LD50 In Mice Research Articles

A Validation of the Equivalence of the Cell-Based Potency Assay Method with a Mouse LD50 Bioassay for the Potency Testing of OnabotulinumtoxinA.

(1) Background: At present, the only potency assay approved in China for the in-country testing of botulinum toxin type A for injection products is the mouse bioassay (MBA). The Chinese market for neurotoxin products is rapidly expanding, but MBAs are subject to high variability due to individual variations in mice, as well as variations in injection sites, in addition to the limited number of batches tested for one MBA. Compared with the mLD50 method, the cell-based potency assay (CBPA) developed for the potency testing of onabotulinumtoxinA (BOTOX) by AbbVie not only does not use any experimental animals but also allows for significant time and cost savings. Due to the significant benefits conferred by the replacement of the mLD50 assay with CBPA in China, the CBPA method has been transferred, validated, and cross-validated to demonstrate the equivalence of the two potency methods. (2) Methods: The differentiated SiMa cells were treated with both BOTOX samples and the reference standard, and the cleaved SNAP25197 in the cell lysates was quantified using Chemi-ECL ELISA. A 4-PL model was used for the data fit and sample relative potency calculation. The method accuracy, linearity, repeatability, and intermediate precision were determined within the range of 50% to 200% of the labeled claim. A statistical equivalence of the two potency methods (CBPA and mLD50) was initially demonstrated by comparing the AbbVie CBPA data with NIFDC mLD50 data on a total of 167 commercial BOTOX lots (85 50U lots and 82 100U lots). In addition, six lots of onabotulinumtoxinA (three 50U and three 100U) were re-tested as cross-validation by these two methods for equivalence. (3) Results: The overall assay's accuracy and intermediate precision were determined as 104% and 9.2%, and the slope, R-square, and Y-intercept for linearity were determined as 1.071, 0.998, and 0.036, respectively. The repeatability was determined as 6.9%. The range with the acceptable criteria of accuracy, linearity, and precision was demonstrated as 50% to 200% of the labeled claim. The 95% equivalence statistic test using margins [80%, 125%] indicates that CBPA and mLD50 methods are equivalent for both BOTOX strengths (i.e., 50U and 100U). The relative potency data from cross-validation were within the range of ≥80% to ≤120%. (4) Conclusions: The CBPA meets all acceptance criteria and is equivalent to mLD50. The replacement of mLD50 with CBPA is well justified in terms of ensuring safety and efficacy, as well as for animal benefits.

Frentizole derivatives with mTOR inhibiting and senomorphic properties

Frentizole is immunosuppressive drug with low acute toxicity and lifespan-prolonging effect. Recently, frentizole´s potential to disrupt toxic amyloid β (Aβ) - Aβ-binding alcohol dehydrogenase (ABAD) interaction in mitochondria in Alzheimer´s brains has been revealed. Another broadly studied drug with anti-aging and immunosuppressive properties is an mTOR inhibitor – rapamycin. Since we do not yet precisely know what is behind the lifespan-prolonging effect of rapamycin and frentizole, whether it is the ability to inhibit the mTOR signaling pathway, reduction in mitochondrial toxicity, immunosuppressive effect, or a combination of all of them, we have decided within our previous work to dock the entire in-house library of almost 240 Aβ-ABAD modulators into the FKBP-rapamycin-binding (FRB) domain of mTOR in order to interlink mTOR-centric and mitochondrial free radical-centric theories of aging and thus to increase the chances of success. Based on the results of the docking study, molecular dynamic simulation and MM-PBSA calculations, we have selected nine frentizole-like compounds (1 – 9). Subsequently, we have determined their real physical-chemical properties (logP, logD, pKa and solubility in water and buffer), cytotoxic/cytostatic, mTOR inhibitory, and in vitro anti-senescence (senolytic and senomorphic) effects. Finally, the three best candidates (4, 8, and 9) have been forwarded for in vivo safety studies to assess their acute toxicity and pharmacokinetic properties. Based on obtained results, only compound 4 demonstrated the best results within in vitro testing, the ability to cross the blood-brain barrier and the lowest acute toxicity (LD50 in male mice 559 mg/kg; LD50 in female mice 575 mg/kg).

First Isolation and Identification of Aeromonas veronii in a Captive Giant Panda (Ailuropoda melanoleuca).

The objective of this study was to understand biological characteristics of one bacteria strain named as VPG which was isolated from multiple organs of a dead captive giant panda cub. Here, we use biochemical tests, 16S rRNA and gyrB genes for bacterial identification, the disk diffusion method for antibiotic resistance phenotype, smart chip real-time PCR for the antibiotic resistance genotype, multiplex PCR for determination of virulence genes, and the acute toxicity test in mice for testing the pathogenicity of isolates. The isolate was identified as A. veronii strain based on the biochemical properties and genetic analysis. We found that the strain carried 31 antibiotic resistance genes, revealed antimicrobial resistance phenotypically to several antibiotics including penicillin, ampicillin, oxacillin, amoxicillin, imipenem, and vancomycin, and carried virulence genes including aer, act, lip, exu, ser, luxs, and tapA. The main pathological changes in giant panda were congestion, necrotic lesions and a large number of bacteria in multiple organs. In addition, the LD50 in Kunming mice infected with strain VGP was 5.14 × 107 CFU/mL by intraperitoneal injection. Infection with strain VGP led to considerable histological lesions such as hemorrhage of internal organs, necrosis of lymphocytes and neurons in Kunming mice. Taken together, these results suggest that infection with strain VGP would be an important causes of death in this giant panda cub.

Preclinical evaluation of a gel composition based on a flavonoid complex for the treatment of periodontal diseases in orthodontic patients

The aim of the work was a preclinical assessment of acute toxicity, skin resorptive, irritant effects, cumulative and catalase activity, as well as sensitizing properties of the local gel composition “Benzidaflaziverdine” (GCB) used for the treatment of periodontal diseases in orthodontic patients. Materials and methods. 119 animals were involved in the experiment, assigned to seven main and two control groups. GCB was administered intragastrically in doses of 300–600 mg/kg and intradermally of 200 μg into the outer surface of the ear. The native solution of GCB was applied to the skin and mucous membranes, administered orally by the method of “subchronic toxicity” and to the surface of the chorioallantoic membrane (CAM) of chicken embryos. The intensity of lipid peroxidation (LPO) was assessed by the level of diene conjugates (DCs) and malondialdehyde (MDA), and the antioxidant system by catalase activity. The specific leukocyte agglomeration reaction (SLAR), the specific leukocyte lysis reaction, and neutrophil damage indicators were used. Results. The median lethal dose LD50 for rats and mice of both sexes exceeded 5000 mg/kg. The irritant effect of GCB on the mucous membranes was manifested by hyperemia on the second day. Symptoms of irritation disappeared after 3–4 days without medical intervention. An analysis of the CAM blood vessels after exposure to GCB in two observations at the 120th second showed the beginning of hemorrhages. In one observation, GCB caused minor hemorrhages at the 300th second of the experiment. It was found that the coefficient of GCB irritant action was 5 (the mean score of Me (Q1; Q3) was 5 (4; 5)). The coefficient of cumulation (Kcum) exceeded 8.2. An insignificant increase in the median or mean values of catalase enzyme activity, DCs, and the amount of LPO end product such as MDA was observed compared to the control group animals. The SLAR test indicated the development of a delayed-type allergic reaction under the influence of GCB in a 1:10 dilution. One-hundred-fold dilution did not cause significant changes in the indicator in the main group compared to the control one. Conclusions. GCB belongs to the 4th class of toxicity – practically non-toxic substances, does not have sex- and species sensitivity, has weak cumulative activity, minimal effect on the system of LPO. GCB can be recommended for the use in clinical periodontology for medical support of orthodontic patients.

Surfactants Accelerate Isotope Exchange-Based 18F-Fluorination in Water.

Radiochemical yields (RCYs) of isotope exchange-based 18F-fluorination of non-carbon-centered substrates in water are rationally enhanced by adding surfactants, which increases both the rate constant k and local reactant concentrations. Among 12 surfactants, the cationic surfactant cetrimonium bromide (CTAB) and two nonionic surfactants (Tween 20 and Tween 80) were selected for their superior catalytic effects, namely, electrostatic effects or solubilization effects. For a model substrate, bis(4-methoxyphenyl)phosphinic fluoride, the 18F-fluorination rate constant (k) increased up to 7-fold, while its saturation concentration rose up to 15-fold due to micelle formation, encapsulating 70-94% of the substrate. With 30.0 mmol/L CTAB, the required 18F-labeling temperature of a typical organofluorosilicon prosthesis ([18F]SiFA) decreased from 95 °C to room temperature, achieving an RCY of 22%. For an E[c(RGDyK)]2-derived peptide tracer with an organofluorophosphine prosthesis, the RCY in water at 90 °C achieved 25%, correspondingly increasing the molar activity (Am). After high-performance liquid chromatography (HPLC) or solid-phase purification, the residual selected surfactant concentrations in the tracer injections were well below the FDA DII (Inactive Ingredient Database) limits or the LD50 in mice.

Dietary phytoestrogen diosgenin interrupts metabolism, physiology, and reproduction of Swiss albino mice: Possible mode of action as an emerging environmental contaminant, endocrine disruptor and reproductive toxicant.

Dietary phytoestrogens are the main source of environmental contamination due to their estrogen-mimicking and endocrine-disrupting effects, posing a threat to microbial, soil, plant, and animal health. Diosgenin, a phytosteroid saponin, is used in many traditional medicines, nutraceuticals, dietary supplements, contraceptives, and hormone replacement therapies against numerous diseases and disorders. It is important to be aware of the potential risks associated with diosgenin, as well as its potential to cause reproductive and endocrine toxicity. Due to the lack of research on the safety and probable adverse side effects of diosgenin, this work evaluated the endocrine-disrupting and reproductive toxicity of diosgenin in albino mice by following acute toxicity (OECD-423), repeated dose 90-day oral toxicity (OECD-468), and F1 extended one-generation reproductive toxicity (OECD-443) studies. Diosgenin was found to be slightly toxic, with LD50 for male and female mice being 546.26 and 538.72 mg/kg, respectively. Chronic exposure of diosgenin (10, 50, 100, and 200 mg/kg) generated oxidative stress, depleted antioxidant enzymes, disturbed homeostasis of the reproductive hormones, and interrupted steroidogenesis, germ cell apoptosis, gametogenesis, sperm quality, estrous cycle, and reproductive performance in the F0 and F1 offspring. Long-term oral exposure of diosgenin to the mice disturbed the endocrine and reproductive functions and generated transgenerational reproductive toxic effects in F0 and F1 offspring. These results suggest that diosgenin should be used carefully in food products and medical applications due to its potential endocrine-disrupting and reproductive toxic effects. The findings of this study provide a better understanding of the potential adverse effects of diosgenin and the need for appropriate risk assessment and management of its use.

Replacement of the Mouse LD50 Assay for Determination of the Potency of AbobotulinumtoxinA with a Cell-Based Method in Both Powder and Liquid Formulations.

Botulinum neurotoxins (BoNTs) are important therapeutic agents. The in vivo median lethal dose (LD50) assay has been commonly used to measure the potency of BoNT commercial preparations. As an alternative, we developed cell-based assays for abobotulinumtoxinA in both powder (Dysport®, Azzalure®) and liquid (Alluzience®) formulations using the in vitro BoCell® system. The assays demonstrated linearity over 50-130% of the expected relative potency, with a correlation coefficient of 0.98. Mean recoveries of 90-108% of the stated potency were observed over this range. The coefficients of variation for powder and liquid formulations, respectively, were 3.6% and 4.0% for repeatability and 8.3% and 5.0% for intermediate precision. A statistically powered comparability assessment of the BoCell® and LD50 assays was performed. Equivalence was demonstrated between the assays for the liquid formulation at release and end of shelf life using a paired equivalence test with predefined equivalence margins. For the powder formulation, the assays were also shown to be equivalent for release samples and when determining loss of potency following thermal degradation. The BoCell® assay was approved for establishing the potency of abobotulinumtoxinA for both powder and liquid formulations in Europe and for the powder formulation only in the USA.

Comparing LD50/LC50 Machine Learning Models for Multiple Species.

The lethal dose or concentration which kills 50% of the animals (LD50 or LC50) is an important parameter for scientists to understand the toxicity of chemicals in different scenarios that can be used to make go-no-go decisions, and ultimately assist in the choice of the right personal protective equipment needed for containment. The LD50 assessment process has also required the use of many animals although modern methods have reduced the number of rats needed. Since a compound is usually considered highly toxic when the LD50 is lower than 25 mg/kg, such a classification provides potentially valuable safety information to synthetic chemists and other safety assessment scientists. The need for finding alternative approaches such as computational methods is important to ultimately reduce animal use for this testing further still. We now summarize our efforts to use public data for building in vivo LD50 or LC50 classification and regression machine learning models for various species (rat, mouse, fish and daphnia) and their 5-fold cross validation statistics with different machine learning algorithms as well as an external curated test set for mouse LD50. These datasets consist of different molecule classes, may cover different activity ranges, and also have a range of dataset sizes. The challenges of using such computational models are that their applicability domain will also need to be understood so that they can be used to make reliable predictions for novel molecules. These machine learning models will also need to be backed up with experimental validation. However, such models could also be used for efforts to bridge gaps in individual toxicity datasets. Making such models available also opens them up to potential misuse or dual use. We will summarize these efforts and propose that they could be used for scoring the millions of commercially available molecules, most of which likely do not have a known LD50 or for that matter any data in vitro or in vivo for toxicity.

Engineered Bacterial Outer Membrane Vesicles with Lipidated Heterologous Antigen as an Adjuvant-Free Vaccine Platform for Streptococcus suis.

Bacterial outer membrane vesicles (OMVs) are considered a promising vaccine platform for their high built-in adjuvanticity and ability to efficiently induce immune responses. OMVs can be engineered with heterologous antigens based on genetic engineering strategies. However, several critical issues should still be validated, including optimal exposure to the OMV surface, increased production of foreign antigens, nontoxicity, and induction of powerful immune protection. In this study, engineered OMVs with the lipoprotein transport machinery (Lpp) were designed to present SaoA antigen as a vaccine platform against Streptococcus suis. The results suggest that Lpp-SaoA fusions can be delivered on the OMV surface and do not have significant toxicity. Moreover, they can be engineered as lipoprotein and significantly accumulated in OMVs at high levels, thus accounting for nearly 10% of total OMV proteins. Immunization with OMVs containing Lpp-SaoA fusion antigen induced strong specific antibody responses and high levels of cytokines, as well as a balanced Th1/Th2 immune response. Furthermore, the decorated OMV vaccination significantly enhanced microbial clearance in a mouse infection model. It was found that antiserum against lipidated OMVs significantly promoted the opsonophagocytic uptake of S. suis in RAW246.7 macrophages. Lastly, OMVs engineered with Lpp-SaoA induced 100% protection against a challenge with 8× the 50% lethal dose (LD50) of S. suis serotype 2 and 80% protection against a challenge with 16× the LD50 in mice. Altogether, the results of this study provide a promising versatile strategy for the engineering of OMVs and suggest that Lpp-based OMVs may be a universal adjuvant-free vaccine platform for important pathogens. IMPORTANCE Bacterial outer membrane vesicles (OMVs) have become a promising vaccine platform due to their excellent built-in adjuvanticity properties. However, the location and amount of the expression of the heterologous antigen in the OMVs delivered by the genetic engineering strategies should be optimized. In this study, we exploited the lipoprotein transport pathway to engineer OMVs with heterologous antigen. Not only did lapidated heterologous antigen accumulate in the engineered OMV compartment at high levels, but also it was engineered to be delivered on the OMV surface, thus leading to the optimal activation of antigen-specific B cells and T cells. Immunization with engineered OMVs induced a strong antigen-specific antibodies in mice and conferred 100% protection against S. suis challenge. In general, the data of this study provide a versatile strategy for the engineering of OMVs and suggest that OMVs engineered with lipidated heterologous antigens may be a vaccine platform for significant pathogens.

The small RNA STnc1480 contributes to the regulation of biofilm formation and pathogenicity in Salmonella typhimurium.

Salmonella Typhimurium (STM) is one of the most important food-borne bacteria that seriously harms livestock and human beings, which is capable of regulating the expression of its own genes in a variety of ways to adapt to a wide variety of adverse environmental stresses. To understand the regulatory roles of sRNA STnc1480 on the capability of STM, the STnc1480 gene-deficient strain △STnc1480 and its complement strain △STnc1480/STnc1480 were generated, and the impacts of STnc1480 gene deficiency on the capability of responding to different environmental stresses, biofilm(BF)formation and pathogenicity were analyzed, respectively. Then the target genes that were regulated by STnc1480 were also analyzed and explored. Compared with parent and complement strains, the deficiency of the STnc1480 gene significantly reduced the BF formation. Moreover, the capacities of adhesion and invasiveness of the △STnc1480 strain to macrophages were also significantly reduced, while the LD50 in mice was significantly increased. The bacterial loads in liver and spleen were significantly reduced, and the pathological damage was alleviated. It was confirmed that the STnc1480 could be complementary to the 5'-UTR (-52 to -71 bases) region of lpfA mRNA. The bacterial dual-plasmid reporting system confirmed that STnc1480 was capable of interacting with the mRNA of the lpfA gene, suggesting that STnc1480 can regulate the 5'-UTR of the lpfA mRNA at post-transcription level to reduce the expression of the bacterial fimbria, thus reducing the BF formation and pathogenicity of STM.

Acute, chronic, and genotoxic studies on the protopine total alkaloids of the Macleaya cordata (willd.) R. Br. in rodents.

The protopine alkaloids are widely distributed within the opium poppy family and have a wide range of pharmacological effects. MPTA is a product of the protopine total alkaloids extracted from the Macleaya cordata (Willd.) R. Br. Previously, we reported good anti-inflammatory activity of MPTA as well as oral acute and sub-chronic toxicity studies in rats. In order to perform a systematic toxicological safety assessment of MPTA, oral acute toxicity, genotoxicity (bone marrow cell chromosome aberration test, sperm abnormality test, bone marrow cell micronucleus test, and rat teratogenicity test), and chronic toxicity in mice were performed in this study. In the oral acute toxicity test, the LD50 in ICR mice was 481.99 mg/kg, with 95% confidence limits ranging from 404.27 to 574.70 mg/kg. All three mutagenicity tests tested negative in the range of 60.25–241.00 mg/kg. The results of the teratogenicity test in rats showed no reproductive or embryonic developmental toxicity at only 7.53 mg/kg, which can be considered as a no observed effect level (NOEL) for the teratogenicity test. Therefore, MPTA is safe for use at the doses tested, but attention should be paid to the potential risk to pregnant animals and the safety evaluation and toxicity mechanisms in target animals should be further investigated.

Development of Live Attenuated Salmonella Typhimurium Vaccine Strain Using Radiation Mutation Enhancement Technology (R-MET).

Salmonella enterica is a leading cause of food-borne diseases in humans worldwide, resulting in severe morbidity and mortality. They are carried asymptomatically in the intestine or gallbladder of livestock, and are transmitted predominantly from animals to humans via the fecal-oral route. Thus, the best preventive strategy is to preemptively prevent transmission to humans by vaccinating livestock. Live attenuated vaccines have been mostly favored because they elicit both cellular and humoral immunity and provide long-term protective immunity. However, developing these vaccines is a laborious and time-consuming process. Therefore, most live attenuated vaccines have been mainly used for phenotypic screening using the auxotrophic replica plate method, and new types of vaccines have not been sufficiently explored. In this study, we used Radiation-Mutation Enhancement Technology (R-MET) to introduce a wide variety of mutations and attenuate the virulence of Salmonella spp. to develop live vaccine strains. The Salmonella Typhimurium, ST454 strain (ST WT) was irradiated with Cobalt60 gamma-irradiator at 1.5 kGy for 1 h to maximize the mutation rate, and attenuated daughter colonies were screened using in vitro macrophage replication capacity and in vivo mouse infection assays. Among 30 candidates, ATOMSal-L6, with 9,961-fold lower virulence than the parent strain (ST454) in the mouse LD50 model, was chosen. This vaccine candidate was mutated at 71 sites, and in particular, lost one bacteriophage. As a vaccine, ATOMSal-L6 induced a Salmonella-specific IgG response to provide effective protective immunity upon intramuscular vaccination of mice. Furthermore, when mice and sows were orally immunized with ATOMSal-L6, we found a strong protective immune response, including multifunctional cellular immunity. These results indicate that ATOMSal-L6 is the first live vaccine candidate to be developed using R-MET, to the best of our knowledge. R-MET can be used as a fast and effective live vaccine development technology that can be used to develop vaccine strains against emerging or serotype-shifting pathogens.

Ethanol Leaf Extract of Synsepalum dulcificum Schumach. & Thonn. (Sapotaceae) Induces Distortions in Renal, Hepatic and Reproductive Indices in Sprague-Dawley Rats

Background and Purpose: Synsepalum dulcificum (Sapotaceae) is used in traditional medicine for treatment of diabetes, cough and cancer. This study was designed to investigate the in vivo toxicological endpoints of the ethanol leaf extract of S. dulcificum in male and female rats.
 Methods: After estimating the LD50 in mice, forty-eight rats were randomly assigned to four groups of twelve rats each in a sex ratio of 1:1 and were orally administered 10 mL/kg distilled water (control) and 118, 237, 475 mg/kg/day of the extract respectively for forty-five days. The animals were thereafter euthanized and blood samples collected for haematological, biochemical and antioxidant assays. Sperm parameters were evaluated and testis, liver, heart and ovary were harvested for histopathology. Constituents of the extract were determined by GC-MS.
 Result: The LD50 (oral) was estimated to be 4750 mg/kg in mice. There was a significant decrease in haemoglobin but lymphocytes and monocytes were significantly increased compared to control. Aspartate transaminase and alanine transaminase were significantly increased compared to control. Creatinine increased, high density lipoprotein (HDL) and albumin decreased significantly in treated rats. There was a significant increase in enzymatic and non-enzymatic antioxidants and a significant reduction in malondialdehyde (MDA). There were significant increases in reproductive markers of sperm count, motility and abnormality. Renovascular congestion and preserved cytoarchitecture in other organs were observed. Twenty-one compounds including n-hexadecanoic acid, oleic acid, 2,3-dihydro-3,5-dihydroxyl-6- methyl-4H-pyran-4-one (DDMP) and phytol were identified.
 Conclusion: Prolonged use of the ethanol leaf extract of S. dulcificum could result in hepatic and renal dysfunctions and may increase the risk for male infertility and cardiovascular diseases.

Identification of two death camas chemotypes within a population and evaluation of toxicity

Foothill death camas (Zigadenus paniculatus) is a native, cool-season, bulbous perennial forb found throughout the western U.S. The toxins in death camas are steroidal alkaloids. Zygacine is often the most abundant alkaloid in death camas and is believed to be the primary toxic component. A population of death camas with plants consisting of two different chemical profiles (chemotypes) growing within the same location were identified. The objective of this study was to determine the percentage of a death camas population represented by each of the different chemotypes and to determine if there was a difference in toxicity between the two chemotypes. One third of the population sampled consisted of chemotype 1, while two-thirds of the population consisted of chemotype 2. The zygacine concentration of chemotype 1 was three times higher than chemotype 2. Chemotype 2 contained higher concentrations of several other steroidal alkaloids than chemotype 1. We hypothesized that chemotype 1, which consisted of higher concentrations of zygacine, would be more toxic than chemotype 2. The acute toxicity of each chemotype was determined in mice and sheep. In the mouse LD50 study, the acute toxicity of the chemotype 1 alkaloids (2.3 mg/kg BW) was different than the chemotype 2 alkaloids (3.2 mg/kg BW). However, in the sheep study there were no differences in the adverse effects between chemotypes. Based upon the results of this study, caution should be taken when livestock are grazing death camas, as both chemotypes of death camas appear to pose a similar risk to grazing livestock.

Evaluation of the toxic effects of the aqueous extract of Niprineem tea in mice and rats

Azadirachta indica is an important plant in traditional complementary and alternative medicine with decoctions (tea) being a common mode of administration. Herbal teas are frequently self-administered thus the need to prepare a standardized dosage form for the administration of such decoctions. The leaf of Azadirachta indica was formulated for administration as tea; thus, this study was designed to determine the safety profile of Niprineem tea. Oral acute and sub-chronic toxicity studies of the aqueous extract of Niprineem tea (NTE) were evaluated. The OECD (No 423) limit test was followed to determine the LD50 in Swiss albino mice, while OECD 407 guideline was used for the sub-chronic toxicity studies in Wistar rats. Acute administration of NTE did not cause detectable signs of toxicity in treated animals and no mortality was recorded. In the 28-day toxicity tests, there were no significant (p<0.05) changes in food and water intake, or urine and faecal output. Haematological analysis did not show deleterious effects in treated rats. Biochemical evaluation of indicators for renal and hepatic functions did not show significant changes after treatment with NTE. Likewise, histological tests did not result in structural changes in cells of the tissues of major organs. The results obtained suggest that Niprineem tea is relatively non-toxic and safe at the tested dose.

The role of eugenol and ferulic acid as the competitive inhibitors of transcriptional regulator RhlR in P. aeruginosa

Search inhibitors of Quorum Sensing (QS) in Pseudomonas aeruginosa are challenging to find therapies due to the broad antibiotic resistance. Therefore, this study aimed to probe ten aromatic compounds as inhibitors of three transcriptional regulators of QS in P. aeruginosa. The methodology consisted in determining the Binding Gibbs Energy (BGE) with software Chimera (tool vina) and Mcule, comparing the averages by the Tukey method (p≤0.05) to find inhibitors of QS. Subsequently, the LD50 in the mice model was evaluated by three QSAR models, and the in silico pharmacokinetic values were obtained from the ADME (the absorption distribution metabolism excretion) and PubChem databases. Found three potential inhibitors of RhlR with the lower BGE values in the range -6.70±0.21 to -7.43±0.35 kcal/mol. On the other side, all compounds were acceptable for Lipinski's rule of fives and the in silico oral mice LD50 and ADME values. Concluding, the ferulic acid and eugenol showed the best total BGE values (-75.07±0.892 and -70.36±1.022 kcal/mol), proposing them as a new therapy against the virulence of P. aeruginosa. Finally, the in silico studies have demonstrated are reproducible and valuable for putative QS inhibitors predicting and obtaining new studies derivatives from the results obtained in the present study.• The key benefits of this methodology are:Use free, licensed, flexible, and efficient software for in silico molecular docking.• Validation and comparison of BGE employing two molecular docking software in three different proteins.• Use classical molecular dynamics to define the stability and the total BGE of interaction protein-ligand and find the best inhibitor of a protein for proposing them as a possible therapy against the virulence of specific pathogens.

Discovery of a Potent and Orally Bioavailable Hypoxia-Inducible Factor 2α (HIF-2α) Agonist and Its Synergistic Therapy with Prolyl Hydroxylase Inhibitors for the Treatment of Renal Anemia.

Activation of hypoxia-inducible factor 2 (HIF-2) has emerged as a potent renal anemia treatment strategy. Here, the benzisothiazole derivative 26 was discovered as a novel HIF-2α agonist, which first demonstrated nanomolar activity (EC50 = 490 nM, Emax = 349.2%) in the luciferase reporter gene assay. Molecular dynamics simulations indicated that 26 could allosterically enhance HIF-2 dimerization. Furthermore, compound 26 had a good pharmacokinetic profile (the oral bioavailability in rats was 41.38%) and an in vivo safety profile (the LD50 in mice was greater than 708 mg·kg-1). In the in vivo efficacy assays, the combination of 26 and the prolyl hydroxylase inhibitor, AKB-6548, was confirmed for the first time to synergistically increase the plasma erythropoietin level in mice (from 260 to 2296 pg·mL-1) and alleviate zebrafish anemia induced by doxorubicin. These results provide new insights for HIF-2α agonists and the treatment of renal anemia.

Evaluation of the Extracts From Rhizomes of Polygonum bistorta for the Median Lethal Dosages in Swiss Albino Mice

Background: Polygonum bistorta has been used as a remedy for jaundice, smallpox, pimples, measles, cholera, diarrhoea, dysentery, expelling worms, insect stings and snakebites. In this study, the crude extract from P. bistorta and two fractions viz. hexane and chloroform obtained from the crude extract were studied for their median Lethal Dosages (LD50) in Swiss albino mice. Methods: Powdered rhizomes of P. bistorta was macerated with chloroform and the crude extract was dissolved in a solvent mixture of methanol/water (95:5). The mixture was then subjected to solvent-solvent partition, first with hexane followed by chloroform. The crude extract and the hexane and chloroform fractions were evaluated for their LD50 in Swiss albino mice of both sexes. Results: The LD50 of the crude extract and the hexane and chloroform fractions were determined to be 142.82, 200 and 200.17mg per kg of the mice body weight, respectively. Conclusion: The LD50 values of the crude extract and the hexane and chloroform fractions from P. bistorta were determined. The crude extract of P. bistorta had greater lethality than the hexane and chloroform fractions. This is the first report on the LD50 values of Swiss albino mice for P. bistorta.

Evaluación de la actividad diurética del extracto acuoso de Eryngium heterophyllum Engelm (hierba del sapo) en la rata

Eryngium heterophyllum Engelm, known as “toad grass”, has been traditionally used in renal diseases. The aim of the study was to evaluate the diuretic activity of the aqueous extract in the rat. The vegetal material was collected, identified, and the preliminary phytochemical study was carried out. For the diuretic evaluation, Wistar rats, female, adult of 200 ± 20 g of body weight (b.w.) were used, and they were distributed in five groups: the vehicle, the furosemide group (4 mg/kg of b.w.) and the aqueous extract at the doses of 200, 400 and 800 mg/kg of b.w., per os. After six hours in metabolic cages, urine and serum samples were obtained to measure the concentrations of sodium, potassium and creatinine. With these data, urine flow and creatinine, Na+ and K+ clearance, excretion and filtered ion load were calculated. LD50 in femal NIH mice, adults of 25 ± 5 g of b.w., treated with the extract (1, 2, 4 and 8 g/kg of b.w.) was determined. Decoction is used and the phytochemical study coumarins, alkaloids, flavonoids, tannins and saponins were detected. In the diuretic evaluation, an increase in the urinary flow, in the urinary excretion and ion clearance in the groups treated with furosemide and at different doses of the extract were observed. The LD50 is higher than 8 g/kg of b.w. Eryngium heterophyllum Engelm diuretic action was induced by direct renal tubular effect. The study of plant species is important to support their empirical use.

DOMESTIC ANTITUMOR COMPOUND 2-[3-(2-CHLOROETHYL)-3-NITROSOUREIDO]-1,3- PROPANEDIOL (CHLONISOL). ACUTE TOXICITY

2-[3-(2-Chloroethyl)-3-nitrosoureido]-1,3-propanediol (Сhlonisol) is a representative of a separate group of derivatives of the class of nitrosoalkylureas – alkylnitrosoureidopropanediols, which are characterized by high antitumor activity on a wide range of experimental tumors. Chlonisol LD50 in male mice for intravenous administration was 35 mg/kg, intraperitoneal – 39 mg/kg, in female mice – 34 mg/kg and 36 mg/kg, respectively. In rats of males with intraperitoneal administration, LD50 was 30 mg/kg, in rats of females – 32 mg/kg. The maximum tolerated dose in mice, rats, guinea pigs and rabbits was 20 mg/kg. The tolerated dose for dogs was a dose of 2 mg/kg. Myelo-depression was a dose-limiting side effect. Lethal and sublethal doses of Chlonisol caused aplasia of the bone marrow and lymphoid organs, damage to the mucous membrane of the gastrointestinal tract, and dystrophic changes in the myocardium, lungs, liver, kidneys, pancreas, and reproductive organs. In the late stages after intraperitoneal administration of sublethal doses of Chlonisol, chylothorax and chyloperitoneum were found in some rats.