Evaluation Of Antifungal Activity Research Articles

Design, Synthesis, and Antifungal Evaluation of Diverse Heterocyclic Hydrazide Derivatives as Potential Succinate Dehydrogenase Inhibitors.

Plant pathogenic fungi pose a significant threat to agricultural production, necessitating the development of new and more effective fungicides. The ring replacement strategy has emerged as a highly successful approach in molecular design. In this study, we employed the ring replacement strategy to successfully design and synthesize 32 novel hydrazide derivatives containing diverse heterocycles, such as thiazole, isoxazole, pyrazole, thiadiazole, 1,3,4-oxadiazole, 1,2,4-oxadiazole, thiophene, pyridine, and pyrazine. Their antifungal activities were evaluated in vitro and in vivo. Bioassay results revealed that most of the title compounds displayed remarkable antifungal activities in vitro against four tested phytopathogenic fungi, including Fusarium graminearum, Botrytis cinerea, Sclerotinia sclerotiorum, and Rhizoctonia solani. Especially, compound 5aa displayed a broad spectrum of antifungal activity against F. graminearum, B. cinerea, S. sclerotiorum, and R. solani, with the corresponding EC50 values of 0.12, 4.48, 0.33, and 0.15 μg/mL, respectively. In the antifungal growth assay, compound 5aa displayed a protection efficacy of 75.5% against Fusarium head blight (FHB) at a concentration of 200 μg/mL. In another in vivo antifungal activity evaluation, compound 5aa exhibited a noteworthy protective efficacy of 92.0% against rape Sclerotinia rot (RSR) at a concentration of 100 μg/mL, which was comparable to the positive control tebuconazole (97.5%). The existing results suggest that compound 5aa has a broad-spectrum antifungal activity. Electron microscopy observations showed that compound 5aa might cause mycelial abnormalities and organelle damage in F. graminearum. Moreover, in the in vitro enzyme assay, we found that the target compounds 5aa, 5ab, and 5ca displayed significant inhibitory effects toward succinate dehydrogenase, with the corresponding IC50 values of 1.62, 1.74, and 1.96 μM, respectively, which were superior to that of boscalid (IC50 = 2.38 μM). Additionally, molecular docking and molecular dynamics simulation results revealed that compounds 5aa, 5ab, and 5ca have the capacity to bind in the active pocket of succinate dehydrogenase (SDH), establishing hydrogen-bonding interactions with neighboring amino acid residues.

Preparation of Ketoconazole-loaded Nanoemulsions for Ophthalmic Delivery: Characterization and In-vitro Antifungal Activity Evaluation

Background: Nanoemulsions (N.E.s) capable of ocular bioavailability elevation can be used for poor water-soluble drugs such as ketoconazole (K.Z.). The current investigation was designed for the purpose of overcoming this issue by developing K.Z. containing N.E.s for ophthalmic drug delivery with appropriate therapeutic efficiency. Methods: The preparation of ketoconazole N.E.s was performed by the low-energy technique. According to the phase diagram, three stable formulations were selected for more physicochemical analyses, including particle size, polydispersity index, pH, refractive index and viscosity. Finally, drug release patterns and in-vitro antifungal activity were assessed for the final selected formulation. Results: The developed N.E. formulations with droplet sizes less than 20 nm showed appropriate physicochemical characteristics for ocular delivery. The selected formulation released 100% of the encapsulated drug during 24 h. Moreover, antifungal assessments showed that prepared N.E. had acceptable in-vitro antifungal activity. Conclusions: Based on our findings, it can be concluded that N.E.s could be applied as effective carriers for the ophthalmic delivery of ketoconazole.

Formulation and Evaluation of Anti-fungal Activity of Aegle Marmelos Ointment

Formulation and Evaluation of Anti-fungal Activity of Aegle Marmelos Ointment

Evaluation and identification of antibacterial, antifungal, antioxidant, and phytotoxic activities of Asplenium dalhousiae Hook. a potential medicinal pteridophyte

Evaluation and identification of antibacterial, antifungal, antioxidant, and phytotoxic activities of Asplenium dalhousiae Hook. a potential medicinal pteridophyte

An Effective and Promising Strategy for Plant Protection: Synthesis of L-Carvone-Based Thiazolinone-Hydrazone/Nanochitosan Complexes with Antifungal Activity and Sustained Releasing Performance.

The development of novel natural product-derived nano-pesticide systems with loading capacity and sustained releasing performance of bioactive compounds is considered an effective and promising plant protection strategy. In this work, 25 L-carvone-based thiazolinone-hydrazone compounds 4a~4y were synthesized by the multi-step modification of L-carvone and structurally confirmed. Compound 4h was found to show favorable and broad-spectrum antifungal activity through the in vitro antifungal activity evaluation of compounds 4a~4y against eight phytopathogenic fungi. Thus, it could serve as a leading compound for new antifungal agents in agriculture. Moreover, the L-carvone-based nanochitosan carrier 7 bearing the 1,3,4-thiadiazole-amide group was rationally designed for the loading and sustained releasing applications of compound 4h, synthesized, and characterized. It was proven that carrier 7 had good thermal stability below 200 °C, dispersed well in the aqueous phase to form numerous nanoparticles with a size of~20 nm, and exhibited an unconsolidated and multi-aperture micro-structure. Finally, L-carvone-based thiazolinone-hydrazone/nanochitosan complexes were fabricated and investigated for their sustained releasing behaviors. Among them, complex 7/4h-2 with a well-distributed, compact, and columnar micro-structure displayed the highest encapsulation efficiency and desirable sustained releasing property for compound 4h and thus showed great potential as an antifungal nano-pesticide for further studies.

Beta maritima mediated silver Nanoparticles: Characterization and evaluation of Antibacterial, Antifungal, and antioxidant activities

Silver nanoparticles (AgNPs) are known for their large surface area, which enhances their energy and antimicrobial activity. This study focused on producing silver nanoparticles using leaves from the Beta maritima (vulgaris) plant. Various techniques such as Fourier transform infrared (FT-IR) spectroscopy, ultraviolet–visible (UV–vis) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction analysis (XRD) to characterize the synthesized AgNPs. The biologically synthesized AgNPs were then evaluated for their antimicrobial (antibacterial and antifungal) and antioxidant properties using different agents such as hydrogen peroxide (H2O2), 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2,2 azobis, 3-ethyl benzothiazoline-6-sulphonic acid (ABTS), and phosphomolybdate. The results showed that the AgNPs exhibited strong antifungal activity, particularly against fluconazole-resistant strains of Aspergillus niger and Aspergillus flavus, with a 61 % inhibition rate. Moreover, the AgNPs demonstrated significant antibacterial activity against various strains. At a concentration of 40 µg/mL, they exhibited 26 % inhibition against Staphylococcus aureus, 22 % against Micrococcus luteus, 18 % against E. coli, and 24 % against Klebsiella pneumonia, outperforming clarithromycin antibiotics. SEM analysis revealed spherical AgNPs, sized using nano measurer 1.2, EDX showed the presence of silver having composition at 80.38 %, and XRD confirmed a face-centered cubic crystalline structure. In addition to their characterization, the AgNPs also displayed strong antioxidant activity. At the same concentration, they showed percentages of 80.78 % (DPPH), 85.38 % (H2O2), 81.78 % (ABTS), and 80.66 % (phosphomolybdate), surpassing the antioxidant activity of the plant leaf extract alone. The synthesis of AgNPs using the extract of the Beta maritima (vulgaris) plant offers several advantages compared to other methods, including ease of handling, cost-effectiveness, wide availability, and eco-friendliness.

Industrial Distillation Fractions of Garlic Essential Oil, Design, Synthesis, and Antifungal Activity Evaluation of Aliphatic Substituted Trisulfide Derivatives.

Garlic oil has a wide range of biological activities, and its broad-spectrum activity against phytopathogenic fungi still has the potential to be explored. In this study, enzymatic treatment of garlic resulted in an increase of approximately 50 % in the yield of essential oil, a feasible GC-MS analytical program for garlic oil was provided. Vacuum fractionation of the volatile oil and determination of its inhibitory activity against 10 fungi demonstrated that garlic oil has good antifungal activity. The antifungal activity levels were ranked as diallyl trisulfide (S-3)>diallyl disulfide (S-2)>diallyl monosulfide (S-1), with an EC50 value of S-3 against Botrytis cinerea reached 8.16 mg/L. Following the structural modification of compound S-3, a series of derivatives, including compounds S-4~7, were synthesized and screened for their antifungal activity. The findings unequivocally demonstrated that the compound dimethyl trisulfide (S-4) exhibited exceptional antifungal activity. The EC50 of S-4 against Sclerotinia sclerotiorum reached 6.83 mg/L. SEM, In vivo experiments, and changes in mycelial nucleic acids, soluble proteins and soluble sugar leakage further confirmed its antifungal activity. The study indicated that the trisulfide bond structure was the key to good antifungal activity, which can be developed into a new type of green plant-derived fungicide for plant protection.

Evaluation of Antifungal Activity of Endophytic Bacillus spp. and Identification of Secondary Metabolites Produced Against the Phytopathogenic Fungi.

Endophytic bacteria serve as a rich source of diverse antimicrobial compounds. Recently, there has been a growing interest in utilizing endophytic Bacillus spp. as biological agents against phytogenic fungi, owing to their potential to produce a wide range of antimicrobial substances. The objective of this research was to investigate the protective abilities of 15 endophytic Bacillus spp. isolated from previous study from wheat plant, against the phytopathogenic fungi, Fusarium graminearum and Macrophomina phaseolina. A dual culture plate assay was conducted as a preliminary analysis, revealing that 7 out of 15 endophytic Bacillus spp. demonstrated inhibition against one or both of the phytopathogenic fungi used in this study. All seven endophytes were further assessed for the presence of diffusible antifungal metabolites. The cultures were grown in potato dextrose broth for 120h, and the cell-free supernatant was extracted and analyzed using the cup plate method. The methanolic extract yielded similar results to the dual culture plate analysis, except for WL2-15. Additionally, deformities in the mycelial structure were examined under the light microscope upon exposure to methanolic extract. Furthermore, the analysis and identification of metabolites were carried out via gas chromatography-mass spectrometry of methanolic extract from selected seven endophytic Bacillus spp. The chromatogram revealed the presence of some major peaks such as tridecanoic acid, methyl ester, hydroperoxide, 1-methylbutyl, 9-octadecenamide, (z)-, hexane-1,3,4-triol, 3,5-dimethyl- tetradecanoic acid. To the best of our knowledge, this is the first report of these biocontrol agents in endophytic Bacillus spp. Interestingly, volatile organic compound production was also seen in all the isolates against the phytopathogenic fungi.

Evaluation of antifungal activity of visible light-activated doped TiO2 nanoparticles.

Titanium dioxide (TiO2) is a well-known material for its biomedical applications, among which its implementation as a photosensitizer in photodynamic therapy has attracted considerable interest due to its photocatalytic properties, biocompatibility, high chemical stability, and low toxicity. However, the photoactivation of TiO2 requires ultraviolet light, which may lead to cell mutation and consequently cancer. To address these challenges, recent research has focused on the incorporation of metal dopants into the TiO2 lattice to shift the band gap to lower energies by introducing allowed energy states within the band gap, thus ensuring the harnessing of visible light. This study presents the synthesis, characterization, and application of TiO2 nanoparticles (NPs) in their undoped, doped, and co-doped forms for antimicrobial photodynamic therapy (APDT) against Candida albicans. Blue light with a wavelength of 450nm was used, with doses ranging from 20 to 60J/cm2 and an NP concentration of 500µg/ml. It was observed that doping TiO2 with Cu, Fe, Ag ions, and co-doping Cu:Fe into the TiO2 nanostructure enhanced the visible light photoactivity of TiO2 NPs. Experimental studies were done to investigate the effects of different ions doped into the TiO2 crystal lattice on their structural, optical, morphological, and chemical composition for APDT applications. In particular, Ag-doped TiO2 emerged as the best candidate, achieving 90-100% eradication of C. albicans.

Preliminary evaluation of in-Vivo and in-Vitro antifungal activity of Piper longum, Origanum majorana, Embelia ribes and Butea monosperma with Gas chromatography-mass spectrometry analysis of phytochemical property of plant extracts against Candida species causing dermatological

: Globally, fungi infections cause more than 1.5 million fatalities annually, mostly in those with weakened immune systems with Candida albicans found to be the chief pathogen. Approximately one to two billion people are affected by dermatological fungal infections involving skin and skin appendages, perhaps very difficult to estimate its exact prevalence due to under-reporting, this augments the requirements for more attention towards new molecules to combat resistance.: Evaluation of antifungal activity of Piper longum, Origanum majorana, Embelia ribes, Butea monosperma both in-vivo and in-vitro analysis against Candida species. This experimental study conducted for evaluating both in-vitro as well as in-vivo anti-fungal activity of Piper longum, Butea monosperma, Embelia ribes and Origanum majorana, and evaluation of phytoconstituent through Gas Chromatography and Mass Spectrometry analysis by GC-MS-QP-2010 plus system to identify the active bio-component. Fluconazole used as the standard control in-vivo and Itraconazole used as a standard drug for in-vitro infection and analysis. Ethical Committee approval was taken (IMS, BHU Dean/2018/CAEC/818). The antifungal activity of the extracts in-vitro was evaluated by Resazurin microtiter assay against Candida sp. Micro broth dilution methods. Rats were given an injection of 0.2 mL (intravenously/i.v) of a 10° UFC/mL inoculum made from a fresh 48-hour Candida albicans culture in sterile saline to cause infection. Induction of candidemia in rats was confirmed using qualitative Gram-stained smear. : The extracts of Butea monosperma (Alc.), Piper longum (Alc.), Origanum majorana (Aq.), and Piper longum (Aq.) showed effective antifungal activity against Candida sp. in-vitro research with a minimum inhibitory concentration (MIC) of less than 0.25 mg/mL. : This study is contributing towards the search for a natural drug candidate to combat resistance caused by the Candida genus, as it is one of the highest contributors to fungal dermatological/skin infections.

Synthesis of Difluorocyclopropanes via Visible‐Light‐Mediated [1+2] Cycloaddition of Diazo Esters with gem‐Difluoroalkenes and Evaluation of their Antifungal Activity

AbstractIn this work, we reported a method for construction of difluorocyclopropanes through visible light‐promoted [1+2] cycloaddition reaction of aryl diazo esters with gem‐difluoroalkenes. The reaction proceeds under mild conditions, encompasses a wide range of substrates (36 examples), exhibits good tolerance to various substituents, and demonstrates a diastereoselectivity of >20:1. Additionally, antifungal activity evaluation revealed that these derivatives exhibited certain activity, the EC50 values for the products towards Botrytis cinerea and Rhizoctonia solani were measured to be 1.51 and 1.36 μM, respectively, which are significantly lower than those of commercial fungicides Hymexazol and Azoxystrobin. This work not only provides an efficient method for the synthesis of difluorocyclopropanyl derivatives, but reveals their potential applications in fungicide creation.

Chemical analysis and bioactive compounds from agrifood by-products of peruvian crops

Many countries face the problem of agroindustrial waste elimination, which is linked to environmental damage caused by improper waste management. These wastes contain bioactive compounds often discarded due to a lack of knowledge. The objective of this study was to analyze five types of agroindustrial waste from Peru, including avocado (Persea americana) seeds, lucuma (Pouteria lucuma) seeds, grape (Vitis vinifera) pomace, mango (Mangifera indica) peel, and cocoa (Theobroma cacao) pods. This study includes proximal analysis, determination of total phenolic compound content, analysis of phenolic compounds by UHPLC– Q/Orbitrap/ESIMS/MS (Ultrahigh-performance liquid chromatography-electrospray ionization Q-Orbitrap mass spectrometry), and the evaluation of antioxidant, antimicrobial, and antifungal activities of different samples. The results showed that lucuma seeds had the highest protein content of 6.59 g/100 g DW. Mango peels showed the highest fat content of 4.89 g/100 g DW, cocoa pods had the highest crude fiber content of 26.91 g/100 g DW, and cocoa pods exhibited the highest ash content of 7.14 g/100 g DW. The highest carbohydrate content was found in avocado seeds at 85.85 g/100 g DW. Mango peels (56.66 mg GAE/g DW), avocado seeds (56.35 mg GAE/g DW), and cocoa pods (51.52 mg GAE/g DW) extracts showed the highest phenolic compound contents. Mango peel extract exhibited the highest antioxidant activities evaluated by the ABTS (995.01 μmol TEAC/g DW), DPPH (953.54 μmol TEAC/g DW), and FRAP (1661.13 μmol TEAC/g DW) assays. Extracts from cocoa pods, grape pomace, and lucuma seeds showed inhibitory activity on the growth of Staphylococcus aureus and Escherichia coli. In contrast, the extract of lucuma seeds was the only one that showed antifungal activity over Penicillium digitatum. As a result, several phenolic compounds were detected in each, indicating their potential use in developing functional foods and food preservation, among other applications.

Synthesis of nanoparticles using Trichoderma Harzianum, characterization, antifungal activity and impact on Plant Growth promoting Bacteria.

Globally cultivated cereals are frequently threatened by various plant pathogenic agents such as Fusarium fungi. To combat these pathogens, researchers have made nanoparticles as potential agricultural pesticides. In this study, selenium and titanium dioxide NPs were synthesized using Trichoderma harzianum metabolites. Characterization of the NPs indicated varying size and shapes of both NPs and functional groups existence to constitute both NPs. The evaluation of antifungal activity of NPs against plant pathogenic fungi, Fusarium culmorum, indicated both NPs maximum antifungal activity at concentration of 100mg/L. The impacts of nanoparticles on some beneficial plant growth promoting bacteria (PGPB) were evaluated and showed their inhibition effect on optical density of PGPB at a concentration of 100mg/L but they did not have any impact on nitrogen fixation by bacteria. Existence of TiO2NPs reduced the intensity of color change to pink compared to the control indicating auxin production. Both NPs demonstrated different impact on phosphate solubilization index. This study suggests that the synthesized nanoparticles have the potential to serve as antifungal compounds at special concentration against plant diseases without significantly reducing the potential of PGPB at low concentrations.

Sulfonate Derivatives Containing a Kakuol Moiety as Potential Fungicidal Candidates: Design, Synthesis and Antifungal Activity Evaluation.

As a part of our continuing exploration to discover new potential promising fungicide candidates, eighteen sulfonate derivatives (3a-3r) containing a kakuol moiety were designed and synthesized. Synthetic sulfonate derivatives were tested comprehensively for antifungal activities against four plant pathogenic fungi (Botrytis (B.) cinerea, Valsa (V.) mali, Fusarium (F.) graminearum, Sclerotinia (S.) sclerotiorum), and their structure activity relationships were summarized. Especially, derivatives 3i and 3j exhibited remarkable activity against V. mali, with the inhibition rates of 99.8 and 100%, which were slightly superior to that of carbendazim (98.9%), a reference fungicide. Moreover, derivatives 3a, 3k and 3q possess the broader antifungal spectrum against three tested plant pathogenic fungi with inhibition rates over 60%. Structure-activity relationship (SAR) analysis indicated that the introduction of 2-F or 3-F into the benzene ring would give rise to a remarkable increase of the antifungal activity against V. mali.

Evaluation of Antifungal Activity of Plant Extracts against Papaya Anthracnose (Colletotrichum gloeosporioides) under In-vitro Condition

The study aimed to assess the effectiveness of various plant extracts against Colletotrichum gloeosporioides in papaya. This investigation employed a completely randomized design and took place at the College of Agriculture in Pune-05 during the academic year 2021-22.Among the six plant extracts tested, garlic (Allium sativum) was found to be superior to the rest, exhibiting the minimum mycelium growth (5.30 mm) and the highest percentage inhibition (94.11%) at a 20% concentration. However, the drumstick leaf (Moringa oleifera) extract was the least effective, with the maximum radial mycelial growth of 44.00 mm (51.11% inhibition) observed. The study indicates that the radial mycelial growth of Colletotrichum gloeosporioides decreases with rise in the concentration of plant extracts.

Comparative evaluation of antifungal activity of Sodium Hypochlorite, Calcium Hypochlorite and modified Salt Solution associated with passive ultrasonic irrigation against Candida albicans - An In-Vitro study.

The study evaluated the antifungal activity of sodium hypochlorite (NaOCl), calcium hypochlorite (Ca(OCl)2), and modified salt solution (MSS) assisted with passive ultrasonic irrigation against Candida albicans. One hundred and thirty-six single-rooted premolars were decoronated and enlarged up to a file #45, autoclaved, inoculated with C. albicans, and incubated for 72 h. The samples were randomly distributed into eight groups (n = 17) according to the protocol for decontamination G1: No treatment, G2: Distilled water (DW), G3: 2.5% NaOCl, G4: 2.5% NaOCl + ultrasonic activation (US), G5: 2.5% Ca(OCl)2, G6: 2.5% Ca(OCl)2 + US, G7: MSS, G8: MSS + US. Microbiological testing (Colony forming Unit [CFU] counting) was performed before and after the treatment. Data were subjected to the one-way analysis of variance followed by the Tukey's post hoc test (P < 0.05). Groups 1 and 2 showed the highest mean contamination (5.41 and 4.31 log10 CFU/mL, respectively), which was statistically different from all the other groups (P < 0.001). G4 showed the lowest mean contamination (0.24 log10 CFU/mL) with statistically significant value (P < 0.001). 2.5% NaOCl with ultrasonic activation can aid in significant fungal reduction. Ultrasonic activation of 2.5% NaOCl, 2.5% Ca(OCl)2, and MSS was also found to have improved antifungal activity against C. albicans.

Evaluation of antibacterial and antifungal activities of Pistacia atlantica and Pistacia khinjuk

Medicinal plants are renowned for their various therapeutic properties, including antibacterial and antifungal activities. This study aimed to investigate the antibacterial and antifungal activities of P. atlantica and P. khinjuk. Hydroalcoholic extracts of P. atlantica and P. khinjuk were prepared to assess their antibacterial and antifungal activities. Standard strains of Bacillus cereus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Aspergillus flavus were utilized for the evaluation of antibacterial and antifungal activities. The inhibitory effects of the extracts on the growth of bacterial and fungal strains were evaluated using minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) through a 96-well microplate analysis following CLSI guidelines. Our findings revealed that the MICs and MBCs of P. atlantica and P. khinjuk for bacterial strains ranged from 0 to 64 mg/mL. Additionally, the MIC and MFC values for fungal strains ranged from 16 to 64 mg/mL. The results indicated that Pseudomonas aeruginosa and Klebsiella pneumonia were the most sensitive bacterial strains to P. atlantica. Furthermore, Aspergillus flavus was identified as the most sensitive fungal strain to P. atlantica. In conclusion, these findings suggest that P. atlantica and P. khinjuk possess antibacterial and antifungal effects. The paper argues that these plant extracts could be used as a supplementary treatment alongside conventional antibacterial and antifungal drugs.

Evaluation of antibacterial, antifungal and antibiofilm activities of A. baumannii-derived tannase and gallic acid against uropathogenic microorganisms

One of the most prevalent infectious diseases and a key driver of antibiotic prescriptions in pediatrics is urinary tract infection (UTI). Due to the emergence of more resistant uropathogenic bacterial and fungal strains, current treatments are no longer effective, necessitating the urgent development of novel antibacterial and antifungal drugs. In this study, the antifungal, antibacterial, and anti-biofilm capabilities of compounds, such as tannase (TN) and gallic acid (GA), which were produced from a novel natural source, Acinetobacter baumannii (AB11) bacteria, were assessed for the inactivation of uropathogenic microorganisms (UMs). Ammonium sulphate precipitation, ion exchange, high-performance liquid chromatography, and gel filtration were used to purify TN and GA that were isolated from A. baumannii. A 43.08 % pure TN with 1221.2 U/mg specific activity and 10.51 mg/mL GA was obtained. The antibacterial, antifungal and anti-biofilm activities of TN and GA were evaluated against UMs and compared to those of commercially available antibiotics including sulfamethoxazole (SXT), levofloxacin (LEV), ciprofloxacin (CIP), amikacin (Ak), and nitrofurantoin (F). The results showed that TN and GA were superior to commercial antibiotics in their ability to inactivate UMs and considerably reduced biofilms formation. Additionally, the GA emerges as the top substitute for currently available medications, demonstrating superior antibacterial and antibiofilm properties against all UMs evaluated in this study. The results of this investigation showed that A. baumannii-derived TN and GA could be utilized as an alternative medication to treat UTIs.

Evaluation of antifungal activity of natural compounds on growth and aflatoxin B1 production of Aspergillus parasiticus and Aspergillus flavus.

Aspergillus species cause broad spectrum infections especially invasive lethal infections in immunocompromised patients. This study aimed to assess the antifungal activity of plants and compounds including Aloe vera, Thyme, carvacrol, and nano-encapsulation of carvacrol on the growth and production of aflatoxin B1 production by Aspergillus parasiticus and Aspergillus flavus. Minimum inhibitory concentrations of extracts Aloe vera, Thyme, carvacrol, and nanocarvacrol, and fluconazole as a control were determined according to Clinical and Laboratory Standards Institute by serial microdilution protocol. Then, the effect of inhibitory concentrations of these compounds on the aflatoxin B1 production level was evaluated by real-time PCR and high-performance liquid chromatography. Our results indicate that the Aspergillus parasiticus and Aspergillus flavusare sensitive to selected plants and compounds. Our findings showed that the compounds are appropriate alternative candidates against growth and production of aflatoxin of Aspergillus spp.

Evaluation of antifungal activity against Corynespora cassiicola by bacteria isolated from soil in the root zone of cucumber plants

Abstract. Duy LQ. 2023. Evaluation of antifungal activity against Corynespora cassiicola by bacteria isolated from soil in the root zone of cucumber plants. Biodiversitas 24: 6584-6591. Target leaf spot caused by Corynespora cassiicola poses a major disease threat to cucumber cultivation worldwide. Reliance on chemical fungicides has raised resistance to environmental and health concerns. As cucumber production expands globally, sustainable solutions are needed. Plant Growth-Promoting Rhizobacteria (PGPR) show promise but remain underexplored against C. cassiicola in cucumber. This study aimed to assess the potency of rhizobacteria in antagonistic activity against C. cassiicola, causing cucumber target leaf spots under in vitro conditions. The present study isolated bacterial strains from cucumber soil rhizosphere and screened for antifungal activity against C. cassiicola using dual culture assays. Using quantitative assays, selected antagonistic strains were further assessed for key biocontrol traits, including ?-1,3-glucanase, chitinase, and siderophore production. Cell-free supernatants were tested for direct fungal growth inhibition using the environmental toxicity. Isolated PGPR strains showed robust C. cassiicola inhibition from 39.8% to 62.6% growth reduction. Most antagonistic isolates produced ?-1,3-glucanase, chitinase, and siderophores and suppressed pathogen growth via metabolites in their supernatants. These results demonstrate multiple biocontrol mechanisms, including enzymatic degradation of fungal cell walls, iron competition through siderophores, and antimicrobial compound secretion. Bacillus siamensis strain TV16 exhibited the strongest overall antagonism against C. cassiicola. These findings reveal the biocontrol potential of PGPR for managing cucumber-target leaf-spot disease, offering a sustainable alternative to chemical pesticides. With further optimization and field testing, PGPR-based biopesticides can be integrated into cucumber production to improve crop health while reducing fungicide reliance.