin as a dual-target inhibitor against Sterol C-24 methyltransferase and Sterol 14-α demethylase of Leishmania donovani: A comprehensive in vitro and in silico study

Parthenium hysterophorus plant has a diverse chemical profile and immense bioactive potential. It exhibits excellent pharmacological properties such as anti-cancer, anti-inflammatory, anti-malarial, microbicidal, and anti-trypanosomal. The present study aims to evaluate the anti-leishmanial potential and toxicological safety of anhydroparthenin isolated from P. hysterophorus. Anydroparthenin was extracted from the leaves of P. hysterophorus and characterized through detailed analysis of 1H, 13C NMR, and HRMS. Dye-based in vitro and ex vivo assays confirmed that anhydroparthenin significantly inhibited both promastigote and amastigote forms of the Leishmania donovani parasites. Both the cytotoxicity experiment and hemolytic assay revealed its non-toxic nature and safety index in the range of 10 to 15. Further, various mechanistic assays suggested that anhydroparthenin led to the generation of oxidative stress, intracellular ATP depletion, alterations in morphology and mitochondrial membrane potential, formation of intracellular lipid bodies, and acidic vesicles, ultimately leading to parasite death. As a dual targeting approach, computational studies and sterol quantification assays confirmed that anhydroparthenin inhibits the Sterol C-24 methyl transferase and Sterol 14-α demethylase proteins involved in the ergosterol biosynthesis in Leishmania parasites. These results suggest that anhydroparthenin could be a promising anti-leishmanial molecule and can be developed as a novel therapeutic stratagem against leishmaniasis.

In-silico identification of potential inhibitors against FabI protein in Klebsiella pneumoniae

The development of new antimicrobial drugs is needed to combat multi-drug resistant and novel hypervirulent strains of Klebsiella pneumoniae (KPN) that are associated with increased morbidity and mortality globally. The FabI protein plays a crucial role in fatty acid biosynthesis and has been identified as an important target for in-silico, in-vitro, and in-vivo drug discovery. In this study we have used computer integrated-drug discovery approaches and binding-free energy calculations to identify three novel inhibitors (21272541, 67724550, and 67724551) of the FabI protein. All inhibitors showed strong affinity including van der Waals energy, electrostatic energy, polar and non-polar energies; however, the 21272541 compound was the most effective inhibitor and bound with the strongest affinity (ΔGbind -59.02 kcal/mol) to the FabI protein. Nevertheless, all three inhibitors are promising targets for new novel antimicrobial drugs that could contribute to the management of antimicrobial resistant KPN infections based on various computational analysis. Additional in-vitro and in-vivo clinical studies will be needed to confirm drug effectiveness for the treatment of KPN infections.

Pharmacodynamic, pharmacokinetic, toxicity, and recent advances in Eugenol's potential benefits against natural and chemical noxious agents: A mechanistic review

The active biological phytochemicals, crucial compounds employed in creating hundreds of medications, are derived from valuable and medicinally significant plants. These phytochemicals offer excellent protection from various illnesses, including inflammatory disorders and chronic conditions caused by oxidative stress. A phenolic monoterpenoid known as eugenol (EUG), it is typically found in the essential oils of many plant species from the Myristicaceae, Myrtaceae, Lamiaceae, and Lauraceae families. One of the main ingredients of clove oil (Syzygium aromaticum (L.), Myrtaceae), it has several applications in industry, including flavoring food, pharmaceutics, dentistry, agriculture, and cosmeceuticals. Due to its excellent potential for avoiding many chronic illnesses, it has lately attracted attention. EUG has been classified as a nonmutant, generally acknowledged as a safe (GRAS) chemical by the World Health Organization (WHO). According to the existing research, EUG possesses notable anti-inflammatory, antioxidant, analgesic, antibacterial, antispasmodic, and apoptosis-promoting properties, which have lately gained attention for its ability to control chronic inflammation, oxidative stress, and mitochondrial malfunction and dramatically impact human wellness. The purpose of this review is to evaluate the scientific evidence from the most significant research studies that have been published regarding the protective role and detoxifying effects of EUG against a wide range of toxins, including biological and chemical toxins, as well as different drugs and pesticides that produce a variety of toxicities, throughout view of the possible advantages of EUG.

Update on fungal lipid biosynthesis inhibitors as antifungal agents

Fungal diseases today represent a world-wide problem. Poor hygiene and decreased immunity are the main reasons behind the manifestation of this disease. After COVID-19, an increase in the rate of fungal infection has been observed in different countries. Different classes of antifungal agents, such as polyenes, azoles, echinocandins, and anti-metabolites, as well as their combinations, are currently employed to treat fungal diseases; these drugs are effective but can cause some side effects and toxicities. Therefore, the identification and development of newer antifungal agents is a current need. The fungal cell comprises many lipids, such as ergosterol, phospholipids, and sphingolipids. Ergosterol is a sterol lipid that is only found in fungal cells. Various pathways synthesize all these lipids, and the activities of multiple enzymes govern these pathways. Inhibiting these enzymes will ultimately impede the lipid synthesis pathway, and this phenomenon could be a potential antifungal therapy. This review will discuss various lipid synthesis pathways and multiple antifungal agents identified as having fungal lipid synthesis inhibition activity. This review will identify novel compounds that can inhibit fungal lipid synthesis, permitting researchers to direct further deep pharmacological investigation and help develop drug delivery systems for such compounds.

Abrogation of efflux pump activity, biofilm formation, and immune escape by candidacidal geraniol in emerging superbug, Candida auris

During the last decade, Candida auris emerged as a threatening human fungal pathogen that notably caused outbreaks around the globe with high mortality. Considering C. auris species as newly discovered fungi, the evolutionary features remain elusive. The antifungal resistance which is a norm in C. auris underlines the need for innovative therapeutic options. ATP Binding Cassette (ABC) superfamily efflux pumps overexpression and biofilms are known to be major contributors to multidrug resistance (MDR) in C. auris. Therefore, herein, we investigated the antifungal potential of geraniol (Ger) as a promising natural compound in the fight against MDR C. auris. Our experiments proved that Ger was fungicidal in nature and impaired rhodamine 6G (R6G) efflux, confirming the specific effect on ABC transporters. Kinetic studies unravelled the competitive mode of inhibition by Ger for R6G efflux since the apparent Km increased with no change in Vmax value. Mechanistic insights also revealed that Ger depleted ergosterol content in C. auris. Furthermore, Ger led to inhibition in biofilm formation as evident from crystal violet staining, biofilm metabolic and biomass measurements. Additionally, enhanced survival of Caenorhabditis elegans model after C. auris infection demonstrated the in vivo efficacy of Ger. Lastly, the in vivo efficacy was confirmed from a THP-1 cell line model which depicted enhanced macrophage-mediated killing in the presence of Ger. Modulation of C. auris efflux pump activity and biofilm formation by Ger represents a promising approach to combat MDR. Together, this study demonstrated the potential therapeutic insights of Ger as a promising addition to the antifungal armamentarium required to treat emerging and resistant C. auris.

Antifungal Annona muricata L. (soursop) extract targets the cell envelope of multi-drug resistant Candida albicans

ETNOPHARMACOLOGICAL RELEVANCE

Annona muricata L. (soursop) is traditionally used in the treatment of inflammatory diseases, cancer, and infections caused by fungi. The therapeutic activity explored by its medicinal use is generally associated with its phytoconstituents, such as acetogenins and alkaloids. However, its potential antifungal bioactivity as well as its mechanism of action remains to be established.

AIM OF THE STUDY

To evaluate the antifungal activity of the ethanolic extract of A. muricata leaves against multidrug-resistant Candida albicans (ATCC® 10231).

MATERIAL AND METHODS

Phytoconstituents were detected by UFLC-QTOF-MS. The minimum inhibitory concentration was determined, followed by the determination of the minimum fungicidal concentration. For planktonic cells, the growth curve and cell density were evaluated. Studies to understand the mechanism of action on the cell envelope involved crystal violet permeability, membrane extravasation, sorbitol protection, exogenous ergosterol binding assay, metabolic activity, and cell viability. Furthermore, mitochondrial membrane potential was assessed.

RESULTS

Our analyses demonstrated a significant inhibitory effect of A. muricata, with the ability to reduce fungal growth by 58% and cell density by 65%. The extract affected both the fungal plasma membrane and cell wall integrity, with significant reduction of the cell viability. Depolarization of the fungal mitochondrial membrane was observed after treatment with A. muricata. Rutin, xi-anomuricine, kaempferol-3O-rutinoside, nornuciferine, xylopine, atherosperminine, caffeic acid, asimilobine, s-norcorydine, loliolide, annohexocin, annomuricin, annopentocin, and sucrose were identified as extract bioactive components.

CONCLUSIONS

Our findings show that the A. muricata extract is a source of chemical diversity, which acts as a potential antifungal agent with promising application to the therapy of infections caused by C. albicans.

Eugenol: A novel therapeutic agent for the inhibition of Candida species infection

The high occurrence and mortality rates related to candidiasis emphasize the urgent need to introduce new therapeutic approaches to treat this infection. Eugenol, the main phenolic component of Clove and Cinnamomum essential oil, has been used to inhibit growth and different virulence factors of Candida, including strains with decreased susceptibility to antifungals, particularly fluconazole. The results showed that this compound could bind to Candida membrane and decrease ergosterol biosynthesis, consequently leading to cell wall and membrane damage. Additionally, eugenol not only reduced germ tube formation, which reduces nutrient absorption from host tissues, but it also increased the levels of lipid peroxidation and reactive oxygen species, which induces oxidative stress and causes high permeability in the fungal cell membrane. Eugenol inhibited Candida cells’ adhesion capacity; additionally, this compound inhibited the formation of biofilms and eliminated established Candida biofilms on a variety of surfaces. Furthermore, by disrupting fungal cell integrity, eugenol could boost the entry of the antifungal drugs into the Candida cell, improving treatment efficacy. Therefore, eugenol could be used in the clinical management of various presentations of candidiasis, especially mucocutaneous presentations such as oral and vulvovaginal infections. However, further investigations, including in vivo and animal studies, toxicology studies and clinical trials, as well as molecular analysis, are needed to improve formulations and develop novel antifungal agents based on eugenol.

Recent Advances in the Application of Essential Oils as Potential Therapeutic Candidates for Candida-Related Infections

Candidiasis (oral, vulvovaginal, or systemic bloodstream infections) are important human fungal infections associated with a high global prevalence in otherwise healthy adults but are also opportunistic infections in immunocompromised patients. With the recent discovery of the multidrug resistant—and often difficult to treat—Candida auris, as well as the rising costs associated with hospitalisations and the treatment of infections caused by Candida species, there is an urgent need to develop effective therapeutics against these pathogenic yeasts. Essential oils have been documented for many years as treatments for different ailments and are widely known and utilised in alternative and complementary therapies, including treating microbial infections. This review highlights knowledge from research on the effects of medicinal plants, and in particular, essential oils, as potential treatments against different Candida species. Studies have been evaluated that describe the experimental approaches used in investigating the anticandidal effects of essential oils (in vivo and in vitro), the established mode of action of the different compounds against different Candida species, the effect of a combination of essential oils with other compounds as potential therapies, and the evidence from clinical trial studies.

Quorum Sensing and Biofilm Disrupting Potential of Imidazole Derivatives in Chromobacterium violaceum Using Antimicrobial and Drug Discovery Approaches

Population of drug-resistant bacteria have increased at an alarming rate in the past few decades. The major reason for increasing drug resistance is the lack of new antibiotics and limited drug targets. It has therefore been a vital task to develop new antibiotics with different drug targets. Two such targets are biofilm formation and quorum sensing. Quorum sensing is cell to cell communication used by bacteria that initiates many important survival processes and aids in establishing pathogenesis. Both biofilm and quorum sensing are inter-related processes and play a major role in physiological and pathogenesis processes. In this study, five novel imidazole derivatives (IMA-1-IMA-5) were synthesised and tested for their antibacterial and anti-quorum sensing activities against Chromobacterium violaceum using different in silico and in vitro techniques following the standard protocols. In silico results revealed that all compounds were able to effectively bind to and interact sufficiently with the target protein CviR. CviR is a protein to which autoinducers bind to initiate the quorum sensing process. In silico results also revealed that the compounds generated favourable structural dynamics implying that the compounds would be able to effectively bind to CviR and inhibit quorum sensing. Susceptibility results revealed that IMA-1 is the most active of all the derivatives against both planktonic cells and biofilms. Qualitative and quantitative evaluation of anti-quorum sensing activity at sub-inhibitory concentrations of these compounds also revealed high activity for IMA-1. Down-regulation of most of the quorum sensing genes when cells were treated with the test compounds affirmed the high anti-quorum sensing activities of these compounds. The results from this study are promising and urges on the use of anti-quorum sensing and biofilm disrupting molecules to combat multi-drug resistance problem.

Eco-friendly 'ochratoxin A' control in stored licorice roots - quality assurance perspective

According to toxicity data, ochratoxin A (OTA) is the second most important mycotoxin and is produced by Aspergillus and Penicillium. As a natural antifungal agent, clove essential oil (CEO) is a substance generally recognised as safe (GRAS) and shows strong activity against fungal pathogens. Here, we aimed to investigate the control efficacy of CEO in nano-emulsions (CEN) against OTA production in licorice roots and rhizomes during storage. The experiments were performed under simulated conditions of all four seasons (i.e. Spring, Summer, Autumn and Winter). Relative humidity (RH) and temperature were simulated in desiccators along with various salt solutions in incubators. Fresh licorice roots were immersed in CEN at various concentrations (150, 300, 600, 1200 and 2400 µl/l). Before utilising the nano-emulsions, we measured their polydispersity index and mean droplet size by the dynamic light scattering (DLS) technique. Also, the chemical composition of the CEO was determined using GC and GC-MS analyses. Sampling was carried out to monitor OTA once every five days. The samples were dried immediately and analysed by high-performance liquid chromatography (HPLC). Results showed that various concentrations of CEN inhibited the growth of fungi and OTA production. The most effective CEN concentrations were 1200 and 2400 µl/l, which reduced OTA production to 19 and 20 ppb under Winter and Autumn conditions, respectively. These results suggest an effective eco-friendly method for the storage of licorice to reduce postharvest fungal decay.

Potential Inhibitors of CYP51 Enzyme in Dermatophytes by Red Sea Soft Coral Nephthea sp.: In Silico and Molecular Networking Studies

In this study, the n-hexane fraction of soft coral Nephthea sp. gathered from the Red Sea was evaluated for its antidermatophyte activity. The antidermatophyte activity was performed versus different fungi, including Microsporum canis, Trichophyton gypseum, and Microsporum mentagrophytes, using a broth microdilution method. The n-hexane fraction showed minimum inhibitory concentrations (MICs) against the tested dermatophytes of 104.2 ± 20.8, 125 ± 0.0, and 83.33 ± 20.83 μg/mL respectively. The chemical constitution of the lipoidal matter (n-hexane fraction) was characterized by gas chromatography coupled with a mass spectrometer (GC-MS). The unsaponifiable fraction (USAP) of Nephthea sp. showed relative percentages of hydrocarbons and vitamins of 69.61% and 3.26%, respectively. Moreover, the percentages of saturated and unsaturated fatty acids were 53.67% and 42.05%, respectively. In addition, a molecular networking study (MN) of the GC-MS analysis performed using the Global Natural Products Social Molecular Networking (GNPS) platform was described. The molecular docking study illustrated that the highest binding energy score for spathulenol toward the CYP51 enzyme was -8.3674 kcal/mol, which predicted the mode of action of the antifungal activity, and then the results were confirmed by the inhibitory effect of Nephthea sp. against CYP51 with an IC₅₀ value of 12.23 μg/mL. Our results highlighted the antifungal potential of Nephthea sp. metabolites.

The association of air pollutants (CO2, MTBE) on Candida albicans and Candida glabrata drug resistance

Introduction

Therapeutic methods are very important in the prevalence of opportunistic fungal infections, which are an important cause of human diseases. In this study, air pollution agents that are in direct contact with microorganisms, and the effects of carbon sources using CO2 and MTBE on growth of fungi, and particularly the evaluation of changes in the expression of interfering genes in susceptibility and drug resistance in these fungi, were investigated.

Materials and Methods

Collecting samples and isolating Candida glabrata and Candida albicans with phenotypic methods were accomplished. We then evaluated the minimum inhibitory concentration (MIC) with the M27A4 protocol of CLSI. We adjusted 20 strains of C. albicans and 10 strains of C. glabrata whose sensitivity was evaluated in the MIC test with 5% CO2 and 5mg/ml methyl tert-butyl ether (MTBE) considered as air pollutants, and followed by re-evaluating MIC testing to separate azole-resistant strains. Interfering agents were also considered.

Results

Upregulation of some genes on the two mentioned yeasts had led to drug resistance in them; they were previously sensitive to both drugs. Correspondingly, 41% of C. glabrata samples in sputum showed sensitivity to these drugs. Upregulation of ERG11 (71%) and EPA1 (90%) were observed in resistant strains. Upregulation of genes associated with aspartate proteins and downregulation of SAP3 genes were recognized in C. glabrata in sputum and a 15% downregulation of bronchoalveolar lavage (BAL) isolate and 50% upregulation of SAP1 gene in C. albicans sensitive samples were observed and compared to fluconazole and itraconazole with the oral and joint sources. Remarkably, decreased SAP2 expression in oral sources and a 60% increase in resistant strains in C. albicans were observed. The downregulation of SAP3 expression showed in the joint samples. An increase in HWP1 expression (30%) was noted in isolated and drug-sensitive samples at the sputum and BAL source. CDR1 expression was increased in MTBE-affected species; however, it decreased in the vicinity of CT.

Conclusions

Air pollutants such as CO2 and MTBE eventually caused drug resistance in Candida, which can be one of the causes of drug resistance in candidiasis infections.

Unravelling the antifungal mode of action of curcumin by potential inhibition of CYP51B: A computational study validated in vitro on mucormycosis agent, Rhizopus oryzae

Like human, fungi too are known to share lot of structural similarities amongst their CYPs (Cytochrome P450 super family of enzymes) which allows antifungal 'azole' compounds to interact with CYPs of human. Clotrimazole, an 'azole' antifungal drug, is a known inhibitor of fungal CYP named CYP51B. Curcumin, a phytochemical obtained from Curcuma longa has the ability to interact with several different human CYPs to induce inhibition. The sequence and the structural similarities amongst both human and fungal CYPs suggest a strong possibility for curcumin to interact with fungal CYP51B to behave like an antifungal agent. To test this hypothesis a study was designed involving mucormycosis agent, Rhizopus oryzae. The ability of curcumin to interact with fungal CYP51B was analysed computationally through molecular docking, MM-GBSA and Molecular Dynamics (MD) simulation assessment. Further, interaction profile for fungal CYP51B-curcumin was compared with human CYP3A4-curcumin, as there are published evidence describing curcumin as an inhibitor of human CYPs. Additionally, to validate in silico findings, an in vitro assay was performed to examine the antifungal potentials of curcumin on the R. oryzae. Conclusive results allow us to determine a plausible mode of action of curcumin to act as an antifungal against a mucormycosis agent.

Antifungal Activities of cis-trans Citral Isomers against Trichophyton rubrum with ERG6 as a Potential Target

Trichophyton rubrum causes ringworm worldwide. Citral (CIT), extracted from Pectis plants, is a monoterpene and naturally composed of geometric isomers neral (cis-citral) and geranial (trans-citral). CIT has promising antifungal activities and ergosterol biosynthesis inhibition effects against several pathogenic fungi. However, no study has focused on neral and geranial against T. rubrum, which hinders the clinical application of CIT. This study aimed to compare antifungal activities of neral and geranial and preliminarily elucidate their ergosterol biosynthesis inhibition mechanism against T. rubrum. Herein, the disc diffusion assays, cellular leakage measurement, flow cytometry, SEM/TEM observation, sterol quantification, and sterol pattern change analyses were employed. The results showed geranial exhibited larger inhibition zones (p < 0.01 or 0.05), higher cellular leakage rates (p < 0.01), increased conidia with damaged membranes (p < 0.01) within 24 h, more distinct shriveled mycelium in SEM, prominent cellular material leakage, membrane damage, and morphological changes in TEM. Furthermore, geranial possessed more promising ergosterol biosynthesis inhibition effects than neral, and both induced the synthesis of 7-Dehydrodesmosterol and Cholesta-5,7,22,24-tetraen-3β-ol, which represented marker sterols when ERG6 was affected. These results suggest geranial is more potent than neral against T. rubrum, and both inhibit ergosterol biosynthesis by affecting ERG6.

In Vitro and In Silico Analysis of Ascorbic Acid Towards Lanosterol 14-α-Demethylase Enzyme of Fluconazole-Resistant Candida albicans

Antibiotic resistance is one of the major concerns and the biggest threats to the world population. The incidents of antibiotic resistance in Candida spp. were frequently recorded. In the present investigation, antifungal potential of ascorbic acid (AA) was evaluated. According to the in vitro analysis, the zone of inhibition of AA (24.75 ± 0.35 mm) against C. albicans was greater as compared to other vitamins tested. AA significantly modulate the growth of C. albicans at 25 mg/ml. The highest percentage (94.67%) of cell viability was observed in untreated cells, and low cell viability (29.36%) was observed in cells treated with 50 mg/ml of AA (2 × MIC). Further, AO/EB (acridine orange/ethidium bromide), propidium iodide staining, and real-time qPCR confirmed the loss of membrane integrity due to membrane lesions that caused cell death. Lanosterol 14-α-demethylase (L-14α-DM) is the product of ERG11 and acted as superior drug target of C. albicans. Molecular docking analysis confirmed that active interaction of ascorbic acid with L-14α-DM. Based on the present investigation, the efficiency of AA was effectively proved through the in vitro and in silico analysis. This finding has evidenced the effectiveness of AA as a potential candidate against C. albicans.

Cellular apoptosis and necrosis as therapeutic targets for novel Eugenol Tosylate Congeners against Candida albicans

Despite the rise of new Candida species, Candida albicans tops the list with high morbidity and mortality rates. To tackle this problem there is a need to explore new antifungals that could replace or augment the current treatment options. We previously reported that tosylation of eugenol on hydroxyl group resulted in molecules with enhanced antifungal potency. In line with that work, we synthesized new eugenol tosylate congeners (ETC-1–ETC-7) with different substituents on pendent sulfonyl group and tested their susceptibility against different fluconazole susceptible and resistant C. albicans strains. We evaluated physiology and mode of cell death in response to the most active derivatives by analyzing major apoptotic markers in yeast such as phosphatidylserine externalization, DNA fragmentation, mitochondrial depolarization and decrease in cytochrome c oxidase activity. The results demonstrated that all C. albicans strains were variably susceptible to the test compounds with MIC ranging from 0.125–512 µg/ml, and the most active compounds (ETC-5, ETC-6 and ETC-7) actuate apoptosis and necrosis in Candida cells in a dose-dependent manner via metacaspase-dependent pathway. Furthermore haemolytic assay showed low cytotoxicity effect of these ETCs. Overall the results indicated that ETCs exhibit potential antifungal activity against C. albicans by activating apoptotic and necrotic pathways.