Maximal Effective Concentration Research Articles

Impacts of methotrexate on survival, dendrite development, and synapse formation of cortical neurons.

Methotrexate (MTX) is an anti-metabolite that has been used for the treatment of patients of acute lymphocytic leukemia or non-Hodgikin lymphoma for decades. In some cases, MTX-treated patients suffer from neurological side effects, including seizures and cognitive dysfunctions. While most patients are at developmental stages, information of the mechanisms of the side effects of MTX treatment on the developing neurons has been limited. Neurons develop in five steps in the human brain: neurogenesis, polarity formation, dendrite and axon development, synapse formation, and neuronal death. Except for neurogenesis, these processes can be recapitulated in the primary culture system of cortical neurons. Using primary cultured cortical neurons, we studied the impact of MTX treatment on dendrite development, synapse formation, and neuronal death in the present report. MTX treatment impaired neuronal survival, dendrite development, and synapse formation. Interestingly, half maximal effective concentrations (EC50 s) of MTX for all three processes are at the similar range and lower than the MTX concentration in the cerebrospinal fluid in treated patients. Our results provide possible mechanisms of neurological side effects in treated patients.

Identification of Piperlongumine as Potent Inhibitor of Necroptosis.

Excessive necroptosis contributes to the pathogenesis of several inflammatory and neurodegenerative diseases. Here, using a high-throughput screening approach, we investigated the anti-necroptosis effects of piperlongumine, an alkaloid isolated from the long pepper plant, in vitro and in a mouse model of systemic inflammatory response syndrome (SIRS). A natural compound library was screened for anti-necroptosis effects in cellular. The underlying mechanism of action of the top candidate piperlongumine was explored by quantifying the necroptosis marker phosphorylated receptor-interacting protein kinase 1 (p-RIPK1) by Western blotting. The anti-inflammatory effect of piperlongumine was assessed in a tumor necrosis factor α (TNFα)-induced SIRS model in mice. Among the compounds investigated, piperlongumine significantly rescued cell viability. The half maximal effective concentration (EC50) of piperlongumine for inhibiting necroptosis was 0.47 μM in HT-29 cells, 6.41 μM in FADD-deficient Jurkat cells, and 2.33 µM in CCRF-CEM cells, while the half maximal inhibitory concentration (IC50) was 95.4 µM in HT-29 cells, 93.02 µM in FADD-deficient Jurkat cells, and 161.1 µM in CCRF-CEM cells. Piperlongumine also significantly inhibited TNFα-induced intracellular RIPK1 Ser166 phosphorylation in cell lines and significantly prevented decreases in body temperature and improved survival in SIRS mice. As a potent necroptosis inhibitor, piperlongumine prevents phosphorylation of RIPK1 at its activation residue Ser166. Piperlongumine thus potently inhibits necroptosis at concentrations safe enough for human cells in vitro and inhibits TNFα-induced SIRS in mice. Piperlongumine has potential clinical translational value for the treatment of the spectrum of diseases associated with necroptosis, including SIRS.

The study of structure and effects of two new proanthocyanidins from Anogeissus pendula leaves on rumen enzyme activities.

Two novel proanthocyanidins, (2R, 3R)-(+)-Gallocatechin-(4β → 8)4-(2R, 3R)-(+)-gallocatechin (compound 1) and 3-O-galloyl-(2S, 3S)-(-)-epicatechin-(4α → 8)-[3-O-galloyl-(2S, 3S)-(-)-epicatechin (4α → 8)]2-(2S, 3S)-(-)-epicatechin (compound 2), were structurally characterized from leaves of Anogeissus pendula. The structures were determined by ultraviolet spectroscopy (UV), proton nuclear magnetic resonance (1H NMR), 13C NMR, and heteronuclear multiple bond correlation. Molinspiration and Osiris property explorer applications were used to predict bioactivity and drug score. Drug scores of 0.08 and 0.05 were predicted for compounds 1 and 2, respectively. Predicted bioactivity scores were high. Due to their molecular weight, chemical structure, and conformation, the newly discovered proanthocyanidins possess an inclination to interact with proteins. Based on this premise, both compounds were subjected to in vitro testing against ruminal enzymes. They exhibited significant inhibition activities (p < 0.01) with a range of half maximal effective concentration (EC50) of 14.80-17.88 mg/mL of glutamic oxaloacetic transaminase in both protozoa and bacteria fractions. The ruminal glutamic pyruvic transaminase activity was significantly inhibited (p < 0.01) from EC50 12.59-16.29 mg/mL, and R-cellulase inhibition was recorded with EC50 18.20-21.98 mg/mL by compounds 1 and 2, respectively. Protease activity decreased with increasing incubation time and concentration of both compounds. The novel proanthocyanidins have potential roles in improving feed conversion ratios and in drug development.

Using in vitro receptor activity studies of synthetic cannabinoids to support the risk assessment of new psychoactive substances – A Swedish strategy to protect public health from harm

In the past 15 years, close to 1000 of new psychoactive substances (NPS) have been reported in Europe and globally. At the time of identification, data on safety, toxicity and carcinogenic potential of many NPS are not available or very limited. To work more efficiently, a strategy and collaboration between the Public Health Agency of Sweden (PHAS) and the National Board of Forensic Medicine was established involving in vitro receptor activity assays to demonstrate neurological activity of NPS. This report summarizes the first results on the synthetic cannabinoid receptor agonists (SCRAs), and subsequent actions taken by PHAS. A total of 18 potential SCRAs were selected by PHAS for in vitro pharmacological characterization. 17 compounds could be acquired and investigated for their activity on the human cannabinoid-1 (CB1) receptors expressed together with the AequoScreen system in CHO-K1 cells. Dose-response curves were established using eight different concentrations in triplicates at three occasions with JWH-018 as reference. For the MDMB-4en-PINACA, MMB-022, ACHMINACA, ADB-BUTINACA, 5F-CUMYL-PeGACLONE, 5C-AKB48, NM-2201, 5F-CUMYL-PINACA, JWH-022, 5Cl-AB-PINACA, MPhP-2201, 5F-AKB57 the half maximal effective concentration values ranged from 2.2 nM (5F-CUMYL-PINACA) to 171 nM (MMB-022). EG-018 and 3,5-AB-CHMFUPPYCA were none-active. The results contributed to 14 of these compounds being scheduled as narcotics in Sweden. In conclusion, many of the emerging SCRAs are potent activators of the CB1 receptor in vitro, although some lack activity or are partial agonists. The new strategy proved useful when data on psychoactive effects of the SCRAs under investigation were not available or limited.

Development of a Peptide Sensor Derived from Human ACE2 for Fluorescence Polarization Assays of the SARS-CoV-2 Receptor Binding Domain.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the continuing emergence of infectious variants have caused a serious pandemic and a global economic slump since 2019. To overcome the situation and prepare for future pandemic-prone diseases, there is a need to establish a convenient diagnostic test that is quickly adaptable to unexpected emergence of virus variants. Here we report a fluorescent peptide sensor 26-Dan and its application to the fluorescence polarization (FP) assay for the highly sensitive and convenient detection of SARS-CoV-2. The 26-Dan sensor was developed by fluorescent labeling of the 26th amino acid of a peptide derived from the N-terminal α-helix of human angiotensin-converting enzyme 2 (hACE2) receptor. The 26-Dan sensor maintained the α-helical structure and showed FP changes in a concentration-dependent manner of the receptor binding domain (RBD) of the virus. The half maximal effective concentrations (EC50's) for RBD of Wuhan-Hu-1 strain, Delta (B.1.617.2), and Omicron (BA.5) variants were 51, 5.2, and 2.2 nM, respectively, demonstrating that the 26-Dan-based FP assay can be adaptable to virus variants that evade standard diagnostic tests. The 26-Dan-based FP assay could also be applied to model screening of a small molecule that inhibits RBD binding to hACE2 and identified glycyrrhizin as a potential inhibitor. The combination of the sensor with a portable microfluidic fluorescence polarization analyzer allowed for the detection of RBD in a femtomolar range within 3 min, demonstrating the assay could be a promising step toward a rapid and convenient test for SARS-CoV-2 and other possible future pandemic-prone diseases.

Surfactant vesicles for enhanced antitoxoplasmic effect of norfloxacin: In vitro and in vivo evaluations

The goal was to scrutinize niosomes as potential carriers for enhanced efficacy of norfloxacin against Toxoplasma gondii RH strain. This was assessed in vitro and in vivo. Standard niosomes of Span 60 and cholesterol were prepared. Gelucire 48/16 or Tween 80 was incorporated as hydrophilic fluidizer. The prepared vesicles were characterized for shape, size, viscosity and norfloxacin release. The in vitro anti-Toxoplasma was assessed by monitoring tachyzoites viability after incubation with niosomes. In vivo efficacy of niosomes encapsulated norfloxacin was evaluated on infected mice. Transmission electron micrographs showed nano-sized spherical vesicles. Norfloxacin release varied with niosomal composition to show faster liberation in presence of fluidizing agent. The half maximum effective concentration of norfloxacin against tachyzoites (EC50) was significantly reduced after niosomal encapsulation compared with simple drug solution with no significant difference between vesicular formulations. Tachyzoite count in the peritoneal fluid of infected mice was reduced by 45.2, 90.8, 88.3 and 84% after treatment with simple drug dispersion, standard niosomes, Gelucire containing and Tween containing vesicles, respectively compared to infected untreated mice. These results correlate with the in vitro data and reflects the efficacy of niosomes. The study introduced surfactant vesicles as a tool for enhanced efficacy of norfloxacin against toxoplasma.

Polyphenolic Content and Radical Scavenging Activities of the Peel, Pulp and Seed of Avocado (Persea americana Mill.) Grown in Tanzania

Avocado is a healthy fruit and the consumption is continuously growing worldwide. The fruit contains polyphenolic compounds with antioxidant effects. Globally, research has been devoted to exploring the fruit quality, especially compounds with antioxidant effects, from different avocado-growing sites. However, the fruit quality of the Tanzanian avocado has so far not been investigated. In this study, the contents of polyphenols in peel, pulp and seed of avocados sampled in south-western Tanzania are described. The levels of total polyphenolic and flavonoid contents were measured, and antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The total polyphenolic content was highest in the seed and lowest in the peel (424 and 200 mg GAE/100 g DW, respectively). As for the total flavonoid content, the pulp had the highest value of 36.98 mg RE/100 g DW, while the seed had the lowest value of 32.54 mg RE/100 g DW. The overall average half maximal effective concentration (EC50) values in decreasing order, corresponding to an increasing antiradical activity, were 4.90 (peel), 3.63 (seed) and 3.24 µg/mL (pulp). The seed and peel possessed high levels of total polyphenolic and flavonoid content, thus demonstrating substantial antioxidant capacity. Seed and peel can potentially be processed and included in the diet to provide inexpensive antioxidant ingredients of natural origin. Consumption of the seed will not only improve human health but also reduce the environmental pollution, as many thousand tonnes of avocado seeds are produced in Tanzania per year; a huge amount currently remains as waste.&#x0D; Keywords: Flavonoid contents; Free radicals; EC50; Polyphenolic content

Antiviral activity evaluation and action mechanism of myricetin derivatives containing thioether quinoline moiety.

A variety of myricetin derivatives containing thioether quinoline moiety were designed and synthesized. Their structures of title compounds were determined by 1H NMR, 13C NMR, 19F NMR, and HRMS. Single-crystal X-ray diffraction experiments were carried out with B4. Antiviral activity indicated that some of the target compounds exhibited remarkable anti-tobacco mosaic virus (TMV) activity. In particular, compound B6 possessed significant activity. The half maximal effective concentration (EC50) value of the curative activity of compound B6 was 169.0μg/mL, which was superior to the control agent ningnanmycin (227.2μg/mL). Meanwhile, the EC50 value of the protective activity of compound B6 was 86.5μg/mL, which was better than ningnanmycin (179.2μg/mL). Microscale thermophoresis (MST) indicated that compound B6 had a strong binding capability to the tobacco mosaic virus coat protein (TMV-CP) with a dissociation constant (Kd) value of 0.013μmol/L, which was superior to that of myricitrin (61.447μmol/L) and ningnanmycin (3.215μmol/L). And the molecular docking studies were consistent with the experimental results. Therefore, these novel myricetin derivatives containing thioether quinoline moiety could become potential alternative templates for novel antiviral agents.

Development of axially chiral urazole scaffolds for antiplant virus applications against potato virus Y.

Potato virus Y (PVY) was first discovered by Smith in 1931 and is currently ranked as the fifth most significant plant virus. It can cause severe damage to plants from the family Solanaceae, which results in billions of dollars of economic loss worldwide every year. To discover new antiviral drugs, a class of multifunctional urazole derivatives bearing a stereogenic CN axis were synthesized with excellent optical purities for antiviral evaluations against PVY. The absolute configurations of the axially chiral compounds exhibited obvious distinctions in antiviral bioactivities, with several of these enantio-enriched axially chiral molecules showing excellent anti-PVY activities. In particular, compound (R)-9f exhibited remarkable curative activities against PVY with a 50% maximal effective concentration (EC50 ) of 224.9μg mL-1 , which was better than that of ningnanmycin (NNM), which had an EC50 of 234.0μg mL-1 . And the EC50 value of the protective activities of compound (R)-9fwas 462.2μg mL-1 , which was comparable to that of NNM (442.0μg mL-1 ). The mechanisms of two enantiomer of the axially chiral compounds 9fwere studied by both molecule docking and defensive enzyme activity tests. Mechanistic studies demonstrated that the axially chiral configurations of the compounds played significant roles in the molecule PVY-CP (PVY Coat Protein) interactions and could enhance the activities of the defense enzymes. The (S)-9f showed only one carbon-hydrogen bond and one π-cation interaction between the chiral molecule and the PVY-CP amino acid sites. In contrast, the (R)-enantiomer of 9f exhibited three hydrogen bonding interactions between the carbonyl groups and the PVY-CP active sites of ARG157 and GLN158. The current study provides significant information on the roles that axial chiralities play in plant protection against viruses, which will facilitate the development of novel green pesticides bearing axial chiralities with excellent optical purities. © 2023 Society of Chemical Industry.

Taxonomic and physiological studies of Parachlorella kimitsuensis sp. nov. (Trebouxiophyceae), which shows high ammonium tolerance

Biological treatments using microalgae represent an environmental-friendly approach to the decontamination of coking wastewater, which contains toxic levels of ammonium; however, few algal species can tolerate such high ammonium levels. In this study, we investigated the morphology, ultrastructure, molecular phylogeny, and physiological characteristics of Parachlorella kimitsuensis sp. nov., a new algal species with high ammonium tolerance. This species was isolated from coking wastewater obtained near a steelworks factory, where the ratio of nitrogen to phosphorus (N/P) exceeded 40, approximately 100-fold that of general culture medium. The growth inhibition test estimated that the effective concentration at 10 % inhibition (EC10) was 3.2 ppm NH4+-N, and the half maximal effective concentration (EC50) was 98.0 ppm NH4+-N, indicating tolerance to fairly high concentrations of ammonium in this species. Parachlorella kimitsuensis has spherical, green cells resembling those of Chlorella species. The major diameter of the cells was 3.7 ± 0.39 μm; cells containing eight autospores appearing in the early logarithmic growth phase were 6.9 ± 0.78 μm in diameter. Molecular phylogenetic analysis showed that the alga was a member of the genus Parachlorella, with 100 % bootstrap support. However, the results of vegetative cell morphology and phylogenetic analyses using 18S rRNA genes were inconsistent with those of other described Parachlorella species. Therefore, we identified the isolate as a new species in the genus Parachlorella. We anticipate that this species will be suitable for biological treatment of wastewater containing high ammonium levels, such as coking wastewater.

Trifluoromethylpyridine piperazine derivatives: synthesis and anti-plant virus activity.

The cucumber mosaic virus (CMV) is well-known for its expansive host range and distribution, resulting in a detrimental effect on agricultural production, thus making it imperative to implement measures for its control. Novel compounds S1-S28 were synthesized by connecting trifluoromethyl pyridine, amide and piperazine scaffolds. Bioassays indicated that most of the synthesized compounds exhibited good curative effects against CMV, with half maximal effective concentration (EC50 ) values of compounds S1, S2, S7, S8, S10, S11, S15, and S28 being 119.6, 168.9, 197.6, 169.1, 97.9, 73.9, 224.4, and 125.2μg mL-1 , respectively, which were lower than the EC50 of ningnanmycin (314.7μg mL-1 ). Compounds S5 and S8 exhibited protective activities with EC50 of 170.8 and 95.0μg mL-1 , respectively, which were lower than ningnanmycin at 171.4μg mL-1 . The inactivation activities of S6 and S8 at 500 μg mL-1 were remarkably high at 66.1% and 78.3%, respectively, surpassing that of ningnanmycin (63.5%). Additionally, their EC50 values were more favorable at 22.2 and 18.1μg mL-1 , respectively, than ningnanmycin (38.4μg mL-1 ). And molecular docking and molecular dynamics simulation showed compound S8 had better binding with CMV-coat protein, providing a possible explanation for the anti-CMV activity of compound S8. Compound S8 showed a strong binding affinity to CMV-coat protein and impacted the self-assemble of CMV particles. Compound S8 could be a potential lead compound for discovering a new anti-plant virus candidate. © 2023 Society of Chemical Industry.

Safety of elexacaftor/tezacaftor/ivacaftor dose reduction: Mechanistic exploration through physiologically based pharmacokinetic modeling and a clinical case series.

Elexacaftor/tezacaftor/ivacaftor (ETI) treatment is associated with significant improvement in lung function in people with cystic fibrosis (pwCF); however, some patients experience adverse effects (AEs) including hepatotoxicity. One potential strategy is dose reduction in ETI with the goal of maintaining therapeutic efficacy while resolving AEs. We report our experience of dose reduction in individuals who experienced AEs following ETI therapy. We provide mechanistic support for ETI dose reduction by exploring predicted lung exposures and underlying pharmacokinetics-pharmacodynamics (PK-PD) relationships. Adults prescribed ETI who underwent dose reduction due to the AEs were included in this case series, and their percent predicted forced expiratory volume in 1 s (ppFEV1 ) and self-reported respiratory symptoms were collected. The full physiologically based pharmacokinetic (PBPK) models of ETI were developed incorporating physiological information and drug-dependent parameters. The models were validated against available pharmacokinetic and dose-response relationship data. The models were then used to predict lung concentrations of ETI at steady-state. Fifteen patients underwent dose reduction in ETI due to AEs. Clinical stability without significant changes in ppFEV1 after dose reduction was observed in all patients. Resolution or improvement of AEs occurred in 13 of the 15 cases. The model-predicted lung concentrations of reduced dose ETI exceeded the reported half maximal effective concentration (EC50 ) from measurement of in vitro chloride transport, providing a hypothesis as to why therapeutic efficacy was maintained. Albeit in a small number of patients, this study provides evidence that reduced ETI doses in pwCF who have experienced AEs may be effective. The PBPK models enable exploration of a mechanistic basis for this finding by simulating target tissue concentrations of ETI that can be compared with drug efficacy in vitro.

Sulfoxide-Containing Bisabolane Sesquiterpenoids with Antimicrobial and Nematicidal Activities from the Marine-Derived Fungus Aspergillus sydowii LW09.

Phytopathogens, such as phytopathogenic bacteria, fungi, and nematodes, have caused great losses of crops every year, seriously threatening human health and agricultural production. Moreover, marine-derived fungi are abundant sources of structurally unique and bioactive secondary metabolites that could be potential candidates for anti-phytopathogenic drugs. One new sulfoxide-containing bisabolane sesquiterpenoid aspersydosulfoxide A (1) and nine known analogues (2-10) were isolated from the marine-derived A. sydowii LW09. The absolute configuration of the sulfur stereogenic center in 1 was determined by electronic circular dichroism (ECD) calculations. Compound 5 showed inhibition activity against Pseudomonas syringae, with a minimum inhibitory concentration (MIC) value of 32 μg/mL, whereas, compounds 2, 7, and 8 showed antibacterial activities toward Ralstonia solanacarum, with the same MIC value at 32 μg/mL. Meanwhile, compounds 3, 7, and 8 inhibited the fungal spore germination of Fusarium oxysporum, with the half maximal effective concentration (EC50) values of 54.55, 77.16, and 1.85 μg/mL, respectively, while compounds 2, 3, 7, and 8 inhibited the fungal spore germination of Alternaria alternata, which could be induced by vacuolization of germ tubes, with EC50 values of 34.04, 44.44, 26.02, and 46.15 μg/mL, respectively. In addition, compounds 3, 7, and 8 exhibited nematicidal activities against Meloidogyne incognita second-stage juveniles (J2s). In addition, compound 8 possessed the strongest nematicidal activity of nearly 80% mortality at 60 h with the half lethal concentration (LC50) values of 192.40 μg/mL. Furthermore, compounds 3, 7, and 8 could paralyze the nematodes and then impair their pathogenicity.

First study on in vitro antiviral and virucidal effects of flavonoids against feline infectious peritonitis virus at the early stage of infection.

Feline infectious peritonitis (FIP), one of the most important infectious diseases in cats is caused by FIP virus (FIPV), a mutated variant of feline coronavirus. Feline infectious peritonitis has a negative impact on feline health, with extremely high mortality in clinical FIP-infected cats, particularly young cats. There are no approved drugs for FIP treatment, and therapeutic possibilities for FIP treatment are limited. This study aimed to utilize nature-derived bioactive flavonoids with antiviral properties to inhibit FIPV infection in Crandell-Rees feline kidney (CRFK) cells. The cytotoxicity of 16 flavonoids was evaluated on CRFK cells using a colorimetric method (MTS) assay. Viral kinetics of FIPV at 50 tissue culture infectious dose (TCID50)/well was determined during the first 24-h post-infection (HPI). Antiviral activity was evaluated based on the replication steps of the virus life cycle, including pre-compound, attachment, penetration, post-viral entry, and virucidal assays. The antiviral efficacy of flavonoids against FIPV was determined based on positive FIPV-infected cells with the immunoperoxidase monolayer assay and viral load quantification using reverse transcription-quantitative polymerase chain reaction. Two flavonoids, namely, isoginkgetin and luteolin, inhibited FIPV replication during post-viral entry in a dose-dependent manner, with 50% maximal effective concentrations = 4.77 ± 0.09 and 36.28 ± 0.03 μM, respectively. Based on viral kinetics, both flavonoids could inhibit FIPV replication at the early stage of infection at 0-6-HPI for isoginkgetin and 2-6-HPI for luteolin using a time-of-addition assay. Isoginkgetin exerted a direct virucidal effect that reduced the viral titers by 2 and 1.89 log10 TCID50/mL at 60 and 120 min, respectively. Isoginkgetin interfered with FIPV replication during both post-viral infection and virucidal experiments on CRFK cells, whereas luteolin inhibited the virus after infection. These results demonstrate the potential of herbal medicine for treating FIP.

The evaluation of in vitro antichagasic and anti-SARS-CoV-2 potential of inclusion complexes of β- and methyl-β-cyclodextrin with naphthoquinone.

The compound 3a,10b-dihydro-1H-cyclopenta[b]naphtho[2,3-d]furan-5,10-dione (IVS320) is a naphthoquinone with antifungal and antichagasic potential, which however has low aqueous solubility. To increase bioavailability, inclusion complexes with β-cyclodextrin (βCD) and methyl-β-cyclodextrin (MβCD) were prepared by physical mixture (PM), kneading (KN) and rotary evaporation (RE), and their in vitro anti-SARS-CoV-2 and antichagasic potential was assessed. The formation of inclusion complexes led to a change in the physicochemical characteristics compared to IVS320 alone as well as a decrease in crystallinity degree that reached 74.44% for the IVS320-MβCD one prepared by RE. The IVS320 and IVS320-MβCD/RE system exhibited anti-SARS-CoV-2 activity, showing half maximal effective concentrations (EC50) of 0.47 and 1.22μg/mL, respectively. Molecular docking simulation suggested IVS320 ability to interact with the SARS-CoV-2 viral protein. Finally, the highest antichagasic activity, expressed as percentage of Tripanosoma cruzi growth inhibition, was observed with IVS320-βCD/KN (70%) and IVS320-MβCD/PM (72%), while IVS320 alone exhibited only approximately 48% inhibition at the highest concentration (100μg/mL).

Molecular Characterization and Fungicide Sensitivity of Jujube Pathogens Colletotrichum gloeosporioides Sensu Stricto and Colletotrichum nymphaeae in South Korea.

Jujube (Ziziphus jujuba) is cultivated across South Korea because of its medicinal and economic value. It is used as a sweetener in jam, tea, and snacks and a garnish in many cuisines. Anthracnose caused by Colletotrichum spp. accounts for huge economic losses for jujube growers. In 2019 and 2020, severe anthracnose was observed in the jujube-growing areas of South Korea. The infected fruit displayed small, water-soaked, sunken, circular spots. Infected fruit were collected from different commercial orchards of Boeungun and Gyeongsan regions of South Korea, and putative causal agents were isolated on potato dextrose agar. Based on the morphological and molecular characteristics, the fungal isolates were identified as Colletotrichum gloeosporioides sensu stricto and C. nymphaeae. The pathogenicity of these isolates was confirmed by inoculating a conidial suspension (1 × 106 conidia ml-1) on healthy fruit. The in vitro sensitivity of the fungal isolates to tebuconazole, carbendazim, and azoxystrobin was also tested. All isolates showed high sensitivity to azoxystrobin in terms of mycelial growth inhibition (half maximal effective concentration value of 0.01 to 0.6 µg/ml). To the best of our knowledge, this is also the first report of jujube anthracnose caused by C. nymphaeae in South Korea.

PX-12 synergistically enhances the therapeutic efficacy of vorinostat under hypoxic tumor microenvironment in oral squamous cell carcinoma in vitro.

Hypoxia is a characteristic feature of solid tumors, including oral squamous cell carcinoma (OSCC), which causes therapeutic resistance. The hypoxia-inducible factor 1-alpha (HIF-1α) is a key regulator of hypoxic tumor microenvironment (TME) and a promising therapeutic target against solid tumors. Among other HIF-1α inhibitors, vorinostat (suberoylanilide hydroxamic acid, SAHA) is a histone deacetylase inhibitor (HDACi) targeting the stability of HIF-1α, and PX-12 (1-methylpropyl 2-imidazolyl disulfide) is a thioredoxin-1 (Trx-1) inhibitor preventing accumulation of HIF-1α. HDACis are effective against cancers; however, they are accompanied by several side effects along with an emerging resistance against it. This can be overcome by using HDACi in a combination regimen with Trx-1 inhibitor, as their inhibitory mechanisms are interconnected. HDACis inhibit Trx-1, leading to an increase in the production of reactive oxygen species (ROS) and inducing apoptosis in cancer cells; thus, the efficacy of HDACi can be elevated by using a Trx-1 inhibitor. In this study, we have tested the EC50 (half maximal effective concentration) doses of vorinostat and PX-12 on CAL-27 (an OSCC cell line) under both normoxic and hypoxic conditions. The combined EC50 dose of vorinostat and PX-12 is significantly reduced under hypoxia, and the interaction of PX-12 with vorinostat was evaluated by combination index (CI). An additive interaction between vorinostat and PX-12 was observed in normoxia, while a synergistic interaction was observed under hypoxia. This study provides the first evidence for vorinostat and PX-12 synergism under hypoxic TME, at the same time highlighting the therapeutically effective combination of vorinostat and PX-12 against OSCC in vitro.

Identification of PXR Activators from Uncaria Rhynchophylla (Gou Teng) and Uncaria Tomentosa (Cat's Claw).

Uncaria rhynchophylla (Gou Teng) and Uncaria tomentosa (cat's claw) are frequently used herbal supplements in Asia and America, respectively. Despite their common usage, information is limited regarding potential herb-drug interactions associated with Gou Teng and cat's claw. The pregnane X receptor (PXR) is a ligand-dependent transcription factor that regulates cytochrome P450 3A4 (CYP3A4) expression and contributes to some known herb-drug interactions. A recent study found that Gou Teng induces CYP3A4 expression, but its mechanism is unknown. Cat's claw has been determined as a PXR-activating herb, but the PXR activators in cat's claw have not been identified. Using a genetically engineered PXR cell line, we found that the extracts of Gou Teng and cat's claw can dose-dependently activate PXR and induce CYP3A4 expression. We next used a metabolomic approach to profile the chemical components in the extracts of Gou Teng and cat's claw followed by screening for PXR activators. Four compounds, isocorynoxeine, rhynchophylline, isorhynchophylline, and corynoxeine, were identified as PXR activators from both Gou Teng and cat's claw extracts. In addition, three more PXR activators were identified from the extracts of cat's claw, including isopteropodine, pteropodine, and mitraphylline. All seven of these compounds showed the half-maximal effective concentration <10 µM for PXR activation. In summary, our work determined Gou Teng as a PXR-activating herb and discovered novel PXR activators from Gou Teng as well as cat's claw. SIGNIFICANCE STATEMENT: This study's data can be used to guide the safe use of Gou Teng and cat's claw by avoiding PXR-mediated herb-drug interactions.

Antifungal activity of 40 plant essential oil components against Diaporthe fusicola from postharvest kiwifruits and their possible action mode

The antifungal activity of essential oils is closely related to their components and contents. The study aimed to explore the structural activity of essential oil (EO) components against Diaporthe fusicola and modes of action. The results showed most of the tested compounds showed inhibitory effects on the growth of D. fusicola and carvacrol was the strongest one with half maximal effective concentration (EC50) of 11.21 μL/L. The chemical structures of the tested compounds had great influences on their antifungal activity, in which the presence of CHO group, CC group or Ar-OH group in any EO components significantly increase the antifungal potency, but the increment of carbon chain length of saturated fatty aldehyde decreased antifungal activity. In order to analyze the antifungal action mode of EO components, the correlations between EC50 and oxidation-reduction potential (ORP), cell-membrane permeability and respiration inhibition of the tested compounds were further evaluated. The results showed antifungal activities of these EO components seemed to be accomplished by increase of cell membrane permeability and inhibition of the respiration of D. fusicola. The levels of increased membrane permeability, inhibited respiration and ORP of chemicals were all significantly correlated with EC50. This results indicated the action mode of these EO components against D. fusicola may be associated with the increment of cell membrane permeability and respiration inhibition via disrupting redox homeostasis in fungal cells, and oxidation-reduction property could be used as a secondary indicator for screening the antifungal agent from EO components.

Pyranonaphthoquinones and Naphthoquinones from the Stem Bark of Ventilago harmandiana and Their Anti-HIV-1 Activity.

Seven previously undescribed compounds, including five pyranonaphthoquinones (ventilanones L-P) and two naphthoquinones (ventilanones Q and R), along with 15 known compounds were isolated from the stem bark of Ventilago harmandiana (Rhamnaceae). The structures were established by extensive analysis of their spectroscopic data. The absolute configuration of ventilanone L was established from single crystal X-ray crystallographic analysis using Cu Kα radiation and from its electronic circular dichroism data. Anti-HIV-1 activity using a syncytium inhibition assay and the cytotoxic activities of some isolated compounds were evaluated. Compounds 12, 13, 15, and 16 showed activity against syncytium formation with half maximal effective concentration (EC50) values ranging from 9.9 to 47 μM (selectivity index (SI) 2.4-4.5).