High Antifungal Activity Research Articles

Initial In Vitro Assessment of the Antifungal Activity of Aqueous Extracts from Three Invasive Plant Species

The development of new, safe, and effective methods of managing fungal pathogens is required. This study was conducted to perform an initial in vitro assessment of the antifungal activity of water-based plant extracts from three plants which are invasive in Egypt: Prosopis juliflora, Ipomoea carnea, and Leucaena leucocephala. These extracts were tested against three pathogenic fungi species that cause high crop losses in Egypt: Fusarium solani, Alternaria solani, and Colletotrichum circinans. Three extract concentrations, 10%, 20%, and 30%, were tested using a completely randomized design, with three replicates per treatment. Antifungal activity was determined based on the effects of plant extracts on fungal radial growth inhibition, average daily growth of fungi, spore formation, spore germination, and total biomass. Inhibition of the growth of fungal strains increased with increasing plant extract concentration, with the highest inhibitory rate at the 30% extract concentration. In addition, spore density, spore germination, and total biomass decreased significantly with increasing extract concentration. The three fungal pathogens differed in their inhibition and their response to these plant extracts. Prosopis juliflora had the highest inhibitory effect on the three fungal pathogens, compared to the extracts from the other two invasive plants. The results of this feasibility study indicate that P. juliflora extracts have high antifungal activity and follow-up in vivo assays should be conducted to determine their efficacy in the safe and sustainable management of these and other fungal pathogens.

Azadirachta indica A. Juss Fruit Mesocarp and Epicarp Extracts Induce Antimicrobial and Antiproliferative Effects against Prostate (PC-3), Breast (MCF-7), and Colorectal Adenocarcinoma (Caco-2) Cancer Cell Lines through Upregulation of Proapoptotic Genes.

Effective alternative strategies and methodological approaches are critically necessary for cancer prevention and therapy. In this study, we investigated the antitumor potential of neem fruit mesocarp and epicarp extracts. The chemical composition of the derived extracts was characterized using GC–MS. Data were collected on the antimicrobial activity of the extracts in addition to the cytotoxicity effect evaluated against PC-3, MCF-7, and Caco-2 cancer cell lines, compared with the normal Vero cells. Cell-cycle arrest, apoptosis, and expression of apoptosis-related genes were assessed on PC-3 cells. Both extracts had significant antiproliferative effects on all tested cell lines in a dose-dependent manner, with the mesocarp extract being more potent. Both extracts also showed high antibacterial and antifungal activities. These results were related to the chemical constituents of the extracts identified by the GC–MS analysis. The extract of neem fruit mesocarp caused cell-cycle arrest at G2/M phase of PC-3 cells. The cytotoxicity of neem mesocarp extract is strongly correlated with the induction of apoptosis, where it caused downregulation of the antiapoptotic BCL2 gene but upregulation of the proapoptotic P53 and BAX genes. This study showed that neem fruit extract is potential anticancer material in the future.

Design, Synthesis, and Antifungal Activities of Hymexazol Glycosides Based on a Biomimetic Strategy

Hymexazol (HYM) is irreplaceable for treating soil-borne diseases due to its high efficiency and low cost, as a broad-spectrum fungicide. However, when HYM is absorbed by plants, it is rapidly converted into two glycoside metabolites, and the antifungal activities of these glycosides are inferior to that of HYM. Therefore, in this study, to maintain strong antifungal activity in vitro and in vivo, HYM was glycosylated with amino sugars that have diverse biological activities to simulate plant glycosylation. The antifungal experiment proved that glycoside 15 has the highest antifungal activity, and N-acetyl glucosamine and HYM had obvious synergistic effects. According to the structure-activity relationship studies, glycoside 15 had greater numbers of active electron-rich regions and front-line orbital electrons due to the introduction of N-acetyl glucosamine. Moreover, glycoside 15 can significantly promote plant growth and induce an increase in plant defense enzyme activity. Additionally, compared to HYM, the results of electron microscopy and proteomics revealed that glycoside 15 has a unique antifungal mechanism. The promising antifungal activity and interactions with plants mean that glycoside 15 is a potential green fungicide candidate. Furthermore, this research conducted an interesting exploration of the agricultural applications of amino sugars.

Antifungal Activity of Endophytic Bacillus K1 Against Botrytis cinerea.

Gray mold caused by Botrytis cinerea is detrimental to plants and fruits. Endophytes have been shown to modify plant disease severity in functional assays. We conducted this study to investigate the endophytic strain Bacillus K1 with excellently antagonistic B. cinerea from the wild grape endosphere. We identified a wild grape endophytic strain K1 with high antifungal activity against B. cinerea both in vitro and in vivo. Combining the phylogenetic results based on 16S rDNA and genome sequencing, K1 was assigned as Bacillus subtilis. The in vitro results displayed that K1 and its volatile substances could significantly inhibit the mycelia growth of B. cinerea. Grape fruit inoculated with Bacillus K1 showed lower gray mold during treatment. The higher levels of defense-related enzymes, including peroxidase, polyphenol oxidase, and phenylalanine ammonia lyase, were induced in grapes after inoculation. Scanning electron microscopy (SEM) suggested that K1 inhibited mycelial growth via bacterial colonization and antibiosis in grapes. The gas chromatography–mass spectrometry analysis identified 33 volatiles in which dibutyl phthalate was the major compound accounting for 74.28%. Dibutyl phthalate demonstrated strong activity in suppressing the mycelia growth of B. cinerea. Genome bioinformatics analysis revealed that the K1 chromosome harbored many known biosynthesis gene clusters encoding subtilosin, bacillaene, bacillibactin, bacilysin, and fengycin. This study provides a potential biological agent to control diseases of post-harvest grape fruit and improves our understanding of the possible biocontrol mechanisms of the Bacillus strain.

Effectiveness of different accelerated green synthesis methods in zinc oxide nanoparticles using red pepper extract: Synthesis and characterization

Abstract Potential ability of red pepper extract in zinc oxide nanoparticles (ZnO NPs) fabrication via three accelerated heating techniques, namely, conventional heating with stirring (at 100°C and 700 rpm, for 30 min), autoclave (at 15 psi and 121°C, for 15 min), and microwave irradiation (power of 800 W for 3 min) was assessed. Fourier transform infrared spectroscopy and gas chromatography mass spectroscopy indicated that the prepared extract contained 20 active compounds including alcohols, aldehydes, ketones, esters, and organic acids with several functional groups such as hydroxyls. Results indicated that ZnO NPs with spherical and hexagonal structures have been formed using three different heating methods, and the minimum crystal size for the fabricated ZnO NPs was 88.44 nm, which was attained using heating by autoclave. Antioxidant activity of the synthesized ZnO NPs was determined using the red pepper extract, and accuracy of this method was 80.21%. Finally, results indicated that the formed ZnO NPs had high antibacterial activity against Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis and high antifungal activity against Aspergillus niger and Aspergillus flavus.

Pb (II) and Hg (II) thiosemicarbazones for inhibiting the broad‐spectrum pathogen Cladosporium sphaerospermum ASU18 (MK387875) and altering its antioxidant system

Pb (II) and Hg (II) ions were reacted in aqueous solution with two tridentate thiosemicarbazones, resulting in four complexes {[Pb(L1)2] 1, [Pb(L2)2] 2, [Hg(L1)2] 3, and [Hg(L2)2] 4; HL1 = 4‐(4‐nitrophenyl)‐1‐[(pyridin‐2‐yl)methylene]thiosemicarbazide and HL2 = 4‐(2‐chlorophenyl)‐1‐[(pyridin‐2‐yl)methylene]thiosemicarbazide}. The solid‐state structures of complexes 2 and 3 were determined by X‐ray crystallography, which also confirmed the monobasic tridentate NNS nature of the ligands, and the octahedral coordination geometry around the metal centers. Complexes 1–4 exhibited high antifungal activity against the pathogen Cladosporium sphaerospermum; all four complexes give rise to a reduction in the fungal dry mass and sugar consumption. Complexes 2 and 4 that inhibited C. sphaerospermum growth at the concentration of 1.8 mM are more efficient inhibitors than the free ligand and metal ions. Further, the complexes gave varied values of the fungal total antioxidants (TA), superoxide dismutase (SOD), and catalase (CAT) activities dependent on their concentrations.

Synthesis and Bioactivity of Novel Sulfonate Scaffold-Containing Pyrazolecarbamide Derivatives as Antifungal and Antiviral Agents.

Novel pyrazolecarbamide derivatives bearing a sulfonate fragment were synthesized to identify potential antifungal and antiviral agents. All the structures of the key intermediates and target compounds were confirmed by nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS). The single-crystal X-ray diffraction of the compound T22 showed that pyrazole carbamide is a sulfonate. The in vitro antifungal activities of the target compounds against Colletotrichum camelliae, Pestalotiopsis theae, Gibberella zeae, and Rhizoctonia solani were evaluated at 50 μg/ml. Among the four pathogens, the target compounds exhibited the highest antifungal activity against Rhizoctonia solani. The compound T24 (EC50 = 0.45 mg/L) had higher antifungal activity than the commercial fungicide hymexazol (EC50 = 10.49 mg/L) against R. solani, almost similar to bixafen (EC50 = 0.25 mg/L). Additionally, the target compounds exhibited protective effects in vivo against TMV. Thus, this study reveals that pyrazolecarbamide derivatives bearing a sulfonate fragment exhibit potential antifungal and antiviral activities.

Identification of the Causal Agent of Brown Leaf Spot on Kiwifruit and Its Sensitivity to Different Active Ingredients of Biological Fungicides.

Kiwifruit (Actinidia chinensis) is an important commercial crop in China, and the occurrence of diseases may cause significant economic loss in its production. In the present study, a new pathogen that causes brown leaf spot disease on kiwifruit was reported. The fungus was isolated from an infected sample and identified as Fusarium graminearum based on morphological and molecular evaluation. Koch’s postulates were confirmed when the pathogen was re-isolated from plants with artificially induced symptoms and identified as F. graminearum. Based on the biological characteristics of the pathogen, it was determined that: its optimal growth temperature was 25 °C; optimal pH was 7; most suitable carbon source was soluble starch; most suitable nitrogen source was yeast powder; and best photoperiod was 12 h light/12 h dark. Further investigations were conducted by determining 50% effective concentrations (EC50) of several active ingredients of biological fungicides against F. graminearum. The results showed that among the studied fungicides, tetramycin and honokiol had the highest antifungal activity against this pathogen. Our findings provide a scientific basis for the prevention and treatment of brown leaf spot disease on kiwifruit.

Deverra triradiata Hochst. ex Boiss. from the Northern Region of Saudi Arabia: Essential Oil Profiling, Plant Extracts and Biological Activities.

Devrra triradiata Hochst. ex Boiss is an occasional plant species in the Northern region of Saudi Arabia. The shrub is favored on sandy desert wadis, gypsaceous substrate, and sandy gravel desert. In folk medicine, the plant is used for many purposes; to relieve stomach pains, against intestinal parasites, and for the regulation of menstruation. The present study describes the chemical composition of the essential oils (EOs) of different plant parts of D. triradiata. In vivo and in vitro biological activities of plant extracts and essential oils were also studied. Phenylpropanoids, elemicin (flowers: 100%), dillapiole (Stems: 82.33%; and seeds: 82.61%), and apiol (roots: 72.16%) were identified as the major compounds. The highest antioxidant activity was recorded for the EOs of roots and stems (IC50 = 0.282 µg/mL and 0.706 µg/mL, respectively). For plant extracts, ethyl acetate showed the highest antioxidant activities (IC50 = 2.47 and 3.18 µg/mL). EOs showed high antifungal activity against yeasts with low azole susceptibilities (i.e., Malassezia spp. and Candida krusei). The MIC values of EOs ranged between 3.4 mg/mL and 56.4 mg/mL. The obtained results also showed phytotoxic potential of plant extracts both on the germination features of Triticum aestivum seeds and the vegetative growth of seedlings.

Posaconazole-amino acid cocrystals for improving solubility and oral bioavailability while maintaining antifungal activity and low In vivo toxicity

The present work contributes to modulate the biopharmaceutical parameters through co-crystallization of posaconazole. The cocrystals of posaconazole were fabricated with amino acids as co-formers, which are zwitterionic, GRAS status, and biological non-hazardous in nature using solvent evaporation and liquid assistant grinding. Preliminary screening was done by using DSC for the suitability of the co-former. Structural characterizations DSC, PXRD, FT-IT, SEM, 1H FT-NMR were conducted to identify cocrystal formation. The equilibrium solubility, % drug release, and stability of cocrystals were explored. Among the two novel cocrystals, posaconazole-l-glutamine cocrystal showed higher solubility (92.42-fold) and dissolution (7.72-fold) enhancement compared to that of the parent molecule. This may be due to the less enthalpy and weaker crystallinity reported in DSC and PXRD respectively. Moreover, both cocrystals maintained their integrity under different conditions of stability studies after 90 days. FT-NMR results revealed that the hydroxyl and triazole group of posaconazole and carboxyl and amino group of amino acids participated in intermolecular ionic interaction. Under bioavailability study, AUC0.24 of Posaconazole-glutamine cocrystals exhibited 13.14-fold and 2.34-fold enhancement than the pure drug and noxafil suspension respectively. Furthermore, In vitro antifungal activity and In vivo acute toxicity studies on novel cocrystal found to have high antifungal activity and no signs of toxicity even at 5000 mg/kg of body weight respectively. These results indicate that the co-crystallization technique has great potential in modulating the physicochemical properties of poorly water-soluble drugs like posaconazole.

Variation in Anti-inflammatory, Anti-arthritic, and Antimicrobial Activities of Different Extracts of Common Egyptian Seaweeds with an Emphasis on Their Phytochemical and Heavy Metal Contents

The anti-inflammatory, anti-arthritic, and antimicrobial activities of some common Egyptian seaweeds in addition to their phytochemical and heavy metal contents were investigated. Phytochemical screening of the seaweed extracts showed the presence of different primary and secondary metabolites with different concentrations according to their species and the used solvent. The ethanolic extract of Colpmenia sinuosa (CSBE2) exhibited the maximum anti-inflammatory and anti-arthritic activity at 1000 μg/ml concentration compared to other seaweed extracts. The dichloromethane extract of Corallina officinalis (CORM) exerted the highest antimicrobial activity with an average inhibition zone diameter (AV) = 15.29 mm and activity index (AI) = 1.53 and with the highest antagonistic activity against Escherichia coli (28 mm). It is followed by Ulva linza ethanolic extract (ULGE2) which recorded (AV) of 14.71 mm and (AI) of 1.30 with the highest antifungal activity against Candida albicans (30 mm). The collected seaweeds would therefore be a very promising source for treating inflammatory, arthritic, and microbial diseases. Moreover, the investigated seaweeds showed variable concentrations of heavy metals among various species. The mean concentrations of the heavy metals took the following order: Fe > Zn > Mn > Ba > Cu > As > Cr > Ni > Pb > V > Cd > Se > Co > Mo. Based on the permissible limits set by the WHO and CEVA, Pb and Ni in the studied seaweeds were found to be within the permissible limits, whereas Cd and Zn contents were at the borderline. Significant correlations were observed between studied parameters. The estimated daily intakes for most heavy metals were lower than the recommended daily intakes.

Structural Analysis and Construction of a Thermostable Antifungal Chitinase.

Chitin is a biopolymer of N-acetyl-d-glucosamine with β-1,4-bond and is the main component of arthropod exoskeletons and the cell walls of many fungi. Chitinase (EC 3.2.1.14) is an enzyme that hydrolyzes the β-1,4-bond in chitin and degrades chitin into oligomers. It has been found in a wide range of organisms. Chitinase from Gazyumaru (Ficus microcarpa) latex exhibits antifungal activity by degrading chitin in the cell wall of fungi and is expected to be used in medical and agricultural fields. However, the enzyme's thermostability is an important factor; chitinase is not thermostable enough to maintain its activity under the actual application conditions. In addition to the fact that thermostable chitinases exhibiting antifungal activity can be used under various conditions, they have some advantages for the production process and long-term preservation, which are highly demanded in industrial use. We solved the crystal structure of chitinase to explore the target sites to improve its thermostability. We rationally introduced proline residues, a disulfide bond, and salt bridges in the chitinase using protein-engineering methods based on the crystal structure and sequence alignment among other chitinases. As a result, we successfully constructed the thermostable mutant chitinases rationally with high antifungal and specific activities. The results provide a useful strategy to enhance the thermostability of this enzyme family. IMPORTANCE We solved the crystal structure of the chitinase from Gazyumaru (Ficus microcarpa) latex exhibiting antifungal activity. Furthermore, we demonstrated that the thermostable mutant enzyme with a melting temperature (Tm) 6.9°C higher than wild type (WT) and a half-life at 60°C that is 15 times longer than WT was constructed through 10 amino acid substitutions, including 5 proline residues substitutions, making disulfide bonding, and building a salt bridge network in the enzyme. These mutations do not affect its high antifungal activity and chitinase activity, and the principle for the construction of the thermostable chitinase was well explained by its crystal structure. Our results provide a useful strategy to enhance the thermostability of this enzyme family and to use the thermostable mutant as a seed for antifungal agents for practical use.

Antiviral and antifungal activities of lanthanum molybdate and copper molybdate

After La2Mo2O9 (LMO), Cu-substituted LMO (LCuMO), and CuMoO4 (CuMO) powders were prepared by complex polymerization method or oxide mixing method, their antiviral and antifungal activities were evaluated. The obtained samples were powders having a crystal structure of either La2Mo2O9 or CuMoO4 with specific surface area of 3.0–6.0 m2/g. These samples exhibited almost equal antiviral activity against bacteriophage Qβ, whereas CuMO was found to have the highest antiviral activity against bacteriophage Φ6. An antifungal activity test based on JIS Z 2911 showed LCuMO and CuMO to have high activity; CuMO had high antiviral and antifungal activity. In fact, CuMO had a large amount of ion leakage to the inoculated suspension. The Cu ion leakage was promoted by that of molybdate ion. The high antifungal activity of CuMO was inferred as attributable to the large amount of ion leakage and the generation of reactive oxygen species.

Biochemical Analyses of Ten Cyanobacterial and Microalgal Strains Isolated from Egyptian Habitats, and Screening for Their Potential against Some Selected Phytopathogenic Fungal Strains

Microalgae and cyanobacteria are rich sources of numerous phytochemical compounds with intrinsic antifungal potential. This research aimed to screen the phytochemical compounds and contents, as well as the antioxidant profiles, in eight cyanobacterial and two microalgal strains isolated from soil and brackish water habitats in Egypt. Our study also evaluated their antifungal activities against three phytopathogenic fungi—namely, Pythium ultimum, Fusarium solani, and Botryodiplodia theobromae, which are known to cause severe plant loss. The biochemical compounds were obtained from the cyanobacterial and algal methanolic extracts, and were identified through comparative phytochemical analyses related to the inhibition of the fungal pathogens. Comparative qualitative analyses of alkaloids, steroids, glycosides, and saponins were also carried out. The quantitative phytochemical screening of the cyanobacterial and algal strains investigated revealed the presence of xylanase, glucanase, and chitinase enzymes, along with some bioactive compounds, such as phenolics, flavonoids, proteins, neutral sugars, and carotenoids, which were species-dependent and detected in variable amounts in the extracts. The unicellular green microalgal strain Dunaliella sp. HSSASE13 displayed the highest level of antioxidant activity. However, the highest antifungal activities were shown by the heterocystous cyanobacterial strain Anabaena sp. HSSASE11 (83.94%), followed by Dunaliella sp. HSSASE13 (81.94%) and the non-heterocystous cyanobacterial strain Oscillatoria nigro-viridis HSSASE 15 (63.42%), against the three fungal pathogens B. theobromae, F. solani, and P. ultimum, respectively. Our results indicate that the highest significant and positive correlations of flavonoids (r = 0.854), phenolics (r = 0.785), DPPH scavenging activity (r = 0.876), total proteins (r = 0.808), xylanase activity (r = 0.876), glucanase activity (r = 0.746), and total neutral sugars (r = 0.764), in terms of their antifungal activities, were recorded against F. solani. Conclusively, the cyanobacterial and algal strains tested in the present study can be useful agents for the management and biocontrol of plant-infecting fungal pathogens.

In Vitro Activity of Ebselen and Diphenyl Diselenide Alone and in Combination with Drugs against Trichophyton mentagrophytes Strains

Background: Dermatophytoses are one of the most prevalent infectious diseases in the world for which the pace of developing new drugs has not kept pace with the observed therapeutic problems. Thus, searching for new antifungals with an alternative and novel mechanism of action is necessary. Objective: This study aimed to evaluate the antifungal activity of ebselen and diphenyl diselenide against Trichophyton mentagrophytes clinical isolates. Methods: In vitro antifungal susceptibility was assessed for organoselenium compounds used alone or in combination with allylamines and azoles according to the 3rd edition of the CLSI M38 protocol. Results: Ebselen demonstrated high antifungal activity with MICGM equal to 0.442 μg/mL and 0.518 μg/mL in the case of human and animal origin strains, respectively. The values of MICGM of diphenyl diselenide were higher: 17.36 μg/mL and 13.45 μg/mL for the human and animal isolates, respectively. Synergistic or additive effects between terbinafine and ebselen or diphenyl diselenide were observed in the case of 12% and 20% strains, respectively. In turn, the combination of itraconazole with diphenyl diselenide showed a synergistic effect only in the case of 6% of the tested strains, whereas no synergism was shown in the combination with ebselen. Conclusions: The results highlight the promising activity of organoselenium compounds against Trichophyton mentagrophytes. However, their use in combinational therapy with antifungal drugs seems to be unjustified due to the weak synergistic effect observed.

Carbon quantum dots-based antifungal coating film for active packaging application of avocado

This study investigated the applicability of carbon dots (CDs) as a functional filler for producing active food packaging films. CDs were synthesized by a one-pot hydrothermal method using glucose as the carbon source. The CDs were used to prepare chitosan/gelatin (Chi/Gel)-based composite films. The addition of CDs increased the UV blocking property of the film by 99% without significant change in mechanical properties, water vapor permeability (WVP), and water contact angle (WCA). In addition, the CDs-added composite films showed potent antioxidant activity. The composite film generates reactive oxygen species (ROS) and exhibits high antibacterial activity against pathogenic bacteria, showing 100% destruction of L. monocytogenes and E. coli. The composite film also exhibited high antifungal activity against mold (Aspergillus flavus and Colletotrichum orbiculare) and had negligible cytotoxicity to L929 cells even after long-term exposure of 72 h. The chitosan/gelatin/CDs-film coating effectively inhibited the growth of mold on the surface of avocados and extended the fruit shelf life by more than 14 days. The CDs are likely to be a value-added, low-cost, and safe, functional nanofiller for preparing functional films for active packaging applications.

Chitosan and Nano-Chitosan for Management of Harpophora maydis: Approaches for Investigating Antifungal Activity, Pathogenicity, Maize-Resistant Lines, and Molecular Diagnosis of Plant Infection.

The rapid spread of late wilt disease among maize cultivations has resulted in serious economic losses in many countries. Harpophora maydis is the main cause of this destructive vascular disease. Here we evaluate the fungicidal activity of chitosan and nano-chitosan against six aggressive isolates of H. maydis collected from different Egyptian governorates. Pathogenicity tests for these isolates show that the highest disease severity was found for the Giza isolate. The isolates were tested for their response to the fungicide Permis, chitosan, and nano-chitosan treatments in vitro and in vivo. Nano-chitosan treatments fully inhibited the radial growth of H. maydis isolates at concentrations of 5 and 10 mM, compared to the full control growth (9 cm in diameter). On the other hand, in vitro, in vivo, and molecular diagnosis results showed high antifungal activity of chitosan and nano-chitosan compared to the Permis fungicide. Chitosan at the nano and normal scales proved a potent ability to enhance plant resistance in response to H. maydis. Disease severity (DS%) was extremely decreased among the tested cultivars by using nano-chitosan; the highest percentage was obtained on Giza 178 cv, where the DS% was 21.7% compared to 42.3% for the control. Meanwhile, the lowest percentage was obtained on Giza 180 cv with DS% 31.2 and the control with 41.3%. The plants treated with nano-chitosan showed the highest growth parameters for all cultivars. Such natural treatments could reduce the impact on the environment as they are non-pollutant natural compounds, protect the plants by reducing fungal activity, and induce plant resistance.

Daylight-Driven Rechargeable TiO2 Nanocatalysts Suppress Wheat Blast Caused by Magnaporthe oryzae Triticum

Abstract Wheat blast, caused by the Magnaporthe oryzae Triticum (MoT) pathotype, threatens wheat production in many countries, including Bangladesh. Traditional fungicides are ineffective in combating this pathogen, and no resistant wheat variety is available. This study investigated the mechanism of wheat blast suppression by a nanostructured TiO2 nanocatalyst (NC) that generates reactive oxygen species through a photocatalytic process under daylight settings. In the presence of sunlight, the NCs displayed a high antifungal activity against MoT in vitro (minimum inhibitory concentration - MIC 0.025 mg/ml), as well as suppressed conidial formation and mycelial growth of MoT. Moreover, the fungal biomass was drastically reduced at NC concentrations ≥0.5 mg/ml. In vivo seedling assays showed inhibition of wheat blast when wheat seedlings were artificially inoculated with conidia. Under daylight conditions, NCs at a concentration from 0.1 to 0.5 mg/ml can protect wheat plants from MoT likely by inducing oxidative stress in the pathogen. Field trials of TiO2 NCs prevented more than 90% of disease incidence, with optimum yields, at NC concentrations ≥0.5 mg/ml. These results indicate that daylight-driven rechargeable NCs effectively suppress MoT in vitro and control wheat blast in the field.

The first selenium containing chitin and chitosan derivatives: Combined synthetic, catalytic and biological studies

Ultrasonic approach to the synthesis of the first selenium-containing derivatives of chitin and chitosan has been developed. The synthetic procedure is simple, provides high yields, does not require harsh conditions, and uses water as the reaction medium. The elaborated chitin and chitosan derivatives and their based nanoparticles are non-toxic and possess high antibacterial and antifungal activity. Their antimicrobial activity exceeds the effect of the classic antibiotics (Ampicillin and Gentamicin) and the antifungal drug Amphotericin B. The obtained selenium-containing cationic chitin and chitosan derivatives exhibit a high transfection activity and are promising gene delivery vectors. Nanoparticles of the synthesized polymers are highly efficient catalysts for the oxidation of 1-phenylethyl alcohol to acetophenone by bromine at room temperature.

Antifungal Thiazolidines: Synthesis and Biological Evaluation of Mycosidine Congeners

Novel derivatives of Mycosidine (3,5-substituted thiazolidine-2,4-diones) are synthesized by Knoevenagel condensation and reactions of thiazolidines with chloroformates or halo-acetic acid esters. Furthermore, 5-Arylidene-2,4-thiazolidinediones and their 2-thioxo analogs containing halogen and hydroxy groups or di(benzyloxy) substituents in 5-benzylidene moiety are tested for antifungal activity in vitro. Some of the synthesized compounds exhibit high antifungal activity, both fungistatic and fungicidal, and lead to morphological changes in the Candida yeast cell wall. Based on the use of limited proteomic screening and toxicity analysis in mutants, we show that Mycosidine activity is associated with glucose transport. This suggests that this first-in-class antifungal drug has a novel mechanism of action that deserves further study.