Lower ED50 Research Articles

Enhancing the Bothropic Antivenom through a Reverse Antivenomics Approach.

Antivenoms are the only effective treatment for snakebite envenomation and have saved countless lives over more than a century. Despite their value, antivenoms present risks of adverse reactions. Current formulations contain a fraction of nonspecific antibodies and serum proteins. While new promising candidates emerge as the next generation of antivenoms, it remains clear that animal-derived antivenoms will still play a critical role for years to come. In this study, we improved the bothropic antivenom (BAv), by capturing toxin-specific antibodies through affinity chromatography using immobilized Bothrops jararaca venom toxins. This process produced an improved antivenom (iBAv) enriched in neutralizing antibodies and depleted of serum proteins. Proteomic analysis showed that iBAv was 87% depleted in albumin and 37-83% lower in other serum proteins compared to BAv. Functional evaluation demonstrated that iBAv had a 2.9-fold higher affinity for venom toxins by surface plasmon resonance and a 2.8-fold lower ED50 in vivo, indicating enhanced potency. Our findings indicate that enriching specific antibodies while depleting serum proteins reduces the total protein dose required and increases the potency of antivenom. Although technical and economic considerations remain for large-scale implementation, this affinity-enriched antivenom represents a significant advancement in improving antivenom efficacy against B. jararaca envenomations.

The Effect of Metoclopramide on the Antinociceptive, Locomotor and Neurobehavioral Effects of Metamizole in Mice

Abstract Combining analgesic medications with distinct pharmacodynamics may result in effective analgesia and reduced adverse effects by lowering dosages of one or both medications. The objective was to investigate the nature of interactions of metoclopramide and metamizole by measuring the antinociceptive and neurobehavioral effects in mice. The drugs were administered intraperitoneally (ip) in mice. The antinociceptive effect was determined by the up-and-down method. Isobolographic analysis was performed by simultaneous injection of the two drugs at ED50 ratios of 1:1 and 0.5:0.5. The treated mice were also subjected to an open-field behavioral test as well as dorsal immobility and negative geotaxis behavioral paradigms. The ED50 of metoclopramide and metamizole were 33.71 and 43 mg/kg ip, respectively. Lower ED50 was established for metoclopramide and metamizole by 48.44% and 47.49%, respectively when given at a ratio of 0.5:0.5, and by 35.81% and 29.88%, respectively at a ratio of 1:1. The combined dose of metoclopramide and metamizole (8 and 10 mg/kg, ip, respectively) significantly decreased the open field-activity test in mice. This was observed by lower number of squares crossing compared to the control. Additionally, the drug combination resulted in a substantial increase in the duration of dorsal immobility response and delayed the negative geotaxis task when compared with the control group. The results indicated that the interaction between metoclopramide and metamizole in lower dose ratio with ED50 50:50, was synergistic in producing analgesia in mice with reduced risk for adverse reaction but with decreased behavioral and motor neuronal activity.

An implementation framework for evaluating the biocidal potential of essential oils in controlling Fusarium wilt in spinach: from in vitro to in planta.

Fusarium wilt, caused by Fusarium oxysporum f. sp. spinaciae, causes a significant challenge on vegetative spinach and seed production. Addressing this issue necessitates continuous research focused on innovative treatments and protocols through comprehensive bioassays. Recent studies have highlighted the potential of plant-based compounds in controlling fungal diseases. The present work aims to conduct a series of experiments, encompassing both in vitro and in planta assessments, to investigate the biocontrol capabilities of different essential oils (EOs) at various application rates, with the ultimate goal of reducing the incidence of Fusarium wilt in spinach. The inhibitory effect of four plant EOs (marjoram, thyme, oregano, and tea tree) was initially assessed on the spore germination of five unknown Fusarium strains. The outcomes revealed diverse sensitivities of Fusarium strains to EOs, with thyme exhibiting the broadest inhibition, followed by oregano at the highest concentration (6.66 μL/mL) in most strains. The tested compounds displayed a diverse range of median effective dose (ED50) values (0.69 to 7.53 µL/mL), with thyme and oregano consistently showing lower ED50 values. The direct and indirect inhibitory impact of these compounds on Fusarium mycelial growth ranged from ~14% to ~100%, wherein thyme and oregano consistently exhibiting the highest effectiveness. Following the results of five distinct inoculation approaches and molecular identification, the highly pathogenic strain F-17536 (F. oxysporum f.sp. spinaciae) was chosen for Fusarium wilt assessment in spinach seedlings, employing two promising EO candidates through seed and soil treatments. Our findings indicate that colonized grain (CG) proved to be a convenient and optimal inoculation method for consistent Fusarium wilt assessment under greenhouse conditions. Seed treatments with thyme and oregano EOs consistently resulted in significantly better disease reduction rates, approximately 54% and 36% respectively, compared to soil treatments (P > 0.05). Notably, thyme, applied at 6.66 µL/mL, exhibited a favorable emergence rate (ERI), exceeding seven, in both treatments, emphasizing its potential for effective disease control in spinach seedlings without inducing phytotoxic effects. This study successfully transitions from in vitro to in planta experiments, highlighting the potential incorporation of EOs into integrated disease management for Fusarium wilt in spinach production.

Aktivitas Antimalaria Ekstrak Sargassum Duplicatum terhadap Plasmodium Berghei Strain ANKA Secara in Vivo

Malaria is a parasitic infection disease caused by Plasmodium and is a global health issue. The search for new antimalarial drugs from natural sources, such as plants, is ongoing to find effective alternatives. Sargassum duplicatum, a brown seaweed, has been known to possess various biological activities; however, its antimalarial potential has not been thoroughly explored. This study aims to evaluate the antimalarial activity of S. duplicatum extract against Plasmodium berghei strain ANKA in vivo in mice. This is an experimental study. A total of 16 mice were divided into 4 groups: a positive control group and groups infected with P. berghei and treated with S. duplicatum extract at doses of 10, 100, and 200 mg/g body weight. Antimalarial activity was measured based on parasitemia levels, percent inhibition, and ED50 values. Parasitemia measurements were taken from day 0 to day 6 after treatment. The results showed that S. duplicatum extract inhibited the growth of P. berghei with parasitemia inhibition percentages of 65.32% at a dose of 10 mg/g body weight, 65.92% at a dose of 100 mg/g body weight, and 86.61% at a dose of 200 mg/g body weight. The ED50 value of S. duplicatum extract was 2.770 mg/kg body weight in mice. The low ED50 value indicates the extract’s potential as a promising antimalarial drug candidate.

Dose-response study of propofol combined with two different doses of esketamine for laryngeal mask airway insertion in women undergoing hysteroscopy

ObjectiveTo prospectively determine the median effective dose (ED50) of propofol for inhibiting a response to laryngeal mask airway (LMA) insertion when combined with different doses of esketamine in female patients. MethodsA total of 58 female patients (aged 20–60 years, ASAⅠ–Ⅱ) scheduled for elective hysteroscopy were enrolled and randomly divided into 2 groups, one of which was administered 0.2 mg/kg of esketamine (K1 group, n = 28) and the other 0.3 mg/kg of esketamine (K2 group, n = 30). The 2 groups received the corresponding doses of esketamine intravenously, followed by an intravenous injection of propofol (injection time was 30 s). The initial dose of propofol was 2 mg/kg, and the dose ratio of propofol in the adjacent patients was 0.9. If a positive reaction occurred due to LMA insertion, the dose ratio in the next patient was increased by 1 gradient; if not, the dose ratio was decreased by 1 gradient. The ED50, 95 % effective dose (ED95) and 95 % confidence interval (CI) of propofol for inhibiting a response to LMA insertion in the 2 esketamine groups were calculated using probit analysis. ResultsThe ED50 of propofol for inhibiting a response to LMA insertion in female patients was 1.95 mg/kg (95 % CI, 1.82–2.08 mg/kg) in the K1 group and 1.60 mg/kg (95 % CI, 1.18–1.83 mg/kg) in the K2 group. The ED95 of propofol for inhibiting a response to LMA insertion in female patients was 2.22 mg/kg (95 % CI, 2.09–2.86 mg/kg) in the K1 group and 2.15 mg/kg (95 % CI, 1.88–3.09 mg/kg) in the K2 group. ConclusionPropofol combined with 0.3 mg/kg of esketamine has low ED50 and ED95 effective doses for inhibiting an LMA insertion response in female patients undergoing hysteroscopy and surgery. There were no significant adverse effects, but the additional dose of propofol and airway pressure were significantly higher than those in the group administered 0.2 mg/kg of esketamine. Based on the results, we recommend the combination of propofol with 0.2 mg/kg esketamine for optimal conditions during LMA insertion in women undergoing hysteroscopy.

Efficacy of Argel (Solenostemma argel (Del) hayne) Shoots’ Extract in the Control of the Red Flour Beetle (Tribolium castaneum Herbst)

Laboratory studies were conducted to evaluate the efficacy ofaqueous and organic extracts of the argel (S. argel) shoots against the 4thlarval instar and adult stages of the red flour beetle (Tribolium castaneum)in the Sudan. Argel shoots were extracted sequentially by organic solventsof increasing polarity (petroleum ether, ethyl acetate and ethanol) as wellas directly by distilled water or ethanol. Extracts were tested atconcentrations ranging between 1% and 10%. The evaluated efficacyparameters were mortality, repellency and antifeedant effects. The testswere conducted in Petri dishes (9 cm i.d) and plastic cups (capacity 200ml) and the obtained data were subjected to the analysis of variance and tothe probit analysis. The results of the mortality data indicated thatpetroleum ether extracts was the most potent against the 4 th larval instar ofT.castaneum as shown by its low LD50 of 8.2%, while ethyl acetateextract was the most potent against the adult of this pest with an LD50value of 16%. The results showed that various types of argel shootextracts induced significant dose dependent repellency against theT. castaneum. The highest 24 hours repellency was caused by thepetroleum ether extract on the adult stage of T. castaneum as indicated byits low ED50 value of 1.58%.The different argel shoot extracts inducedsignificant antifeedant action against the test insect. The lowest feedingratio (0.02) was recorded in ethyl acetate extract- treated crushed wheatgrains

Investigations on the Antimalarial Properties of Cleistopholis patens (Annonaceae) Leaf Methanol Extract and Its Partitioned Fractions in Mice

Aim: The methanol extract and partitioned fractions of Cleistopholis patens leaf were evaluated for antiplasmodial activities with a view to establishing its antimalarial potential and identifying the most active partitioned fraction.
 Methods: The leaf was collected, authenticated, air-dried and powdered. The extract, prepared by maceration in methanol was tested (0-800 mg/kg) against P. berghei berghei in mice using Peter’s four-day test. Normal saline and Chloroquine (10 mg/kg) were negative and positive control respectively. Percentage parasitemia, percentage chemosuppression, effective doses, survival times and percentage survivors were the parameters used for the assessment. The extract was thereafter suspended in water and successively partitioned into n-hexane, dichloromethane and ethyl acetate and the resulting fractions and the aqueous phase were similarly tested at doses 10-80 mg/kg.
 Results: The methanol extract which was comparable (P=.06) in activity to chloroquine gave 1.05±0.09 percentage parasitemia, 77.45±4.39 percentage chemosuppression at 40 mg/kg and an ED50 and ED90 of 255.83±3.60 and 471.35±15.05 mg/kg. The most active n-hexane fraction elicited a percentage chemosuppression of 82%, 0.87 percentage parasitaemia at 80 mg/kg, moderately high percentage survivor and relatively low ED50 and ED90 of 28.87±5.29 and 56.30±8.44 mg/kg.
 Conclusion: The methanol extract of C. patens leaf is active against P. berghei berghei and the antimalarial compounds is likely to be concentrated in the n-hexane fraction.

Combination of curcumin and piperine synergistically improves pain-like behaviors in mouse models of pain with no potential CNS side effects

BackgroundCurcumin and piperine are major bioactive compounds of Curcuma longa and Piper nigrum, widely consumed as spices and flock medicine. The combinational use of these plants is a common practice in Southeast Asia. Synergism between curcumin and piperine has been found in several animal models but not in periodontal disease and diabetes, and the antinociceptive interaction is still unknown. Hence, the present study aimed to assess the interaction between curcumin and piperine in pain and its potential CNS side effect profile.MethodsFormalin test and in vitro LPS-stimulated RAW 264.7 macrophage cells were used to assess the synergistic interaction of curcumin and piperine in a mouse model of inflammatory pain. Tail-flick and cold plate tests were applied to determine the antinociceptive synergism between piperine and curcumin. The interaction was determined by applying isobolographic analysis. The potential CNS-side effects of the curcumin and piperine combination were also assessed using LABORAS automated home-cage behavioral analysis.ResultsCurcumin alone dose-dependently improved pain-like behaviors in the formalin, tail-flick, and cold plate tests with the ED50 of 71.4, 34.4, and 31.9 mg/kg, respectively. Additionally, piperine exhibited efficacy in the formalin, tail-flick, and cold plate tests with the ED50 of 18.4, 8.1, and 28.1 mg/kg, respectively. The combination of curcumin and piperine (1:1 ED50 ratio) produced synergistic interaction in the formalin, tail-flick, and cold plate tests as assessed significantly lower experimental ED50 values (5.9, 5.2, and 5.5 mg/kg) compared to theoretical ED50 values (44.9, 21.3, and 30.0 mg/kg), isobologram analysis, and interaction index values of 0.13, 0.24 and 0.18, respectively. The synergistic interaction of curcumin and piperine was further confirmed by the efficacy of the combination in LPS-stimulated RAW 264.7 macrophage cells. Curcumin and piperine interacted synergistically, reducing proinflammatory mediators. The combination also demonstrated better compatibility profiles with neuronal cells. Furthermore, the curcumin-piperine combination had no effects on mouse spontaneous locomotor behaviors in LABORAS automated home cage monitoring.ConclusionOverall, the present study demonstrates strong antinociceptive synergism between curcumin and piperine in mouse models with no potential CNS side effects, suggesting its possible use in clinical trials.

Methanolic extract of Nauclea diderrichii (stem-bark) show anti-microbial, anti-oxidant and anti-inflammatory bioactivities

The aqueous stem-bark extract of the tropical plant Nauclea diderrichii is used in ethnomedicine to manage symptoms of rheumatism through minimally examined mechanisms. The objective of the study is to examine the scientific bases for the ethnomedicinal use of the plant for the management of rheumatism. As part of this effort to explain its ethnomedicinal efficacy, this study compared and contrasted the anti-microbial, anti-oxidant and anti-inflammatory activities of the methanolic extract with that of the diethylether extract. Broth dilution assay, DPPH radical scavenging assay and carrageenan-induced foot swelling of 7-day old chicks were utilized for the experimental assessment of the bioactivities of Nauclea diderrichii. Polar methanolic extract exhibited a higher antioxidant status in vitro as estimated quantitative differences in total phenolic content, in total antioxidant capacity and in DPPH and H2O2 radical scavenging converged to show the methanolic extract as a more potent anti-oxidant. The methanolic extract also possess better in vivo anti-inflammatory activity as demonstrated by the 1.5-fold lower ED50 relative to that of the diethylether. The methanolic extract demonstrated better broad-spectrum anti-microbial activity against a panel of six clinical isolates of bacterial and fungi pathogens in vitro. The relative strength of the bioactivities of the methanolic extract derives from a higher slew of phytochemical content that is a 3-fold difference larger. The results of this study support the beneficial effect of Nauclea diderrichii in its continuing ethnomedicinal use to target rheumatism chemotherapeutically.

Design, Synthesis and Anticonvulsant Activity of New Phenoxyalkyl, Phenoxyethoxyethyl and Phenoxyacetyl Derivatives of Aminoalkanols

AbstractForty new aminoalkanol derivatives with potential anticonvulsant activity were designed and synthesized. In vivo studies (mice, intraperitoneal administration) showed anticonvulsant activity (maximal electroshock seizure test, MES test) of nineteen compounds, (ED50 values and protective indices PI ranging 22.62–78.30 mg/kg b.w. and 1.78–4.25, respectively). Compounds 30 (R,S‐1‐((2‐(2‐(2‐chloro‐5‐methylphenoxy)ethoxy)ethyl)amino)propan‐2‐ol), 31 (R,S‐2‐((2‐(2‐(2‐chloro‐5‐methylphenoxy)ethoxy)ethyl)amino)propan‐1‐ol) and 33 (S enantiomer of 31) showed relatively low ED50 values (26.45–34.26 mg/kg b.w.) accompanied by PI indexes above 3. Compounds 30 and 31 were investigated in terms of mechanism of action (5‐HT1A receptors binding assay and in silico database screening) and safety against gastrointestinal flora (both compounds proved safe). An integral part of the study was also a comprehensive structure‐activity relationship, including current and previously obtained results for aminoalkanol derivatives.

Florpyrauxifen-Benzyl Selectivity to Rice

Florpyrauxifen-benzyl (FPB) is a new class of auxinic herbicide developed for selective weed control in rice. This study aimed to evaluate the effect of environmental conditions, P450 inhibitors, rice cultivar response, and gene expression on FPB selectivity in rice. Field experiments established in a randomized block design showed that rice plant injury due to two FPB rates (30 and 60 g ai ha−1) was affected by planting time and rice stage at herbicide application. The injury was higher at the earliest planting season and more in younger plants (V2) than larger (V6 and R0). However, no yield reduction was detected. Under greenhouse conditions, two dose-response experiments in a randomized block design showed that spraying malathion (1 kg ha−1) before FPB application did not reduce herbicide selectivity. The addition of two P450 inhibitors (dietholate and piperonyl butoxide, 10 g a.i. seed-kg−1 and 4.2 kg ai ha−1, respectively) decreased the doses to cause 50% of plant injury (ED50) and growth reduction (GR50). However, it seems not to compromise crop selectivity. BRS Pampeira cultivar showed lower ED50 and GR50 than IRGA 424 RI. A growth chamber experiment was conducted in a completely randomized design to evaluate the gene expression of rice plants sprayed with FPB (30 and 60 g ai ha−1). Results showed downregulation of OsWAKL21.2, an esterase probably related to bio-activation of FPB-ester. However, no effect was detected on CYP71A21 monooxygenase and OsGSTL transferase, enzymes probably related to FPB degradation. Further research should focus on understanding FBP bio-activation as the selective mechanism.

In vitro activity of isothiocyanates against Fusarium graminearum

AbstractIsothiocyanates are biotoxic degradation products formed as a result of enzymatic hydrolysis of glucosinolates present in Brassica species. The application of biofumigant Brassica crops, as an alternative crop protection method for soilborne pathogens and pests is increasingly gaining interest. However, little is known of the potential of biofumigation to reduce the inoculum of Fusarium species affecting cereals. The aim of this study was to evaluate the antifungal activity of five isothiocyanates, namely allyl, benzyl, ethyl, 2‐phenylethyl and methyl isothiocyanates, against germination and growth of Fusarium graminearum under in vitro conditions. Aromatic isothiocyanates were more inhibitory than the aliphatic isothiocyanates against mycelial growth, whereas the reverse was observed for conidial germination. Among the tested isothiocyanates, allyl and methyl isothiocyanates were more efficient overall, showing lower ED50 values (35–150 mg/L) for conidial germination and mycelial radial growth. The findings suggest that Brassica plants containing allyl and methyl glucosinolates could have a suppressive effect, reducing the inoculum of F. graminearum in soil prior to cereal production.

Aggressiveness of Spanish Isolates of Xylella fastidiosa to Almond Plants of Different Cultivars Under Greenhouse Conditions.

The aggressiveness of Spanish isolates of Xylella fastidiosa, representing different sequence types, were studied in almond plants of several cultivars by means of the dynamics of the population levels and symptoms, colonization and spread, and dose-effect relationships. Pathogen dynamics in almond plants under greenhouse conditions showed doubling times of 2.1 to 2.5 days during the exponential growth phase, with a maximum population size of about 35 days postinoculation (dpi). Differences in patterns in population dynamics were observed between sap and xylem tissue after the exponential growth, as population levels in the xylem tissue remained stable while viable cells in sap decreased. Population levels were higher in two upward zones than in the downward zone with respect to the inoculation area. The first symptoms were observed between 20 and 60 dpi, and disease severity increased over time at doubling times of 30 days, with a maximum observed at 120 dpi. Strains tested showed differences in population levels in the cultivars studied and were able to spread with different intensity from contaminated plant parts to new growing shoots after pruning. Two almond isolates showed different performance in dose-effect relationships when inoculated in cultivar Avijor. Whereas IVIA 5387.2 reached high population levels but showed high median effective dose (ED50) and minimal infective dose (MID) values, IVIA 5901.2 showed low population levels and low ED50 and MID values. This study has implications for the epidemiology of X. fastidiosa in almond crops, estimating doubling times of the pathogen in planta and of symptom development and showing differences in aggressiveness between strains.

Investigation on the antimalarial properties of Plumeria alba Linn (apocynaceae) cultivated in Nigeria

Many of the African antimalarial ethno medicinal plants are good sources of promising antimalarial compounds. The stem bark of Plumeria alba Linn, was evaluated for in vivo chemosuppressive antimalarial activities in order to identify the most active solvent fraction from which antimalarial constituents can be isolated. The stem-bark of Plumeria alba Linn, family Apocynaceae was collected, air-dried, powdered, macerated in methanol and the extract concentrated in vacuo. The acute toxicity study was performed on the extract using Lorke’s method. The extract was thereafter tested for chemosuppressive antiplasmodial activities against Plasmodium berghei berghei NK65- infected mice using Peter’s four-day test at doses 100-800 mg /kg with normal saline (0.2 ml) and chloroquine (10 mg/kg) as negative and positive control drugs respectively. The average percentage parasitaemia, percentage chemosuppression and effective doses (ED50 and ED90), the survival times and percentage survivors elicited in all the mice were determined as indices of antimalarial activity. The active extract was subsequently partitioned successively into n-hexane, dichloromethane, ethyl acetate and butanol. The respective partitioned fractions with the aqueous phase were also tested as above at doses 0-80 mg/kg. All results were subjected to statistical analysis using ANOVA with Student Newman Keul’s post hoc test. Crude extracts of P. alba gave considerable reduction of percentage parasitaemia up to 200 mg/kg. The percentage chemosuppression at all doses, were significantly higher (p<0.05) than the negative but lower than the positive control with 200 mg/kg dose showing the highest activity of 65.88 %. The effective doses, ED50 and ED90 were 305.82±9.99 and 389.74± 9.60, respectively. The most active n-hexane partitioned fraction elicited a percentage chemosuppression of 67.75 and a significantly lower (p<0.05) ED50 and ED90 of 31.27±0.85 and 54.80±1.75 mg/kg. The butanol and ethyl acetate partitioned fractions gave significantly higher (p<0.05) survival time value than those of the crude extract, other partition fractions and the positive control, while the n-hexane, dichloromethane and the aqueous, just like chloroquine, gave high percentage survivors. The study concluded that Plumeria alba stem-bark extract was active as an antimalarial drug with its antiplasmodial and the survival time–enhancing activity concentrated in the n-hexane and ethyl acetate with butanol partitioned fractions respectively, thus confirming and justifying its ethnomedical application in malaria.

Antiseizure effects of the cannabinoids in the amygdala-kindling model.

Focal impaired awareness seizures (FIASs) are the most common seizure type in adults and are often refractory to medication. Management of FIASs is clinically challenging, and new interventions are needed for better seizure control. The amygdala-kindling model is a preclinical model of FIASs with secondary generalization. The present study assessed the efficacy of cannabidiol (CBD), ∆9-tetrahydrocannabinol (THC), and a combination of CBD and THC in a 15:1 ratio at suppressing focal and secondarily generalized seizures in the amygdala-kindled rat. Fully kindled, male Sprague Dawley rats, with bipolar electrodes implanted in the right amygdala, were given either CBD (0-320mg/kg), THC (0-40mg/kg), or a combination of CBD and THC (15:1 ratio, multiple doses) intraperitoneally. Suprathreshold kindling stimulation was administered 1 h (THC) or 2 h (CBD) after drug injection, and outcomes were assessed using focal electroencephalographic recording and the Racine seizure scale. CBD alone produced a partial suppression of both generalized seizures (median effective dose [ED50 ] = 283mg/kg) and focal seizures (ED40 = 320mg/kg) at doses that did not produce ataxia. THC alone also produced partial suppression of generalized (ED50 = 10mg/kg) and focal (ED50 = 30mg/kg) seizures, but doses of 10 mg/kg and above produced hypolocomotion, although not ataxia. The addition of a low dose of THC to CBD (15:1) left-shifted the CBD dose-response curve, producing much lower ED50 s for both generalized (ED50 = 26 + 1.73mg/kg) and focal (ED50 = 40 + 2.66mg/kg) seizures. No ataxia or hypolocomotion was seen at these doses of the CBD+THC combination. CBD and THC both have antiseizure properties in the amygdala-kindling model, although THC produces suppression of the amygdala focus only at doses that produce hypolocomotion. The addition of small amounts of THC greatly improves the effectiveness of CBD. A combination of CBD and THC might be useful for the management of FIASs.

Effect of herbicides and doses on short‐ and long‐term control of Eleusine tristachya

AbstractIn Argentina, Eleusine tristachya has been recently reported as a problematic weed that can occur at high densities in spring and summer in fallows and in maize and soyabean. The reason for the increase in E. tristachya populations is that once the weed is established, it is difficult to eliminate because it produces a high number of seeds and plant regrowth occurs after herbicide treatments. The aim of this study was to determine the effect of post‐emergence application of herbicides (glyphosate, haloxyfop‐methyl and clethodim) at the seedling, vegetative and reproductive stages on the short‐term (biomass 30 days after treatment—30 DAT) and long‐term (tiller number and height and seed production—regrowth at 330 DAT) control of E. tristachya selected biotypes in outdoor pot experiments. Data fitted to a log‐logistic model. For all the herbicides considered, at the seedling and vegetative stages, short‐term control was achieved with low ED50 and ED90 values, whereas at the reproductive stage, ED90 values were three‐ to sixfold (glyphosate), six‐ to 52‐fold (haloxyfop‐methyl) and five‐ to 13‐fold (clethodim) higher. Long‐term control at the recommended dose or lower was not possible at the reproductive stage as tiller regrowth and seed production occurred with all herbicides. It is advisable to control Eleusine tristachya when plants are small at the beginning of the growing season using the recommended herbicide dose. A delayed application will produce tiller regeneration the following year, and consequently, control would only be achieved applying an overdose, which can cause risks to health and the environment. We concluded that a management programme based on the combination of glyphosate with post‐emergence graminicides applied at early stages will be effective to control future infestations.

Pharmacological Profile of the Novel Antiepileptic Drug Candidate Padsevonil: Interactions with Synaptic Vesicle 2 Proteins and the GABAA Receptor.

Padsevonil is an antiepileptic drug (AED) candidate synthesized in a medicinal chemistry program initiated to rationally design compounds with high affinity for synaptic vesicle 2 (SV2) proteins and low-to-moderate affinity for the benzodiazepine binding site on GABAA receptors. The pharmacological profile of padsevonil was characterized in binding and electrophysiological experiments. At recombinant SV2 proteins, padsevonil's affinity for SV2A was greater than that of levetiracetam and brivaracetam (pKi 8.5, 5.2, and 6.6, respectively). Unlike the latter AEDs, both selective SV2A ligands, padsevonil also displayed high affinity for the SV2B and SV2C isoforms (pKi 7.9 and 8.5, respectively). Padsevonil's interaction with SV2A differed from that of levetiracetam and brivaracetam; it exhibited slower binding kinetics: dissociation t 1/2 30 minutes from the human protein at 37°C compared with <0.5 minute for levetiracetam and brivaracetam. In addition, its binding was not potentiated by the allosteric modulator UCB1244283. At recombinant GABAA receptors, padsevonil displayed low to moderate affinity (pIC50≤6.1) for the benzodiazepine site, and in electrophysiological studies, its relative efficacy compared with zolpidem (full-agonist reference drug) was 40%, indicating partial agonist properties. In in vivo (mice) receptor occupancy studies, padsevonil exhibited SV2A occupancy at low ED50 (0.2 mg/kg) and benzodiazepine site occupancy at higher doses (ED50 36 mg/kg), supporting in vitro results. Padsevonil's selectivity for its intended targets was confirmed in profiling studies, where it lacked significant effects on a wide variety of ion channels, receptors, transporters, and enzymes. Padsevonil is a first-in-class AED candidate with a unique target profile allowing for presynaptic and postsynaptic activity. SIGNIFICANCE STATEMENT: Padsevonil is an antiepileptic drug candidate developed as a single molecular entity interacting with both presynaptic and postsynaptic targets. Results of in vitro and in vivo radioligand binding assays confirmed this target profile: padsevonil displayed nanomolar affinity for the three synaptic vesicle 2 protein isoforms (SV2A, B, and C) and micromolar affinity for the benzodiazepine binding site on GABAA receptors. Furthermore, padsevonil showed greater affinity for and slower binding kinetics at SV2A than the selective SV2A ligands, levetiracetam, and brivaracetam.

Vascular α1-adrenergic sensitivity is enhanced in chronic kidney disease.

Chronic kidney disease (CKD) is often complicated by difficult-to-control hypertension, in part due to chronic overactivation of the sympathetic nervous system (SNS). CKD patients also exhibit a greater increase in arterial blood pressure for a given increase in sympathetic nerve activation, suggesting an augmented vasoconstrictive response to SNS activation (i.e., neurovascular transduction). One potential mechanism of increased sympathetic neurovascular transduction is heightened sensitivity of the vascular α1-adrenergic receptors (α1ARs), the major effectors of vasoconstriction in response to norepinephrine release at the sympathetic nerve terminals. Therefore, we hypothesized that patients with CKD have increased vascular α1AR sensitivity. We studied 32 patients with CKD stages III and IV (age 59.9 ± 1.3 yr) and 19 age-matched controls (CON, age 63.2 ± 1.6 yr). Using a linear variable differential transformer (LVDT), we measured change in venoconstriction in response to exponentially increasing doses of the selective α1AR agonist phenylephrine (PE) administered sequentially into a dorsal hand vein. Individual semilogarithmic PE dose-response curves were constructed for each participant to determine the PE dose at which 50% of maximum venoconstriction occurred (ED50), reflecting α1AR sensitivity. In support of our hypothesis, CKD patients had a lower PE ED50 than CON (CKD = 2.23 ± 0.11 vs. CON = 2.63 ± 0.20, P = 0.023), demonstrating increased vascular α1AR sensitivity. Additionally, CKD patients had a greater venoconstrictive capacity to PE than CON (P = 0.015). Augmented α1AR sensitivity may contribute mechanistically to enhanced neurovascular transduction in CKD and may explain, in part, the greater blood pressure reactivity exhibited in these patients.

Hepatitis E vaccine candidate harboring a non-particulate immunogen of E2 fused with CRM197 fragment A

The Hepatitis E vaccine (Hecolin, licensed in China) harbors a potent particulate immunogen, p239, designed from a 26-aa N-terminal extension of its poorly immunogenic parental protein, E2. Although an effective vaccine, we sought to design a fusion protein in a non-particulate form that could improve the delivery and immunogenicity of E2 epitopes. The non-toxic mutant of diphtheria toxin, CRM197 (Cross-Reacting Material 197) has been successfully used as a carrier protein for conjugated vaccines to enhance the immunogenicity of polysaccharides. Here, we designed a fusion non-particulate protein of E2 and the catalytic domain (fragment A) of CRM197 and evaluated its antigenicity, immunogenicity and disease prevention efficacy in primates. This fusion protein, named CRM197(A)-E2, was bacterially expressed and purified by chromatography. CRM197(A)-E2 presented as a homodimer in solution, similar to its parental E2 protein, and exhibited excellent antigenicity against representative neutralizing monoclonal antibodies, like E2 and p239. However, CRM197(A)-E2 manifested higher immunogenicity in mice compared with that achieved by the particulate p239, as indicated by the 10-times lower ED50 value and 2-log higher HEV-specific antibody level that could persist for at least 28 weeks. In addition, both the 1 μg and 10 μg doses of CRM197(A)-E2 adjuvanted with aluminum could protect vaccinated monkeys against HEV challenge, matching that achieved with only the higher (10 μg) dose of the p239 vaccine. These results suggest that the CRM197 fragment A alone serves as an intra-molecular adjuvant to remarkably enhance the immunogenicity of the target of interest in a non-particulate form. These findings may pave the way for rational vaccine design, especially in cases where particulates are not accessible.

Synthesis, in vivo and in silico evaluation of novel 2,3-dihydroquinazolin-4(1H)-one derivatives as potential anticonvulsant agents.

In light of the pharmacophoric structural requirements for achieving anticonvulsant activity, a series of N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)benzamide (4a-g) and N-(1-methyl-4-oxo-2-un/substituted-1,2-dihydroquinazolin-3[4H]-yl)-2-phenylacetamide (4h-n) derivatives were synthesized in two steps starting from the reaction of N-methyl isatoic anhydride with the appropriate hydrazide and followed by condensation with the appropriate aldehyde. The anticonvulsant activities of the synthesized compounds were evaluated according to the anticonvulsant drug development (ADD) programme protocol. Among the synthesized compounds, 4n showed promising activity in both the maximal electroshock (MES) and pentylenetetrazole (PTZ) tests with median effective dose (ED50 ) values of 40.7 and 6 mg/kg, respectively. The six most promising derivatives, 4b, 4a, 4c, 4f, 4j, and 4i, showed very low ED50 values in the PTZ test (3.1, 4.96, 8.68, 9.89, 12, and 13.53 mg/kg, respectively). All the tested compounds showed no to low neurotoxicity in the rotarod test with a wide therapeutic index. Docking studies of compound 4n suggested that GABAA binding could be the mechanism of action of these derivatives. The in silico drug likeliness parameters indicated that none of the designed compounds violate Lipinski's rule of five and that they are able to cross the blood-brain barrier. Hit, Lead & Candidate Discovery.