Butyl isothiocyanate exhibits antifungal and anti-biofilm activity against Candida albicans by targeting cell membrane integrity, cell cycle progression and oxidative stress.

The prevalence of Candida albicans infection has increased during the past few years, which contributes to the need for new, effective treatments due to the increasing concerns regarding antifungal drug toxicity and multidrug resistance. Butyl isothiocyanate (butylITC) is a glucosinolate derivative, and has shown a significant antifungal effect contrary to Candida albicans. Additionally, how butylITC affects the virulence traits of C. albicans and molecular mode of actions are not well known. Present study shows that at 17.36 mM concentration butylITC inhibit planktonic growth. butylITC initially slowed the hyphal transition at 0.542 mM concentration. butylITC hampered biofilm development, and inhibits biofilm formation at 17.36 mM concentration which was analysed using metabolic assay (XTT assay) and Scanning Electron Microscopy (SEM). In addition, it was noted that butylITC inhibits ergosterol biosynthesis. The permeability of cell membranes was enhanced by butylITC treatment. Moreover, butylITC arrests cells at S-phase and induces intracellular Reactive Oxygen Species (ROS) accumulation in C. albicans. The results suggest that butylITC may have a dual mode of action, inhibit virulence factors and modulate cellular processes like inhibit ergosterol biosynthesis, cell cycle arrest, induces ROS production which leads to cell death in C. albicans.

Ethyl Isothiocyanate as a Novel Antifungal Agent Against Candida albicans.

In the recent years, occurrence of candidiasis has increased drastically which leads to significant mortality and morbidity mainly in immune compromised patients. Glucosinolate (GLS) derivatives are reported to have antifungal activities. Ethyl isothiocyanate (EITC) and its antifungal activity and mechanism of action is still unclear against Candida albicans. The present work was designed to get a mechanistic insight in to the anti-Candida efficacy of EITC through in vitro and in vivo studies. EITC inhibited C. albicans planktonic growth at 0.5 mg/ml and virulence factors like yeast to hyphal form morphogenesis (0.0312 mg/ml), adhesion to polystyrene surface (0.0312 mg/ml) and biofilm formation (developing biofilm at 2 mg/ml and mature biofilm at 0.5 mg/ml) effectively. EITC blocked ergosterol biosynthesis and arrested C. albicans cells at S-phase. EITC caused ROS-dependent cellular death and nuclear or DNA fragmentation. EITC at 0.0312 mg/ml concentration regulated the expression of genes involved in the signal transduction pathway and inhibited yeast to hyphal form morphogenesis by upregulating TUP1, MIG1, and NRG1 by 3.10, 5.84 and 2.64-fold, respectively and downregulating PDE2 and CEK1 genes by 15.38 and 2.10-fold, respectively. EITC has showed haemolytic activity at 0.5 mg/ml concentration. In vivo study in silk worm model showed that EITC has toxicity to C. albicans at 0.5 mg/ml concentration. Thus, from present study we conclude that EITC has antifungal activity and to reduce its MIC and toxicity, combination study with other antifungal drugs need to be done. EITC and its combinations might be used as alternative therapeutics for the prevention and treatment of C. albicans infections.

Andrographis paniculata (Burm. F) Wall ex Nees: Antiviral properties.

Andrographis paniculata is home to a rich variety of molecules especially andrographolide and its derivatives. Clinical properties of the andrographolide are multifarious and include: analgesic, antipyretic, antiretroviral, antiproliferative, antimalarial, antithrombotic, antihyperglycemic, antiurolethial, antilesihmaniasis, hepatoprotective, immune-modulatory, protective against alcohol induced toxicity and cardioproetcive activity and anticancer activity. Andrographolide, neoandrographolide, dehydroandrographolide and several natural and synthetic derivatives of it: 14-deoxy-11,12-didehydroandrographolide and 14-deoxyandrographolide, dehydroandrographolide succinic acid monoester (DAMS), 14-ά-lipoyl andrographolide (AL-1), 14-acetyl-3,9-isopropyl-ideneandrographolide, 14-acetylandrographolide, 3,14,19-triacetylandrographolide, and 3,9-isopropyl-idene andrographolide, are shown to possess significant antiviral activity against HIV, influenza A, HBV, HCV, HPP and HSV. Studies on SARS CoV 2 is restricted to in silico molecular docking studies on viral targets and selected host target proteins. The main targets of andrographolide and its derivatives are fusion and adsorption of virus to the host cell, binding to viral receptor and co-receptor, enzymes involved in DNA/RNA/Genome replication by the virus, translation, post-translation and reverse transcription. Andrographolide as a drug is yet to reach its full therapeutic potential since this molecule shows low bioavailability. Andrographolide therapy is in need of an appropriate delivery system that may increase its bioavailability. Further high-quality studies are needed to firmly establish the clinical efficacy of the plant.

Limonene inhibits Candida albicans growth by inducing apoptosis.

Anti-Candida potential of limonene was evaluated against planktonic growth, biofilm (adhesion, development and maturation) and morphogenesis of Candida albicans in this study. Limonene is a major constituent of citrus oil and most frequently used terpene in food and beverage industry due to its pleasant fragrance, nontoxic, and is generally recognized as safe (GRAS) flavoring agent as well as treatment option in many gastrointestinal diseases.Limonene exhibited excellent anti-Candida activity and was equally effective against planktonic growth of C. albicans isolates differentially susceptible to FLC (N = 35). Limonene inhibited morphogenesis significantly at low concentration. However, it showed stage dependent activity against biofilm formation, that is, it was more effective against adhesion followed by development and maturation. Limonene also exhibited excellent synergy with FLC against planktonic and biofilm growth. SWATH-MS analysis led to identification of limonene responsive proteins that provided molecular insight of its anti-Candida activity. Proteomic analysis revealed upregulation of proteins involved in cell wall glucan synthesis (Kre6); oxidative stress (Rhr2, Adh7 and Ebp1); DNA damage stress (Mbf1 and Npl3); nucleolar stress (Rpl11, Rpl7, Rpl29, Rpl15) and down regulation of cytoskeleton organization (Crn1, Pin3, Cct8, Rbl2), and so forth, in response to limonene. Limonene mediated down regulation of Tps3 indicates activation of caspase (CaMca1) and induction of apoptosis in C. albicans. These results suggest that limonene inhibits C. albicans growth by cell wall/membrane damage induced oxidative stress that leads to DNA damage resulting into modulation of cell cycle and induction of apoptosis through nucleolar stress and metacaspase dependent pathway.

The antibacterial agent, moxifloxacin inhibits virulence factors of Candida albicans through multitargeting.

Fluoroquinolines are broad spectrum fourth generation antibiotics. Some of the Fluoroquinolines exhibit antifungal activity. We are reporting the potential mechanism of action of a fluoroquinoline antibiotic, moxifloxacin on the growth, morphogenesis and biofilm formation of the human pathogen Candida albicans. Moxifloxacin was found to be Candidacidal in nature. Moxifloxacin seems to inhibit the yeast to Hyphal morphogenesis by affecting signaling pathways. It arrested the cell cycle of C. albicans at S phase. Docking of moxifloxacin with predicted structure of C. albicans DNA Topoisomerase II suggests that moxifloxacin may bind and inhibit the activity of DNA Topoisomerase II in C. albicans. Moxifloxacin could be used as a dual purpose antibiotic for treating mixed infections caused by bacteria as well as C. albicans. In addition chances of developing moxifloxacin resistance in C. albicans are less considering the fact that moxifloxacin may target multiple steps in yeast to hyphal transition in C. albicans.

Hydroxychloroquine an Antimalarial Drug, Exhibits Potent Antifungal Efficacy Against Candida albicans Through Multitargeting.

Candida albicans is the primary etiological agent associated with candidiasis in humans. Unrestricted growth of C. albicans can progress to systemic infections in the worst situation. This study investigates the antifungal activity of Hydroxychloroquine (HCQ) and mode of action against C. albicans. HCQ inhibited the planktonic growth and yeast to hyphal form morphogenesis of C. albicans significantly at 0.5 mg/ml concentration. The minimum inhibitory concentrations (MIC50) of HCQ for C. albicans adhesion and biofilm formation on the polystyrene surface was at 2 mg/ml and 4 mg/ml respectively. Various methods, such as scanning electron microscopy, exploration of the ergosterol biosynthesis pathway, cell cycle analysis, and assessment of S oxygen species (ROS) generation, were employed to investigate HCQ exerting its antifungal effects. HCQ was observed to reduce ergosterol levels in the cell membranes of C. albicans in a dose-dependent manner. Furthermore, HCQ treatment caused a substantial arrest of the C. albicans cell cycle at the G0/G1 phase, which impeded normal cell growth. Gene expression analysis revealed upregulation of SOD2, SOD1, and CAT1 genes after HCQ treatment, while genes like HWP1, RAS1, TEC1, and CDC 35 were downregulated. The study also assessed the in vivo efficacy of HCQ in a mice model, revealing a reduction in the pathogenicity of C. albicans after HCQ treatment. These results indicate that HCQ holds for the development of novel antifungal therapies.

Topoisomerase II as a target for repurposed antibiotics in Candida albicans: an in silico study.

Fluoroquinolines, the widely used antibacterial antibiotics, have been shown to interact with human DNA topoisomerases supporting their use as repurposed cancer drugs in humans. In this communication molecular docking of eleven Fluoroquinolines against predicted structure of Candida albicans DNA Topoisomerase II is reported for the first time. C. albicans topoisomerase II structure prediction was done by using homology modeling tool. Ligand preparation and molecular docking with C. albicans topoisomerase II were done by using Autodock tool. These antibiotics formed hydrogen bond with good binding affinity at ARG 841, GLN803, ALA840 amino acid residues in the active site of C. albicans Topoisomerase II. We hypothesize that DNA toposiomerases may be the targets of Fluroquinoline group of antibiotics in C. albicans causing inhibition of growth.

Molecular targets of biofabricated silver nanoparticles in Candida albicans.

We have analyzed the expressions of genes which regulate Ras-cAMP-EFG1 and CEK1-MAPK pathways involved in yeast to hyphal form morphogenesis in Candida albicans. The expression profile of genes associated with serum-induced morphogenesis showed reduced expressions of genes involved in these pathways by the treatment with biofabricated silver nanoparticles. Cell elongation gene, ECE1, was downregulated by 5.1 fold by the treatment of silver nanoparticles. Expression of hyphal inducer gene, TEC1 was downregulated by 6.28 fold. Negative regulators of yeast to hyphal transition, TUP1 and RFG1 were downregulated by 2.45 and 5.43 fold, respectively. Current study suggests that silver nanoparticles affect gene expression and may subsequently reduce virulence in C. albicans. Targeting genes involved in virulence may be an acceptable novel treatment strategy for pathogenic fungal infections.

The human muscarinic acetylcholine receptor antagonist, Dicyclomine targets signal transduction genes and inhibits the virulence factors in the human pathogen, Candida albicans.

Dicyclomine is a human muscarinic acetylcholine receptor antagonist used for the treatment of abdominal cramps. We are reporting here that dicyclomine can inhibit the in vitro growth and virulence factors of the human pathogen Candida albicans very effectively. Dicyclomine inhibited adhesion, early biofilm, mature biofilm, and planktonic growth. Yeast to hyphal form transition of C. albicans in various inducer media such as serum, proline, glucose, and N-acetylglucosamine was inhibited. Dicyclomine also could kill C. albicans cells within 15 min of exposure. Dicyclomine appears to inhibit the yeast to hyphal conversion by affecting signal transduction pathway. The expression of selected genes associated with yeast to hyphal form transition in serum in presence of dicyclomine was studied using real-time polymerase chain reaction (RtPCR). The RtPCR analysis showed that dicyclomine targets both cAMP pathway as well as MAPK cascade. Eight genes were upregulated. Out of these, three major upregulated genes were Bcy1, Tup1, and Mig1. Dicyclomine downregulated Ume6, Ece1, and Pde2 genes which are involved in cAMP signaling pathway and also downregulated the DNA binding protein gene, Rfg1. Dicyclomine significantly upregulated the master negative regulator of hyphal formation, Tup1. Based on this study we suggest that the muscarinic acetylcholine receptor antagonist, dicyclomine could be repositioned as a potential anti-Candida albicans as well as anti-virulence agent.

Anticancer Drugs as Antibiofilm Agents in Candida albicans: Potential Targets.

The human pathogen Candida albicans can grow as a biofilm on host tissues and on the surfaces of different prosthetic devices in a patient's body. Various studies have reported that biofilms formed by C. albicans are resistant to most of the currently used antibiotics including the widely prescribed drug, fluconazole. As such, novel strategies for the treatment of drug-resistant biofilms are required. Drug repositioning or the use of drugs outside their unique indication has the potential to radically change drug development. We have tested 16 anticancer drugs for their activities against C. albicans. For the first time, we are reporting repositioning of anticancer drugs as potential antibiofilm agents in C. albicans. Nine categories of drugs with different chemical modes of action effectively inhibited biofilms at a concentration range of 0.25-4 mg/mL, establishing their potential for the inhibition of biofilms. Human genes targeted by these drugs show significant identity with their homologous genes in C. albicans at the amino acid as well as nucleotide levels. This study indicates that anticancer drugs could be potential candidates for repositioning as anti-Candida biofilm agents.

Activity of Allyl Isothiocyanate and Its Synergy with Fluconazole against Candida albicans Biofilms.

Candidiasis involving the biofilms of Candida albicans is a threat to immunocompromised patients. Candida biofilms are intrinsically resistant to the antifungal drugs and hence novel treatment strategies are desired. The study intended to evaluate the anti-Candida activity of allyl isothiocyanate (AITC) alone and with fluconazole (FLC), particularly against the biofilms. Results revealed the concentration-dependent activity of AITC against the planktonic growth and virulence factors of C. albicans. Significant (p <0.05) inhibition of the biofilms was evident at < or =1 mg/ml concentrations of AITC. Notably, a combination of 0.004 mg/ml of FLC and 0.125 mg/ml of AITC prevented the biofilm formation. Similarly, the preformed biofilms were significantly (p <0.05) inhibited by the AITC-FLC combination. The fractional inhibitory concentration indices ranging from 0.132 to 0.312 indicated the synergistic activity of AITC and FLC against the biofilm formation and the preformed biofilms. No hemolytic activity at the biofilm inhibitory concentrations of AITC and the AITC-FLC combination suggested the absence of cytotoxic effects. The recognizable synergy between AITC and FLC offers a potential therapeutic strategy against biofilm-associated Candida infections.

The Dietary Food Components Capric Acid and Caprylic Acid Inhibit Virulence Factors in Candida albicans Through Multitargeting.

Capric acid and caprylic acid are the dietary food components. They are found to inhibit the virulence factors like morphogenesis, adhesion, and biofilm formation in the human pathogenic yeast Candida albicans. Our study demonstrated that yeast-to-hyphal signal transduction pathways were affected by capric acid and caprylic acid. The expression profile of genes associated with serum-induced morphogenesis showed reduced expressions of Cdc35, Hwp1, Hst7, and Cph1 by the treatment with both the fatty acids. Cell elongation gene, Ece1, was surprisingly downregulated by 5208-fold by the treatment of caprylic acid. Nrg1 and Tup1, negative regulators of hyphal formation, were overexpressed in presence of capric or caprylic acid. Cell cycle studies revealed that capric and caprylic acids arrested cell cycle at G2/M and S phase. Targeting the virulence factors like yeast-to-hyphal transition is efficacious for treatment of opportunistic fungal infections. This research suggests that both capric and caprylic acid may be effective interventions for treating C. albicans yeast infections.

Molecular docking studies on thirteen fluoroquinolines with human topoisomerase II a and b.

DNA relaxation is an important step in DNA replication. DNA topoisomerases play a major role in DNA relaxation. Hence these enzymes are important targets for cancer drugs. DNA topoisomerase inhibitors bind to the transient enzyme-DNA complex and inhibit DNA replication. Various inhibitors of topoisomerase I and II are prescribed as drugs. Topoisomerase II is considered as an important target for the development of anticancer drugs. In this study we have demonstrated molecular docking of thirteen fluoroquinolines with human DNA topoisomerase II alpha (a) and beta (b). Fluoroquinolines are broad spectrum antibacterial antibiotics and it is highly effective against various bacterial infections. Some of the fluoroquinolines like moxifloxacin exert antifungal as well as anti-cancer activity. It forms complexes with topoisomerase II a and are responsible for stoppage DNA replication. Molecular docking studies showed that fluoroquinolines has shown formation of hydrogen bond and good binding affinity with human Topo2a and Topo2b. Hence FQs may inhibit the activity of enzyme topoisomerase by binding at its active site. Ofloxacin, sparafloxacin, ciprofloxacin and moxifloxacin are predicted to be the most potent inhibitors among the thirteen FQs docked. GLN773, ASN770, LYS723 and TRP931 amino acid residues of Topo2a are involved in binding with FQs while ASP479, SER480, ARG820, ARG503, LYS456 and GLN778 amino acid residues of Topo2b are involved in binding with FQs. Our in silico study suggests that fluoroquinolines could be repositioned as DNA topoisomerase II inhibitors hence can be used as anticancer drugs. In vitro and in vivo experiments need to be done to confirm their efficacy.

Phytochemicals as Inhibitors of Candida Biofilm.

BACKGROUND: Candida biofilm and associated infections is a serious threat to the large population of immunocompromised patients. Biofilm growth on prosthetic devices or host tissue shows reduced sensitivity to antifungal agents and persists as a reservoir of infective cells. Options for successful treatment of biofilm associated Candida infections are restricted because most of the available antifungal drugs fail to eradicate biofilms. OBJECTIVE: Various plant actives are known to possess interesting antifungal properties. To explore and review the potential of phytochemicals as a novel strategy against Candida biofilms is the intent of present article. METHOD: Thorough literature search is performed to identify Candida biofilm inhibitors of plant origin. An account of efficacy of selected phytochemicals is presented taking into consideration their biofilm inhibitory concentrations. RESULTS: This review discusses biofilm formation by Candida species, their involvement in human infections, and associated drug resistance. It gives insight into the biofilm inhibitory potential of various phytochemicals. Based on the available reports including the work done in our laboratory, several plant extracts, essential oils and phytomolecules have been identified as excellent inhibitors of biofilms of C. albicans and non-albicans Candida species (NACS). CONCLUSION: Selected phytochemicals which exhibit activities at low concentrations without displaying toxicity to host are potential therapeutic agents against biofilm associated Candida infections. In vivo testing in animal models and clinical trials in humans are required to be taken up seriously to propose few of the phytochemicals as candidate drug molecules.

Lipid-polyethylene glycol based nano-ocular formulation of ketoconazole.

Ophthalmic mycoses including corneal keratitis or endophthalmitis affects 6-million persons/year and can cause blindness. Its management requires antifungals to penetrate the ocular tissue. Oral use of Ketoconazole (KTZ), the first broad-spectrum antifungal to be marketed, is now restricted to life-threatening infections due to severe adverse effects and drug-interactions. Local use of KTZ loaded nanocarrier system can address its toxicity, poor solubility, photodegradation, permeation and bioavailability issues. Solid lipid nanoparticles (SLNs) comprising Compritol(®) 888 ATO and PEG 600 matrix, were presently prepared using hot high-pressure homogenization. Employing extensive characterization: TEM, NMR, DSC, XRD and FTIR, it is proposed that SLNs comprise of a polyethylene glycol (PEG) core into which KTZ is dissolved. PEG endows the lipid matrix with amorphousness and imperfections; rigidity; and, stability to aggregation, on storage and autoclaving. PEG is a simple, cost-effective and safe polymer with superior solubilizing and surfactant-supporting properties. Without its inclusion KTZ could not be loaded into SLNs. It ensured high incorporation efficiency (70%) of KTZ; small size (126 nm); and, better permeation into the eye. Pharmacokinetic studies indicated 2.5 and 1.6 fold higher bioavailability (AUC) in aqueous and vitreous humor, respectively. Biocompatibility and in vitro (both in corneal and retinal cell lines) and in vivo (in rabbits) ocular safety is the other highlight of developed formulation.

Sensitization of Candida albicans biofilms to fluconazole by terpenoids of plant origin.

Infections associated with the biofilms of Candida albicans are a challenge to antifungal treatment. Combinatorial therapy involving plant molecules with antifungal drugs would be an effective complementary approach against drug-resistant Candida biofilms. The aim of this study was to evaluate the efficacy of three bioactive terpenoids (carvacrol, eugenol and thymol) in combination with fluconazole against planktonic cells, biofilm development and mature biofilms of C. albicans. Activities of the selected molecules were tested using a microplate-based methodology, while their combinations with fluconazole were performed in a checkerboard format. Biofilms were quantitated by XTT-metabolic assay and confirmed by microscopic observations. Combinations of carvacrol and eugenol with fluconazole were found synergistic against planktonic growth of C. albicans, while that of thymol with fluconazole did not have any interaction. Biofilm development and mature biofilms were highly resistant to fluconazole, but susceptible to three terpenoids. Sensitization of cells by sub-inhibitory concentrations of carvacrol and eugenol resulted in prevention of biofilm formation at low fluconazole concentrations, i.e. 0.032 and 0.002 mg ml(-1), respectively. Addition of thymol could not potentiate activity of fluconazole against biofilm formation by C. albicans. Fractional inhibitory concentration indices (FICI) for carvacrol-fluconazole and eugenol-fluconazole combinations for biofilm formation were 0.311 and 0.25, respectively. The FICI value of 1.003 indicated a status of indifference for the combination of thymol and fluconazole against biofilm formation. Eugenol and thymol combinations with fluconazole did not have useful interaction against mature biofilms of C. albicans, but the presence of 0.5 mg ml(-1) of carvacrol caused inhibition of mature biofilms at a significantly low concentration (i.e. 0.032 mg ml(-1)) of fluconazole. The study indicated that carvacrol and eugenol combinations with fluconazole would be a potential alternative strategy for prevention and control of biofilm-associated C. albicans infections.

Phenylpropanoids of plant origin as inhibitors of biofilm formation by Candida albicans.

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ≤0.5 mg/ml, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ≤0.5 mg/ml concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

Chloroquine sensitizes biofilms of Candida albicans to antifungal azoles.

Biofilms formed by Candida albicans, a human pathogen, are known to be resistant to different antifungal agents. Novel strategies to combat the biofilm associated Candida infections like multiple drug therapy are being explored. In this study, potential of chloroquine to be a partner drug in combination with four antifungal agents, namely fluconazole, voriconazole, amphotericin B, and caspofungin, was explored against biofilms of C. albicans. Activity of various concentrations of chloroquine in combination with a particular antifungal drug was analyzed in a checkerboard format. Growth of biofilm in presence of drugs was analyzed by XTT-assay, in terms of relative metabolic activity compared to that of drug free control. Results obtained by XTT-metabolic assay were confirmed by scanning electron microscopy. The interactions between chloroquine and four antifungal drugs were determined by calculating fractional inhibitory concentration indices. Azole resistance in biofilms was reverted significantly (p<0.05) in presence of 250µg/mL of chloroquine, which resulted in inhibition of biofilms at very low concentrations of antifungal drugs. No significant alteration in the sensitivity of biofilms to caspofungin and amphotericin B was evident in combination with chloroquine. This study for the first time indicates that chloroquine potentiates anti-biofilm activity of fluconazole and voriconazole.

Chloroquine sensitizes biofilms of Candida albicans to antifungal azoles

Biofilms formed by Candida albicans, a human pathogen, are known to be resistant to different antifungal agents. Novel strategies to combat the biofilm associated Candida infections like multiple drug therapy are being explored. In this study, potential of chloroquine to be a partner drug in combination with four antifungal agents, namely fluconazole, voriconazole, amphotericin B, and caspofungin, was explored against biofilms of C. albicans. Activity of various concentrations of chloroquine in combination with a particular antifungal drug was analyzed in a checkerboard format. Growth of biofilm in presence of drugs was analyzed by XTT-assay, in terms of relative metabolic activity compared to that of drug free control. Results obtained by XTT-metabolic assay were confirmed by scanning electron microscopy. The interactions between chloroquine and four antifungal drugs were determined by calculating fractional inhibitory concentration indices. Azole resistance in biofilms was reverted significantly (p < 0.05) in presence of 250 µg/mL of chloroquine, which resulted in inhibition of biofilms at very low concentrations of antifungal drugs. No significant alteration in the sensitivity of biofilms to caspofungin and amphotericin B was evident in combination with chloroquine. This study for the first time indicates that chloroquine potentiates anti-biofilm activity of fluconazole and voriconazole.