Progress in the application of nanoparticles for the treatment of fungal infections: A review.

The burden of fungal infections on human health is increasing worldwide. Aspergillus, Candida, and Cryptococcus are the top three human pathogenic fungi that are responsible for over 90% of infection-related deaths. Moreover, effective antifungal therapeutics are lacking, primarily due to host toxicity, pathogen resistance, and immunodeficiency. In recent years, nanomaterials have proved not only to be more efficient antifungal therapeutic agents but also to overcome resistance against fungal medication. This review will examine the limitations of standard antifungal therapy as well as focus on the development of nanomaterials.

Multifaceted chemical and bioactive features of Ag@TiO2 and Ag@SeO2 core/shell nanoparticles biosynthesized using Beta vulgaris L. extract.

Due to increasing concerns about environmental impact and toxicity, developing green and sustainable methods for nanoparticle synthesis is attracting significant interest. This work reports the successful green synthesis of silver (Ag), silver-titanium dioxide (Ag@TiO2), and silver-selenium dioxide (Ag@SeO2) nanoparticles (NPs) using Beta vulgaris L. extract. Characterization by XRD, SEM, TEM, and EDX confirmed the successful formation of uniformly distributed spherical NPs with controlled size (25 ± 4.9 nm) and desired elemental composition. All synthesized NPs and the B. vulgaris extract exhibited potent free radical scavenging activity, indicating significant antioxidant potential. However, Ag@SeO2 displayed lower hemocompatibility compared to other NPs, while Ag@SeO2 and the extract demonstrated reduced inflammation in a carrageenan-induced paw edema animal model. Interestingly, Ag@TiO2 and Ag@SeO2 exhibited strong antifungal activity against Rhizoctonia solani and Sclerotia sclerotium, as evidenced by TEM and FTIR analyses. Generally, the findings suggest that B. vulgaris-derived NPs possess diverse biological activities with potential applications in various fields such as medicine and agriculture. Ag@TiO2 and Ag@SeO2, in particular, warrant further investigation for their potential as novel bioactive agents.

Formulation and evaluation of fluconazole emulgels for potential treatment of vaginal candidiasis.

Localised treatment of vaginal candidiasis could improve the therapeutic outcomes of patients with vaginal candidiasis as well as reduce drug dosage and dosing interval. The aim of the research project was to develop fluconazole emulgel formulations, and evaluate their physicochemical, drug release, antifungal, safety, and stability profile, for potential treatment of vaginal candidiasis. Xanthan gum and HPMC E5LV-based fluconazole emulgels were prepared using the spontaneous emulsification method and their physicochemical properties, drug content, drug release profile, anti-fungal activity against Candida albicans, in vivo vaginal biocompatibility and stability profile were evaluated using standard protocols. The fluconazole emulgels exhibited satisfactory properties: pH: 5.2-5.4; spreadability: 1.6-2.5 cm; apparent viscosity: 85-314 cP; zone of inhibition against Candida albicans: 22-38 mm; drug content: 91-102 %, and vaginal biocompatibility. All the studied fluconazole emulgels exhibited controlled fluconazole release over 6 h and their drug release kinetics fitted well with Korsmeyer-Peppas model. HPMC-based emulgels exhibited unsatisfactory real-time stability profile. To our knowledge, this is the first report where xanthan gum and HPMC E5LV-based fluconazole emulgels have been studied for possible treatment of vaginal candidiasis. Xanthan gum-based fluconazole emulgels are promising drug formulations that could reduce the drug dosage and dosing frequency. In addition, they could serve as alternative dosage forms to Flucos® gel.

Bacillus sp. alone or combined with salicylic acid inhibited Trichoderma spp. infection on harvested white Hypsizygus marmoreus.

Introduction: White Hypsizygus marmoreus is a popular edible mushroom. It is rich in nutrition and flavor but vulnerable to fungal disease, resulting in nutrient loss and aging. Methods: In this study, the pathogenic fungus Trichoderma spp. BBP-6 and its antagonist Bacillus sp. 1-23 were isolated and identified. The negative effects caused by this pathogen were judged by detecting a series of changes in the infected white H. marmoreus. The effects of Bacillus sp. 1-23 on Trichoderma spp. BBP-6 and the infected white H. marmoreus were detected. The effect of Bacillus sp. 1-23 treatment combined with salicylic acid (SA) was also considered. Results: The results showed that Trichoderma spp. BBP-6 could affect the activities of antioxidant enzymes PAL, POD, CAT, SOD, GR, PPO, and APX to interfere with the stability of the white H. marmoreus antioxidant enzyme system and cause the mushroom severe browning and nutrition loss, as well as general quality deterioration. Bacillus sp. 1-23 could produce chitinase and chitosanase enzymes to inhibit Trichoderma spp. BBP-6 directly. SA reinforced this inhibitory. Bacillus sp. 1-23 alone or combined with SA could help white H. marmoreus from the Trichoderma spp. BBP-6 infection to effectively maintain nutrients, restore and stabilize the antioxidant system, and reduce the production of malondialdehyde, superoxide anion and hydrogen peroxide. Discussion: Thus, such treatments could be considered potential methods to alleviate damage from disease and extend the shelf life of white H. marmoreus.

Synthesis of biopolymer blends nanocomposites embedded with mono-(Ag, Fe) and bi-(Ag-Fe) metallic nanoparticles using an eco-friendly approach for antimicrobial activities.

Plant-mediated solution casting is used to develop eco-friendly polymer blend nanocomposites from polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) doped with Silver (Ag), Ferrous (Fe) monometallic and Silver-Ferrous (Ag-Fe) bimetallic nanoparticles (NPs). These nanocomposites were studied to understand their electromagnetic interface (EMI) shielding efficiency and antimicrobial activities, besides evaluating their physical and chemical properties. The Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray (EDX) characterization techniques were used to examine the interactions between the polymers, the presence of silver and ferrous particles in the composites, the crystallinity shift, the surface morphology, the shape and size of the nanoparticles and the distribution of the nanoparticles in the composites. The FTIR spectra showed the interactions among the components of the composites. According to XRD spectra, the incorporation of nanoparticles into the PVA polymer significantly reduced the crystalline character of the polymer from 0.38 to 0.24 for the composition consisting of silver and iron nanoparticles in equal proportion. The results from SEM, EDX and XRD corroborate the presence of nanoparticle forms. The thermogravimetric analysis (TGA) tests reveal that the thermal stability of bimetallic composites is greater than that of monometallic composites. The tensile properties showed that the addition of nanoparticles to the PVA/PVP polymer matrix increased its mechanical strength from 59.3 MPa to 85.5 MPa. We examined its efficacy against Escherichia coli, Staphylococcus aureus and Candida albicans as microorganisms. Good antibacterial and antifungal activity was observed. The bimetallic composites demonstrated greater activity than monometallic composites against these bacterial and fungal species. All bimetallic nanocomposites have shown enhanced, loss due to reflection, loss due to absorption, and the total EMI shielding efficiency at 8 GHz (X-band) and 16 GHz (Ku-band) frequency. All these results ratify, that these newly developed bio nanocomposites are most suitable in many applications, in EMI shielding, nanotechnology, and medical fields.

Efficacy and safety of oral ibrexafungerp in Chinese patients with vulvovaginal candidiasis: a phase III, randomized, double-blind study.

PURPOSE: To evaluate the efficacy and safety of oral ibrexafungerp (HS-10366) versus placebo in Chinese patients with vulvovaginal candidiasis (VVC). METHODS: A double-blind, placebo-controlled, randomized, multicenter phase III study was conducted in symptomatic VVC patients. Patients received (2:1) twice-daily oral ibrexafungerp 300 mg or matching placebo for 1 day. The primary endpoint was clinical cure (vulvovaginal signs and symptoms [VSS] score = 0) at test-of-cure (TOC) on day 11 ± 3. The secondary endpoints included mycological eradication, overall response, and clinical improvement (VSS score ≤ 1) at TOC, and vulvovaginal symptom resolution at follow-up on day 25 ± 4. RESULTS: In total, 360 patients were included in the modified intention-to-treat set (defined as positive Candida cultured and receiving at least one study drug; 239 for ibrexafungerp, 121 for placebo). Compared with placebo, patients receiving ibrexafungerp had a significantly higher proportion of clinical cure (51.0% vs. 25.6%), mycological eradication (55.6% vs. 18.2%), overall response (33.9%, vs. 8.3%) at TOC and complete symptom resolution (74.5% vs. 39.7%, all P < 0.001) at follow-up. Subgroup analysis of clinical cure indicated that patients with C. albicans could benefit from ibrexafungerp over placebo. A similar benefit trend was also observed in those with non-albicans Candida by post-hoc analysis. Further analyses revealed similar efficacy of ibrexafungerp between patients with fluconazole non-susceptible C. albicans and fluconazole susceptible C. albicans regarding clinical cure and mycological eradication. Ibrexafungerp was generally well tolerated. Adverse events were primarily gastrointestinal and were mainly mild in severity. CONCLUSIONS: As a first-in-class antifungal agent, ibrexafungerp demonstrated promising efficacy and favorable safety for VVC treatment in Chinese patients. CHINADRUGTRIALS.ORG. CN REGISTRY NUMBER: CTR20220918.

The potent effect of selenium nanoparticles insight into: the antifungal activity and preservation of postharvest strawberries from gray mold diseases.

BACKGROUND: Most microorganisms cause food decay and the lower shelf life of foods is fungi. Nanotechnologies can combat various diseases and deals with the application of nanomaterial to target cell or tissue. In this study was synthesized selenium nanoparticle (Se-NPs) by using ascorbic acids, and characterized by UV-Visible, TEM, XRD, and zeta potential. The different concentrations of As/Se-NPs were tested against different fungi such as, Alternaria linicola, Alternaria padwickii, Botrytis cinerea; Bipolaris sp, Cephalosporium acremonium; Fusarium moniliform; Fusarium semitectum. This study tested the influence of coated As/Se-NPs on healthy and infected strawberries fruits with Botrytis cinerea during 16 days of storage periods on shelf life, decay percentage, weight loss, total titratable acidity percentage (TA), total soluble solids content (TSS), and anthocyanin content. RESULTS: The results indicated the EDX analysis showed only two elements Selenium and Oxygen. TEM image demonstrates the size ranged between 26 to 39 nm, and rhombohedral in shape. Selenium nanoparticles have antifungal activities against all tested fungi, the most effective against Botrytis cinerea, Cephalosporium acremonium, and Fusarium semitectum. During storage periods of strawberries fruits coated with As/Se-NPs, the shelf life was increased, and the number of decaying fruits was less than in control (uncoated) and coated infected fruits. The decline in weight loss is lower in coated fruits than control. CONCLUSION: These findings displayed that As/Se-NPs could effectively maintain the postharvest quality of strawberries, even when the fruit was infected with B. cinerea. This article is protected by copyright. All rights reserved.

Probiotic Potential of Bacillus Subtilis Strain I3: Antagonistic Activity Against Chalkbrood Pathogen and Pesticide Degradation for Enhancing Honeybee Health.

To explore the potential of probiotic candidates beneficial for honeybee health through the modulation of the gut microbiome, bee gut microbes were isolated from bumblebee (Bombus terrestris) and honeybee (Apis mellifera) using diverse media and cultural conditions. A total of 77 bee gut bacteria, classified under the phyla Proteobacteria, Firmicutes, and Actinobacteria, were identified. The antagonistic activity of the isolates against Ascosphaera apis, a fungal pathogen responsible for chalkbrood disease in honeybee larvae, was investigated. The highest growth inhibition percentage against A. apis was demonstrated by Bacillus subtilis strain I3 among the bacterial strains. The presence of antimicrobial peptide genes in the I3 strain was detected using PCR amplification of gene fragments encoding surfactin and fengycin utilizing specific primers. The export of antimicrobial peptides by the I3 strain into growth medium was verified using liquid chromatography coupled with mass spectroscopy. Furthermore, the strain's capabilities for degrading pesticides, used for controlling varroa mites, and its spent growth medium antioxidant activity were substantiated. The survival rate of honeybees infected with (A) apis was investigated after feeding larvae with only medium (fructose + glucose + yeast extract + royal jelly), (B) subtilis I3 strain, A. apis with medium and I3 strain + A. apis with medium. Honeybees receiving the I3 strain + A. apis exhibited a 50% reduction in mortality rate due to I3 strain supplementation under experimental conditions, compared to the control group. In silico molecular docking revealed that fengycin hydrolase from I3 strain effectively interacted with tau-fluvalinate, suggesting its potential in bee health and environmental protection. Further studies are needed to confirm the effects of the I3 strain in different populations of honey bees across several regions to account for genetic and environmental variations.

Isolation of Streptomyces inhibiting multiple-phytopathogenic fungi and characterization of lucensomycin biosynthetic gene cluster.

Soil microorganisms with diverse bioactive compounds such as Streptomyces are appreciated as valuable resources for the discovery of eco-friendly fungicides. This study isolated a novel Streptomyces from soil samples collected in the organic green tea fields in South Korea. The isolation process involved antifungal activity screening around 2400 culture extracts, revealing a strain designated as S. collinus Inha504 with remarkable antifungal activity against diverse phytopathogenic fungi. S. collinus Inha504 not only inhibited seven phytopathogenic fungi including Fusarium oxysporum and Aspergillus niger in bioassays and but also showed a control effect against F. oxysporum infected red pepper, strawberry, and tomato in the in vivo pot test. Genome mining of S. collinus Inha504 revealed the presence of the biosynthetic gene cluster (BGC) in the chromosome encoding a polyene macrolide which is highly homologous to the lucensomycin (LCM), a compound known for effective in crop disease control. Through genetic confirmation and bioassays, the antifungal activity of S. collinus Inha504 was attributed to the presence of LCM BGC in the chromosome. These results could serve as an effective strategy to select novel Streptomyces strains with valuable biological activity through bioassay-based screening and identify biosynthetic gene clusters responsible for the metabolites using genome mining approach.

Invasive Pulmonary Aspergillosis in an Immunocompetent Patient: An Atypical Presentation.

Invasive pulmonary aspergillosis (IPA) is a severe fungal infection primarily affecting immunocompromised individuals. However, rare cases of IPA in immunocompetent patients have been reported, presenting diagnostic and therapeutic challenges. Here, we present a case of a 41-year-old immunocompetent male who presented with fever, cough with mucoid expectoration, and breathlessness. Despite the absence of traditional risk factors, imaging and laboratory findings led to the diagnosis of IPA. Prompt initiation of antifungal therapy resulted in clinical improvement. This case highlights the importance of considering IPA in the differential diagnosis of respiratory symptoms, even in immunocompetent individuals.

Cryptococcosis and Cryptococcal Meningitis: A Narrative Review and the Up-to-Date Management Approach.

Cryptococcosis is a fungal infectious disease that enormously impacts human health worldwide. Cryptococcal meningitis is the most severe disease caused by the fungus Cryptococcus, and can lead to death, if left untreated. Many patients develop resistance and progress to death even after treatment. It requires a prolonged treatment course in people with AIDS. This narrative review provides an evidence-based summary of the current treatment modalities and future trial options, including newer ones, namely, 18B7, T-2307, VT-1598, AR12, manogepix, and miltefosine. This review also evaluated the management and empiric treatment of cryptococcus meningitis. The disease can easily evade diagnosis with subacute presentation. Despite the severity of the disease, treatment options for cryptococcosis remain limited, and more research is needed.

Candida auris in Greek healthcare facilities: Active surveillance results on first cases and outbreaks from eleven hospitals within Attica region.

BACKGROUND: Candida auris was sporadically detected in Greece until 2019. Thereupon, there has been an increase in isolations among inpatients of healthcare facilities. AIM: We aim to report active surveillance data on MALDI-TOF confirmed Candida auris cases and outbreaks, from November 2019 to September 2021. METHODS: A retrospective study on hospital-based Candida auris data, over a 23-month period was conducted, involving 11 hospitals within Attica region. Antifungal susceptibility testing and genotyping were conducted. Case mortality and fatality rates were calculated and p-values less than 0.05 were considered statistically significant. Infection control measures were enforced and enhanced. RESULTS: Twenty cases with invasive infection and 25 colonized were identified (median age: 72 years), all admitted to hospitals for reasons other than fungal infections. Median hospitalisation time until diagnosis was 26 days. Common risk factors among cases were the presence of indwelling devices (91.1 %), concurrent bacterial infections during hospitalisation (60.0 %), multiple antimicrobial drug treatment courses prior to hospitalisation (57.8 %), and admission in the ICU (44.4 %). Overall mortality rate was 53 %, after a median of 41.5 hospitalisation days. Resistance to fluconazole and amphotericin B was identified in 100 % and 3 % of tested clinical isolates, respectively. All isolates belonged to South Asian clade I. Outbreaks were identified in six hospitals, while remaining hospitals detected sporadic C. auris cases. CONCLUSION: Candida auris has proven its ability to rapidly spread and persist among inpatients and environment of healthcare facilities. Surveillance focused on the presence of risk factors and local epidemiology, and implementation of strict infection control measures remain the most useful interventions.

Impact of sphingolipid synthesis inhibition on the drug susceptibility patterns of Trichophyton species.

The well known dermatophyte infections caused by Trichophyton species are an ambiguous problem to treat using the present arsenal of antifungals. This study expounds on the effect of inhibition of sphingolipid pathway on Trichophyton growth. Findings from the drug susceptibility assays suggest sphingolipid inhibition severely restricts the growth of T. interdigitale and T. tonsurans. The observed synergistic effects of combinations of sphingolipid inhibitor and conventional drugs provide a promising treatment strategy against Trichophyton infection.

Comparison of Different Antibiotic Medications on Microorganisms: An Original Research.

Introduction: The onset and maintenance of disease can be significantly influenced by the colonization of the mouth cavity by pathogenic microorganisms or by an imbalance of the physiological microbiome. Hence, in the current study, various commonly used antibiotics have been tested for their antibacterial and antifungal activity. Materials and Methods: The current research was performed as an in vitro study. The commonly used antibiotics Augmentin (CV), Ceftriaxone-Cephalosporin (CF), and Linezolid were tested for the microorganisms, lactobacillus, and Escherichia coli. The "Radius of Zone of Inhibition (mm)- RZI" after 24 and 48 h were tested by the agar-well diffusion method. Results: For E. coli, the antibiotics tested were CV (5 µl and 2.5 µl), CF (5 µl and 2.5 µl), and Linezolid (5 µl and 2.5 µl). The results showed that the radius of the zone of inhibition was consistent for each antibiotic concentration, with a range of 0.8-1.4 mm at both time points. For Lactobacillus, the antibiotics tested were CV (5 µl and 2.5 µl), CF (5 µl and 2.5 µl), and Linezolid (5 µl and 2.5 µl). The results showed that the radius of the zone of inhibition varied between antibiotics and concentrations, with a range of 0.5-1.8 mm at both time points. Conclusion: This study highlights antibiotics' antibacterial action against E. coli and Lactobacillus. The data imply that antibiotic efficacy varied by organism and drug concentration. These organisms' antibiotic resistance mechanisms and new antibiotic resistance methods need more study.

Comparison of Different Betadine and Saline Combinations on Microorganisms: An Original Research.

Introduction: Pathogenic bacteria in the oral cavity or a physiological microbiome imbalance can cause or maintain disease. Thus, this work examined a novel betadine-saline combination for antibacterial and antifungal activities. Materials and Methods: This study was in vitro. Betadine, saline, and their mixtures were tested for Bacillus subtilis, Staphylococcus aureus (gram-positive), Pseudomonas aeruginosa, Escherichia coli, and Aspergillus niger (gram-negative). Pour plate and disc diffusion methods were used to test CFUs, DZI, and RZI for various agent combinations. Results: For Lactobacillus acidophilus, Betadine 90% + saline 10% had the greatest DZI and RZI at 24 and 12 mm, respectively. For E. coli, Betadine 50% + saline 50% had the highest at 16 and 8 mm. Betadine 60% + saline 40% had 14 mm RZI and the highest antifungal activity. Conclusion: The novel betadine-saline antibacterial and antifungal combination performed well. In vivo research should confirm the existing findings.

The activity of leaf extracts, fractions, and isolated compounds from Ptaeroxylon obliquum against nine phytopathogenic fungi and the nematode Meloidogyne incognita.

Phytopathogenic fungi and nematodes cause great losses in economically important crops and food production especially in developing countries. To minimize the use of fungicides and nematicides, researchers have concentrated on the use of natural products for crop disease prevention or control. The aim of the study was to investigate the antifungal activity of Ptaeroxylon obliquum leaf extracts, fractions, and isolated compounds (obliquumol and a mixture of lupeol and ß-amyrin) and nematocidal activity of fractions (hexane, chloroform and 30% water in methanol and the isolated compounds) on Meloidogyne incognita. Nine phytopathogenic fungi (Aspergillus niger, A. parasiticus, Colletotrichum gloeosporioides, Fusarium oxysporum, Penicillium digitatum, P. expansum, P. italicum, P. janthinellum, and Rhizoctonia solani) were used for testing and nematocidal activity was determined on motility of plant parasitic nematode Meloidogyne incognita race 2 juveniles. Serial microdilution test was utilized to determine the minimum inhibitory concentration (MIC) of each sample against the fungus. Motility tests was done on the second-stage juveniles (J2s) of M. incognita. The most susceptible phytopathogenic fungal species to the acetone crude leaf extracts were A. niger, C. gloeosporioides and P. digitatum with MIC of 80 µg/ml which is considered pharmacological significant. Rhizoctonia solani was the most susceptible fungus against obliquumol and, lupeol and ß-amyrin mixture with MIC values of 8 µg/ml and 16 µg/ml respectively. Lupeol & ß-amyrin mixture had good activity on juvenile motility at high concentrations used which was significantly high (p ≤ 0.05) after 24 h, further incubation resulted in temporary paralysis at lower concentrations. Fractions and obliquumol showed good activity after 48 h, stable paralysis was observed up to 72 h. The extracts and isolated compounds may be useful as fungicides if the in vitro results can be confirmed under field conditions at levels not toxic to beneficial soil organisms.

Clinical Distribution and Drug Susceptibility Characterization of Invasive Candida Isolates in a Tertiary Hospital of Xinjiang Province.

Objective: This study aims to investigate the clinical distribution characteristics and drug susceptibility profiles of invasive Candida isolates in a tertiary hospital in Urumqi. Methods: The examination was conducted on samples obtained from patients who were clinically diagnosed with invasive candidiasis in this hospital. A total of 109 strains of Candida strains were identified through the use of internal transcribed spacer (ITS) sequencing and fungal cultivation methods.The clinical distribution of the strains was analyzed. Antifungal drug susceptibility tests were performed using the Sensititre YO10 fungal drug susceptibility plate based on the micro-broth dilution method. Results: Candida albicans had the highest percentage (51.38%) among 109 Candida isolates, followed by C. glabrata (18.35%) and C. tropicalis (15.60%). The isolates were predominantly found in the respiratory department (41.28%), intensive care unit (ICU) (31.19%), and infection department (9.17%).The results of drug susceptibility tests indicated that amphotericin B, 5-fluorocytosine, and echinocandins exhibited good in vitro antifungal activity, with a susceptibility rate of over 96%. However, the azoles demonstrated low antifungal activity, especially posaconazole and voriconazole, which had high resistance rates of 64.71% for C. tropicalis and 70% for C. glabrata, respectively. Conclusion: In our hospital, Candida albicans was identified as the primary causal agent of invasive candidiasis. In terms of in vitro antifungal activity, echinocandins, amphotericin B, and 5-fluorocytosine demonstrated efficacy against invasive Candida infections. However, it was important to note that C. glabrata and C. tropicalis exhibited low susceptibility to azoles.

Design, selective synthesis and biological activities evaluation of novel thiazol-2-ylbenzamide and thiazole-2-ylbenzimidoyl chloride derivatives.

To promote the development and exploitation of novel antifungal agents, a series of thiazol-2-ylbenzamide derivatives (3A-3V) and thiazole-2-ylbenzimidoyl chloride derivatives (4A-4V) were designed and selective synthesis. The bioassay results showed that most of the target compounds exhibited excellent in vitro antifungal activities against five plant pathogenic fungi (Valsa mali, Sclerotinia scleotiorum, Botrytis cinerea, Rhizoctonia solani and Trichoderma viride). The antifungal effects of compounds 3B (EC50 = 0.72 mg/L) and 4B (EC50 = 0.65 mg/L) against S. scleotiorum were comparable to succinate dehydrogenase inhibitors (SDHIs) thifluzamide (EC50 = 1.08 mg/L) and boscalid (EC50 = 0.78 mg/L). Especially, compounds 3B (EC50 = 0.87 mg/L) and 4B (EC50 = 1.08 mg/L) showed higher activity against R. solani than boscalid (EC50 = 2.25 mg/L). In vivo experiments in rice leaves revealed that compounds 3B (86.8 %) and 4B (85.3 %) exhibited excellent protective activities against R. solani comparable to thifluzamide (88.5 %). Scanning electron microscopy (SEM) results exhibited that compounds 3B and 4B dramatically disrupted the typical structure and morphology of R. solani mycelium. Molecular docking demonstrated that compounds 3B and 4B had significant interactions with succinate dehydrogenase (SDH). Meanwhile, SDH inhibition assay results further proved their potential as SDHIs. In addition, acute oral toxicity tests on A. mellifera L. showed only low toxicity for compounds 3B and 4B to A. mellifera L. populations. These results suggested that these two series of compounds had merit for further investigation as potential low-risk agricultural SDHI fungicides.

Four new tirucallane-type triterpenoids from Aphanamixis polystachya.

Four new tirucallane-type triterpenoids, polystanins H-K (1-4), were obtained from the stems and leaves of Aphanamixis polystachya. Their structures were elucidated by analysis of the spectroscopic data and comparison with literature data. Compounds 1 and 2 showed week inhibitory effects against NO production in LPS-stimulated RAW264.7 cells. All the isolates were investigated for their antifungal activities against drug-resistant Candida albicans.

Efficient Control of Rhizoctonia solani Using Environmentally Friendly pH-Responsive Tannic Acid-Rosin Nano-Microcapsules.

A nanomicrocapsule system was constructed through the polymerization of tannic acid (TA) and emulsifier OP-10 (OP-10), followed by the chelation of iron ions, to develop a safe and effective method for controlling Rhizoctonia solani in agriculture. The encapsulated active component is a rosin-based triazole derivative (RTD) previously synthesized by our research group (RTD@OP10-TA-Fe). The encapsulation efficiency of the nanomicrocapsules is 82.39%, with an effective compound loading capacity of 96.49%. Through the encapsulation of the RTD via nanomicrocapsules, we improved its water solubility, optimized its stability, and increased its adhesion to the leaf surface. Under acidic conditions (pH = 5.0), the release rate of nanomicrocapsules at 96 h is 96.31 ± 0.8%, which is 2.04 times higher than the release rate under normal conditions (pH = 7.0). Additionally, the results of in vitro and in vivo antifungal assays indicate that compared with the original compound, the nanomicrocapsules exhibit superior antifungal activity (EC50 values of RTD and RTD@OP10-TA-Fe are 1.237 and 0.860 mg/L, respectively). The results of field efficacy trials indicate that compared with RTD, RTD@OP10-TA-Fe exhibits a more prolonged period of effectiveness. Even after 3 weeks, the antifungal rate of RTD@OP10-TA-Fe remains at 40%, whereas RTD, owing to degradation, shows an antifungal rate of 11.11% during the same period. Furthermore, safety assessment results indicate that compared with the control, RTD@OP10-TA-Fe has almost no impact on the growth of rice seedlings and exhibits low toxicity to zebrafish. This study provides valuable insights into controlling R. solani and enhancing the compound performance.