Minimum Fungicidal Concentration Research Articles

In Vitro Evaluation of Synergistic Essential Oils Combination for Enhanced Antifungal Activity against Candida spp.

In recent years, a significant number of infections have been attributed to non-albicidal Candida species (NAC), mainly due to the increasing resistance of NAC to antifungal agents. As only a few antifungal agents are available (azoles, echinocandins, polyenes, allylamines and nucleoside analogues), it is very important to look for possible alternatives to inhibit resistant fungi. One possibility could be essential oils (EOs), which have been shown to have significant antifungal and antibacterial activity. Therefore, in this study, the efficacy of 12 EOs and their combinations was evaluated against four yeasts of the genus Candida (C. albicas, C. glabrata, C. tropicalis and C. parapsilosis). GC-MS and GC-MS FID techniques were used for the chemical analysis of all EOs. VITEK-2XL was used to determine the antifungal susceptibility of the tested Candida spp. strains. The agar disc diffusion method was used for primary screening of the efficacy of the tested EOs. The broth dilution method was used to determine the minimum inhibitory concentrations (MICs) of the most potent EOs. After MIC cultivation, the minimum fungicidal concentration (MFC) was determined on Petri dishes (60 mm). The synergistic effect of combined EOs was evaluated using the checkerboard method and expressed as a fractional inhibitory concentration index (FICI). The results showed that ginger > ho-sho > absinth > dill > fennel > star anise > and cardamom were the most effective EOs. For all Candida species tested, the synergy was mainly observed in these combinations: ginger/fennel for C. albicans FICI 0.25 and C. glabrata, C. tropicalis and C. parapsilosis FICI 0.5 and absinth/fennel for C. albicans FICI 0.3125, C. tropicalis FICI 0.3125 and C. parapsilosis FICI 0.375. Our results suggest that the resistance of fungal pathogens to available antifungals could be reduced by combining appropriate EOs.

In Vitro Antifungal Activity of White Thyme, Oregano, and Savory Oils Against Five Monilinia fructicola Isolates from the Southeastern United States

Monilinia fructicola is a primary pathogen causing fruit brown rot of peach during pre- and postharvest in the southeast of the United States. In this in vitro study, we assessed the antifungal activity of four plant essential oil treatments against five isolates of M. fructicola obtained from naturally infected peaches in Florida, Georgia, and South Carolina. The tested essential oils were white thyme oil, oregano oil, summer savory oil, and a 1:1 mixture of thyme and oregano oils. We evaluated isolates’ growth using a Gompertz growth curve model. All tested essential oils exhibited antifungal activity against all isolates, with thyme, oregano, and the 1:1 mixture of thyme and oregano oils showing no significant differences and no evidence of synergy. Savory oil showed the least effectiveness and stability of the four essential oil treatments. We observed diverse sensitivities of different M. fructicola isolates to the essential oils. The minimum inhibitory concentration values for the essential oils ranged from 200 to 500 μl/liter, and the minimum fungicidal concentration values varied from 500 to 750 μl/liter, depending on the fungal isolate and essential oil treatment. All isolates were inhibited by the essential oils at 500 μl/liter and killed at 750 μl/liter. Our findings provide a basis for future in vivo research on the use of these essential oils for controlling fruit brown rot caused by M. fructicola in peach postharvest handling. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY 4.0 International license .

Effects of efflux pumps on antifungal activity of chitosan against Candida albicans

ABSTRACT Background Antifungal resistance is a major problem, commonly caused by drug-efflux pump overexpression. To evaluate if chitosan could be effective in drug-resistant Candida infections, we investigated the effects of efflux pumps on antifungal activity of chitosan. Materials and Methods The minimal fungicidal concentration (MFC) of oligomer (7–9 kD) and polymer (900–1,000 kD) chitosan against Saccharomyces cerevisiae and Candida albicans were evaluated by broth and agar dilution methods. The MFCs of S. cerevisiae with single deletion of efflux pump genes, with deletion of seven efflux pumps (AD∆), and AD∆ overexpressing C. albicans efflux pump genes (CDR1, CDR2 and MDR1) were determined. C. albicans with homozygous deletions of CDR1 and of CDR2 were generated using CRISPR-Cas9 system and tested for chitosan susceptibility. Results While deleting any individual efflux pump genes had no effect on chitosan susceptibility, simultaneous deletion of multiple pumps (in AD∆) increased sensitivity to both types of chitosan. Interestingly, the overexpression of CDR1, CDR2 or MDR1 in AD∆ barely affected its sensitivity. Moreover, C. albicans with homozygous deletions of CDR1 and/or CDR2 showed similar sensitivity to wildtype. Conclusion Thus, C. albicans susceptibility to chitosan was not affected by drug-efflux pumps. Chitosan may be a promising antifungal agent against pump-overexpressing azole-resistant C. albicans.

Antifungal Potential of Secondary Metabolites Derived from Arcangelisia flava (L.) Merr.: An Analysis of In Silico Enzymatic Inhibition and In Vitro Efficacy against Candida Species

Considering the escalating resistance to conventional antifungal medications, it is critical to identify novel compounds that can efficiently counteract this challenge. The purpose of this research was to elucidate the fungicidal properties of secondary metabolites derived from Arcangelisia flava, with a specific focus on their efficacy against Candida species. This study utilized a combination approach comprising laboratory simulations and experiments to discern and evaluate the biologically active constituents present in the dichloromethane extract of A. flava. The in vitro experiments demonstrated that compounds 1 (palmatine) and 2 (fibraurin) exhibited antifungal properties. The compounds exhibited minimum inhibitory concentrations (MICs) ranging from 15.62 to 62.5 µg/mL against Candida sp. Moreover, compound 1 demonstrated a minimum fungicidal concentration (MFC) of 62.5 µg/mL against Candida glabrata and C. krusei. In contrast, compound 2 exhibited an MFC of 125 µg/mL against both Candida species. Based on a molecular docking study, it was shown that compounds 1 and 2 have a binding free energy of −6.6377 and −6.7075 kcal/mol, respectively, which indicates a strong affinity and specificity for fungal enzymatic targets. This study utilized pharmacophore modeling and Density Functional Theory (DFT) simulations to better understand the interaction dynamics and structural properties crucial for antifungal activity. The findings underscore the potential of secondary metabolites derived from A. flava to act as a foundation for creating novel and highly efficient antifungal treatments, specifically targeting fungal diseases resistant to existing treatment methods. Thus, the results regarding these compounds can provide references for the next stage in antifungal drug design. Further investigation is necessary to thoroughly evaluate these natural substances’ clinical feasibility and safety characteristics, which show great potential as antifungal agents.

Antifungal activity of bio-active cell-free culture extracts and volatile organic compounds (VOCs) synthesised by endophytic fungal isolates of Garden Nasturtium

Antimicrobial resistance in fungal pathogens (both human and plant) is increasing alarmingly, leading to massive economic crises. The existing anti-fungal agents are becoming ineffective, and the situation worsens on a logarithmic scale. Novel antifungals from unique natural sources are highly sought to cope sustainably with the situation. Metabolites from endophytic microbes are the best-fitted alternatives in this case. Endophytes are the untapped sources of ‘plants’ internal microbial population’ and are promising sources of effective bio-therapeutic agents. Fungal endophytes were isolated from Tropaeolum majus and checked for antifungal activity against selected plant and human pathogens. Bioactive metabolites were identified through chromatographic techniques. The mode of action of those metabolites was evaluated through various spectroscopic techniques. The production of antifungal metabolite was optimized also. In particular VOCs (volatile organic compounds) of TML9 were tested in vitro for their anti-phytopathogenic activity. Ethyl acetate (EA) extract of cell-free culture components of Colletotrichum aenigma TML3 exhibited broad-spectrum antifungal activity against four species of Candida and the major constituents reported were 6-pentyl-2H-pyran-2-one, 2-Nonanone, 1 propanol 2-amino. The volatile metabolites, trans-ocimene, geraniol, and 4-terpinyl acetate, produced from Curvularia lunata TML9, inhibited the growth of some selected phyto pathogens. EA extract hampered the biofilm formation, minimised the haemolytic effect, and blocked the transformation of Candida albicans (MTCC 4748) from yeast to hyphal form with a Minimum Fungicidal Concentration (MFC) of 200–600 µg mL−1. Central carbohydrate metabolism, ergosterol synthesis, and membrane permeability were adversely affected and caused the lethal leakage of necessary macromolecules of C. albicans. Volatile metabolites inhibited the growth of phytopathogens i.e., Rhizoctonia solani, Alternaria alternata, Botrytis cinerea, Cercospora beticola, Penicillium digitatum, Aspergillus fumigatus, Ceratocystis ulmi, Pythium ultimum up to 89% with an IC50 value of 21.3–69.6 µL 50 mL−1 and caused leakage of soluble proteins and other intracellular molecules. Citrusy sweet odor volatiles of TML9 cultured in wheat-husk minimised the infections of Penicillium digitatum (green mold), in VOC-exposed sweet oranges (Citrus sinensis). Volatile and non-volatile antifungal metabolites of these two T. majus endophytes hold agricultural and pharmaceutical interests. Metabolites of TML3 have strong anti-Candida activity and require further assessment for therapeutic applications. Also, volatile metabolites of TML9 can be further studied as a source of antifungals. The present investigational outcomes bio-prospects the efficacy of fungal endophytes of Garden Nasturtium.

Exploring the antifungal, antibiofilm and antienzymatic potential of Rottlerin in an in vitro and in vivo approach

Candida species have been responsible for a high number of invasive infections worldwide. In this sense, Rottlerin has demonstrated a wide range of pharmacological activities. Therefore, this study aimed to evaluate the antifungal, antibiofilm and antivirulence activity of Rottlerin in vitro against Candida spp. and its toxicity and antifungal activity in vivo. Rottlerin showed antifungal activity against all yeasts evaluated, presenting Minimum Inhibitory and Fungicidal Concentration (MIC and MFC) values of 7.81 to > 1000 µg/mL. Futhermore, it was able to significantly inhibit biofilm production, presenting Biofilm Inhibitory Concentration (MICB50) values that ranged from 15.62 to 250 µg/mL and inhibition of the cell viability of the biofilm by 50% (IC50) from 2.24 to 12.76 µg/mL. There was a considerable reduction in all hydrolytic enzymes evaluated, with emphasis on hemolysin where Rottlerin showed a reduction of up to 20%. In the scanning electron microscopy (SEM) analysis, Rottlerin was able to completely inhibit filamentation by C. albicans. Regarding in vivo tests, Rottlerin did not demonstrate toxicity at the therapeutic concentrations demonstrated here and was able to increase the survival of C. elegans larvae infected. The results herein presented are innovative and pioneering in terms of Rottlerin’s multipotentiality against these fungal infections.

Antifungal activity of Carica papaya fruit extract against Microsporum canis: in vitro and in vivo study.

Tinea capitis (T. capitis), commonly known as scalp ringworm, is a fungal infection affecting the scalp and hair. Among the causative agents, Microsporum canis (M. canis) stands out, often transmitted from cats to humans (zoonotic disease). In this study, we investigated the efficacy of Carica papaya (C. papaya), fruit extract against dermatophytes, particularly M. canis, both in vitro and in vivo. Additionally, we aimed to identify the active compounds responsible for suppressing fungal growth and assess the toxicity of C. papaya on human cells. It conducted in two parts. First, In Vitro Study include the preparation of C. papaya fruit extract using methanol as the solvent, Phytochemical analysis of the plant extract including Gas chromatography-mass spectrometry (GC-MS) and Fourier-transform infrared spectroscopy (FTIR) was conducted, Cytotoxicity assays were performed using HUH-7 cells, employing the MTT assay (1-(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), Antimicrobial activity against M. canis was evaluated, including: Zone of inhibition (ZI), Minimum inhibitory concentration (MIC), Minimum fungicidal concentration (MFC), M. canis cell alterations were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Second, In Vivo, Albino Wistar male rats were included. The phytochemical analysis of the methanolic extract from papaya revealed several functional groups, including hydroxyl, ammonia, alkane, carbonate, and alcohol. Additionally, the GC-MS analysis identified 15 compounds, with xanthosine and decanoic acid being the predominant components. The methanolic extract of papaya fruits demonstrated potent antifungal activity: ZI = 37 mm, MIC = 1,000 μg/mL, MFC = 1900 μg/mL, MTT results indicated lower cytotoxicity of the fruit extract at concentrations of 20 μg/mL, 50 μg/mL, 100 μg/mL, 150 μg/mL, and 200 μg/mL, The IC50 revealed a significant decrease in cell viability with increasing extract concentration. Notably, papaya extract induced considerable alterations in the morphology of M. canis hyphae and spores. In animal tissue, improvements were observed among the group of rats which treated with Papaya extract. This study highlights the potential of C. papaya fruits as a natural antifungal agent, warranting further exploration for clinical applications.

Incorporation of Inclusion Complexes in the Dissolvable Microneedle Ocular Patch System for the Efficiency of Fluconazole in the Therapy of Fungal Keratitis.

Fluconazole (FNL) is one of the first-line treatments for fungal keratitis as it is an effective broad-spectrum antimicrobial commonly administered orally or topically. However, FNL has a very low water solubility, limiting its drug formulation, therapeutic application, and bioavailability through tissues. To overcome these limitations, this study aimed to develop FNL inclusion complexes (FNL-IC) with cyclodextrin (α-cyclodextrin, sulfobutylether-β-cyclodextrin, and hydroxypropyl-γ cyclodextrin) and incorporate it into a dissolvable microneedle (DMN) system to improve solubility and drug penetration. FNL-IC was evaluated for saturation solubility, Fourier transform infrared spectroscopy, differential scanning calorimetry, in vitro release, minimum inhibitory concentration, minimum fungicidal concentration, and time-killing assay. DMN-FNL-IC was evaluated for mechanical and insertion properties, surface pH, moisture absorption ability, water vapor transmission, and drug content recovery. Moreover, ocular kinetic, ex vivo antimicrobial, in vivo antifungal, and chorioallantoic membrane (HET-CAM) assays were conducted to assess the overall performance of the formulation. Mechanical strength and insertion properties revealed that DMN-FNL-IC has great mechanical and insertion properties. The in vitro release of FNL-IC was significantly improved, exhibiting a 9-fold increase compared to pure FNL. The ex vivo antifungal activity showed significant inhibition of Candida albicans from 6.54 to 0.73 log cfu/mL or 100-0.94%. In vivo numbers of colonies of 0.87 ± 0.13 log cfu/mL (F2), 4.76 ± 0.26 log cfu/mL (FNL eye drops), 3.89 ± 0.24 log cfu/mL (FNL ointments), and 8.04 ± 0.58 log cfu/mL (control) showed the effectiveness of DMN preparations against other standard commercial preparations. The HET-CAM assay showed that DMN-FNL-IC (F2) did not show any vascular damage. Finally, a combination of FNL-IC and DMN was developed appropriately for ocular delivery of FNL, which was safe and increased the effectiveness of treatments for fungal keratitis.

Development of treatment strategies by comparing the minimum inhibitory concentrations and minimum fungicidal concentrations of azole drugs in dermatophytes.

We compared the minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of azoles in antifungal drug-susceptible, terbinafine-resistant, and lowly itraconazole (ITCZ)-susceptible strains of dermatophytes. To assess the MICs of ITCZ, ravuconazole (RVCZ), efinaconazole (EFCZ), and luliconazole (LUCZ) in the isolates, broth microdilution assays were performed based on the Clinical and Laboratory Standards Institute M38-A2 guidelines with modifications. After the assays for determining the MICs, the inoculum suspensions in wells were resuspended, then 10 μL of the growth solution in each well was inoculated onto potato dextrose agar with the use of a pipette. After 7 days of incubation at 28°C, the MFCs were determined as the lowest concentration of a drug that allowed the growth of colonies on the potato dextrose agar. The MICs in the dermatophytes were <0.03 to >32 mg/L for ITCZ, <0.03 to 4 mg/L for RVCZ, <0.03 to 2 mg/L for EFCZ, and <0.03 mg/L for LUCZ. The MFCs in the dermatophytes were 1 to >32 mg/L for ITCZ, 0.06 to >32 mg/L for RVCZ, <0.03 to 4 mg/L for EFCZ, and <0.03 to 2 mg/L for LUCZ. If the drug susceptibility test shows that the fungi are resistant to the drug, the treatment can be changed to a susceptible drug in advance, or if the fungi are low-susceptible, the treatment can be done with the recognition that it may require a longer treatment period than usual.

Hytochemical Analysis and Determination of MIC and MFC of Cacao Leaves Extract (Theobroma cacao L.) against Malassezia furfur

Pityriasis versicolor is a disease caused by Malassezia furfur. One of the plants that can potentially act as antifungal is cacao leaves (Theobroma cacao L.), which contain several secondary metabolite compounds, including alkaloids, flavonoids, tannins, quinones, terpenoids, and saponins. This study aims to determine the phytochemical analysis and the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC) of cacao leaves ethanolic extract against M. furfur. Extracts were obtained by maceration using 70% ethanol and phytochemicals analysis using Herborne’s method. Furthermore, the extracts were made into concentrations’ variations of 3.125%; 6.25%; 12.5%; 25%; 50%; and 100% for testing antifungal activity, with 10% DMSO as negative control and 2% Ketoconazole and Itraconazole as positive controls. MIC was performed with liquid macrodilution method, and MFC was performed with spread method. The results of phytochemical analysis showed that the extract contained alkaloids, flavonoids, phenols, tannins, quinones, terpenoids and saponins. MIC value was obtained at concentration of 50% and MFC value was obtained at 100%. Cacao leaves ethanolic extract with concentration of 50% can inhibit M. furfur’s growth and with 100% can eliminate M. furfur.

Antifungal Activity, Mode of Action, and Cytotoxicity of 4-chlorobenzyl p-coumarate: a Promising New Molecule.

Fungal infections represent a serious health problem worldwide. The study evaluated the antifungal activity of 4-chlorobenzyl p-coumarate, an unprecedented semi-synthetic molecule. Docking molecular and assay experiments were conducted to determine the Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MFC), mode of action, effect on growth, fungal death kinetics, drug association, effects on biofilm, micromorphology, and against human keratinocytes. The investigation included 16 strains ofCandidaspp, includingC. albicans,C. krusei,C. glabrata,C. tropicalis,C. dubliniensis,C. lusitaniae,C. utilis,C. rugosa,C. guilhermondi, andC. parapsilosis. Docking analysis predicted affinity between the molecule and all tested targets. MIC and MFC values ranged from 3.9 µg/mL (13.54 µM) to 62.5 µg/mL (217.01 µM), indicating a probable effect on the plasma membrane. The molecule inhibited growth from the first hour of testing. Association with nystatin proved to be indifferent. All concentrations of the molecule reduced fungal biofilm. The compound altered fungal micromorphology. The tested compound exhibited an IC50 of 7.90 ± 0.40 µg/mL (27.45 ± 1.42 µM) for keratinocytes. 4-chlorobenzyl p-coumarate showed strong fungicidal effects, likely through its action on the plasma membrane and alteration of fungal micromorphology, and mildly cytotoxic to human keratinocytes.

Evaluation Of the Antifungal Activity of Cassia fistula (Linn) On Phytopathogenic Fungi Isolated from Citrus sinensis

Citrus sinensis is a prominent tropical fruit with nutritional and economic benefits for humans. However, it can also be plagued by fungal diseases, causing global economic and production reduction. The extensive application of synthetic fungicides in agricultural systems has posed increased toxicological risks to humans and ecosystems. However, the varying phytochemicals found in medicinal plants have enabled them to be regarded as safe and effective alternatives. However, few studies have evaluated the use of Cassia fistula extracts as potential bio-fungicides. This research purposed to evaluate the antifungal activity of Cassia fistula leaflet extracts against phytopathogenic fungi. Ethanol as well as aqueous extracts of Cassia fistula leaves were assessed for antifungal activity. The agar well-diffusion technique was implemented for in vitro screening, minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of all different extracts against isolated fungal species of Aspergillus, Penicillium and Geotrichum. All fungal isolates identified from the spoiled oranges were Aspergillus flavus, Aspergillus fumigatus, Geotrichum sp. and Fusarium sp. Preliminary phytochemical screening exhibited the presence of carbohydrates, terpenoids, quinones and saponins in both ethanolic and aqueous extracts. At 1000 mg/ml, the aqueous and ethanolic extracts had the highest antifungal activity against A. flavus (40 mm) and Fusarium sp. (38 mm), respectively. Both extracts had no antifungal activity against A. fumigatus at 62.5 mg/ml but zones of inhibition were observed from the positive and negative controls of ketoconazole and DMSO, respectively. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were evaluated at 62.5 mg/ml and 250 mg/ml, respectively. This study’s findings demonstrated the antifungal potential of C. fistula leaf extracts as a bio-fungicidal agent against fungal invasion in plants.

ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF SOME HYDRAZONES SYNTHESIZED FROM NICOTINIC ACID HYDRAZIDE

N’-(2-pyridinylmethylene)nicotinohydrazide A, N’-(4-pyridinylmethylene)nicotinohydrazide B, N’-(2- ethoxybenzylidene)nicotinohydrazide C, N’-(4- ethoxybenzyldene)nicotinohydrazide D and N’-(2-hydroxyl-5-methoxybenzylidene)nicotinohydrazide E, was prepared by refluxing the ethanolic solution of nictonic acid hydrazide and ethanolic solutions of 2-pyridinrcarboxaldehyde, 4-pyridinecarboxaldehyde, 2-ethoxybenzaldehyde, 4-ethoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde in 1:1 mole ratio for 4 hours in a separate reactions. The compounds obtained had a melting point between (120-236 oC) and a percentage yield between (52.38-77.70 %). They were crystalline solids. The compounds' solubility were assessed in water, ethanol, methanol, acetone, hexane, diethyl ether, dimethyl sulfoxide (DMSO), ethyl acetate, and chloroform. The substances were discovered to be fully soluble in DMSO and methanol. FT-IR, 1H-NMR and 13C-NMR were used for the characterization of the compounds. The antibacterial and antifungal properties were tested against Methicillin-resistant Staphylococcus Aureus, Vancomycin-resistant Enterococci, S. aureus, S. typhi, P. aeruginosa, A. nigre, A. flavus, and C. albicans. The zones of inhibitions ranged from 22 to 28 mm and the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were found to be 0.063 mg/mL, 0.125 mg/mL and 0.125 mg/mL respectively. These indicated that the compounds might be good potential drug candidates.

Total Phenolic Compound and Antimicrobial Activity of Spirogyra spp.

Spirogyra spp. is widely distributed in freshwater habitats and is included in the category of natural resources whose significance and advantages have been researched. In this study, 6 samples of Spirogyra spp. were collected: Spirogyra ellipsospora Transeua from Bueng Kan province, Spirogyra sp.1 from Sakon Nakhon Province and S. neglecta (Hassall) Kützing, S. ellipsospora Transeua, Spirogyra sp.2, and Spirogyra sp.3 from Nakhon Phanom province. The highest value of total phenolic compound was measured at 18.53±0.23 mg GAE/mg in Spirogyra sp. 2. The evaluation of antimicrobial activity of algal extracts against fungal Candida sp. and bacteria Staphylococcus aureus and Escherichia coli was performed by using the disk diffusion method along with determination of minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC) and minimum bacterial concentration (MBC). The result of disk diffusion and MIC determination showed the efficiency of all extract samples against all tested strains at a concentration of 10 mg/mL. The most effective algal extract against Candida sp. showed with the MFC’s ranged from 10 to 20 mg/mL, whereas MBC of all extracts destroyed the two tested bacterial strains ranged from 10 to 20 mg/mL within 24 hours and up to 30 mg/mL after 48 hours. The results of this study support that Spirogyra spp. contains bioactive compounds that are the basis for further application in cosmeceuticals.

Comparison of Antifungal Activity of Thymus Vulgaris Essential Oil and Triple Antibiotic Paste Against Candida Albicans Isolated from Root Canal (In Vitro Study)

Background The main objective of chemomechanical endodontic therapy is to reduce or eliminate microorganisms from the root canal system, and intracanal medications are used to accelerate the disinfection process. The aim of this study this study was to assess the antifungal activity of thymus vulgaris essential oil against C. albicans compared to that of triple antibiotic paste. Materials and methods C. albicans was isolated from patients who required endodontic treatment. Using the agar well diffusion method, the efficacy of Thymus vulgaris essential oil against C. albicans was determined at 25 mg/ml, 10 mg/ml, 8 mg/ml, 6 mg/ml, 4 mg/ml, and 2 mg/ml and compared to the triple antibiotic paste. The minimum inhibitory and fungicidal concentrations against Candida albicans were determined using the microbroth dilution method. The constituents were identified using a gas chromatography–mass spectrometer. Results Thymus vulgaris essential oil demonstrated antifungal activity against C. albicans, which appeared to increase as the extract concentration increased, and the difference between all concentrations and triple antibiotic paste was significant (p ≤ 0.01). The MIC and MFC for Thymus vulgaris essential oil were 0.015 mg/ml and 0.031 mg/ml, respectively. 53 compounds were identified by (GC-MS) analysis, which represented more than 95% of the oil composition. The main component was thymol (35.48%). Conclusion Thymus vulgaris essential oil is effective against C. albicans, suggesting that it has the potential to be applied as an intracanal medication.

Analysis of the effectiveness of a new antimicrobial agent for disinfection in veterinary practice

The loss of effectiveness of standard treatment methods and the increased risk of rapid spread of infections are serious consequences of this problem. This underscores the need to develop new approaches to combating pathogen resistance and ensuring effective control of infections. Studies of antimicrobial activity were conducted on strains of C. albicans, A. niger, and B. subtilis. The minimal fungicidal concentration was determined based on the growth of microorganisms C. albicans, A. niger on Sabouraud agar media containing different concentrations of a new substance – a derivative of thiadiazole. The sporicidal activity was determined by culturing the test culture B. subtilis in meat-peptone broth, followed by seeding on meat-peptone agar. Sporicidal activity was determined by inoculating the test culture of B. subtilis into meat-peptone broth, followed by plating on meat-peptone agar. Control assays were performed by inoculating the test cultures on corresponding media without the test substances. The new disinfectant – a derivative of thiadiazole – demonstrated high antimicrobial activity. The aim of this research was to study the new chemical substance for antimicrobial (antifungal and sporicidal) activity and the creation of new types of biocides. The studies showed that the minimum fungicidal concentration of the 0.3% solution in a 30% alcohol solution against C. albicans RCPGY401 was 1.56 ± 1.06 μg/mL, A. niger 137a – 1.56 ± 1.29 μg/mL. Furthermore, the material exhibited sporicidal activity against B. subtilis ATCC 10702, with an effective concentration of – 3.12 ± 1.34 μg/mL. The research confirms the activity of the new compound against the studied microorganisms and allows for its recommendation for further study (treatment regimens, safety, control methods, etc.) for use in veterinary practice for various treatment purposes.

Profiling Key Aroma Compounds of Senecio glaucus L. and their Antimicrobial and Antioxidant Activities: Multiplex of GC-MS, NMR and In Silico Studies.

The essential oils of Senecio plants have been used to treat a wide range of ailments. The current study aimed to extract the essential oil of Senecio glaucus obtained from Egypt's Nile delta and determine its chemical profile using GC-MS and NMR analysis. Then, the antimicrobial activity of the oil has been investigated against different fungal and bacterial strains. In addition, its activity as radical scavenger has been evaluated using DPPH, ABTS, and metal chelating techniques. The results revealed the identification of 50 compounds representing 98.80 % of the oil total mass. Sesquiterpenes, including dehydrofukinone (27.15 %) and 4,5-di-epi-aristolochene (10.27 %), as well as monoterpenes, including p-cymene (4.77 %), represented the most predominant constituents. The dehydrofukinone has been isolated and structurally confirmed using 1D and 2D NMR techniques. The oil has showed remarkable antifungal activity against Candida glabrata and C. albicans where the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) values were 3.13 μg/mL and 1.50 μg/mL and 12.50 μg/mL and 6.30 μg/mL, respectively that could be attributed to the sesquiterpene ketones present in the aerial tissues of the plant. Also, this oil inhibited the growth of the tested bacteria with MIC ranging from 12.50-100.00 μg/mL. In comparison to ascorbic acid and Trolox, the EO had remarkable scavenging activity of DPPH, ABTS and metal chelating with IC50 values of 313.17±13.4, 493.83±20.1, and 409.13±16.7 μg/mL. The docking studies of the identified compounds of the oil to different microbial targets, including Gyrase B and α-sterol demethylase, showed that the phytol possessed the best binding affinities toward the active sites of both enzymes with ΔG=-7.42 and -7.78 kcal/mol, respectively. In addition, the phytol revealed the highest binding affinity to tyrosine kinase Hck with ΔG=-7.44 kcal/mol.

Antifungal activity, synergistic effect and mode of action of Caraway (Carum carvi L.) essential oil and carvone against Aspergillus fumigatus

IntroductionCurrently available antifungal therapies often have limitations such as toxicity and the development of resistance. The aim of this study was to investigate the antifungal activity and mode of action of Caraway (Carum carvi L.) essential oil (EO) and its constituent carvone against A. fumigatus, a fungal pathogen responsible for invasive aspergillosis. MethodsCaraway EO was obtained by hydrodistillation, and its antifungal activity was assessed by the broth microdilution method according to the CLSI protocol. The ergosterol content of fungal mycelia was measured using a spectrophotometric method. The mode of action of Caraway EO was assessed by electron microscopy. The interaction between Caraway EO and two known antifungals, itraconazole and caspofungin, was evaluated by determining the fractional inhibitory concentration index (FICI). ResultsAt twofold dilutions ranging from 3.12 to 400 µg/mL, Caraway EO inhibited A. fumigatus growth by 10.27–100 %, with a minimum inhibitory concentration (MIC) of 200 µg/mL, while carvone inhibited fungal growth by 7.31–67.58 %, with an MIC of 400 µg/mL. The IC50 values of the Caraway EO and carvone were 56.09 and 47.68 μg/mL, respectively. Moreover, the minimum fungicidal concentration (MFC) of the Caraway EO was reported to be 400 μg/mL. Both Caraway EO and carvone significantly inhibited ergosterol biosynthesis in A. fumigatus. Caraway EO showed synergistic antifungal activity in combination with itraconazole (FICI=0.38) and additive antifungal activity (FICI=0.75) in combination with caspofungin. ConclusionCaraway EO and its constituent carvone showed strong antifungal activity against A. fumigatus by inhibiting ergosterol biosynthesis and destroying essential compartments of fungal mycelia, such as mitochondria. In addition, the combination of carvone with itraconazole or caspofungin had synergistic/additive effects, suggesting potential therapeutic efficacy for the treatment of A. fumigatus-related infections.

The inhibitory effects of carvacrol, nystatin, and their combination on oral candidiasis isolates

BackgroundCandida, a common oral microbiota, can cause opportunistic fungal infections. With rising Candida infections and limited effective antifungals, new treatments are needed. This study investigates carvacrol essential oil’s effect on oral candidiasis, alone and with nystatin, compared to nystatin alone.Materials and methodsIn this study, oral samples were collected from dental clinic patients, especially denture users. The presence of Candida was confirmed and cultured from these samples. Candidiasis was detected by observing Candida colonies. Drug sensitivity was tested on 100 positive samples. The minimum concentration of inhibition and lethality of each isolate was evaluated using nystatin and carvacrol. The results were compared using two-way analysis of variance. Finally, the minimum inhibitory concentration (MIC) of nystatin and carvacrol was calculated individually and in combination.ResultsThe present study found that Candida albicans and non-albicans species were equally prevalent. Carvacrol showed significant biological activity against all Candida species, with an average MTT of 50.01%. The average MIC value of carvacrol was 24.96 µg/ml, indicating its potential to inhibit Candida growth. The mean Minimum Fungicidal Concentration (MFC) value of carvacrol was 23.48 µg/ml, suggesting its effectiveness in killing the fungi.ConclusionThe study’s findings reveal that the MIC of carvacrol was significantly lower than that of nystatin and the combination of nystatin and carvacrol. This suggests that carvacrol holds potential as an effective herbal remedy for candidiasis.

Anticandidal Activity of a Siderophore from Marine Endophyte Pseudomonas aeruginosa Mgrv7.

An endophytic symbiont P. aeruginosa-producing anticandidal siderophore was recovered from mangrove leaves for the first time. Production was optimal in a succinate medium supplemented with 0.4% citric acid and 15 µM iron at pH 7 and 35 °C after 60 h of fermentation. UV spectra of the acidic preparation after purification with Amberlite XAD-4 resin gave a peak at 400 nm, while the neutralized form gave a peak at 360 nm. A prominent peak with RP-HPLC was obtained at RT 18.95 min, confirming its homogeneity. It was pH stable at 5.0-9.5 and thermally stable at elevated temperatures, which encourages the possibility of its application in extreme environments. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) against Candida spp. Were in the range of 128 µg/mL and lower. It enhanced the intracellular iron accumulation with 3.2-4.2-fold (as judged by atomic absorption spectrometry) with a subsequent increase in the intracellular antioxidative enzymes SOD and CAT. Furthermore, the malondialdehyde (MDA) concentration due to cellular lipid peroxidation increased to 3.8-fold and 7.3-fold in C. albicans and C. tropicalis, respectively. The scanning electron microscope (SEM) confirmed cellular damage in the form of roughness, malformation, and production of defensive exopolysaccharides and/or proteins after exposure to siderophore. In conclusion, this anticandidal siderophore may be a promising biocontrol, nonpolluting agent against waterborne pathogens and pathogens of the skin. It indirectly kills Candida spp. by ferroptosis and mediation of hyperaccumulation of iron rather than directly attacking the cell targets, which triggers the activation of antioxidative enzymes.