Minimum Fungicidal Concentration Research Articles

Phytochemical Profiles and Antimicrobial Activity of Selected Populus spp. Bud Extracts.

Buds of poplar trees (Populus species) are often covered with sticky, usually polyphenol-rich, exudates. Moreover, accessible data showed that some Populus bud extracts may be excellent antibacterial agents, especially against Gram-positive bacteria. Due to the fragmentary nature of the data found, we conducted a systematic screening study. The antimicrobial activity of two extract types (semi-polar-ethanolic and polar-ethanolic-water (50/50; V/V)) from 27 bud samples of different poplar taxons were compared. Antimicrobial assays were performed against Gram-positive (five strains) and Gram-negative (six strains) bacteria as well as fungi (three strains) and covered the determination of minimal inhibitory, bactericidal, and fungicidal concentrations. The composition of extracts was later investigated by ultra-high-performance liquid chromatography coupled with ultraviolet detection (UHPLC-DAD) and with electrospray-quadrupole-time-of-flight tandem mass spectrometry (UHPLC-ESI-qTOF-MS). As a result, most of the extracts exhibited good (MIC ≤ 62.5 µg/mL) or moderate (62.5 < MIC ≤ 500 µg/mL) activity against Gram-positives and Helicobacter pylori, as well as fungi. The most active were ethanolic extracts from P. trichocarpa, P. trichocarpa clone 'Robusta', and P. tacamahaca × P. trichocarpa. The strongest activity was observed for P. tacamahaca × P. trichocarpa. Antibacterial activity was supposedly connected with the abundant presence of flavonoids (pinobanksin, pinobanksin 3-acetate, chrysin, pinocembrin, galangin, isosakuranetin dihydrochalcone, pinocembrin dihydrochalcone, and 2',6'-dihydroxy-4'-methoxydihydrochalcone), hydroxycinnamic acids monoesters (p-methoxycinnamic acid cinnamyl ester, caffeic acid phenethylate and different isomers of prenyl esters), and some minor components (balsacones).

Efficacy of calcium hypochlorite in disinfection of gutta-percha cones contaminated with Candida albicans.

This study aimed to compare the efficacy of 2.5% sodium hypochlorite (NaOCl), 2.5% calcium hypochlorite [Ca(OCl)2], and 2% chlorhexidine (CHX) in the rapid disinfection of gutta-percha cones contaminated with Candida albicans. The minimum inhibitory and minimum fungicidal concentrations of each solution for C. albicans were determined and the ability of each solution to destroy and inhibit biofilm in culture wells was tested. In addition, ninety-eight gutta-percha cones contaminated with the fungal suspension were disinfected according to the type of solution (2.5% NaOCl, 2.5% Ca(OCl)2 or 2% CHX) in its different application methods (without agitation, ultrasonicagitation or agitation with Easy Clean), and regarding the exposure time to each irrigating solution (1 or 5min). Next, the samples were checked for turbidity and evaluation of viable colonies. The compounds that showed the best performance in biofilm destruction were NaOCl and Ca(OCl)2 at a concentration of 2xMIC (p < 0.001). Regarding inhibited biofilm, the only compound that was effective at all MIC concentrations tested was 2.5% Ca(OCl)2 (p < 0.0001). Regarding the viable colonies, all solutions were effective concerning the control group, for all application methods, in 1 and 5min (p < 0.05). The densitometer reading showed that CHX was the only effective solution in all application methods performed (p < 0.05). The results demonstrate that all tested solutions were effective in the rapid decontamination of cones contaminated with C. albicans.

Combined in vitro/in silico approaches, molecular dynamics simulations and safety assessment of the multifunctional properties of thymol and carvacrol: A comparative insight.

Bioactive compounds derived from medicinal plants have acquired immense attentiveness in drug discovery and development. The present study investigated in vitro and predicted in silico the antibacterial, antifungal, and antiviral properties of thymol and carvacrol, and assessed their safety. The performed microbiological assays against Pseudomonas aeruginosa, Escherichia coli, Salmonella enterica Typhimurium revealed that the minimal inhibitory concentration values ranged from (0.078 to 0.312 mg/mL) and the minimal fungicidal concentration against Candida albicans was 0.625 mg/mL. Molecular docking simulations, stipulated that these compounds could inhibit bacterial replication and transcription functions by targeting DNA and RNA polymerases receptors with docking scores varying between (-5.1 to -6.9 kcal/mol). Studied hydroxylated monoterpenes could hinder C. albicans growth by impeding lanosterol 14α-demethylase enzyme and showed a (ΔG=-6.2 and -6.3 kcal/mol). Computational studies revealed that thymol and carvacrol could target the SARS-Cov-2 spike protein of the Omicron variant RBD domain. Molecular dynamics simulations disclosed that these compounds have a stable dynamic behavior over 100 ns as compared to remdesivir. Chemo-computational toxicity prediction using Protox II webserver indicated that thymol and carvacrol could be safely and effectively used as drug candidates to tackle bacterial, fungal, and viral infections as compared to chemical medication.

The chemical composition, in vitro, and in silico studies of Lavandula mairei essential oil

Lavandula mairei is an aromatic, and medicinal plant endemic to Morocco, mainly found in the southeastern region of the Kingdom, and used in traditional medicine for its many benefits. The purpose of the study was to identify the chemical composition of Lavandula mairei essential oil using Gas Chromatography - Tandem Mass Spectrometry, to evaluate the antimicrobial activity of the plant against bacterial strains (Staphylococcus aureus, Staphylococcus aureus MRSA, Enterococcus faecalis, Escherichia coli ATCC 25922, Escherichia coli ESBL, Klebsiella pneumoniae ATCC 700603), and two fungal strains (Aspergillus niger ATCC 10231, Candida albicans ATCC 16404) in order to measure the microbial growth inhibition zone diameter, and to determine the minimum inhibitory, bactericidal, and fungicidal concentration of the essential oil (MIC, MBC, and MFC). Concerning antioxidant activity, six assays (6DPPH, and 1ABTS Free Radical Scavenging Assay, Total Antioxidant Capacity, Hydroxyl Radical, Reducing Power, and β-Carotene Bleaching Inhibition) were performed to determine the antioxidant potential of the essential oil. For the in silico aspect, molecular docking studies were performed to explore the potential interactions of some compounds with five microbial targets (i) Dihydropteroate synthase (1AJ0), ii) The elongation factor EF-Tu (1OB2), iii) d-alanine ligase (2I80), iv) DNA gyrase (2XCT), v) The cytochrome P450 monooxygenase (5V5Z), and 2ADMET prediction analysis was completed on a compound designated as dehydroabietinol. Carvacrol was identified as the major compound (36.38%) by analysis of the chemical composition, E. coli ATCC 25922 (MIC = 1.87 mg/mL ± 0.00, MBC = 15.00 mg/mL ± 0.00), and Enterococcus faecalis (MIC = 0.23 mg/mL ± 0.00, MBC = 5.53 mg/mL ± 2.77) were the most sensitive to the antibacterial treatment, and Candida albicans was resistant to the essential oil. The highest antioxidant potential of the plant was observed in the β-carotene bleaching inhibition test (IC50 = 1.55 mg/mL ± 0.009 and 90 % of inhibition). In the in silico study, the compound dehydroabietinol provided relevant evidence for molecular docking, and this was confirmed by the ADMET prediction analysis. The results of the study were significant, and further experiments will be necessary to find out more about the biological properties of Lavandula mairei.

Oxytetracycline degradation and antidermatophytic activity of novel biosynthesized MoS2 photocatalysts

The presence of environmental contamination poses a significant threat to life on our planet. Oxytetracycline, an antibiotic with a broad spectrum of effectiveness, demonstrates resistance to biodegradation, potentially resulting in an ecological hazard. In this study, we synthesized both pure and biosynthesized Molybdenum Disulfide (MoS2) nanoparticles using extracts from the bark of Ficusreligiosa L (FR) and leaves of ZiziphusjujubeL (ZJ). These nanopartices were characterized by various analytical methods to assess their efficiency in photocatalytic degradation of oxytetracycline (OTC) and their antidermatophytic activity. X-ray diffraction patterns revealed that the prepared MoS2 catalysts typically exhibited hexagonal phase structure with crystalline size of approximately 13, 6, and 4 nm. Both pure and biosynthesized MoS2 nanoparticles displayed a nanoflake-like morphology with a spherical size distribution. BET surface area analyses exhibited an increase in surface area for biosynthesized MoS2 nanoparticles from 79 to 121 m2g−1. Optical absorption revealed a red shift in band gap energy, decreasing from 2.37 to 2.03 eV for biosynthesized MoS2 nanoparticles. The biosynthesized MoS2:FR nanoparticles exhibited remarkable OTC degradation with 99 % achieved within 100 min along with strong antifungal activity (Minimum Inhibitory Concentration - MIC of 12.5 µg/mL, Minimum Fungicidal Concentration - MFC of 25 µg/mL). These biosynthesized MoS2 catalysts are promising for water treatment purposes.

Butylated hydroxyanisole controls anthracnose on postharvest citrus fruit by inducing autophagosome formation in Colletotrichum gloeosporioides

Citrus anthracnose, caused by Colletotrichum gloeosporioides, is a preharvest and postharvest disease that results in economic losses by affecting citrus fruit quality, shelf life, and market value. To date, research on environmental safety, high efficiency and viable alternatives has not been reported. In this study, butylated hydroxyanisole (BHA) was screened and verified to inhibit C. gloeosporioides of citrus. The results showed that BHA could completely inhibit mycelial growth in vitro (0.25 g/L) and absolutely lose its virulence in vivo (20 × Minimum fungicidal concentration (MFC) = 5 g/L). Furthermore, some transparent irregularly shaped vacuolar structures in the cytosol of the BHA-treated conidia were detected by Transmission Electron Microscope (TEM), and autophagosome formation was verified by monodansylcadaverine(MDC) staining. In addition, staining experiments indicated that BHA induced the accumulation of excessive reactive oxygen species (ROS, the DCFH-DA staining rates of C. gloeosporioides conidia treated with 1/2 × MIC and MIC were 26.4% and 83%, respectively), which implied that BHA destroyed spore organelles and damaged cell membrane integrity (the electrical conductivity of conidia treated with 1/2 × Minimum inhibitory concentration (MIC), MIC and MFC was 48.37%, 64.79% and 97.95%, respectively), further resulting in reduced pathogenicity and virulence. In summary, this study provides evidence that BHA has the potential to be a valuable alternative for controlling citrus anthracnose in the future.

Uncovering the antimicrobial activity of G-type lysozyme 2 derived from Cyprinus carpio mucus against bacterial and fungal pathogens

This study aimed to explore the antimicrobic potential of mucus samples collected from Cyprinus carpio and identify the specific antimicrobial peptides responsible for its activity. The crude extract was tested against various bacterial and fungal pathogens, and its protein content and profile were analyzed. Purification steps, including gel filtration chromatography, were employed to isolate the most active fraction (peak IV), which was further identified via liquid chromatography and mass spectroscopy. The results revealed varying degrees of antimicrobial activity of the crude extract against different bacterial and fungal strains, with Leclercia adecarboxylata, Candida glabrata, and Candida parapsilosis showing the highest susceptibility. SDS-PAGE analysis demonstrated the existence of multiple low molecular weight protein bands in the crude extract, while fraction IV obtained from gel filtration chromatography exhibited the strongest antimicrobial activity. Peak IV displayed a range of minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) values against the tested pathogens, spanning from 0.038 to 4.960 mg/mL. Further investigation identified the purified peptide derived from peak IV as G-type lysozyme 2, characterized by a molecular weight of 21 kDa. These findings shed light on the existence of a highly effective antimicrobial peptide, G-type lysozyme 2, within the mucus of Cyprinus carpio. This peptide demonstrates notable activity against diverse bacterial and fungal pathogens. The insights from this study enhance our understanding of the fish's antimicrobial defense mechanisms and hold promise for developing novel antimicrobial agents.

Antifungal Activity of Morinda citrifolia Methanolic Extract against Candida albicans: An In Vitro Study.

Natural medicine used as an alternative and/or complementary treatment to counteract diseases is of great importance in public health. Therefore, the purpose of the present study was to assess the in vitro antifungal activity of Morinda citrifolia methanolic extract of peel, pulp, and seed against Candida albicans. The present study was experimental in vitro and cross-sectional. Eight replicates were prepared in Sabouraud dextrose agar with five wells each, where 0.12% chlorhexidine, distilled water, and methanolic extract of seed, peel, and pulp of Morinda citrifolia fruit were placed at concentrations of 10,690, 8,270, and 6,430 mg/mL, respectively, to evaluate sensitivity according to Duraffourd's scale. In addition, the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) were determined by dilution and agar seeding method. Statistical analysis was performed by analysis of variance (ANOVA) and Tukey's post hoc test, considering a significance level of P < 0.05. The inhibition halos of Morinda citrifolia methanolic extract of seed, peel, and pulp against Candida albicans measured on average 15.94, 11.94, and 11.56 mm, respectively. The MIC of seed, peel, and pulp extract were 1366.25, 2067.5, and 1607.5 mg/mL respectively, whereas the MFC for seed, peel, and pulp extract were 2672.50, 2067.5, and 3215 mg/mL, respectively. Moreover, seed extract presented significantly higher antifungal activity than peel and pulp (P < 0.001). Morinda citrifolia methanolic extract of peel, pulp, and seed showed fungistatic and fungicidal effect against Candida albicans, being this very sensitive to seed extract with a MIC of 1366.25 mg/mL and a MFC of 2672.5 mg/mL, which allows recommending the development of effective pharmacological formulations for the control of candidiasis.

Antifungal Effect and Durability of Chitosan Oligosaccharide Coating on Heat-cured Polymethylmethacrylate Surface

This study aimed to investigate the antifungal effect against Candida albicans (ATCC® 10231) and the durability of chitosan oligosaccharide (COS) coated on heat-polymerized polymethylmethacrylate (PMMA). The various concentrations of COS solution, 0.5, 1 and 2-fold of minimum fungicidal concentration (0.5, 1 and 2 MFC) were prepared and applied to PMMA specimens treated with sandblasting (SB), application of 3-aminopropyltriethoxysilane (APS), and a combination of both procedures (SB&amp;APS). The toothbrush abrasion test was done to evaluate the remaining COS (n=10). The antifungal effect was determined through the colony count method (n=3). The number of fungal colonies was recorded at 16 and 48 hours. Data were analyzed using two-way and one-way ANOVA at the 95% confidence level. The result of the toothbrush abrasion test revealed that COS concentration and surface treatment affected coating durability. APS and SB&amp;APS groups showed a high percentage of COS and significantly differed from SB groups (P = 0.00). For the antifungal effect, coatings with 1 MFC and 2 MFC demonstrated no difference, but coating with 0.5 MFC differed from others (P = 0.00). At 16 and 48 hours, PMMA coated with 1 MFC and 2 MFC by APS and SB&amp;APS methods inhibited C.albicans. COS can be coated onto PMMA using APS and can inhibit C.albicans. With further development, this method could be applied to treat denture stomatitis alternatively to conventional antifungal drugs. Keywords: Candida albicans, Chitosan, Oligochitosan, Polymethylmethacrylate, Silanes

Investigation of the antimicrobial efficacy and cytotoxicity of a natural disinfectant Syzygium cumini (L.) skeels leaf extract on vero cell lines

Disinfectants are vital for infection prevention and environmental health maintenance. However, the use of chemical disinfectants has adverse effects on human health, including the development of antibiotic-resistance genes and resistance to disinfectants due to overuse and abuse. There is a critical need to find natural alternatives to reduce the problems caused by chemical disinfectants. The present study analyzed the antimicrobial activity of Syzygium cumini leaf extract (SCLE) against Staphylococcus aureus, Pseudomonas aeruginosa, Mucor sp., Candida albicans, and Aspergillus niger and its efficacy as a natural disinfectant was also evaluated, along with GC-MS analysis and in vitro toxicity test. The study showed that SCLE exhibited antimicrobial activity against all test organisms except A. niger. The minimum inhibitory concentration (MIC) against S. aureus, P. aeruginosa, Mucor sp., and C. albicans was 625, 1,250, 78, and 1,250 μg/ml, respectively. The minimum bactericidal concentration (MBC) against S. aureus and P. aeruginosa was 1,250 and 2,500 μg/ml, respectively. The minimum fungicidal concentration (MFC) against Mucor sp. and C. albicans was 156 and 5,000 μg/ml, respectively. SCLE demonstrated bactericidal and fungicidal properties based on MIC: MBC and MIC: MFC, with significant reductions in P. aeruginosa (99.99%), S. aureus (90.71%), Mucor sp. (92%), and C. albicans (73.45%) after the treatment. Syzygium cumini leaf extract, identified as nontoxic with an IC50 of 320μg/ml, proves promising as a potent natural disinfectant. This study marks the first report on the efficacy of S. cumini leaf extract against test organisms, showcasing its potential as a natural disinfecting agent against test organisms.

Lavandula dentata L. essential oil: a promising antifungal and antibiofilm agent against oral Candida albicans.

Candida albicans is the main fungal species involved in oral candidiasis, and its increasing resistance to pharmacological treatment encourages the search for improved antifungal agents. Lavandula dentata L. essential oil (LD-EO) has been recognized for its antimicrobial activity, but little is known about its role against oral C. albicans. This study evaluated the antifungal and antibiofilm activities, mechanisms of action, and toxicity of LD-EO from Brazil against oral strains of C. albicans. Antifungal activity was assessed based on Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), association study with miconazole (Checkerboard method), and sorbitol and ergosterol assays. Inhibition of biofilm formation and disruption of preformed biofilm were considered when studying the effects of the product. Additionally, the toxicity of LD-EO was evaluated by a hemolysis assay on human erythrocytes. Phytochemical analysis by gas chromatography-mass spectrometry identified eucalyptol (33.1%), camphor (18.3%), and fenchone (15.6%) as major constituents. The test substance showed mainly fungicidal activity (MIC100 = 8 μg/mL; MFC = 16 μg/mL), including against two miconazole-resistant isolates of C. albicans. The effects of LD-EO were synergistic with those of miconazole and appeared not to involve damage to the fungal cell wall or plasma membrane. Its effectiveness in inhibiting biofilm formation was higher than the effect of disrupting preformed biofilm. Finally, the product exhibited low hemolytic activity at MIC. Based on the favorable and novel results described here, LD-EO could constitute a promising therapeutic alternative for oral candidiasis, including miconazole-resistant cases.

Evaluation of (-)-Fenchone antimicrobial activity against oral Candida albicans and toxicological parameters: an in silico, in vitro and ex vivo study.

Candida albicans is the primary species causing oral candidiasis. Its increasing drug resistance drives the search for more effective antifungal agents. Therefore, we assessed toxicological parameters and the antimicrobial activity and mechanisms of action of the monoterpene (-)-fenchone against oral C. albicans. We conducted an in silico study using PASS online and AdmetSAR, followed by evaluation of antifungal activity through Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), association study with miconazole, and assays with sorbitol and ergosterol. Inhibition of biofilm formation and disruption of preformed biofilm were considered. Toxicity was also assessed through hemolysis assay. The in silico study revealed a higher likelihood of the compound being active for antifungal activity, as well as promising pharmacokinetic and toxicity characteristics. Subsequently, (-)-fenchone exhibited predominantly fungicidal activity (MIC90 = 8 μg/mL; MFC = 16 μg/mL), including against miconazole-resistant C. albicans isolates. The substance does not appear to act by damaging the fungal cell wall or plasma membrane, and exhibited synergy with miconazole. There was activity in inhibiting biofilm formation but not in disrupting preformed biofilm. Finally, the product exerted low hemolytic activity at more than MIC×10. Based on these results, (-)-fenchone may represent a promising therapeutic alternative for oral candidiasis.

Evaluation of Antimicrobial activity of AAROGYA-5 against the Pan-drug-resistant Resistant Pathogenic Microorganisms

Background: Antimicrobial resistance (AMR) is emerging as a severe healthcare crisis worldwide. It is a most significant threat to global health, food security, and development, according to the World Health Organization (WHO). The world is entering the "post-antibiotic era", and over 10 million people will die from AMR by 2050. This rising resistance has rekindled interest among researchers in discovering and developing novel, more potent antibacterial drugs to combat AMR. Objectives: In this study, the antimicrobial effectiveness of aqueous/hydro-alcoholic extracts of AAROGYA-5 (Rajata Bhasma, powders of Ocimum tenuiflorum, Tinospora cordifolia, Ficus benghalensis, and Azadirachta indica), a Herbo-mineral formulation will be evaluated against the gram-negative, gram-positive bacteria and fungi. Methods: The formulation was studied for its antimicrobial activity by measuring the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) against Candida Albicans (fungal strain) and Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniae, and Escherichia coli (bacterial strains) at different concentrations: 100mg/mL, 50mg/mL, 25mg/mL, 12.5mg/mL, 6.25mg/mL, 3.125mg/mL, 1.5625 mg/mL, and 0.78125 mg/mL by Kirby Bauer and broth microdilution method. Result: AAROGYA-5 in the form of extracts has shown significant activity at a strength of 12.5mg/mL against the Gram-positive bacteria, i.e., S. aureus and E. faecalis, and the hydro-alcoholic extract of AAROGYA-5 was found to be effective at a strength of 6.25 mg/mL against C. albicans. Discussion: The ayurvedic formulation AAROGYA-5 was effective against the Multidrug-resistant (MDR) gram-positive cocci, i.e., S. aureus and E. faecalis. Moreover, the hydro-alcoholic extract is effective against C. albicans. In addition, the AAROGYA-5 has no activity against Gram-negative bacteria in either extract. Conclusion: Based on these results, the present study demonstrated that AAROGYA-5 has significant antimicrobial activity against MDR- S. aureus, E. faecalis, and C. albicans.

Antifungal activity of 2-chloro-N-phenylacetamide: a new molecule with fungicidal and antibiofilm activity against fluconazole-resistant Candida spp.

In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL-1, and a MFC of 512-1,024 µg.mL-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

Antimicrobial and antibiofilm activities of Inga cylindrica trypsin inhibitor.

Inga cylindrica, a tropical fruit tree of the Fabaceae family (subfamily Mimosoideae), is native to South America. The seeds from this family are an essential source of trypsin inhibitors, which display promising bioactivity for increasing host defense against pathogens. The aim of the present study was to characterize the antimicrobial and antibiofilm activities of the trypsin inhibitor extracted from I. cylindrica seeds, ICTI. ICTI demonstrated antifungal activity with a minimum inhibitory concentration (MIC) of 32.11 μmol.L-1, and a minimum fungicidal concentration (MFC) of 32.1 μmol.L-1, against Cryptococcus gattii, Candida albicans, Candida glabrata and Candida guilliermondii. Combining ICTI with Amphotericin B had a significant synergistic effect, reducing the concentration of the antibiotic by 75% for C. albicans and 94% for C. gatti. The significant increase (16 x) in activity observed with ergosterol (1.01 mol.L-1) for C. albicans and C. gatti, and the lack of activity against bacterial strains, suggests that ICTI interferes with the integrity of the fungal cell membrane. Treatment with ICTI at 10 x MIC resulted in a 51% reduction in biofilm formation and a 56% decrease in mature biofilm colonies for C. albicans. Finally, ICTI displayed no toxicity in the in vivo Galleria mellonella model. Given its antifungal and antibiofilm properties, ICTI could be a promising candidate for the development of new antimicrobial drug prototypes.

Glandular trichomes as a source of antifungal metabolites in a karyologically characterized population of Argyrochosma flava: Morphology and histochemistry

Argyrochosma, a xeric-adapted fern genus mostly from the New World, includes both farinose and non-farinose species. The yellow farina appears to be a synapomorphy of A. flava. The aims of this research were to study the morphology, location, distribution, and density of glandular trichomes; perform a histochemical analysis of the farina secretion; evaluate the biological activity of farinas against phytopathogenic fungi; and characterize the species genetically by making chromosome counts and building the karyotype of A. flava. Usual methods in plant anatomy and histochemistry were performed. Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) of farina against four phytopathogenic fungi were determined by the broth microdilution technique. Chromosome counts and karyotyping metaphase plates were obtained from fiddleheads. The distribution of glandular trichomes in pinnules changes along the ontogenetic development of the frond. The histochemical study of the trichomes revealed the complex nature of the secreted material, including flavonoids and terpenes along with other metabolites. The farina was active against the four pathogenic fungi evaluated, with MICs between 31.25 and 125 μg/mL showing the highest inhibition for Monilinia fructicola. Botrytis cinerea displayed a MIC value of only one-fold dilutions more than the commercial fungicide Carbendazim. Cytogenetically, the base number proposed for the genus is x = 27, which is derived from aneuploidy of x = 29. The genus has diploid and tetraploid forms. The results obtained support the important role of glandular trichomes and farinous exudate secretion in the protection against phytopathogenic fungi. The obtained chromosome numbers support the taxonomic placement of A. flava.

Antifungal activity of Annona crassiflora Mart. dichloromethane fraction against strains of C. albicans.

Products derived from medicinal plants with antimicrobial activity are considered a promising alternative in the treatment of fungal infections. In this perspective, this study proposed to evaluate the antifungal activity of the dichloromethane fraction of Annona crassiflora Mart. against C. albicans strains. Tests were carried out to determine Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC), microbial growth kinetics, fungal cell wall and membrane mechanisms of action, antifungal biofilm activity, and cytotoxic effects on human erythrocytes. The extract presented MIC and MFC values that ranged from 256 µg/mL to 1,024 µg/mL, with fungicidal activity in the microbial growth kinetics assay. The mechanism of action did not occur through damage to the cell wall or via binding to ergosterol in the membrane, though the fraction presents activity against biofilm and is not cytotoxic in human erythrocytes. The dichloromethane fraction of Annona crassiflora Mart. presented antifungal activity and reduced biofilm growth, without toxicity against human erythrocytes; however, further studies are needed to define its mechanism of action.

Microwave-assisted synthesis, characterization, and in vitro biological evaluation of a novel nanocomposite using molybdenum and [2,2'-bipyridine]-4,4'-dicarboxylic acid.

Currently, nanocomposites are synthesized and used in various fields. One of the applications of these nanostructures is in the medical field. Therefore, the synthesis of new composites with biological properties is important. In this study, under microwave conditions, a new nanocomposite containing molybdenum and [2,2'-bipyridine]-4,4'-dicarboxylic acid (Mo/BPDA) was synthesized. The synthesized Mo/BPDA composite was subjected to biological evaluations such as antibacterial and antifungal properties by clinical and laboratory standards institute guidelines, and anticancer properties by MTT method. Characterization and structure characteristics of the Mo/BPDA nanocomposite were evaluated using XRD (X-ray diffraction pattern), FT-IR (Fourier-transform infrared), EDAX (energy-dispersive X-ray), EA (elemental analysis), TGA/DTG (thermogravimetric analysis/differential thermogravimetry), SEM (scanning electron microscopy) and BET (Brunauer-Emmett-Teller) analysis. The results indicated relatively high thermal stability (300 °C), high specific surface area (35 cm3 g-1) and uniform morphology of the synthesized Mo/BPDA nanocomposite. In antibacterial and antifungal activity, minimum inhibitory concentration (between 2 and 256 μg mL-1), minimum bactericidal concentration (between 4 and 128 μg mL-1), and minimum fungicidal concentration (between 64 and 256 μg mL-1) were tested and reported. The results showed that the antibacterial and antifungal activity of Mo/BPDA nanocomposite is higher than that of antibiotic drugs such as ampicillin, cefazolin, ketoconazole, and nystatin. In the investigation of the anticancer activity that was tested against bone cancer cells and breast cancer cells for 24 and 48 hours, cell proliferation and viability (37.3648-82.0674 tan control) and IC50 (33-43 μg mL-1) were observed. As a final result, it can be stated that the synthesized Mo/BPDA nanocomposite after the additional biological evaluations, such as in vivo study, can be used as an efficient option in treating bone cancer cells and breast cancer cells and a strong antibiotic on a wide range of infectious diseases.

Monoterpene antifungal activities: evaluating geraniol, citronellal, and linalool on Candida biofilm, host inflammatory responses, and structure-activity relationships.

Introduction: Despite the rising concern with fungal resistance, a myriad of molecules has yet to be explored. Geraniol, linalool, and citronellal are monoterpenes with the same molecular formula (C10H18O), however, neither the effect of these compounds on inflammatory axis induced by Candida spp. nor the antibiofilm Structure-Activity Relationship (SAR) have been well-investigated. Herein we analyzed geraniol, linalool and citronellal antifungal activity, cytotoxicity, and distinctive antibiofilm SAR, also the influence of geraniol on Candida spp induced dysregulated inflammatory axis, and in vivo toxicity. Methods: Minimal inhibitory (MIC) and fungicidal (MFC) concentrations against Candida spp were defined, followed by antibiofilm activity (CFU-colony forming unit/mL/g of dry weight). Cytotoxic activity was assessed using human monocytes (THP-1) and oral squamous cell (TR146). Geraniol was selected for further analysis based on antifungal, antibiofilm and cytotoxic results. Geraniol was tested using a dual-chamber co-culture model with TR146 cells infected with C. albicans, and THP-1 cells, used to mimic oral epithelium upon fungal infection. Expression of Candida enzymes (phospholipase-PLB and aspartyl proteases-SAP) and host inflammatory cytokines (interleukins: IL-1β, IL-6, IL-17, IL-18, IL-10, and Tumor necrosis factor-TNF) were analyzed. Lastly, geraniol in vivo toxicity was assessed using Galleria mellonella. Results: MIC values obtained were 1.25-5mM/mL for geraniol, 25-100mM/mL for linalool, and 100-200mM/mL for citronellal. Geraniol 5 and 50mM/mL reduced yeast viability during biofilm analysis, only 500mM/mL of linalool was effective against a 72h biofilm and no biofilm activity was seen for citronellal. LD50 for TR146 and THP-1 were, respectively: geraniol 5.883 and 8.027mM/mL; linalool 1.432 and 1.709mM/mL; and citronellal 0.3006 and 0.1825mM/mL. Geraniol was able to downregulate expression of fungal enzymes and host pro-inflammatory cytokines IL-1β, IL-6, and IL-18. Finally, safety in vivo parameters were observed up to 20mM/Kg. Discussion: Despite chemical similarities, geraniol presented better antifungal, antibiofilm activity, and lower cytotoxicity when compared to the other monoterpenes. It also showed low in vivo toxicity and capacity to downregulate the expression of fungal enzymes and host pro-inflammatory cytokines. Thus, it can be highlighted as a viable option for oral candidiasis treatment.

In vitro antifungal activity of MMV Pathogen Box® compounds alone or in combination with antifungal drugs against mucormycosis agents

Mucormycosis is a severe fungal infection that demands immediate and decisive intervention upon suspicion. The causative agents of mucormycosis exhibit inherent resistance to echinocandins and voriconazole, and their in vitro susceptibility to terbinafine is highly variable and species-specific. Considering these factors and the limitations of currently available antifungal therapies, the identification of novel antifungals with potent activity against mucormycosis is of paramount importance. This study aims to identify compounds from the MMV Pathogen Box® presenting antifungal activity against selected mucormycosis agents and to evaluate their potential synergistic effects when combined with antifungal drugs. A screening of the Pathogen Box® compounds was conducted, isolated or in combination with sub-inhibitory concentrations of amphotericin B, isavuconazole or posaconazole, against a Rhizopus oryzae strain. Hits from the screenings were further evaluated against eight Mucoralean strains for minimal inhibitory and fungicidal concentration determinations and to confirm synergistic interactions using the checkerboard method. Ultrastructural studies were performed using scanning electron microscopy. MMV675968 exhibited fungicidal activity against a R. oryzae strain. All but one Rhizopus spp. strains presented MIC ≤ 1 μg/mL, with a geometric mean of 0.78 μg/mL observed across all isolates for this compound, which did not change significantly the cellular structure of this fungus. The combination screening with antifungal drugs revealed six additional compounds potentially active against the R. oryzae strain, two of them demonstrated proven synergism through the checkerboard assay. This first study with the MMV Pathogen Box® and Zigomycetes highlights promising new treatment options for mucormycosis in the future.