•Fungi are disease-causing agents in human and the Candida genus is the most studied.•Increased resistance to candida ssp. to microbiocidal antifungals is a problem.•PDT is usable in highly-localized ...fungal infections where light delivery is feasible.•Dimethyl methylene blue zinc chloride double salt (DMMB) and red LED light were used for dual PDT in vitro.•Double application of PDT resulted in 99.991% inhibition the proliferation of C. albicans in vitro.
This study aimed to evaluate, in vitro, the efficacy of photodynamic therapy - PDT using dimethyl methylene blue zinc chloride double salt (DMMB) and red LED light on planktonic cultures of Candida albicans. The tests were performed using the ATCC 90,028 strain grown at 37 °C for 24 h, according to a growth curve of C. albicans. The colonies were resuspended in sterile saline adjusted to a concentration of 2 × 108 cells / mL, with three experimental protocols being tested (Protocol 1, 2 and 3) with a fixed concentration of 750 ɳg/mL obtained through the IC50, and energy density 20 J/cm2. Protocol 1 was carried out using conventional PDT, Protocol 2 was applied double PDT in a single session, and Protocol 3 was applied double PDT in two sessions with a 24 h interval. The results showed logarithmic reductions of 3 (4.252575 ± 0.068526) and 4 logs (2.669533 ± 0.058592) of total fungal load in protocols 3 and 2 respectively in comparison to the Control (6.633547 ± 0.065384). Our results indicated that double application in a single session of PDT was the most effective approach for inhibiting the proliferation of Candida albicans (99.991% inhibition).
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It is difficult to effectively eradicate C. albicans using traditional antifungal agents, mainly because the low permeability of the C. albicans cell wall creates strong drug ...resistance. The aim of this study was to investigate the synergistic fungicidal effect and the underlying mechanisms of low-frequency and low-intensity ultrasound combined with a treatment of amphotericin B-loaded nanoparticles (AmB-NPs) against C. albicans. AmB-NPs were prepared by a poly(lactic-co-glycolic acid) (PLGA) double emulsion method. C. albicans was treated by AmB-NPs combined with 42 kHz ultrasound irradiation at an intensity of 0.30 W/cm2 for 15 min. The results demonstrate that the application of ultrasound enhanced the antibacterial effectiveness of AmB-NPs (P < 0.01), and the antifungal efficiency increased significantly with increasing AmB concentration of drug-loaded nanoparticles under ultrasonic irradiation. Additionally, the mycelial morphology of C. albicans suffered from the most severe damage and loss of normal microbial morphology after the combined treatment of AmB-NPs and ultrasound, as revealed by electron microscope. Furthermore, we verified the safe use of low-frequency ultrasound on exposed skin and discussed the potential mechanism of ultrasound enhanced fungicidal activity. The results reveal that the mechanism may be associated with the ultrasound cavitation effect and an increase in intracellular reactive oxygen species.
Abstract
Candida albicans is a member of pathogens with potential drug resistance threat that needs novel chemotherapeutic strategies. Considering the multifarious biological activities including ...bioenhancer activity, anti-Candida potential of piperine was evaluated against planktonic/biofilm and hyphal growth of C. albicans alone or in combination as a synergistic agent with fluconazole. Piperine inhibits planktonic growth at or less than 15 μg/ml, hyphae induction at 5 μg/ml concentration, and exhibits stage-dependent activity against biofilm growth of a fluconazole-resistant strain of C. albicans (ATCC10231). Though piperine couldn't kill inoculum completely at minimum inhibitory concentration (MIC), it is fungicidal at higher concentrations, as shown in apoptosis assay. FIC index values indicate that piperine exhibits excellent synergistic activity with fluconazole against planktonic (0.123) and biofilm (0.215) growth of an FLC resistant strain. Mode of anti-Candida activity was studied by identifying piperine responsive proteins wherein the abundance of 25 proteins involved in stress response, signal transduction and cell cycle were modulated (22 up and 3 down-regulated) significantly in response to piperine (MIC50). Modulation of the proteins involved suggests that piperine affects membrane integrity leading to oxidative stress followed by cell cycle arrest and apoptosis in C. albicans. Flow cytometry-based mitochondrial membrane potential (MMP), cell cycle and apoptosis assay, as well as real-time quantitative polymerase chain reaction analysis of selected genes, confirms piperine induced oxidative stress (TRR1), cell cycle arrest and apoptosis (CaMCA1). Based on our results, we conclude that piperine inhibits planktonic and difficult-to treat-biofilm growth of C. albicans by affecting membrane integrity thereby inducing oxidative stress and apoptosis.
Lay Abstract
Piperine inhibit Candida albicans growth (planktonic and biofilm) significantly in our study. Piperine exhibits excellent synergistic potential with fluconazole The proteome analysis suggests that piperine induced membrane damage leads to oxidative stress followed by cell cycle arrest and apoptosis.
Abstract
Aims
This study aimed to investigate whether berberine (BBR) can inhibit the iron reduction mechanism of Candida albicans, lowering the iron uptake of the yeast and perhaps having ...antimicrobial effects.
Methods and results
We determined that BBR may cause extensive transcriptional remodeling in C. albicans and that iron permease Ftr1 played a crucial role in this process through eukaryotic transcriptome sequencing. Mechanistic research showed that BBR might selectively inhibit the iron reduction pathway to lower the uptake of exogenous iron ions, inhibiting C. albicans from growing and metabolizing. Subsequent research revealed that BBR caused significant mitochondrial dysfunction, which triggered the process of mitochondrial autophagy. Moreover, we discovered that C. albicans redox homeostasis, susceptibility to antifungal drugs, and hyphal growth are all impacted by the suppression of this mechanism by BBR.
Conclusions
The iron reduction mechanism in C. albicans is disrupted by BBR, which disrupts mitochondrial function and inhibits fungal growth. These findings highlight the potential promise of BBR in antifungal applications.
•UPLC-MS/MS method developed to quantify obliquumol concentration in P. obliquum acetone extracts.•Ptaeroxylinol had MIC values as low as 8 µg/mL and 16 µg/mL against C. albicans ATCC 10,231 and ...cryptococcus neoformans respectively.•Ptaeroxylinol had some antimycobacterial activity with MIC value of 62.5 µg/mL against both M. bovis BCG and M. fortuitum.•Ptaeroxylinol had low toxicity against both vero and human liver (C3A) cells with IC50 = 85.7 and 126.51 µg/mL respectively.
Quantification of compounds in plant extracts is rarely conducted to determine variation in concentrations of bioactive constituents. The aim of the study was to develop a method using ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) to identify and quantify obliquumol (12-O-acetylptaeroxylinol) in Ptaeroxylon obliquum leaves collected from different localities in South Africa. Additionally, biological activity of a semi-synthesized derivative, ptaeroxylinol was investigated. Column chromatography was used to isolate obliquumol from P. obliquum leaves, and thereafter it was saponified to ptaeroxylinol. Ultra-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UPLC-qTof-MS) was carried out on the different P. obliquum extracts to quantify obliquumol. A serial microdilution method was used to determine the minimum inhibitory concentration (MIC) against non-pathogenic mycobacteria and fungi. The cytotoxicity was determined using Vero monkey kidney and human liver (C3A) cells. A method was developed to isolate large quantities of obliquumol (0.14%) from dried P. obliquum leaves. The different P. obliquum acetone extracts had variable obliquumol concentrations between 0.1–38.5 µg/mg. Ptaeroxylinol had an MIC as low as 8 µg/mL and 16 µg/mL against Candida albicans ATCC 10,231 and Cryptococcus neoformans, respectively. With an IC50 of 85.7 μg/mL for Vero cells and 126.51 μg/mL for C3A cells, respectively, ptaeroxylinol had low cytotoxicity to the cells tested. A UPLC-MS/MS method was developed to quantify obliquumol content in the P. obliquum acetone extracts. Ptaeroxylinol had good activity against C. albicans (MIC = 8 µg/mL) and it appears that the cleavage of the acetoxy to alcohol group played a role in the antimicrobial activity.
Abstract
Oral candidiasis, the most common mycotic infection of the human oral cavity is non-life-threatening yet, if untreated, may advance as systemic infections. The ability of Candida albicans to ...adapt sessile lifestyle imparts resistance to drugs and host immunity. Consequently, due to the limited effectiveness of conventional antifungal treatment, novel therapeutic strategies are required. In the present study, synergistic interaction of phytochemicals, piperine, and cinnamaldehyde against the biofilm and hyphal of C. albicans was evaluated. Minimum inhibitory concentration (MIC) and biofilm inhibitory concentration (BIC) of piperine and cinnamaldehyde against C. albicans were analyzed through microbroth dilution assay and crystal violet staining method, respectively. Combinatorial biofilm and hyphal inhibitory effect were investigated through checkerboard assay. In vitro results were validated through gene expression analysis. BIC of piperine and cinnamaldehyde was determined to be 32 μg/ml and 64 μg/ml, respectively. Interaction between these two phytocomponents was found to be synergistic and six different synergistic antibiofilm combinations were identified. Microscopic analysis of biofilm architecture also evidenced the biofilm and surface adherence inhibitory potential of piperine and cinnamaldehyde combinations. Phenotypic switching between yeast and hyphal morphological forms was influenced by synergistic combinations. qPCR analysis corroborated the results of in vitro activities. nrg1 and trp1, the negative transcriptional regulators of filamentous growth were upregulated whereas other genes that are involved in biofilm formation, filamentous growth, adhesion, etc. were found to be downregulated. These proficient phytochemical combinations provide a new therapeutic avenue for the treatment of biofilm-associated oral candidiasis and to combat the recurrent infections due to antibiotic resistance.
Lay abstract
Resistance to antibiotics and antifungals is seemingly increasing due to biofilm-associated infections.
The present study incorporated antibiofilm therapy and a combinatorial approach to diminish the biofilm associated C. albicans infection.
is an opportunistic fungal pathogen and most prevalent species among clinical outbreaks. It causes a range of infections, including from mild mucosal infections to serious life-threatening candidemia ...and disseminated candidiasis. Multiple virulence factors account for the pathogenic nature of
, and its morphological transition from budding yeast to hyphal form and subsequent biofilm formation is regarded as the most important reason for the severity of
infections. To address the demanding need for novel antifungals, we investigated the anti-biofilm activities of various methylindoles against
using a crystal violet assay, and the metabolic activity was assessed by using a 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide reduction assay. Changes in biofilm morphologies and thicknesses were determined by confocal laser scanning microscopy and scanning electron microscopy, respectively. Of the 21 methylindoles tested, 1-methylindole-2-carboxylic acid (1MI2CA) at 0.1 mM (17.5 μg ml
) and 5-methylindole-2-carboxylic acid (5MI2CA) at 0.1 mM effectively inhibited biofilm formation by
DAY185 and ATCC10231 strains. Moreover, 1MI2CA and 5MI2CA both effectively inhibited hyphal formation, and thus, improved
infected nematode survival without inducing acute toxic effects. Furthermore, our
molecular modeling findings were in-line with
observations. This study provides information useful for the development of novel strategies targeting candidiasis and biofilm-related infections.
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