antifungal agents

By harnessing the power of nature, researchers can potentially discover new therapeutic options that are safe, effective, and sustainable for the management of diseases. Recently, natural products have been extensively studied for the treatment of diseases due to their diverse chemical composition and potential therapeutic properties. Therefore, this study aimed to investigate the antifungal activity of carvone and linalool against Malassezia species to find alternative treatments for pityriasis versicolor.

The in vitro antifungal activity of monoterpenes was assessed using a microdilution method, following the guidelines specified in the Clinical and Laboratory Standards Institute document M27-A3 with modifications, including the use of Christensen’s urea broth supplemented with various lipids to optimize the growth condition for Malassezia.

The minimum inhibitory concentration ranges for linalool and carvone were found to be 0.3-5.4 and 0.3-24 mg/mL, respectively. Additionally, the growth of Malassezia species was inhibited at concentrations of 0.001-0.003 and 0.006-0.1 mg/mL for amphotericin B and ketoconazole, respectively.

Given the remarkable antifungal properties exhibited by linalool and carvone against Malassezia species, these terpene compounds have the potential to be utilized for the treatment of Malassezia infections, provided that additional research is conducted.

Capparis spinosa is a plant belonging to the genus Capari which is important for medicinal purposes. It is also known as a multipurpose plant in Persian medicine. In this study, we searched for natural active ingredients in mouthwash for immunocompromised patients and examined the antifungal plus antibacterial properties of the hydroalcoholic extract of the root of the Capparis plant against Streptococcus mutans (S. mutans) PTCC 1683 and Candida albicans (C. albicans) ATCC-10231 was investigated.

Ethanol extracts of plant roots were extracted by the percolation method. The diameter of the growth inhibition zone of C. albicans and S. mutans extracts was measured using the well plate method. Minimum inhibitory concentrations (MICs) were calculated for bacterial and fungal strains. In addition, the minimum sterilization concentration (MBC) and minimum sterilization concentration (MFC) of the extract were investigated using the broth microdilution method. The results were compared with an antibacterial and antifungal drug of 0.2% chlorhexidine nystatin. 

The results for both pathogens revealed that the diameter of the growth inhibition zone increased with elevation of the extract concentration. The MIC and MBC of S. mutans extract were 62.5 and 62.5 mg/ml, compared to 0.39 and 0.39 mg/ml for chlorhexidine. The MIC and MFC of the plant against the fungus C. albicans were 7.812 and 31.25 mg/ml, compared to 0.25 and 1.25 μg/ml for nystatin.

 The ethanol extract of the Caparis plant had an antifungal effect on C. albicans and an antibacterial effect on S. mutans. However, the inhibitory and lethal effects against bacterial and fungal strains were lower than those of nystatin and chlorhexidine.

Considering the novelty of nanotechnology and its applications in dentistry, and the existing conflicts and scarcity of studies regarding the antimicrobial activity of TiO2, ZnO, and SiO2 nanoparticles, this study aimed to fabricate acrylic nanocomposites containing different percentages of mineral nanoparticles and assess their antimicrobial activity. In this in vitro, experimental study, standard-strain Streptococcus mutans (S. mutans) (ATCC35668) and Candida albicans (C. albicans) (ATCC10231) were cultured and biochemically confirmed. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of zinc oxide (ZnO), titanium dioxide (TiO2), silver (Ag), and silicon dioxide (SiO2) nanoparticles were determined by the broth macrodilution and agar well diffusion method. Remarkably, the results revealed that, TiO2, SiO2, and ZnO in 1, 0.5, 0.25, 0.125, and 0.062wt% concentrations had no inhibitory effect against S. mutans and C. albicans. While, silver nanoparticles (AgNPs) showed in vitro activity against S. mutans (MIC=MBC 62.5 µg/ml) and C. albicans (MIC 125 µg/ml) . However, nanocomposites containing 0.125, 0.25, 0.5, 1, and 2wt% TiO2 had no in vitro activity against S. mutans and C. albicans. In the present study, only AgNPs showed antimicrobial activity against S. mutans and C. albicans in 1, 0.5, 0.25, 0.125, and 0.062wt% concentrations. However, further studies are warranted to correlate these findings with clinical outcomes.

Ficus johannis Boiss. is a shrubby species in the family Moraceae, exclusively found in Iran, Afghanistan, and Pakistan. This research studies the total phenolic content, flavonoid concentrations, antioxidant capacity, and antimicrobial activity of this biologically unknown species.

The Leaves and fruits of the plant were gathered from the northern slope of Taftan Mountain in Sistan and Baluchestan, in the summer of 2022. After washing, drying, grinding, and obtaining hydroalcoholic extracts of the fruits and leaves, quantifying the phenolic and flavonoid concentrations was done spectrophotometrically utilizing the Folin-Ciocalteu and aluminum chloride colorimetric techniques, respectively. The anti-radical activity of the organs was assayed via the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) protocol and their antimicrobial effects were assessed using the broth microdilution and streak plate techniques against six bacterial, and three fungal pathogens including Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Staphylococcus epidermidis, Streptococcus pyogenes, Bacillus cereus, Aspergillus fumigatus, Fusarium oxysporum, and Candida albicans.

The phenolic compounds were found to be evenly distributed in both leaf and fruit extracts (around 43 mg GAE/g dry extract) while flavonoids were detected in significantly higher concentrations in the fruit extract (14.62 vs 9.57 mg QrE/g dry extract). The leaf extract was better at scavenging free radicals compared to the fruit extract (IC50 93.79 vs 239.62 μg/ml, respectively), while both extracts showed higher IC50 values than the positive control. The leaf extract showed better inhibitory effects on the tested microorganisms compared to the fruit extract. The leaf extract was effective against all tested bacteria, whereas, among the investigated fungi, only Aspergillus fumigatus was vulnerable to it. Conversely, the fruit extract was able to prevent the growth of all investigated fungal strains, but only two bacterial strains (Streptococcus pyogenes and Klebsiella pneumonia) were affected by it. Moreover, both lea and fruit extracts showed the best antimicrobial activity against Aspergillus fumigatus with MIC values of 128 and 512, repectively.

The Ficus johannis fruits and leaves are great sources of phenolic and flavonoid compounds with moderate anti-radical capacity. Moreover, the fruit extract mainly contains antifungal ingredients while the leaf extract chiefly includes antibacterial agents.

Candida species can produce a variety of clinical manifestations, and several non-albicans species of Candida, including Candida auris, have been linked to the rise of invasive fungal infections with high rates of treatment failure. Nosocomial outbreaks and high mortality rates in healthcare institutions across the globe have been associated with C. auris, an emerging infectious yeast that was initially discovered in the ear canal of an elderly Japanese patient in 2009. The fact that C. auris has been found on six continents after it was initially isolated has raised serious concerns among scientists and healthcare practitioners.  At present, healthcare facilities lack defined protocols for the effective prevention and control of C. auris infections, as well as appropriate treatment alternatives. This leads to frequent therapeutic failures and complicates the eradication of C. auris infection in healthcare facilities. Studies on C. auris in South India are often limited, and healthcare workers urgently need to be made aware of infections caused by it in order to assess its impact and possible implications for the healthcare system. This study aimed to report seven patients hospitalized in our center who developed C. auris infections with varying clinical manifestations.

Regarding the wide-spectrum antimicrobial effects of curcumin and silver, this study aimed to evaluate the antifungal activity of green-synthesized curcumin-coated silver nanoparticles (Cur-Ag NPs) against a set of Candida and Aspergillus species.

Cur-Ag NPs were synthesized by mixing 200 µL of curcumin solution (40 mM) and 15 mL of deionized water. The mixture was stirred for 3-5 min, followed by the addition of 2.5 mL of silver nitrate solution (2.5 mM). The resulting solution was incubated for 3 days. Antifungal susceptibility of 30 fungal isolates of Aspergillus and Candida to fluconazole and itraconazole, as well as the activity of Cur-Ag NPs against the isolates, were determined, both alone and in combination, using broth microdilution according to the Clinical and Laboratory Standards Institute guidelines.

Cur-Ag NPs demonstrated promising antifungal activity, particularly against Candida species. The geometric mean value of the minimum inhibitory concentration of Cur-Ag NPs was significantly lower than that of fluconazole for all the studied fungi. Similarly, it was lower than those of itraconazole in C. albicans and A. fumigatus. The minimum fungicidal concentrations of Cur-Ag NPs were markedly better than those of fluconazole but still inferior to those of itraconazole.

Cur-Ag NPs demonstrated indisputable antifungal activity and great potential that can be harnessed to combat fungal infections, particularly those caused by azole-resistant strains of Aspergillus and Candida.

Essential oils have been utilized for various purposes throughout history. These aromatic substances have become increasingly popular in alternative medicine, aromatherapy, and personal care products.

In this study, essential oils from the aerial parts of four Allium species and three Brassicaceae members, namely Fortuynia garcinii, Draba verna, and Thlaspi arvense were evaluated for their antioxidant, antibacterial, and antifungal properties.

The radical-scavenging properties were tested using DPPH assay. Antimicrobial activities were examined on nine standard pathogens: three Gram-positive bacteria including Staphylococcus aureus, Bacillus cereus, Streptococcus pyogenes, three Gram-negative bacteria including Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica subsp. enterica and two fungi Aspergillus fumigatus, Fusarium oxysporum as well as the yeast Candida albicans.

The IC50 values of antioxidant assay ranged from 124.66 to 155.04 μg/ml. Allium zagricum showed the best antioxidant effects with IC50 of 124.66 μg/ml compared to standard vitamin E (IC50 = 10.40 μg/ml). Similarly, the MIC values of 25-400 μg/ml with Fortuynia garcinii fruits-Zahedan were assessed as the best antimicrobial effects, while they were higher than the MIC values recorded for positive controls (0.06-16 for amikacin and 32-256 for clotrimazole).

Essential oils extracted from Allium zagricum and Fortuynia garcinii can be prescribed for the treatment of oxidative stress-related and infectious diseases.

This study aimed to compare the antifungal efficacy of Ganoderma lucidum (G. lucidum) and clotrimazole for treatment of denture stomatitis (DS).

This double-blind randomized clinical trial was conducted on 50 patients with DS types I and II assigned to two groups (N=25). In the first group, G. lucidum extract was administered in the form of 5% gel while 1% clotrimazole gel was prescribed for the second group. Pain intensity according to the visual analog scale (VAS), and the percentage of DS recovery based on the Budtz-Jorgenson index were evaluated and recorded after 7 and 14 days. Data were analyzed using the Chi-square test, independent samples t-test, repeated measures ANOVA, and logistic regression (alpha=0.05).

The percentage of complete recovery on day 7 in the G. lucidum group (28%) was higher than that in the clotrimazole group (16%) but not significantly (P=0.592). Not wearing dentures overnight significantly increased the odds of recovery by 6.56 times, while the odds of recovery decreased by 0.03 times in DS type II, as compared to DS type I (P= 0.009).

No significant difference existed between the antifungal efficacy of G. lucidum and clotrimazole for clinical treatment of DS. Thus, Ganoderma may be regarded as an alternative treatment, especially in patients’ resistant to azoles. Nonetheless, further clinical studies are required to shed more light on this topic.

Anabasis setifera and Caroxylon imbricatum are two halophytic and xerophytic plant species belonging to the family Chenopoodiaceae s.str., that are distributed widely in dry environments of the Old World. This study investigated the antioxidant and antibacterial properties of the hydroethanolic extracts of fruit-bearing branches of these species collected from Zabol in the east of Iran.

The antimicrobial effect was essayed using broth microdilution and streak plate protocols against nine pathogenic microorganisms from different genera, including Klebsiella, Pseudomonas, Escherichia, Bacillus, Staphylococcus, Streptococcus, Aspergillus, Fusarium and Candida. The antioxidant activity was measured by the DPPH free radical scavenging method.

Extracts were effective on all tested bacterial and fungal strains except for Candida albicans, which Caroxylon imbricatum didn’t affect. The MIC values ranged from 8 to 2048 μg/ml. The IC50 values of 76.40 and 154.05 μg/ml were observed with Anabasis setifera and Caroxylon imbricatum extracts, respectively.

These plant species can efficiently treat infectious and oxidative stress-related diseases due to their broad spectrum antimicrobial properties and acceptable antioxidant activities.

Aspergillus species are found as opportunistic agents to cause a wide variety of clinical manifestations. Regarding the drug resistance emergence against Aspergillus species, new aspects of using nanoparticles (NPs) as antifungal agents are considerable. This study takes a new approach to biosynthesized NPs of zinc oxide, copper oxide, cerium oxide, silver, gold, and selenium influence on the clinical isolates of Aspergillus species.

The antifungal activities of six NPs were examined against a total of 12 clinical isolates of Aspergillus species, including A. flavus (n=4), A. welwitschiae (n= 4), and A. fumigatus (n=4) based on the M38-A2 guideline.

According to minimum inhibitory concentration (MIC) values, NPs of ZnO, Ag, Au, and Se showed a significant antifungal effect. CuO-NPs and CeO2-NPs didn’t show an inhibitory effect against Aspergillus isolates. The MIC ranges of ZnO-NPs, Ag-NPs, Au-NPs, and Se-NPs were 128-512, 26-53, 21-85, and 6-26 µg⁄mL for A. fumigatus; and 512->512, 26-53, 85, and 1-13 µg⁄mL for A. welwitschiae, respectively. In addition, the MIC ranges of Ag-NPs and Se-NPs were 26-53 and 106-425 µg⁄mL for A. flavus, respectively. However, A. flavus were not inhibited by NPs of ZnO and Au.

Among the examined NPs, ZnO, Ag, Au, and Se showed a significant effect against Aspergillus isolates except for CuO and CeO2. However, Ag-NPs seemed to be the most effective nanoparticle against the Aspergillus species. Compared to other Aspergillus species, A. flavus was not inhibited by NPs of ZnO and Au.

Denture stomatitis (DS) is a common oral condition which usually occurs under the maxillary removable complete dentures. Infection by Candida albicans (C. albicans) is considered as the main etiology of this lesion. The aim of the present study was to assess the oral health-related quality of life (OHRQoL) of patients with DS and its improvement after antifungal treatment.   

In the present quasi-experimental study, the patients were classified into three groups with natural teeth, complete denture wearers without DS, and DS group. The Oral Health Impact Profile (OHIP-14) questionnaire was completed once by the first two groups and twice by the DS group (before and after prescription of 100 mg fluconazole daily for 14 days). Data analysis was performed by one-way ANOVA, Fisher’s exact test, and Pearson’s correlation coefficient at a confidence interval of 95%.

A total of 85 patients were included with a mean age of 69.74±7.95 years. The mean OHIP score was significantly lower in the DS group in comparison with the other two groups (P=0.0001). OHRQoL significantly improved after prescription of fluconazole for DS patients (P=0.0001).

It appears that DS disrupts the OHRQoL of the affected patients, and systemic antifungal therapy has the potential to improve it.

Previous researchers showed the antimicrobial ability of ionic liquids (ILs) on different infec- tive agents. ILs can dissolve organic components, especially DNA molecules. Among synthesized eight binary ILs mixtures, we have chosen ([Met-HCl] [PyS]) IL for determining the antifungal ability of IL against Candida albicans cells.

Well diffusion assay, chrome agar and Germ tube tests were used to detect the Candida samples. PCR, real-time-PCR, and flow cytometry tests were performed to determine the IL's rate of toxic ability.

Well diffusion assay revealed the diameters of the growth inhibition zones were the largest in IL with methionine and Proline amino acids. Minimum inhibitory concentration (MIC) and the Minimum fungicidal concentration (MFC) tests showed that they inhibited the growth of the C. albicans at a range from 250 μg/ml for sensitivity and 400 μg/ml for resis- tance, MIC average of all samples were 341.62 ± 4.153 μg/ml. IL reduced the expression of CDR1 and CDR2 the genes encoded by the major protein of ABC system transporter by 2.1 (P= 0.009) and 1.2 fold (P= 0.693), revealed by PCR and real time-PCR. In the flow cytometry test, there were increasing dead cells after treating with the ([Met-HCl] [PyS]) even in the most resistant strain.

The novel IL was effective against the most clinical and standard C. albicans.

Considering the increase of dermatomycoses and the emergence of new strains resistant to antifungal treatment, it is important to find an alternative treatment of natural origin. This study aimed to extract and purify β-carotenoid from two types of Rhodotorula diobovata and Rhodotorula mucilaginosa and test its reactivity toward some yeasts isolated from dermatomycoses infection.
Materials &

Rhodotorula samples were isolated from extreme environmental soils, and after cultivation, they were identified genetically and apparently. Then their pigments were extracted and purified. Beta-carotene was detected by ultraviolet and infrared regions. The activity of β-carotene was tested using three different concentrations using the agar diffusion method against four isolates of Candida and Cutaneotrichosporon dermatis pathogenic species by comparing its reactivity with the antifungal Nystatin.

All tested isolates, including Candida albicans HAM25, Candida dubliniensis, Candida tropicales HAM13, and Cutaneotrichosporon dermatis Judy 4, showed resistance against β-carotene purified from R. diobovata and Nystatin at the concentration 0.01mg/ml. However, β-carotene and Nystatin showed activity against all isolates with concentrations of 0.02 and 0.03mg/ml. The purified compound from R. mucilaginosa showed activity against all isolates in three concentrations, according to concentration and type. There was a significant difference between the antifungal activity of both purified β-carotene and Nystatin (p<0.0001).

Both isolates of Rhodotorula diobovata and Rhodotorula mucilaginosa produce β-carotene, and the preference quantitatively is to isolate R. diobovata first. The activity of β-carotene against all tested yeast isolates are higher than the antifungal Nystatin.

Computer-aided drug designing is a promising approach to defeating the dry pipeline of drug discovery. It aims at reduced experimental efforts with cost-effectiveness. Naturally occurring large molecules with molecular weight higher than 500 Dalton such as cationic peptides, cyclic peptides, glycopeptides and lipopeptides are a few examples of large molecules which have successful applications as the broad spectrum antibacterial, anticancer, antiviral, antifungal and antithrombotic drugs. Utilization of microbial metabolites as potential drug candidates incur cost effectiveness through large scale production of such molecules rather than a synthetic approach. Computational studies on such compounds generate tremendous possibilities to develop novel leads with challenges to handle these complex molecules with available computational tools. The opportunities begin with the desired structural modifications in the parent drug molecule. Virtual modifications followed by molecular interaction studies at the target site through molecular modeling simulations and identification of structure-activity relationship models to develop more prominent and potential drug molecules. Lead optimization studies to develop novel compounds with increased specificity and reduced off targeting is a big challenge computationally for large molecules. Prediction of optimized pharmacokinetic properties facilitates development of a compound with lower toxicity as compared to the natural compounds. Generating the library of compounds and studies for target specificity and ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) for large molecules are laborious and incur huge cost and chemical wastage through in-vitro methods. Hence, computational methods need to be explored to develop novel compounds from natural large molecules with higher specificity. This review article is focusing on possible challenges and opportunities in the pathway of computeraided drug discovery of large molecule therapeutics.

Head‑and‑neck radiotherapy can change oral Candida species and cause candidiasis resistance to common antifungals by making the changes to the oral cavity environment. Voriconazole is a synthetic azole with extensive antifungal activity. The current study aimed at comparing the antifungal activity of fluconazole and voriconazole on Candida species isolated from the oral cavity of patients undergoing head‑and‑neck radiotherapy.

The present in vitro study was performed on samples isolated from patients undergoing head‑and‑neck radiotherapy, before and during radiotherapy. After the identification of the species, the antifungal effect of fluconazole and voriconazole was determined by the microdilution method, and the minimum inhibitory concentration (MIC), the minimum fungicidal concentration, and the antifungal susceptibility of the isolated strains were also measured. The data were analyzed by the Chi‑squared and then two‑sided Fisher’s exact tests. P < 0.05 was considered statistically significant.

The study findings showed no significant difference in the susceptibility of Candida albicans to voriconazole and fluconazole before and during radiotherapy. Before radiotherapy, both voriconazole and fluconazole had similar effects on Candida tropicalis, but after radiotherapy, voriconazole was less effective. However, both before and during radiotherapy, fluconazole had a greater antifungal effect than voriconazole on Candida glabrata strains. The MICs of voriconazole and fluconazole for both Candida parapsilosis and Candida krusei isolates were within the susceptible or dose‑dependent range.

The current study results showed that voriconazole was not more effective than fluconazole in the treatment of oral candidiasis in patients undergoing head‑and‑neck radiotherapy.

 Otomycosis is defined as a superficial fungal infection, accounting for about 10% of infectious otitis externa cases.

 This study investigated patients with suspicious symptoms through the examination of their demographic information, isolate etiological agents, and in vitro antifungal susceptibility patterns.

 The samples of 170 patients with otitis externa symptoms were collected and confirmed for otomycosis by mycological examination (e.g., potassium hydroxide, methylene blue staining, and fungal culture) and molecular sequencing. In vitro antifungal susceptibility tests against miconazole, fluconazole, itraconazole, voriconazole, posaconazole, amphotericin B, and caspofungin were performed according to the Clinical and Laboratory Standards Institute (M27-A3/S4 and M38-A2).

 Out of 170 patients, 145 subjects (85.29%) showed positive mycological findings. In this study, 55.8% of the patients were male, and the most common age group affected was 50 - 59 years (26.2%). Hearing loss and pruritus were the most common clinical manifestations. The most common occupation was being a housewife (47.5%), and most cases occurred during the winter (40%). Aspergillus niger was the most common species, followed by Aspergillus fumigatus, Candida albicans, and Candida glabrata. Caspofungin showed the highest activity against Aspergillus and Candida isolates; nevertheless, itraconazole demonstrated the lowest activity against Aspergillus isolates. Fluconazole showed the weakest power against Candida species.

 Due to climatic conditions, humidity, and dust, otomycosis has a high occurrence in Iran. Although otomycosis needs long-term antifungal therapy and recurrence is high in some cases, it is rarely life-threatening, and eardrop antifungals are usually enough to eradicate the infection. Local information about the antifungal pattern is useful for the control, prevention, and treatment of otomycosis.