Toxicity Assays Research Articles

Magnetic carbon nanotubes modified with proteins and hydrophilic monomers: Cytocompatibility, in-vitro toxicity assays and permeation across biological interfaces

Carbon nanotubes are promising materials for biomedical applications like delivery systems and tissue scaffolds. In this paper, magnetic carbon nanotubes (M-CNTs) covered with bovine serum albumin (M-CNTs-BSA) or functionalized with hydrophilic monomers (M-CNTs-HL) were synthesized, characterized, and evaluated concerning their interaction with Caco-2 cells. There is no comparison between these two types of functionalization, and this study aimed to verify their influence on the material's interaction with the cells. Different concentrations of the nanotubes were applied to investigate cytotoxicity, cell metabolism, oxidative stress, apoptosis, and capability to cross biomimetic barriers. The materials showed cytocompatibility up to 100 μg mL−1 and a hemolysis rate below 2 %. Nanotubes' suspensions were allowed to permeate Caco-2 monolayers for up to 8 h under the effect of the magnetic field. Magnetic nanoparticles associated with the nanotubes allowed estimation of permeation through the monolayers, with values ranging from 0.50 to 7.19 and 0.27 to 9.30 × 10−3 μg (equivalent to 0.43 to 6.22 and 0.23 to 9.54 × 10−2 % of the initially estimated mass of magnetic nanoparticles) for cells exposed and non-exposed to the magnets, respectively. Together, these results support that the developed materials are promising for applications in biomedical and biotechnological fields.

Toxicity and Phytochemical Analysis of Five Medicinal Plants

Recent studies have shown that long-term uses of herbs have been associated with a rise in morbidity and mortality rates. While most researches are focused on bioactivity investigations, the toxicity of many plants has not been reported. There is a paucity of data on the potential toxicity of the following plants: Harungana madagascariensis (HM), Pterocarpus osun (PO), Phoenix dactylifera (PD), Annona muricata (AM), and Rutidea parviflora (RP). To evaluate the toxicity of the above-mentioned plants; two tests were employed namely: The Brine shrimp lethality test (BSLT) and the Allium cepa test. A correlation between the oral acute toxicity assay in mice and the LC50 obtained from BSLT has been established. Allium cepa test measures the potential genotoxic effects of plant extracts exerted on the root meristem of A. cepa (onions). Plant extracts were administered in concentrations ranging from 100 to 2500 µg/ml to the A. cepa for 72 h to obtain their Mitotic Indices (MI) and EC50. Results of the MI at 2500 µg/ml for HM, PO, PD, AM, and RP were 3.75, 4.96, 5.96, 6.10, and 6.71 while 281.81, 398.11, 501.19, 630.96, and 707.9 µg/ml were obtained as the respective EC50 values. Furthermore, 10-1000 mcg/ml concentrations were administered in the BSLT and the obtained LC50 values were 116.3, 250, 581.5, 581.5, and 750 µg/ml. The toxicity result demonstrated that the five plants were moderately toxic, with RP exhibiting minimal toxicity values and thus potentially having a good safety profile. The phytochemical screening of these plants revealed the presence of some pharmacologically important classes of compounds that are abundant. Several bioactive and toxic compounds were identified in the GC-MS analysis for some of the plants.

Synthesis, Pharmacokinetic Profile, Anticancer Activity and Toxicity of the New Amides of Betulonic Acid-In Silico and In Vitro Study.

Betulonic acid (B(O)A) is a pentacyclic lupane-type triterpenoid that widely exists in plants. There are scientific reports indicating anticancer activity of B(O)A, as well as the amides and esters of this triterpenoid. In the first step of the study, the synthesis of novel amide derivatives of B(O)A containing an acetylenic moiety was developed. Subsequently, the medium-soluble compounds (EB171 and EB173) and the parent compound, i.e., B(O)A, were investigated for potential cytotoxic activity against breast cancer (MCF-7 and MDA-MB-231) and melanoma (C32, COLO 829 and A375) cell lines, as well as normal human fibroblasts. Screening analysis using the WST-1 test was applied. Moreover, the lipophilicity and ADME parameters of the obtained derivatives were determined using experimental and in silico methods. The toxicity assay using zebrafish embryos and larvae was also performed. The study showed that the compound EB171 exhibited a significant cytotoxic effect on cancer cell lines: MCF-7, A-375 and COLO 829, while it did not affect the survival of normal cells. Moreover, studies on embryos and larvae showed no toxicity of EB171 in an animal model. Compared to EB171, the compound EB173 had a weaker effect on all tested cancer cell lines and produced less desirable effects against normal cells. The results of the WST-1 assay obtained for B(O)A revealed its strong cytotoxic activity on the examined cancer cell lines, but also on normal cells. In conclusion, this article describes new derivatives of betulonic acid-from synthesis to biological properties. The results allowed to indicate a promising direction for the functionalization of B(O)A to obtain derivatives with selective anticancer activity and low toxicity.

Life cycle exposure to titanium dioxide nanoparticles (TiO2-NPs) induces filial toxicity and population decline in the nematode Caenorhabditis elegans.

Titanium dioxide nanoparticle (TiO2-NP) exposure has raised significant concern due to their potential toxicity and adverse ecological impacts. Despite their ubiquitous presence in various environmental compartments, the long-term consequences of TiO2-NPs remain poorly understood. In this study, we combined data of in vivo toxicity and modeling to investigate the potential negative impacts of TiO2-NP exposure. We employed the nematode Caenorhabditis elegans, an environmental organism, to conduct a full life cycle TiO2-NP toxicity assays. Moreover, to assess the potential impact of TiO2-NP toxicity on population dynamics, we applied a stage-constructed matrix population model (MPM). Results showed that TiO2-NPs caused significant reductions in reproduction, survival, and growth of parental C. elegans (P0) at the examined concentrations. Moreover, these toxic effects were even more pronounced in the subsequent generation (F1) when exposed to TiO2-NPs. Furthermore, parental TiO2-NP exposure resulted in significant toxicity in non-exposed C. elegans progeny (TiO2-NPs free), adversely affecting their reproduction, survival, and growth. MPM analysis revealed decreased transition probabilities of surviving (Pi), growth (Gi), and fertility (Fi) in scenarios with TiO2-NP exposure. Additionally, the population growth rate (λmax) was found to be less than 1 in both P0 and F1, indicating a declining population trend after successive generations. Sensitivity analysis pinpointed L1 larvae as the most vulnerable stage, significantly contributing to the observed population decline in both P0 and F1 generations under TiO2-NP exposure. Our findings provide insight into the potential risk of an environmental organism like nematode by life cycle exposure to TiO2-NPs.

D-limonene combined with Bacillus thuringiensis against Spodotera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae)

Focusing on alternatives for better control of S. frugiperda, research has proven the efficiency of using natural compounds to reduce the emergence of resistance. Consequently, the combination of different modes of action of natural insecticide, capable of enhancing the action of each molecule, promoting a barrier to the pest resistance. So, this work evaluated the toxicity of d-limonene associated with entomopathogenic microorganisms against S. frugiperda. A population of caterpillars was assembled in the laboratory to conduct in vitro toxicity assays. A range of insecticide dilutions was carried out and then applied to larvae, with the aim of obtaining the dose-response curve. After determining the lethality of each product and aiming to determine the synergistic potential between them, several binary combinations were established. D-limonene essential oil promoted high mortality of caterpillar at very low concentrations, and the subspecies of bacilli used ensured high caterpillar mortality. However, the strain of B. bassiana used promoted caterpillar mortality only at a very high dose. B. bassiana + d-limonene presents synergistic properties with very high toxicity to S. frugiperda. B. thuringiensis + d-limonene, although resulting in toxicity for larvae, does not appear to be synergistic.

Methylmercury exposure of the sponge O. lobularis induces strong tissue and cell defects

Mediterranean marine biota suffers from various anthropogenic threats. Among them, pollutants such as mercury (Hg) represent important environmental issues that are exacerbated by bioaccumulation and bioamplification along food webs via its organic form, monomethylmercury (MMHg). To date, very little is known regarding the impact of mercury on Porifera and the few available studies have been exclusively focused on Demospongiae. This work studies the effect of MMHgCl at different biological levels of Oscarella lobularis (Porifera, Homoscleromorpha). Bioaccumulation assays show that MMHgCl significantly accumulated in sponge tissues after a 96-h exposure to 0.1 μg L−1. Toxicity assays (LC5096h) show a sensibility that depends on life-stage (adult vs bud). Additionally, we show that the exposure to 1 μg L−1 MMHgCl negatively impacts the epithelial integrity and the regeneration process in buds, as shown by the loss of cell-cell contacts and the alteration of osculum morphogenesis. For the first time in a sponge, a whole set of genes classically involved in metal detoxification and in antioxidant response were identified. Significant changes in catalase, superoxide dismutase and nuclear factor (erythroid-derived 2)-like 2 expressions in exposed juveniles were measured. Such an integrative approach from the physiological to the molecular scales on a non-model organism expands our knowledge concerning sensitivity and toxicity mechanisms induced by MMHg in Porifera, raising new questions regarding the possible defences used by marine sponges.

Unveiling the molecular networks underlying cellular impairment in Saccharomyces cerevisiae: investigating the effects of magnesium oxide nanoparticles on cell wall integrity and endoplasmic reticulum stress response.

Nanoparticles, particularly magnesium oxide nanoparticles (MgO-NPs), are increasingly utilized in various fields, yet their potential impact on cellular systems remains a topic of concern. This study aimed to comprehensively investigate the molecular mechanisms underlying MgO-NP-induced cellular impairment in Saccharomyces cerevisiae, with a focus on cell wall integrity, endoplasmic reticulum (ER) stress response, mitochondrial function, lipid metabolism, autophagy, and epigenetic alterations. MgO-NPs were synthesized through a chemical reduction method, characterized for morphology, size distribution, and elemental composition. Concentration-dependent toxicity assays were conducted to evaluate the inhibitory effect on yeast growth, accompanied by propidium iodide (PI) staining to assess membrane damage. Intracellular reactive oxygen species (ROS) accumulation was measured, and chitin synthesis, indicative of cell wall perturbation, was examined along with the expression of chitin synthesis genes. Mitochondrial function was assessed through Psd1 localization, and ER structure was analyzed using dsRed-HDEL marker. The unfolded protein response (UPR) pathway activation was monitored, and lipid droplet formation and autophagy induction were investigated. Results demonstrated a dose-dependent inhibition of yeast growth by MgO-NPs, with concomitant membrane damage and ROS accumulation. Cell wall perturbation was evidenced by increased chitin synthesis and upregulation of chitin synthesis genes. MgO-NPs impaired mitochondrial function, disrupted ER structure, and activated the UPR pathway. Lipid droplet formation and autophagy were induced, indicating cellular stress responses. Additionally, MgO-NPs exhibited differential cytotoxicity on histone mutant strains, implicating specific histone residues in cellular response to nanoparticle stress. Immunoblotting revealed alterations in histone posttranslational modifications, particularly enhanced methylation of H3K4me. This study provides comprehensive insights into the multifaceted effects of MgO-NPs on S. cerevisiae, elucidating key molecular pathways involved in nanoparticle-induced cellular impairment. Understanding these mechanisms is crucial for assessing nanoparticle toxicity and developing strategies for safer nanoparticle applications.

Potential of White Rot Fungi from Berbak-Sembilang National Park, Indonesia for Decolorization and Detoxification Commercial Direct Dyes

Commercial direct dyes are frequently employed in the dyeing of Jumputan, a traditional craft originating from South Sumatra, Indonesia. The introduction of synthetic dyes into the environment can have a detrimental impact on ecosystem stability, necessitating the implementation of remedial measures. There has been a growing interest in the utilization of White Rot Fungi (WRF) as a viable biological agent for the purpose of decolorizing and detoxifying synthetic colors. However, it is imperative to investigate the isolated WRF from Berbak-Sembilang National Park (TNBS) due to the varying capacities of decolorization and detoxification exhibited by each WRF. The study involved 5 WRF from TNBS screened in solid media, and grown in a liquid medium containing commercial direct dyes (direct turquoise, direct orange and direct yellow). WRF grown on liquid medium contains a single dye, mixture dyes and temperature characterization. It measured decolorization, biomass and enzyme activities. Toxicity is measured by the BSLT method. The findings indicated that 3 specific fungi, namely Phellinus noxius (BRB 11), Lentinus sajor-caju (BRB 12) and Leotrametes menziesii (BRB 73), exhibited a significant capacity to remove the color from both individual and mixture of direct dyes through the production of laccase and MnP enzymes. The optimal temperature for decolorization of the mixture of direct dyes was 35 °C for BRB 11 (61.4 %) and BRB 73 (60.7 %), whereas BRB 12 (47.4 %) exhibited optimal temperature at 30 °C. The toxicity assay conducted using A. salina showed a progressive rise in the LC50 value, from 15.37 mgL−1 in the control group to a range of 21.63 - 35.84 mgL−1 in the treated group, indicating a detoxification process. However, the most toxic isolate was BRB 12. This study proposes the potential of 2 isolates, Phellinus noxius (BRB 11) and Leotrametes menziesii BRB 73, from TNBS for degradation of single and mixture dye wastewater in the environment. HIGHLIGHTS The discovery of 3 White Rot Fungi from TNBS (Indonesia) has the ability to remove color and reduce the level of toxicity of commercial direct dyes, both individual and mixture of commercial direct dyes. Uncovering one of White Rot Fungi has not been widely published for decolorization and detoxification commercial direct dyes, namely Leotrametes menziesii (BRB 73). The optimal temperature was 35 °C for decolorization of commercial direct dyes by Phellinus noxius (BRB 11) and Leotrametes menziesii (BRB 73) GRAPHICAL ABSTRACT

New phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamides as dual inhibitors against α-glucosidase and PTP-1B for the treatment of type 2 diabetes.

This study describes the design, synthesis, and evaluation of a novel series of phenylthiosemicarbazide-phenoxy-1,2,3-triazole-N-phenylacetamide derivatives (7a-l) as dual inhibitors of α-glucosidase and protein tyrosine phosphatase 1-B (PTB-1B). The latter enzymes are two important targets in the treatment of type 2 diabetes. The in vitro obtained data demonstrated that all title compounds 7a-l were more potent than the standard inhibitor acarbose against α-glucosidase while only four derivatives (7a, 7g, 7h, and 7h) were more potent than the standard inhibitor suramin against PTP-1B. Furthermore, these data showed that the most potent α-glucosidase inhibitor was compound 7i, with sixfold higher inhibitory activity than acarbose, and the most potent PTP-1B inhibitor was compound 7a with 3.5-fold higher inhibitory activity than suramin. Kinetic studies of compounds 7i and 7a revealed that they inhibited their target enzymes in a competitive mode. The docking study demonstrated that compounds 7i and 7a well occupied the active site pockets of α-glucosidase and PTP-1B, respectively. In silico pharmacokinetic and toxicity assays of the most potent compounds were performed, and the obtained results were compared with those of the standard inhibitors.

Acute Toxicity Assays with the Artemia salina Model: Assessment of Variables.

The use of the brine shrimp Artemia salina (Leach) in acute toxicity assays has great potential due to its simplicity, low cost and reproducibility. In the current study, some of the variables that can influence the reliability of the assay in terms of test organism survival, were evaluated as part of its implementation in our laboratory. The quality and type of water used, the buffer components and other parameters (salinity, pH and dissolved oxygen level), were all evaluated for optimisation purposes. DMSO (dimethyl sulphoxide) was used as the test substance in the toxicity assay, to evaluate the concentration limits as a solvent in sample preparation. Regarding the buffer salinity, pH and dissolved oxygen level, we found that a 25% to 30% deviation from the standard values did not affect the survival of the nauplii (the first-instar larval stage) under assay conditions. In summary, we corroborate the potential use of this model for the prediction of the toxic potential of substances, to inform future testing strategies.

Toxicity of butylone and its enantiomers to Daphnia magna and its degradation/toxicity potential using advanced oxidation technologies

Butylone (BTL) is a chiral synthetic cathinone available as a racemate and reported as contaminant in wastewater effluents. However, there are no studies on its impact on ecosystems and possible enantioselectivity in ecotoxicity. This work aimed to evaluate: (i) the possible ecotoxicity of BTL as racemate or its isolated (R)- and (S)- enantiomers using Daphnia magna; and (ii) the efficiency of advanced oxidation technologies (AOTs) in the removal of BTL and reduction of toxic effects caused by wastewaters. Enantiomers of BTL were obtained by liquid chromatography (LC) using a chiral semi-preparative column. Enantiomeric purity of each enantiomer was > 97 %. For toxicity assessment, a 9-day sub-chronic assay was performed with the racemate (at 0.10, 1.0 or 10 μg L−1) or each enantiomer (at 0.10 or 1.0 μg L−1). Changes in morphophysiological, behavioural, biochemical and reproductive endpoints were observed, which were dependent on the form of the substance and life stage of the organism (juvenile or adult). Removal rates of BTL in spiked wastewater (10 μg L−1) treated with different AOTs (ultraviolet, UV; ozonation, O3; and UV/O3) were similar and lower than 29 %. The 48 h D. magna acute toxicity assays demonstrated a reduction in the toxicity of the treated spiked effluents, but no differences were found amongst AOTs treatments. These results warn for the contamination and negative impact of BTL on ecosystems and highlight the need for efficient removal processes.

Assessment of the Artemia salina toxicity assay as a substitute of the mouse lethality assay in the determination of venom-induced toxicity and preclinical efficacy of antivenom

Mice are routinely used in snake venom research but are costly and subject to pain and suffering. The crustacean Artemia salina could be an alternative to mice, but data to support its adoption in snake venom research is limited. The aim of the present study was to evaluate the suitability of A. salina as a surrogate of mice in assessing the toxicity of venoms and the preclinical efficacy of antivenoms. The toxicity of venoms from 22 snakes of medical importance in sub–Saharan Africa was evaluated in mice (intraperitoneally; i.p. and intravenously; i.v.) and in A. salina. Subsequently, the capacity of a commercial antivenom to neutralize the toxicity of these venoms in mice and A. salina was investigated. There was a positive correlation between the i.v. median lethal doses (LD50s) and the i.p. LD50s in mice (r = 0.804; p < 0.0001), a moderate correlation between the i.v. LD50s in mice and the median lethal concentrations (LC50s) in A. salina (r = 0.606; p = 0.003), and a moderate correlation between the i.p. LD50s in mice and the LC50s in A. salina (r = 0.426; p = 0.048). Moreover, there was a strong correlation between the i.p. median effective doses (ED50s) and the i.v. ED50s in mice (r = 0.941, p < 0.0001), between the i.p. ED50s in mice and the ED50s in A. salina (r = 0.818, p < 0.0001), and between the i.v. ED50s in mice and the ED50s in A. salina (r = 0.972, p < 0.0001). These findings present A. salina as a promising candidate for reducing reliance on mice in snake venom research. Future investigations should build upon these findings, addressing potential limitations and expanding the scope of A. salina in venom research and antivenom development.

A comparative study with vermifilter and geofilter for domestic wastewater treatment and its Phyto-toxicity efficacy

The present study investigated the role of earthworms in pollutant removal and toxicity assay of domestic wastewater. An indigenous reactor (vermigratings as an active layer) was set up for 60 days with a hydraulic loading rate of 1 m3 / m2 -d and hydraulic retention time of 3.5 h to evaluate its performance. Removal of total suspended solids, total dissolved solids, biochemical oxygen demand, chemical oxygen demand, and sulfate was found to be 92 %, 93 %, 89 %, 86 %, and 63.43 %, respectively. The Phyto-toxicity test reveals a higher germination rate and plant growth with vermifilter effluent than with geofilter effluent and raw wastewater. Additionally, vermifilter achieved heterotrophic bacteria removal by 1.54-fold. Hence, treated effluent can be used for irrigation purposes. Overall, this study will establish a potential alternative to the conventional wastewater treatment system and achieve Sustainable Development Goals 6.

Identification of small molecule inhibitors of penicillin-binding protein 2a of methicillin-resistant Staphylococcus aureus for the therapeutics of bacterial infection.

The penicillin binding protein 2a (PBP2a) is a key enzyme associated with bacterial cell wall synthesis and bacterial infection. Therefore, targeting PBPa2 offers a promising approach for the therapeutics of bacterial resistance and infection. This study presents a comprehensive analysis of alpha-mangostin as a potential inhibitor of PBPa2. Molecular docking simulations revealed a strong binding affinity between alpha-mangostin and PBP2a, with an affinity score of -6.01 kcal/mol. Notably, alpha-mangostin formed a preferential hydrogen bond with THR216 of PBP2a, alongside several other polar and hydrophobic interactions. ADME and Toxicity predictions indicated that alpha-mangostin possesses favourable pharmacokinetic properties, suggesting its potential as a therapeutic agent. PASS analysis further highlighted its broad range of favourable biological properties. SwissTargetPrediction analysis reinforced these findings, indicating alpha-mangostin's association with various biological processes. Cell toxicity assays demonstrated that alpha-mangostin had no significant impact on the viability of HEK-293 cells, suggesting its potential safety for further development. The IC50 value for alpha-mangostin was found to be 33.43µM. Fluorescence-based binding assays showed that alpha-mangostin effectively inhibited PBP2a activity in a concentration-dependent manner, supporting its role as an inhibitor. In conclusion, the results suggest alpha-mangostin as a promising candidate for inhibiting PBP2a. Further, extensive studies are warranted to explore its clinical applications.

Zebrafish-A Suitable Model for Rapid Translation of Effective Therapies for Pediatric Cancers.

Pediatric cancers are the leading cause of disease-related deaths in children and adolescents. Most of these tumors are difficult to treat and have poor overall survival. Concerns have also been raised about drug toxicity and long-term detrimental side effects of therapies. In this review, we discuss the advantages and unique attributes of zebrafish as pediatric cancer models and their importance in targeted drug discovery and toxicity assays. We have also placed a special focus on zebrafish models of pediatric brain cancers-the most common and difficult solid tumor to treat.

New pyridine-based chalcones and pyrazolines with anticancer, antibacterial, and antiplasmodial activities.

New pyridine-based chalcones 4a-h and pyrazolines 5a-h (N-acetyl), 6a-h (N-phenyl), and 7a-h (N-4-chlorophenyl) were synthesized and evaluated by the National Cancer Institute (NCI) against 60 different human cancer cell lines. Pyrazolines 6a, 6c-h, and 7a-h satisfied the pre-determined threshold inhibition criteria, obtaining that compounds 6c and 6f exhibited high antiproliferative activity, reaching submicromolar GI50 values from 0.38 to 0.45 μM, respectively. Moreover, compound 7g (4-CH3) exhibited the highest cytostatic activity of these series against different cancer cell lines from leukemia, nonsmall cell lung, colon, ovarian, renal, and prostate cancer, with LC50 values ranging from 5.41 to 8.35 μM, showing better cytotoxic activity than doxorubicin. Furthermore, the compounds were tested for antibacterial and antiplasmodial activities. Chalcone 4c was the most active with minimal inhibitory concentration (MIC) = 2 μg/mL against methicillin-resistant Staphylococcus aureus (MRSA), while the pyrazoline 6h showed a MIC = 8 μg/mL against Neisseria gonorrhoeae. For anti-Plasmodium falciparum activity, the chalcones display higher activity with EC50 values ranging from 10.26 to 10.94 μg/mL. Docking studies were conducted against relevant proteins from P. falciparum, exhibiting the minimum binding energy with plasmepsin II. In vivo toxicity assay in Galleria mellonella suggests that most compounds are low or nontoxic.

Acute and Subchronic Toxicological Study of the Cocktail Extract from Curcuma xanthorrhiza Roxb, Phyllanthus niruri L. and Morinda citrifolia L.

Curcuma xanthorrhiza Roxb, Phyllanthus niruri L., and Morinda citrifolia L. are Indonesian medicinal herbs used empirically as traditional therapeutics for maintaining health. The cocktail extract of these three plants (CECPM) had been developed and demonstrated immunostimulant activity in rats. This study aimed to evaluate the acute and subchronic toxicity of CECPM in vivo. The acute toxicity assay was conducted by orally administering a range dose of CECPM (313, 625, 1250, 2500, or 5000 mg/kg body weight (bw) on female mice once and then evaluating the toxic symptom every day for 14 days later. The chronic toxicity test was carried out by giving various doses of CECPM (600, 800, and 1000 mg/kg·bw) to female and male rats orally continuously for 90 consecutive days. The signs of toxicities were evaluated at the 90- and 28 days postadministration. The acute oral toxicity assays showed that there was no toxic syndrome and mortality found during the period of the experiment. The lethal dose level (LD50) of CECPM was more than 5000 g/kg, which was categorized as practically non-toxic. Meanwhile, in the sub-chronic toxicity study, some parameters tested at 90 days postadministration and after 28 days of withdrawal, such as the body weight, relative organ weight, food intake, hematological and biochemical blood parameters, and also histopathological examination of five primary tissues (heart, liver, kidney, spleen, and lung) revealed no abnormalities. There was no-observed adverse effect level (NOAEL) for the present study of CECPM 1000 mg/kg·bw of the rat. Therefore, it is concluded that the orally administered CECPM was relatively nontoxic during acute and subchronic toxicology studies.

Unraveling the mechanism of antifungal action of encapsulated eugenol/chitosan nanoparticles against Aspergillus fumigatus

Aspergillus fumigatus can cause an invasive life-threatening infection in people who have weakened immune systems, underlying diseases or respiratory infections such as COVID-19. Azole-resistant A. fumigatus infections are difficult to treat and have high mortality. This study aimed to investigate the efficacy of encapsulated eugenol in chitosan biopolymer nanoparticles (NPs) to increase its antifungal activity against A. fumigatus. The physical properties of eugenol-encapsulated chitosan nanoparticles (EECNPs), size, polydispersity and the release profile of eugenol were examined by DLS, XRD and FTRI techniques. The antifungal activity of EECNPs against A. fumigatus was examined using CLSI-M38 microbroth dilution assay, time killing assay, reactive oxygen species (ROS) activity, destruction of cell membrane integrity/permeability, and cell wall morphological damage by electron microscopy. The eugenol/chitosan ratio of 1.00:1.00 was considered the optimal ratio with the highest encapsulation efficiency (43.1%) and loading capacity (30.8%). EECNPs were characterized by a hydrodynamic radius of 330.9 nm, a polydispersity index (PDI) of 0.298 and the zeta potential of 18.9 mv. The average size of the EECNPs was 300 nm according to TEM micrographs. The antifungal activities were determined at 150–300 μg/mL as MIC concentrations. The time killing assay showed that the nanoparticles could inhibit the fungal growth after 12 h. The toxicity assay revealed more than 60% survival of human embryonic kidney (HEK293) cell line in 2 × MIC concentration. The release of reactive oxygen species (ROS), and extracellular potassium in A. fumigatus caused more damaging on cell membrane integrity, through increasing 600 μg/mL concentration of nanoparticles. Our results revealed that the encapsulation of eugenol in chitosan biopolymer to produce EECNPs not only increased the half-life of eugenol but also improved its antifungal activity against A. fumigatus by a combined mechanism of damaging cell surfaces, cell membrane integrity, and the induction of ROS activity. This study is the first to report that EECNPs has the potency to use as a natural antimicrobial agent due to embracing the destructive properties on cell membrane integrity in A. fumigatus.

A molecular extraction process for vanadium based on tandem selective complexation and precipitation

Recycling vanadium from alternative sources is essential due to its expanding demand, depletion in natural sources, and environmental issues with terrestrial mining. Here, we present a complexation-precipitation method to selectively recover pentavalent vanadium ions, V(V), from complex metal ion mixtures, using an acid-stable metal binding agent, the cyclic imidedioxime, naphthalimidedioxime (H2CIDIII). H2CIDIII showed high extraction capacity and fast binding towards V(V) with crystal structures showing a 1:1 M:L dimer, [V2(O)3(C12H6N3O2)2]2−, 1, and 1:2 M:L non-oxido, [V(C12H6N3O2)2] ̶ complex, 2. Complexation selectivity studies showed only 1 and 2 were anionic, allowing facile separation of the V(V) complexes by pH-controlled precipitation, removing the need for solid support. The tandem complexation-precipitation technique achieved high recovery selectivity for V(V) with a selectivity coefficient above 3 × 105 from synthetic mixed metal solutions and real oil sand tailings. Zebrafish toxicity assay confirmed the non-toxicity of 1 and 2, highlighting H2CIDIII’s potential for practical and large-scale V(V) recovery.

Abstract 5931: Investigating the therapeutic potential of STK17A inhibition in GBM

Abstract For decades, the survival rate for glioblastoma (GBM) has remained nearly stagnant, and currently the 5-year survival rate is only 5%. There is an unmet medical need for therapeutic development, as GBM is the most common primary brain tumor, yet only four FDA approved drugs have been developed for GBM over the last century. GBM is notoriously heterogeneous, and this has posed a challenge for researchers seeking to find therapeutic targets. However, by taking advantage of RNA sequencing, a potential biomarker and target for GBM has been identified: the kinase STK17A (Serine/Threonine Kinase 17A), also known as DRAK1. We confirmed that STK17A is overexpressed in brain cancers by analyzing public databases and single-cell RNA sequencing data from GBM patients, and further associated it with poor patient outcome. Little is known about STK17A, but it has been found to be involved with cell proliferation, tumorigenesis, and tumor metastasis. The role of STK17A in GBM pathophysiology and its therapeutic potential as a drug target remains a critical knowledge gap.In order to better understand STK17A’s role in GBM pathophysiology, we first knocked down STK17A in GBM cell lines and determined that STK17A had functional roles in proliferation and morphology. Similar conclusions were drawn after knocking down STK17A in vivo in GBM xenograft mouse models. These findings supported STK17A as a viable therapeutic target. We then designed and optimized novel brain-penetrant STK17A inhibitors with IC50 values of &amp;lt;20nM in enzyme assays and &amp;lt;1μM in cell-based targeting engagement and proliferative assays. The designed and prepared novel STK17A inhibitors were further evaluated through kinase enzymatic assays and biological assays as well as in vitro proliferation and toxicity assays. We further characterized the inhibitors by showing Drug Metabolism and Pharmacokinetics (DMPK) properties in vivo in mouse models at 10 mg/kg via oral administration. We then used these potent, selective, and highly brain penetrant STK17A inhibitors to investigate the anti-tumor effects of STK17A inhibition in GBM in vivo and demonstrate the efficacy of our novel STK17A inhibitors.In conclusion, this work seeks to contribute to the field of targeted therapies for GBM by optimizing and examining the first iterations of novel brain penetrant STK17A inhibitors, initiating studies for the treatment of GBM in vitro and in vivo, and providing proof of efficacy for further studies in GBM patients. Ultimately, the results from our findings will lead to novel strategies for targeted drug development and more robust therapeutic options for GBM patients. Citation Format: Jesus R. Castro. Investigating the therapeutic potential of STK17A inhibition in GBM [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5931.