Hot Plate Research Articles

Total Phosphorous and Mineral Content Determination in Rock Phosphates using ICP-MS

ABSTRACT Phosphorous (P) is an essential element for plant growth and development, and its scarcity is a severe crop output constraint. Determination of total P in soil and fertilizers is very important in agriculture as the amount of P is related to crop production. Rock phosphate (RP) is an excellent natural source of P widely used for P fertilizer production. The objective of this study was to compare two different digestion methods, microwave digestion and hot plate digestion, and to evaluate the performance of two analytical techniques, inductively coupled plasma mass spectroscopy (ICP-MS) and colorimetry (UV-VIS), for measuring total P in imported RP samples. The validation of microwave digestion followed by analysis in ICP-MS was performed. Phosphorus has detection and quantification limits of 1 mg L−1 and 5 mg L−1 respectively through ICP-MS analysis. Average P recovery was found 92.12–96.53%. Precision in terms of intra-day (%RSDR = 2.76–5.98 evaluated using ICP-MS) and inter-day (%RSDr = 2.92–6.75) were found to be within the acceptable range (20%), indicating consistency of the proposed method to determine total-P over traditional UV-VIS method. The combination of microwave-assisted digestion and ICP-MS offers superior efficiency in determining both phosphorus (P) and heavy metals, including aluminum, iron, zinc, cadmium, strontium, manganese and chromium, in RP samples. Hence, this method is novel and rapid and is used for the quantification of total P in different RP samples for quality control.

A novel investigation of placebo analgesia through social communication in mice

Background and aimsIn rodents, placebo analgesia is often investigated through direct conditioning of stimuli, but humans can experience placebo analgesia through expectation without experience. In this study, we sought to determine whether placebo analgesia could be elicited through social communication. MethodsMale and female mice were housed in pairs (designated “Active” and “Bystander”) and tested for thermal thresholds on a hot plate (53 °C). Food restriction (1 hr/day) was implemented. The Active mouse was taken to a new cage with food dusted with cocoa (COC) or cinnamon (CINN). The Bystander mice were given regular chow in the home cage. After feeding, the Active mice were given morphine (5 mg/kg, SC) or saline and tested on the hot plate. After 5 pairings of a flavor and treatment (counterbalanced), Active mice were tested following access to a flavored food. Bystander mice were given their first direct exposure to a flavored food and tested on the hot plate. The protocol was repeated with naloxone (10 mg/kg, IP) administered prior to testing. Finally, mice were tested in a two-choice test with both flavored foods available. ResultsActive mice showed a conditioned analgesic response to the morphine-paired flavor that was reduced by naloxone. Bystander mice showed a placebo analgesic response to their cagemate’s morphine-paired flavor that was not significantly impacted by naloxone. Bystander mice spent more time in the chamber associated with their cagemate’s morphine-paired flavor. ConclusionsTo our knowledge, this is the first investigation of placebo analgesia without direct conditioning, instead relying on social communication between mice. The lack of effect with naloxone pretreatment suggests an opioid-independent effect in the Bystander mice. Placebo analgesia in mice may be possible without direct conditioning to better model the effect of expectation of a novel analgesic in humans.

The effect of acute crocin on behavioral changes and BDNF expression level in socially isolated rats.

Social isolation is a reliable method used for the induction of depression and psychiatric disorders in rodents. It has been suggested that social isolation can lead to hyperlocomotion, as a schizophrenic-like symptom in rodents. On the other hand, crocin (the major constituent of Crocus sativus) induces a wide-range of neuroprotective and mood enhancer effects. In the present study, we aimed to investigate the effect of acute crocin on social isolation-induced behavioral changes and BDNF expression in the hippocampus. Novelty-suppressed feeding test, open field test, marble burying test, hot plate, forced swim test, and the shuttle box were used to assess anxiety-like behavior, locomotor activity, obsessive-compulsive-like (OCD-like) behavior, pain threshold, depressive-like behavior, and passive avoidance memory, respectively. Real-time PCR was used to assess BDNF hippocampal expression level. The results showed that social isolation decreased anxiety- and depressive-like behavior, pain threshold, and BDNF expression, and induced OCD-like behavior and hyperlocomotion. Crocin dose-dependently restored the effect of social isolation on pain threshold, locomotor activity, depressive-like behavior, OCD-like behavior, and BDNF expression. Passive avoidance memory performance was also unaffected. In conclusion, we showed a hyperlocomotion profile and OCD-like behaviors, and a robust decrease in pain threshold in socially isolated rats. It can be suggested that social isolation from adolescence induces a "hyperlocomotion state" that affects all the behavioral functions of rats. Also, the function of BDNF can be related to a hyperlocomotion state and OCD-like symptom. It seems that BDNF expression level can be related to the therapeutic effect of crocin.

Solar thermoelectric generator and thermoelectric cooler performance: analysis and comparison using a different shape geometry

Abstract Thermoelectric devices are one of the technologies used either to generate electricity by applying a temperature difference using thermal energy or as a heating/cooling system by applying an electrical voltage. The number of materials required to produce a product is an important factor in determining its price. Production costs associated with these materials, as well as their availability and quality, play a crucial role in price determination by manufacturers. In this context, a method that employs a uniform volume distribution was implemented. This approach enabled the analysis to focus on other variables, thereby promoting a more precise and relevant evaluation of overall performance. Based on the finite element method, this study investigated the influence of geometric shape, including Rect-leg, Y-leg, Pin-leg and X-leg designs, on the performance of solar thermoelectric generators and thermoelectric coolers. The study was conducted considering the same hot alumina junction surface that receives solar radiation; however, the effective surface, which corresponded to the heat flow area and had a similar area near the exposed surface, varied depending on the chosen leg geometry, thus impacting the heat flux due to the variation in thermal resistance. In the case of a solar thermoelectric generator, the Rect-leg model, having the same effective surface area, presented the lowest heat loss value resulting from convection and radiation in the heat spreader and the hot alumina plate. Under the same conditions, the Y-leg showed the highest value. The Rect-leg design generated, by using thermal and optical concentration, the highest output power of 0.028 and 0.054 W, and efficiency of 3.47% and 4.7%, respectively, whereas the Y-leg generated lower values of 0.006523 and 0.018744 W for power, and 2.83% and 2.71% for efficiency, respectively. In the case of the thermoelectric coolers, the Y-leg generated the highest temperature difference between the hot and cold sides of 67.28 K at an electric current value of 1.8 A, whereas the Rect-leg, Pin-leg and X-leg generated ~66.25, ~67.02 and ~67.19 K at 6.1, 2.7 and 2.6 A.

Pyroptosis and necroptosis inhibitor necrosulfonamide ameliorates lipopolysaccharide-induced inflammatory hyperalgesia in mice

Objectives: This study aimed to investigate the effect of the gasdermin D (GSDMD) and mixed lineage kinase domain-like pseudokinase (MLKL) inhibitor, necrosulfonamide (NSA), on lipopolysaccharide (LPS)-induced hyperalgesia in mice. Methods: Reaction time to a thermal stimulus within 30 seconds was measured in male mice injected with saline, LPS, and/or NSA after 6 hours using the hot plate test. Immunoblotting studies were performed to determine changes in caspase-11/GSDMD-mediated pyroptosis, receptor-interacting serine/threonine-protein kinase (RIPK) 1/RIPK3/MLKL necrosome-mediated necroptosis, demyelination, and remyelination in the brains and spinal cords of animals. Results: NSA demonstrated significant antinociceptive activity compared with LPS-treated mice. In the tissues of LPS-treated mice, NSA decreased expression of caspase-11 p20, p30-GSDMD, interleukin-1β, high-mobility-group-box 1, and semaphorin 3A, and activity of RIPK1, RIPK3, and MLKL. NSA also increased the expression of myelin proteolipid protein. Conclusion: Therefore, NSA may have therapeutic potential in the treatment of inflammatory painful conditions due to bacterial infections.

Assessment of Insulation against Contact Heat and Radiant Heat of Composites with TiO2-ZrO2-Al and Parylene C Coatings Intended for Protective Gloves Supported by Computational Fluid Dynamics

This article concerns research on the use of two types of coatings (parylene C and TiO2-ZrO2-Al) in multilayer composites with potential use in metallurgical protective gloves to improve their insulation against contact heat and radiation heat. To evaluate the thermal safety of the glove user, the composites were examined under the conditions of exposure to contact heat (using a heating cylinder, according to EN ISO 12127-1) and radiant heat (using a copper plate calorimeter, according to EN ISO 6942). Moreover, heat transfer through composites exposed to the heat of a hot plate was examined using thermography. The experimental studies were supported by heat transfer simulations through 3D models of composites. The contact heat method showed that composites achieved insulation against contact heat for both contact temperatures Tc, but composites with parylene C have a longer tt of 9 s (for Tc = 100 °C) and 7 s (250 °C) compared to composites with TiO2-ZrO2-Al. The radiant heat method showed that composites achieved the fourth (highest) level of RHTI24 under exposure to a radiant heat flux of 20 kW m−2. The modeling results showed that the parylene C coating increases the thermal barrier of the composite by approximately 10%, while the TiO2-ZrO2-Al coating increases it by 2%. The applied research techniques demonstrated the usefulness of using both types of coatings in the design of metallurgical protective gloves based on multilayer composites.

Research on the effects of processing Heishunpian from Aconiti lateralis radix on components and efficacy using the “step knockout” strategy

Heishunpian is obtained through complex processing of Aconiti lateralis radix praeparata. However, the impact of each processing step on chemical compositions and pharmacological activities is still unclear. The mechanism of the processing needs to be further studied. The samples were all prepared using the “step knockout” strategy for UPLC-QTOF-MS analysis, and analgesic and anti-inflammatory efficacy evaluation. Each sample was analyzed by UPLC-QTOF-MS to determine the component differences. The hot plate test and acetic acid writhing test were used to evaluate the analgesic effect. Anti-inflammatory efficacy was evaluated by xylene-induced ear edema test. The correlation between components and efficacies was studied to screen the effective components for further investigating the processing of Heishunpian. Mass spectrum analysis results showed that 49 components were identified, and it appeared that brine immersion and rinsing had a great influence on the components. In the hot plate test, ibuprofen and Heishunpian had the most significant effect, while ibuprofen and the sample without rinsing showed the best efficacy for the acetic acid writhing test. The sample without dyeing had the best effect on ear edema. The correlation analysis indicated that mesaconine, aconine, 3-deoxyaconine, delbruine, and asperglaucide were potentially considered effective analgesic components. It is not recommended to remove brine immersion and rinsing. Boiling and steaming are necessary processes that improve efficacy. Dyeing, which does not have a significant impact on components and efficacy, may be an unnecessary process. This research has been of great significance in identifying anti-inflammatory and analgesic components and optimizing processing for Heishunpian.

Sex difference affects fear extinction but not lithium efficacy in rats following fear-conditioning with respect to the hippocampal level of BDNF

In rodents, exposure to electrical shock and creating a strong fear memory using fear-conditioning model can induce PTSD-like behavior. In this study, we induced a fear-conditioning model in rats and investigated freezing (PTSD-like) behavior, 21 days after three shocks exposure (0.6 mA, 3 s, 30 seconds interval) in both male and female rats. Lithium was injected intraperitoneally (100 mg/kg) in three protocols: (1) 1 h after fear-conditioning (2) 1 h, 24 h, and 48 h after fear-conditioning (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning. Extinction training (20 sounds without shocks, 75 dB, 3 s, 30 seconds interval) was performed in three protocols: (1) 1 h after fear-conditioning (one session), (2) 1 h, 24 h, and 48 h after fear-conditioning (three sessions), (3), 1 h, 24 h, 48 h, 72 h, and 96 h after fear-conditioning (five sessions). Forced swim test (FST) and hot plate were used to assess behavior. Results showed that lithium in all protocols had no effect on freezing behavior, FST, and pain subthreshold in all rats. Extinction training decreased freezing behavior, with more efficacy in females. In males, only 5-session training was effective, while in females all protocols were effective. Extinction training also altered pain perception and the results of FST, depending on the sessions and was different in males and females. Brain-derived neurotrophic factor (BDNF) mRNA level was increased in females following 3 and 5 sessions, and in males following 5 sessions extinction training. In conclusion, we suggested that there is a sex difference for the effect of extinction training on freezing behavior and BDNF mRNA level in a rat model of fear-conditioning.

Rubia cordifolia L. Attenuates Diabetic Neuropathy by Inhibiting Apoptosis and Oxidative Stress in Rats.

Diabetic neuropathy is a debilitating manifestation of long-term diabetes mellitus. The present study explored the effects of the roots of Rubia cordifolia L. (R. cordifolia L.) in the Wistar rat model for diabetic neuropathy and possible neuroprotective, antidiabetic, and analgesic mechanisms underlying this effect. Rats were divided into five experimental groups. An amount of 0.25% carboxy methyl cellulose (CMC) in saline and streptozotocin (STZ) (60 mg/kg) was given to group 1 and group 2, respectively. Group 3 was treated with STZ and glibenclamide simultaneously while groups 4 and 5 were simultaneously treated with STZ and hydroalcoholic extract of the root of R. cordifolia, respectively. Hot plate and cold allodynias were used to evaluate the pain threshold. The antioxidant effects of R. cordifolia were assessed by measuring Thiobarbituric acid reactive substances (TBARS), reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). At the end of the study, sciatic nerve and brain tissues were collected for histopathological study. Bcl-2 proteins, cleaved caspase-3, and Bax were assessed through the Western blot method. R. cordifolia significantly attenuated paw withdrawal and tail flick latency in diabetic neuropathic rats. R. cordifolia significantly (p < 0.01) improved the levels of oxidative stress. It was found to decrease blood glucose levels and to increase animal weight in R. cordifolia-treated groups. Treatment with R. cordifolia suppressed the cleaved caspase-3 and reduced the Bax:Bcl2 ratio in sciatic nerve and brain tissue compared to the diabetic group. Histopathological analysis also revealed a marked improvement in architecture and loss of axons in brain and sciatic nerve tissues at a higher dose of R. cordifolia (400 mg/kg). R. cordifolia attenuated diabetic neuropathy through its antidiabetic and analgesic properties by ameliorating apoptosis and oxidative stress.

Analgesic Activity of 5-Acetamido-2-Hydroxy Benzoic Acid Derivatives and an In-Vivo and In-Silico Analysis of Their Target Interactions.

The design, synthesis, and evaluation of novel non-steroidal anti-inflammatory drugs (NSAIDs) with better activity and lower side effects are big challenges today. In this work, two 5-acetamido-2-hydroxy benzoic acid derivatives were proposed, increasing the alkyl position (methyl) in an acetamide moiety, and synthesized, and their structural elucidation was performed using 1H NMR and 13C NMR. The changes in methyl in larger groups such as phenyl and benzyl aim to increase their selectivity over cyclooxygenase 2 (COX-2). These 5-acetamido-2-hydroxy benzoic acid derivatives were prepared using classic methods of acylation reactions with anhydride or acyl chloride. Pharmacokinetics and toxicological properties were predicted using computational tools, and their binding affinity (kcal/mol) with COX-2 receptors (Mus musculus and Homo sapiens) was analyzed using docking studies (PDB ID 4PH9, 5KIR, 1PXX and 5F1A). An in-silico study showed that 5-acetamido-2-hydroxy benzoic acid derivates have a better bioavailability and binding affinity with the COX-2 receptor, and in-vivo anti-nociceptive activity was investigated by means of a writhing test induced by acetic acid and a hot plate. PS3, at doses of 20 and 50 mg/kg, reduced painful activity by 74% and 75%, respectively, when compared to the control group (20 mg/kg). Regarding the anti-nociceptive activity, the benzyl showed reductions in painful activity when compared to acetaminophen and 5-acetamido-2-hydroxy benzoic acid. However, the proposed derivatives are potentially more active than 5-acetamido-2-hydroxy benzoic acid and they support the design of novel and safer derivative candidates. Consequently, more studies need to be conducted to evaluate the different pharmacological actions, the toxicity of possible metabolites that can be generated, and their potential use in inflammation and pain therapy.

Experimental investigation of moisture content on suppressing ignition of accumulated dust

The moisture content sprayed into the dust layer in industrial sites was one of the main factors affecting the occurrence of reignition, which could prevent fire and explosion accidents. Although moisture was traditionally considered to inhibit ignition by endothermic and delayed drying, its effect on the thermophysical properties of the dust layer cannot be ignored due to a certain degree of influence on the heat transfer and heat absorption processes of the dust layer. In present study, six wheat straw samples with MCs from <0.2% to 50% MCs were tested with the hot plate methods, and the heat and mass transfer at four stages during the smouldering processes were discussed. The effect of MC on the ignition time, critical ignition temperature, and mass-loss characteristic parameters of the samples was determined. As MCs increased, the thermal conductivity of the sample increased from 0.110 to 0.248 W/(m·K), as well as the heat sink density (ΔHs) increased from 6.66 × 105 to 16.28 × 105 J/kg. It was necessary to make ΔHs higher than the heat increase value (ΔQ) for suppressing ignition.

Phosphor thermometry evaluation of heat transfer enhancement on a hot plate achieved by a vortex-based fluidic oscillator

Recently, a vortex-based feedback fluidic oscillator has been proposed as an alternative to conventional feedback fluidic oscillators. This study aimed to compare the heat transfer performance of a newly designed fluidic oscillator with that of conventional feedback fluidic oscillators with and without an output diffuser using phosphor thermometry. To obtain the instantaneous temperature field in a wide range of high temperatures, a lifetime-based method was employed in two-dimensional phosphor thermography, with Mg4FGeO6: Mn serving as the sensor material and being excited by a UV-LED. A high-speed camera was used to capture images of the hot plate at 4,000 fps. The calibration test was conducted in the temperature range of 25–325 ˚C, and the results were compared with data from thermocouples. The study investigated the impact of the mass flow rate and throat-to-plate distance ratio of three fluidic oscillators to obtain the optimum Nusselt number. The results demonstrated that the newly designed fluidic oscillator exhibited significantly superior cooling effects in comparison to other types of fluidic oscillators. At the lowest ratio of the throat-to-wall distance to the outlet throat height (Z/D = 4.5) and a flow rate of 100 Lpm, the vortex-based fluidic oscillator demonstrated 78 % and 45 % higher heat transfer rates compared to the conventional oscillator with and without an external diffuser, respectively. Furthermore, the newly designed oscillator was more sensitive to the mass flow rate and throat-to-plate distance ratio than the other oscillators.

Phytochemical characterization of Typha domingensis and the assessment of therapeutic potential using in vitro and in vivo biological activities and in silico studies.

Typha domingensis, a medicinal plant with significant traditional importance for curing various human diseases, has potentially bioactive compounds but was less explored previously. Therefore, this study aims to investigate the therapeutic potential of T. domingensis by evaluating the phytochemical profile through high-performance liquid chromatography (HPLC) techniques and its biological activities (in vitro and in vivo) from the methanolic extract derived from the entire plant (TDME). The secondary metabolite profile of TDME regulated by reverse phase ultra-high-performance liquid chromatography-mass spectrometry (RP-UHPLC-MS) revealed some bioactive compounds by -ve and +ve modes of ionization. The HPLC quantification study showed the precise quantity of polyphenols (p-coumaric acid, 207.47; gallic acid, 96.25; and kaempferol, 95.78μg/g extract). The enzyme inhibition assays revealed the IC50 of TDME as 44.75 ± 0.51, 52.71 ± 0.01, and 67.19 ± 0.68µgmL-1, which were significant compared to their respective standards (indomethacin, 18.03 ± 0.12; quercetin, 4.11 ± 0.01; and thiourea, 8.97 ± 0.11) for lipoxygenase, α-glucosidase, and urease, respectively. Safety was assessed by in vitro hemolysis (4.25% ± 0.16% compared to triton × 100, 93.51% ± 0.36%), which was further confirmed (up to 10g/kg) by an in vivo model of rats. TDME demonstrated significant (p < 0.05) potential in analgesic activity by hot plate and tail immersion tests and anti-inflammatory activity by the carrageenan-induced hind paw edema model. Pain latency decreased significantly, and the anti-inflammatory effect increased in a dose-dependent way. Additionally, in silico molecular docking revealed that 1,3,4,5-tetracaffeoylquinic acid and formononetin 7-O-glucoside-6″-O-malonate possibly contribute to enzyme inhibitory activities due to their higher binding affinities compared to standard inhibitors. An in silico absorption, distribution, metabolism, excretion, and toxicological study also predicted the pharmacokinetics and safety of the chosen compounds identified from TDME. To sum up, it was shown that TDME contains bioactive chemicals and has strong biological activities. The current investigations on T. domingensis could be extended to explore its potential applications in nutraceutical industries and encourage the isolation of novel molecules with anti-inflammatory and analgesic effects.

Optimizing the Heat Loss from an Insulation Material and Boundary Layer Thickness of Airflow through a Hot Plate Using Nonlinear Least-Squares Error and Linear Programming Algorithms.

Heat loss is a major challenge in heat transfer problems. Several researchers have minimized heat loss for different heat transfer cases, focusing on one optimization technique; however, not all optimization techniques are suitable for a given problem. A limited number of studies have compared different techniques for a given problem under boundary conditions and constraints. This review revisits basic heat transfer problems and identifies a promising technique for each problem to minimize heat loss. The paper considers three techniques: nonlinear least-squares error (LSE), interior point linear programming (IPLP), and genetic algorithm. Two cases are studied: 1. heat loss optimization from cylindrical insulating surfaces and 2. laminar airflow on a heated plate. The results are compared for each technique, and a suitable technique is recommended for each considered case. Nonlinear LSE is found to be most suitable for case 1. IPLP and GA are recommended for the Case 2 problem. The average thermal conductivity is found to be 0.081 W/mK. The average insulation thickness is found to be 213.25 mm. This research will act as a basis for future research to justify and implement suitable techniques for different heat transfer problems.

Development of state of art test setup to measure thermal conductivity of soils infused with treated and un‐treated natural microorganisms

AbstractSoil is a natural heterogeneous material and from its formation process, heat transfer capacity (thermal conductivity) of soil is playing vital role in many engineering applications. The aim of this research study is to enhance thermal conductivity using natural and treated bacteria from soil samples procured from four different regions namely Dholera, Navsari, Sabarmati River, and Madhavpur of Gujarat, India. To fulfill this objective, thermal conductivity test set‐up was indigenously developed based on guarded hot plate method and is calibrated up to 150°C temperature. The colonies of microorganisms available in soil were studied by serial dilution and spread plate technique. Further, influence of microorganisms on soil structure aggregation pre and post treatment was analyzed by microscope. Four types of microorganisms were introduced in the soil and the thermal conductivity of sample is measured for curing period of 7, 14, 21, and 28 days. The results indicate increment in k value for thermal conductivity in clayey soil up to 26.67% and decrement in sandy soil is up to 45.45%, while most optimum results were observed for 7 days curing period. Present research demonstrates use of microbes available in various soils to enhance heat transfer mechanism through proper identification and treatment.

Synthesis and properties of highly thermally stable ultrathin films of fluorine‐containing hyperbranched polybenzoxazoles

AbstractIn this paper, we aimed to develop ultrathin films of hyperbranched polybenzoxazole with a thickness in the range between 1 and 100 nm. They are expected to have great potential for various applications as functional materials due to their high thermal stability, good chemical resistance and mechanical strength. The synthesis of various hyperbranched poly(o‐hydroxyamide)s as precursors of polybenzoxazole was examined by the polycondensation of 2,2‐bis(3‐amino‐4‐hydroxyphenyl)propane (AHP) and 2,2‐bis(3‐amino‐4‐hydroxyphenyl)hexafluoropropane (AHFP) with 1,3,5‐benzenetricarbonyl trichloride (BCC), yielding the corresponding hyperbranched poly(o‐hydroxyamide), poly(AHFPm‐co‐AHPn‐co‐BCC2.0), with Mn in the range between 12,870 and 22,210 in satisfactory yields. Poly(AHFP3.0‐co‐BCC2.0), poly(AHFP2.25‐co‐AHP0.75‐co‐BCC2.0), and poly(AHFP1.50‐co‐AHP1.50‐co‐BCC2.0) showed good solubility and film‐forming ability, and ultrathin films 8.9–88.6 nm thick were prepared on silicon wafers. Heating of the ultrathin films of poly(AHFPm‐co‐AHPn‐co‐BCC2.0) on a hot plate at 350 °C for 1 h afforded the corresponding ultrathin films of hyperbranched polybenzoxazole, poly(AHFPm‐cyclo‐AHPn‐cyclo‐BCC2.0), with a thickness of 5.3–82.4 nm. Double‐layer thin films consisting of resist materials on top of hyperbranched polybenzoxazole were also prepared.

Assessment of the anti-inflammatory and analgesic effects of Opuntia ficus indica L. Cladodes extract

ABSTRACT This study aimed to evaluate the anti-inflammatory and analgesic properties of the methanolic extract of Opuntia ficus indica L. in small animal (rats and mice model). The current treatment for febrile conditions often involves the use of non-steroidal anti-inflammatory drugs (NSAIDs), which can have adverse effects, particularly gastrointestinal ulcers. Therefore, there is a growing need to explore natural alternatives with fewer side effects. The study utilized various experimental models to assess the effects of the extract. The results demonstrated a significant analgesic effect of the extract, as evidenced by a reduction in pain induced by acetic acid and hot plate tests. Additionally, the extract exhibited anti-inflammatory effects, as indicated by a decrease in carrageenan-induced paw edema and dextran-induced inflammation. To gain insights into the chemical composition of the extract, HPLC analysis was conducted. The analysis successfully identified and quantified 20 compounds, including luteolin, galangin, catechin, thymol, methylated quercetin, quercetin, rutin, acacetin, hesperidin, apigenin, kaempferol, pinocembrin, chrysin, gallic acid, caffeic acid, ascorbic acid, ferulic acid, m-coumaric acid, rosmarinic acid, and trans-cinnamic acid.The findings suggest that Opuntia ficus indica L. extract holds promise as an effective and reasonably priced natural remedy for pain and inflammation in rats and mice model. The comprehensive chemical composition analysis provided valuable insights into the presence of various bioactive compounds, which may contribute to the observed therapeutic effects. Further research and exploration of the extract’s mechanisms of action are warranted to fully understand its potential in small animal healthcare.

Amiloride alleviates morphine tolerance by suppressing ASIC3-dependent neuroinflammation in the spinal cord

BackgroundThe use of morphine in clinical medicine is severely constrained by tolerance. Therefore, it is essential to examine pharmacological therapies that suppress the development of morphine tolerance. Amiloride suppressed the expression of inflammatory cytokines by inhibiting microglial activation. Microglia play a crucial role in the establishment of morphine tolerance. Thus, we anticipated that amiloride might suppress the development of morphine tolerance. During this investigation, we assessed the impact of amiloride on mouse morphine tolerance. MethodsMice received morphine (10 mg/kg, s.c.) twice daily with intrathecally injected amiloride (0.3 μg/5 μl, 1 μg/5 μl, and 3 μg/5 μl) for nine continuous days. To assess morphine tolerance, mice underwent the tail-flick and hot plate tests. BV-2 cells were used to investigate the mechanism of amiloride. By using Western blotting, real-time PCR, and immunofluorescence labeling methods, the levels of acid-sensing ion channels (ASICs), nuclear factor kappa B (NF-kB) p65, p38 mitogen-activated protein kinase (MAPK) proteins, and neuroinflammation-related cytokines were determined. ResultsThe levels of ASIC3 in the spinal cord were considerably increased after long-term morphine administration. Amiloride was found to delay the development of tolerance to chronic morphine assessed via tail-flick and hot plate tests. Amiloride reduced microglial activation and downregulated the cytokines IL-1β and TNF-a by inhibiting ASIC3 in response to morphine. Furthermore, amiloride reduced p38 MAPK phosphorylation and inhibited NF-κB expression. ConclusionsAmiloride effectively reduces chronic morphine tolerance by suppressing microglial activation caused by morphine by inhibiting ASIC3.

Antinociceptive effect of Nephelium lappaceum L. fruit peel and the participation of nitric oxide, opioid receptors, and ATP-sensitive potassium channels.

Introduction: Nephelium lappaceum L. (Sapindaceae) is a plant known as rambutan. It is used for various purposes in traditional medicine. Objective: We aimed to evaluate the antinociceptive effects of the ethanol extract of the fruit peel of N. lappaceum (EENL), the mechanisms involved in these effects, and the acute toxicity in zebrafish. Methods: We performed chromatography coupled to mass spectrometry, acute toxicity assay in zebrafish, and evaluation in mice submitted to models of nociception and locomotor activity. Results: We identified (epi)-catechin, procyanidin B, and ellagic acid and its derivatives in EENL. We did not find any toxicity in zebrafish embryos incubated with EENL. The locomotor activity of mice submitted to oral pretreatment with EENL was not changed, but it reduced the abdominal constrictions induced by acetic acid, the licking/biting time in both the first and second phase of formalin testing and capsaicin testing, and carrageenan-induced paw mechanical allodynia. Oral pretreatment with EENL increased latency time in the hot plate test. This antinociceptive effect was significantly reversed by naloxone, L-arginine, and glibenclamide respectively showing the participation of opioid receptors, nitric oxide, and KATP channels as mediators of EENL-induced antinociception. Conclusion: EENL causes antinociception with the participation of opioid receptors, nitric oxide, and KATP channels, and is not toxic to zebrafish.

Analgesic effect of Centaurium erythraea and molecular docking investigation of the major component swertiamarin

Centaurium erythraea Rafn is employed in Algerian traditional medicine for treating pain. The analgesic activity of the ethanolic extract (EE) from the flowering aerial parts of this plant was examined, and molecular docking of the main bioactive compound was performed. The EE, characterised by the iridoid swertiamarin, was administered to Wistar albino rats in pain models. Peripheral analgesic activity was evaluated using the acetic acid-induced writhing test, and a hot plate test was performed for central antinociceptive activity evaluation. Treatment with EE significantly decreased rats’ writhing induced by acetic acid suggesting peripheral analgesic activity. Furthermore, the elevation of mean basal reaction time in the hot plate method indicated central analgesic activity. Molecular docking studies showed good docking energy with acceptable binding interactions of swertiamarin with cyclooxygenase-2 protein. This supports the analgesic activity of C. erythraea EE, justifying the traditional use of the plant as an analgesic herbal remedy.