Antinociceptive Activity Research Articles

Screening for Antinociceptive Action of Gastroretentive Drug delivery System of Tramadol hydrochloride in Mice

The floating drug delivery system is to avoid the problem of drug waste and to limit the frequency of administration. Here the drug Tramadol is being centrally acting opioid analgesic can be formulated as sustained release formulation by adopting the method gastroretentive drug delivery system through effervescent floating drug delivery system with different grades of polymer Hyperomellose. The Pharmacological activity on Mice by both Hot Plate and Tail Flick Methods also suggest that when the Tramadol Hcl increased with its dosage form shows significant Analgesic Activity in animals which shows a spontaneous dose dependent increase in Analgesic activity was found it shows that the dosage form deserve for designed method of gastroretentive drug delivery system.

(-)-Fenchone Prevents Cysteamine-Induced Duodenal Ulcers and Accelerates Healing Promoting Re-Epithelialization of Gastric Ulcers in Rats via Antioxidant and Immunomodulatory Mechanisms.

(-)-Fenchone is a naturally occurring monoterpene found in the essential oils of Foeniculum vulgare Mill., Thuja occidentalis L., and Peumus boldus Molina. Pharmacological studies have reported its antinociceptive, antimicrobial, anti-inflammatory, antidiarrheal, and antioxidant activities. The preventive antiulcer effects of (-)-Fenchone were assessed through oral pretreatment in cysteamine-induced duodenal lesion models. Gastric healing, the underlying mechanisms, and toxicity after repeated doses were evaluated using the acetic acid-induced gastric ulcer rat model with oral treatment administered for 14 days. In the cysteamine-induced duodenal ulcer model, fenchone (37.5-300 mg/kg) significantly decreased the ulcer area and prevented lesion formation. In the acetic acid-induced ulcer model, fenchone (150 mg/kg) reduced (p < 0.001) ulcerative injury. These effects were associated with increased levels of reduced glutathione (GSH), superoxide dismutase (SOD), interleukin (IL)-10, and transforming growth factor-beta (TGF-β). Furthermore, treatment with (-)-Fenchone (150 mg/kg) significantly reduced (p < 0.001) malondialdehyde (MDA), myeloperoxidase (MPO), interleukin-1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and nuclear transcription factor kappa B (NF-κB). A 14-day oral toxicity investigation revealed no alterations in heart, liver, spleen, or kidney weight, nor in the biochemical and hematological parameters assessed. (-)-Fenchone protected animals from body weight loss while maintaining feed and water intake. (-)-Fenchone exhibits low toxicity, prevents duodenal ulcers, and enhances gastric healing activities. Antioxidant and immunomodulatory properties appear to be involved in its therapeutic effects.

Promising Effects of Casearins in Tumor-Bearing Mice and Antinociceptive Action against Oncologic Pain: Molecular Docking and In Vivo Findings.

Safer analgesic drugs remain a hard challenge because of cardiovascular and/or gastrointestinal toxicity, mainly. So, this study evaluated in vivo the antiproliferative actions of a fraction with casearins (FC) from Casearia sylvestris leaves against human colorectal carcinomas and antihyperalgesic effects on inflammatory- or opiate-based pain relief and oncologic pain in Sarcoma 180 (S180)-bearing mice. Moreover, docking investigations evaluated the binding among Casearin X and NMDA(N-methyl-D-aspartate)-type glutamate receptors. HCT-116 colorectal carcinoma-xenografted mice were treated with FC for 15 days. Antinociceptive assays included chemically induced algesia and investigated mechanisms by pharmacological blockade. Intraplantar region S180-bearing animals received a single dose of FC and were examined for mechanical allodynia and behavior alterations. AutoDock Vina determined molecular interactions among Cas X and NMDA receptor subunits. FC reduced tumor growth at i.p. (5 and 10 mg/kg) and oral (25 mg/kg/day) doses (31.12-39.27%). FC reduced abdominal pain, as confirmed by formalin and glutamate protocols, whose antinociception activity was blocked by naloxone and L-NAME (neurogenic phase) and naloxone, atropine, and flumazenil (inflammatory phase). Meanwhile, glibenclamide potentiated the FC analgesic effects. FC increased the paw withdrawal threshold without producing changes in exploratory parameters or motor coordination. Cas X generated a more stable complex with active sites of the NMDA receptor GluN2B subunits. FC is a promising antitumor agent against colorectal carcinomas, has peripheral analgesic effects by desensitizing secondary afferent neurons, and inhibits glutamate release from presynaptic neurons and/or their action on cognate receptors. These findings emphasize the use of clerodane diterpenes against cancer-related pain conditions.

Valorization of guabirobeira leaf extracts (Campomanesia xanthocarpa) through pressurized liquid extraction and aqueous infusion: assessment of phytochemical composition, antibacterial, and antioxidant activities

AbstractBACKGROUNDThe leaves of guabirobeira contain important phenolic and flavonoid compounds, known for their antioxidant, anti‐inflammatory, antibacterial, and antinociceptive activities. The purpose of this work was to obtain extracts from guabirobeira leaves through aqueous infusion and pressurized liquid extraction with water, ethanol, and a combination of water–ethanol (ratio 1:1, v/v; PLE‐W:E). Subsequently, we used liquid chromatography coupled with mass spectrometry to identify the chemical compounds, and to study the antioxidant activity in rat brain cells; thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) antibacterial activity against Gram‐negative and Gram‐positive bacteria were also seen.RESULTSAccording to the findings, all four extracts contained a significant amount of phytochemical compounds. Among them, the PLE‐W:E extract showed a higher concentration of flavonoids, demonstrating significant antioxidant activity in in vitro assays of TBARS and ROS in rat brain cells. It also exhibited antibacterial activity against both Gram‐positive and Gram‐negative bacteria.CONCLUSIONGuabirobeira leaf extracts hold promise as a potential source of bioactive compounds. These extracts can be applied across various sectors, including cosmetics and skincare products, pharmaceuticals, food and beverages, natural preservatives, and functional materials. By exploring these potential applications, valuable contributions can be made to the field of sustainable chemistry and pharmacy, furthering the utilization of guabirobeira leaf extracts in diverse industries. This approach also aligns with the promotion of environmentally friendly and sustainable practices. © 2024 Society of Chemical Industry (SCI).

Almond fixed oil from Syagrus coronata (Mart.) Becc. has antinociceptive and anti-inflammatory potential, without showing oral toxicity in mice

Ethnopharmacological relevanceSyagrus coronata, a palm tree found in northeastern Brazil, popularly known as licuri, has socioeconomic importance for the production of vegetable oil rich in fatty acids with nutritional and pharmacological effects. Licuri oil is used in traditional medicine to treat inflammation, wound healing, mycosis, back discomfort, eye irritation, and other conditions. Aim of the studyThe study aimed to evaluate the antinociceptive, anti-inflammatory, and antipyretic effects of treatment with Syagrus coronata fixed oil (ScFO), as well as to determine the safety of use in mice. Materials and methodsInitially, the chemical characterization was performed by gas chromatography-mass spectrometry. Acute single-dose oral toxicity was evaluated in mice at a dose of 2000 mg/kg. Antinociceptive activity was evaluated through abdominal writhing, formalin, and tail dipping tests, and the anti-inflammatory potential was evaluated through the model of acute inflammation of ear edema, peritonitis, and fever at concentrations of 25, 50, and 100 mg/kg from ScFO. ResultsIn the chemical analysis of ScFO, lauric (43.64%), caprylic (11.7%), and capric (7.2%) acids were detected as major. No mortality or behavioral abnormalities in the mice were evidenced over the 14 days of observation in the acute toxicity test. ScFO treatment decreased abdominal writhing by 27.07, 28.23, and 51.78% at 25, 50, and 100 mg/kg. ScFO demonstrated central and peripheral action in the formalin test, possibly via opioidergic and muscarinic systems. In the tail dipping test, ScFO showed action from the first hour after treatment at all concentrations. ScFO (100 mg/kg) reduced ear edema by 63.76% and leukocyte and neutrophil migration and IL-1β and TNF-α production in the peritonitis test. ConclusionMice treated with ScFO had a reduction in fever after 60 min at all concentrations regardless of dose. Therefore, the fixed oil of S. coronata has the potential for the development of new pharmaceutical formulations for the treatment of pain, inflammation, and fever.

Synergistic Antinociceptive Effect of β-Caryophyllene Oxide in Combination with Paracetamol, and the Corresponding Gastroprotective Activity.

Pain is the most frequent symptom of disease. In treating pain, a lower incidence of adverse effects is found for paracetamol versus other non-steroidal anti-inflammatory drugs. Nevertheless, paracetamol can trigger side effects when taken regularly. Combined therapy is a common way of lowering the dose of a drug and thus of reducing adverse reactions. Since β-caryophyllene oxide (a natural bicyclic sesquiterpene) is known to produce an analgesic effect, this study aimed to determine the anti-nociceptive and gastroprotective activity of administering the combination of paracetamol plus β-caryophyllene oxide to CD1 mice. Anti-nociception was evaluated with the formalin model and gastroprotection with the model of ethanol-induced gastric lesions. According to the isobolographic analysis, the anti-nociceptive interaction of paracetamol and β-caryophyllene oxide was synergistic. Various pain-related pathways were explored for their possible participation in the mechanism of action of the anti-nociceptive effect of β-caryophyllene oxide, finding that NO, opioid receptors, serotonin receptors, and K+ATP channels are not involved. The combined treatment showed gastroprotective activity against ethanol-induced gastric damage. Hence, the synergistic anti-nociceptive effect of combining paracetamol with β-caryophyllene oxide could be advantageous for the management of inflammatory pain, and the gastroprotective activity should help to protect against the adverse effects of chronic use.

Naringenin relieves paclitaxel-induced pain by suppressing calcitonin gene-related peptide signalling and enhances the anti-tumour action of paclitaxel.

Chemotherapy-induced peripheral neuropathy (CIPN) commonly causes neuropathic pain, but its pathogenesis remains unclear, and effective therapies are lacking. Naringenin, a natural dihydroflavonoid compound, has anti-inflammatory, anti-nociceptive and anti-tumour activities. However, the effects of naringenin on chemotherapy-induced pain and chemotherapy effectiveness remain unexplored. Female and male mouse models of chemotherapy-induced pain were established using paclitaxel. Effects of naringenin were assessed on pain induced by paclitaxel or calcitonin gene-related peptide (CGRP) and on CGRP expression in dorsal root ganglia (DRG) and spinal cord tissue. Additionally, we examined peripheral macrophage infiltration, glial activation, c-fos expression, DRG neuron excitability, microglial M1/M2 polarization, and phosphorylation of spinal NF-κB. Furthermore, we investigated the synergic effect and related mechanisms of naringenin and paclitaxel on cell survival of cancer cells in vitro. Systemic administration of naringenin attenuated paclitaxel-induced pain in both sexes. Naringenin reduced paclitaxel-enhanced CGRP expression in DRGs and the spinal cord, and alleviated CGRP-induced pain in naïve mice of both sexes. Naringenin mitigated macrophage infiltration and reversed paclitaxel-elevated c-fos expression and DRG neuron excitability. Naringenin decreased spinal glial activation and NF-κB phosphorylation in both sexes but influenced microglial M1/M2 polarization only in females. Co-administration of naringenin with paclitaxel enhanced paclitaxel's anti-tumour effect, impeded by an apoptosis inhibitor. Naringenin's anti-nociceptive mechanism involves CGRP signalling and neuroimmunoregulation. Furthermore, naringenin facilitates paclitaxel's anti-tumour action, possibly involving apoptosis. This study demonstrates naringenin's potential as a supplementary treatment in cancer therapy by mitigating side effects and potentiating efficacy of chemotherapy.

Launaea fragilis extract attenuated arthritis in rats through modulation of IL-1β, TNF-α, IL-6, NF-κB, COX-2, IL-4, and IL-10.

Launaea fragilis (Asso) Pau is a Cholistan desert medicinal plant. Launaea species are used as traditional remedies against various inflammatory conditions. The current research was designed to evaluate the anti-nociceptive, anti-inflammatory, and anti-arthritic potential of ethanolic extract of L. fragilis (Et-LF). The plant extract was prepared by triple maceration. GC-MS screening explored the presence of various bioactive phytoconstituents including n-tetracosanol-1, 1-heptacosanol, and n-hexadecanoic acid. DPPH assay demonstrated the antioxidant potential of Et-LF. Safety profile data indicated that Et-LF was safe up to the oral dose of 5000mg/kg in female rats. Anti-nociceptive activity of Et-LF was assessed in hot plate method and acetic acid-induced writhing model and the results suggested that Et-LF had significant analgesic effects in both animal models. Carrageenan, histamine, and serotonin-induced edema models were used to estimate the anti-inflammatory effects of Et-LF and were found to prevent paw edema development dose dependently. The anti-arthritic effect of Et-LF was estimated in CFA-induced arthritic rat model. Treatment with Et-LF 125, 250, 500 and flurbiprofen (FP) 10mg/kg/day significantly attenuated the paw edema, reversed the reduced body weight, and restored the altered hematological parameters in arthritic rats. Gene expression studies revealed the significant downregulation of IL-1β, TNF-α, IL-6, NF‑κB, and COX-2, and upregulation of IL-4 and IL-10 in arthritic rats treated with various doses of plant extract. Histological evaluation of ankle joints showed that Et-LF mitigated pannus formation, infiltration of inflammatory cells, and fibrous connective tissue formation in the diseased rats. Thereof, it may be concluded that the recent study demonstrated the anti-nociceptive, anti-inflammatory, and anti-arthritic effects ascribed to the signifying presence of phytoconstituents in L. fragilis.

Bioassay-guided isolation of anti-inflammatory and antinociceptive metabolites among three Moroccan Juniperus leaves extract supported with in vitro enzyme inhibitory assays

Ethnopharmacological relevanceHerbs of the genus Juniperus (family Cupressaceae) have been commonly used in ancestral folk medicine known as “Al'Araar” for treatment of rheumatism, diabetes, inflammation, pain, and fever. Bioassay-guided isolation of bioactives from medicinal plants is recognized as a potential approach for the discovery of novel drug candidates. In particular, non-addictive painkillers are of special interest among herbal phytochemicals. Aim of the studyThe current study aimed to assess the safety of J. thurifera, J. phoenicea, and J. oxycedrus aqueous extracts in oral treatments; validating the traditionally reported anti-inflammatory and analgesic effects. Further phytochemical investigations, especially for the most bioactive species, may lead to isolation of bioactive metabolites responsible for such bioactivities supported with in vitro enzyme inhibition assays. Materials and methodsFirstly, the acute toxicity study was investigated following the OECD Guidelines. Then, the antinociceptive, and anti-inflammatory bioactivities were evaluated based on chemical and mechanical trauma assays and investigated their underlying mechanisms. The most active J. thurifera n-butanol fraction was subjected to chromatographic studies for isolating the major anti-inflammatory metabolites. Moreover, several enzymatic inhibition assays (e.g., 5-lipoxygenase, protease, elastase, collagenase, and tyrosinase) were assessed for the crude extracts and isolated compounds. ResultsThe results showed that acute oral administration of the extracts (300–500 mg/kg, p. o.) inhibited both mechanically and chemically triggered inflammatory edema in mice (up to 70% in case of J. thurifera) with a dose-dependent antinociceptive (tail flick) and anti-inflammatory pain (formalin assay) activities. This effect was partially mediated by naloxone inhibition of the opioid receptor (2 mg/kg, i. p.). In addition, 3-methoxy gallic acid (1), quercetin (2), kaempferol (3), and ellagic acid (4) were successfully identified being involved most likely in J. thurifera extract bioactivities. Nevertheless, quercetin was found to be the most potent against 5-LOX, tyrosinase, and protease with IC50 of 1.52 ± 0.01, 192.90 ± 6.20, and 399 ± 9.05 μM, respectively. ConclusionJ. thurifera extract with its major metabolites are prospective drug candidates for inflammatory pain supported with inhibition of inflammatory enzymes. Interestingly, antagonism of opioid and non-opioid receptors is potentially involved.

Multitarget μ-Opioid Receptor Agonists─Neuropeptide FF Receptor Antagonists Induce Potent Antinociception with Reduced Adverse Side Effects.

The design of bifunctional compounds is a promising approach toward the development of strong analgesics with reduced side effects. We here report the optimization of the previously published lead peptide KGFF09, which contains opioid receptor agonist and neuropeptide FF receptor antagonist pharmacophores and is shown to induce potent antinociception and reduced side effects. We evaluated the novel hybrid peptides for their in vitro activity at MOP, NPFFR1, and NPFFR2 and selected four of them (DP08/14/32/50) for assessment of their acute antinociceptive activity in mice. We further selected DP32 and DP50 and observed that their antinociceptive activity is mostly peripherally mediated; they produced no respiratory depression, no hyperalgesia, significantly less tolerance, and strongly attenuated withdrawal syndrome, as compared to morphine and the recently FDA-approved TRV130. Overall, these data suggest that MOP agonist/NPFF receptor antagonist hybrids might represent an interesting strategy to develop novel analgesics with reduced side effects.

The Analgesic Potential of Litsea Species: A Systematic Review.

Various plant species from the Litsea genus have been claimed to be beneficial for pain relief. The PRISMA approach was adopted to identify studies that reported analgesic properties of plants from the Litsea genus. Out of 450 records returned, 19 primary studies revealed the analgesic potential of nine Litsea species including (1) Litsea cubeba, (2) Litsea elliptibacea, (3) Litsea japonica, (4) Litsea glutinosa, (5) Litsea glaucescens, (6) Litsea guatemalensis, (7) Litsea lancifolia, (8) Litsea liyuyingi and (9) Litsea monopetala. Six of the species, 1, 3, 4, 7, 8 and 9, demonstrated peripheral antinociceptive properties as they inhibited acetic-acid-induced writhing in animal models. Species 1, 3, 4, 8 and 9 further showed effects via the central analgesic route at the spinal level by increasing the latencies of heat stimulated-nocifensive responses in the tail flick assay. The hot plate assay also revealed the efficacies of 4 and 9 at the supraspinal level. Species 6 was reported to ameliorate hyperalgesia induced via partial sciatic nerve ligation (PSNL). The antinociceptive effects of 1 and 3 were attributed to the regulatory effects of their bioactive compounds on inflammatory mediators. As for 2 and 5, their analgesic effect may be a result of their activity with the 5-hydroxytryptamine 1A receptor (5-HT1AR) which disrupted the pain-stimulating actions of 5-HT. Antinociceptive activities were documented for various major compounds of the Litsea plants. Overall, the findings suggested Litsea species as good sources of antinociceptive compounds that can be further developed to complement or substitute prescription drugs for pain management.

One pot synthesis of 5-hydroxyalkylated thiadiazine thiones: Implication in pain management and bactericidal properties

The synthesis of a new series of thiadiazine thiones including 5-(2-hydroxyethyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (1–5), 5-(2-hydroxypropyl)-3-alkyl/aryl-1, 3, 5-thiadiazine-2-thiones (6–8), 3,5-dipropyl-1, 3, 5-thiadiazine-2-thione (9) and (2-(5-alkyl/aryl-6-thioxo-1, 3, 5-thiadiazine-3-yl) alkyl acetate/benzoate) (10–17) was accomplished via one pot reaction. The structures of the synthesized compounds were characterized through NMR and Mass spectrometry. The anti-nociceptive activity of compounds was performed on BALB/C mice by hot plate method, where compounds 3, 5 (50 μg/kg), and 8 (50, 100 μg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time of 15, 30, and 60 min, while compounds 6 and 16 (100 μg/kg) exhibited significant effect (P < 0.01, P < 0.05) in latency time interval of 15 and 30 min. Compounds 1, 12–13, and 15 showed moderate activity. Among the tested hits, compounds 5 (17.3 ± 2.2), 11 (16.2 ± 2.1), and 8 (16.1 ± 2.1) showed significant anti-nociceptive potential. Molecular docking studies on the most active anti-nociceptive hits indicated that the activity might be attributed to the ability of the compounds to target μ-opioid receptor (μOR) effectively. Furthermore, compounds 14 and 11 showed anti-bacterial activity against Pseudomonas aeruginosa and MSRA with MIC of 40.97 and 54.77 μg/mL, respectively. In addition, the predicted ADMET profile of 5, 9, and 11 indicates that these molecules follow the drug-likeness criteria, and their activity can be enhanced through structural optimization.

Phellintremulins A-C, antinociceptive sesquiterpenoids from the medicinal fungus Phellinus tremulae

Phellintremulin A (1), a rearranged sesquiterpenoid with an unprecedented bicyclic backbone, and two previously unreported illudane-type sesquiterpenoids, namely phellintremulin B (2) and phellintremulin C (3), together with two known analogues (±)‒4 and (±)‒5, were isolated from cultures of the medicinal fungus Phellinus tremulae. Their structures and absolute configurations were established by means of spectroscopic data and HRESIMS analyses, as well as ECD and NMR calculations. A plausible biogenesis for 1 was discussed. The electrophysiological experiments showed that phellintremulins (A‒C) can inhibit Nav current in DRG neuron cells at 10 μM, with percentage inhibitions of 23.2%, 49.3%, and 31.7%, respectively. The antinociceptive activities of phellintremulins (A‒C) were evaluated via the acetic acid-induced writhing test in mice at a dose of 3 mg/kg. They showed significant antinociceptive effects with percentages of inhibition of 43.8%, 54.4%, and 50.6%, respectively, and phellintremulin B and C expressed more potent analgesic effect than lidocaine.

Evaluation of Rhododendri Mollis Flos and its representative component as a potential analgesic.

Rhododendri Mollis Flos (R. mole Flos), the dried flowers of Rhododendron mole G. Don, have the ability to relieve pain, dispel wind and dampness, and dissolve blood stasis, but they are highly poisonous. The significance of this study is to explore the analgesic application potential of R. mole Flos and its representative component. According to the selected processing methods recorded in ancient literature, the analgesic activities of wine- and vinegar-processed R. mole Flos, as well as the raw product, were evaluated in a writhing test with acetic acid and a formalin-induced pain test. Subsequently, the HPLC-TOP-MS technique was utilized to investigate the changes in active components before and after processing once the variations in activities were confirmed. Based on the results, rhodojaponin VI (RJ-Vl) was chosen for further study. After processing, especially in vinegar, R. mole Flos did not only maintain the anti-nociception but also showed reduced toxicity, and the chemical composition corresponding to these effects also changed significantly. Further investigation of its representative components revealed that RJ-VI has considerable anti-nociceptive activity, particularly in inflammatory pain (0.3mg/kg) and peripheral neuropathic pain (0.6mg/kg). Its toxicity was about three times lower than that of rhodojaponin III, which is another representative component of R. mole Flos. Additionally, RJ-VI mildly inhibits several subtypes of voltage-gated sodium channels (IC50 > 200μM) that are associated with pain or cardiotoxicity. In conclusion, the chemical substances and biological effects of R. mole Flos changed significantly before and after processing, and the representative component RJ-VI has the potential to be developed into an effective analgesic.

Chemical Constituents and Their Bioactivities of Plants from the Genus Eupatorium (2015-Present).

The genus Eupatorium belongs to the Asteraceae (Compositae) family and has multiple properties, such as invasiveness and toxicity, and is used in folk medicine. The last review on the chemical constituents of this genus and their biological activities was published in 2015. The present review provides an overview of 192 natural products discovered from 2015 to the present. These products include 63 sesquiterpenoids, 53 benzofuran derivatives, 39 thymol derivatives, 15 fatty acids, 7 diterpenoids, 5 monoterpenoids, 4 acetophenones, and 6 other compounds. We also characterized their respective chemical structures and cytotoxic, antifungal, insecticidal, antibacterial, anti-inflammatory, and antinociceptive activities.

A triple cysteine motif as major determinant of the modulation of neuronal KV7 channels by the paracetamol metabolite N-acetyl-p-benzo quinone imine.

The analgesic action of paracetamol involves KV7 channels, and its metabolite N-acetyl-p-benzo quinone imine (NAPQI), a cysteine modifying reagent, was shown to increase currents through such channels in nociceptors. Modification of cysteine residues by N-ethylmaleimide, H2O2, or nitric oxide has been found to modulate currents through KV7 channels. The study aims to identify whether, and if so which, cysteine residues in neuronal KV7 channels might be responsible for the effects of NAPQI. To address this question, we used a combination of perforated patch-clamp recordings, site-directed mutagenesis, and mass spectrometry applied to recombinant KV7.1 to KV7.5 channels. Currents through the cardiac subtype KV7.1 were reduced by NAPQI. Currents through all other subtypes were increased, either by an isolated shift of the channel voltage dependence to more negative values (KV7.3) or by such a shift combined with increased maximal current levels (KV7.2, KV7.4, KV7.5). A stretch of three cysteine residues in the S2-S3 linker region of KV7.2 was necessary and sufficient to mediate these effects. The paracetamol metabolite N-acetyl-p-benzo quinone imine (NAPQI) modifies cysteine residues of KV7 subunits and reinforces channel gating in homomeric and heteromeric KV7.2 to KV7.5, but not in KV7.1 channels. In KV7.2, a triple cysteine motif located within the S2-S3 linker region mediates this reinforcement that can be expected to reduce the excitability of nociceptors and to mediate antinociceptive actions of paracetamol.

Potential Therapeutic Targets to Modulate the Endocannabinoid System in Alzheimer's Disease.

Alzheimer's disease (AD), the most common neurodegenerative disease (NDD), is characterized by chronic neuronal cell death through progressive loss of cognitive function. Amyloid beta (Aβ) deposition, neuroinflammation, oxidative stress, and hyperphosphorylated tau proteins are considered the hallmarks of AD pathology. Different therapeutic approaches approved by the Food and Drug Administration can only target a single altered pathway instead of various mechanisms that are involved in AD pathology, resulting in limited symptomatic relief and almost no effect in slowing down the disease progression. Growing evidence on modulating the components of the endocannabinoid system (ECS) proclaimed their neuroprotective effects by reducing neurochemical alterations and preventing cellular dysfunction. Recent studies on AD mouse models have reported that the inhibitors of the fatty acid amide hydrolase (FAAH) and monoacylglycerol (MAGL), hydrolytic enzymes for N-arachidonoyl ethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), respectively, might be promising candidates as therapeutical intervention. The FAAH and MAGL inhibitors alone or in combination seem to produce neuroprotection by reversing cognitive deficits along with Aβ-induced neuroinflammation, oxidative responses, and neuronal death, delaying AD progression. Their exact signaling mechanisms need to be elucidated for understanding the brain intrinsic repair mechanism. The aim of this review was to shed light on physiology and pathophysiology of AD and to summarize the experimental data on neuroprotective roles of FAAH and MAGL inhibitors. In this review, we have also included CB1R and CB2R modulators with their diverse roles to modulate ECS mediated responses such as anti-nociceptive, anxiolytic, and anti-inflammatory actions in AD. Future research would provide the directions in understanding the molecular mechanisms and development of new therapeutic interventions for the treatment of AD.

Synthesis, characterization, and biological study of new synthetic opioid hemorphin-4 peptides containing sterically restricted nonnatural amino acids.

Some new hemorphin-4 analogs with structures of Xxx-Pro-Trp-Thr-NH2 and Tyr-Yyy-Trp-Thr-NH2, where Xxx is 2-amino-3-(4-hydroxy-2,6-dimethylphenyl)propanoic acid or 2-amino-3-(4-dibenzylamino-2,6-dimethylphenyl)propanoic acid, and Yyy is (2S,4S)-4-amino-pyrrolidine-2-carboxylic acid, were synthesized and characterized by electrochemical and spectral analyses. In vivo anticonvulsant and antinociceptive activities of peptide derivatives were studied after intracerebroventricular injection in mice. The therapeutic effects of the modified peptides on seizures and pain in mice were evaluated to provide valuable insights into the potential applications of the novel compounds. Electrochemical characterization showed that the compounds behave as weak protolytes and that they are in a soluble, stable molecular form at physiological pH values. The antioxidant activityof the peptides was evaluated with voltammetric analyses, which were confirmed by applying the 2,2-Diphenyl-1-picrylhydrazyl method. The compounds showed satisfactory results regarding their structural stability, reaching the desired centers for the manifestation of biological activity without hydrolysis processes at 37°C and physiological pH. Dm-H4 and H4-P1 exhibited 100% and 83% potency to suppress the psychomotor seizures in the 6-Hz test compared to 67% activity of H4. Notably, only the H4-P1 had efficacy in blocking the tonic component in the maximal electroshock test with a potency comparable to H4. All investigated peptides containing unnatural conformationally restricted amino acids showed antinociceptive effects. The analogs Db-H4 and H4-P1 showed the most pronounced and long-lasting effect in both experimental models of pain induced by thermal and chemical stimuli. Dm-H4 produced a dose-dependent thermal antinociception and H4-P2 inhibited only formalin-induced pain behavior.

Deformable Vesicles with Edge Activators for the Transdermal Delivery of Non-Psychoactive Cannabinoids.

Transdermal delivery of highly lipophilic molecules is challenging due to the strong barrier function of the skin. Vesicles with penetration enhancers are safe and efficient systems that could improve the transdermal delivery of non-psychoactive cannabinoids such as cannabidiol and desoxy-cannabidiol. In the last decades, research interest in desoxy-cannabidiol as a potent drug with anti-nociceptive properties has risen. Still, its scarce market availability poses a limit for both research and clinical applications. Therefore, it is necessary to improve the synthesis to produce sufficient amounts of desoxy-cannabidiol. Moreover, also the formulation aspects for this drug are challenging and require to be addressed to meet an efficient delivery to the patients. This work aimed to develop innovative phospholipid-based vesicles with propylene glycol (PG), oleic acid (OA), or limonene as edge activators, for the transdermal delivery of highly lipophilic drugs such as non-psychoactive cannabinoids. In particular, desoxy-cannabidiol was selected thanks to its anti-nociceptive activity, and its synthesis was improved enhancing the stereoselectivity of its synthon's production. Desoxy-cannabidiol was synthesized by Lewis acid-mediated condensation of p-mentha-2,8-dien- 1-ol and m-pentylphenol, improving the stereoselectivity of the first synthon's production. Transethosomes containing 20-50% w/w PG, 0.4-0.8% w/w OA, or 0.1-1% w/w limonene were optimized and loaded with cannabidiol or desoxy-cannabidiol (0.07-0.8% w/w, 0.6-7.0 mg/mL). Ex-vivo studies were performed to assess both the skin permeation and accumulation of the cannabinoids, as well as the penetration depth of fluorescein- loaded systems used as models. An enantioselective bromination was added to the pathway, thus raising the production yield of pmentha- 2,8-dien-1-ol to 81% against 35%, and the overall yield of desoxy-cannabidiol synthesis from 12% to 48%. Optimized transethosomes containing 0.6 mg/mL cannabinoids were prepared with 1:10 PG:lipid weight ratio, 0.54 OA:lipid molar ratio, and 0.3 limonene:lipid molar ratio, showing good nanometric size (208 ± 20.8 nm - 321 ± 26.3 nm) and entrapment efficiency (> 80%). Ex-vivo tests showed both improved skin permeation rates of cannabinoids (up to 21.32 ± 4.27 μg/cm2 cannabidiol), and skin penetration (depth of fluorescein up to 240 μm, with PG). Desoxy-cannabidiol was successfully produced at high yields, and formulated into transethosomes optimized for transdermal delivery. Loaded vesicles showed improved skin penetration of desoxy-cannabidiol, cannabidiol and a lipophilic probe. These results suggest the potential of these carriers for the transdermal delivery of highly lipophilic drugs.

Ethnomedicinal Importance of Patuletin in Medicine: Pharmacological Activities and Analytical Aspects.

Plant-derived bioactive molecules have been a major source of therapeutic agents for human and veterinarian purposes. Different traditional medicine system across the globe had relied on natural resources to meet their demand of healthcare. Still in modern world, pharmaceutical industries look for phytochemicals to develop new drugs. The current review explores patuletin, a flavonoid for its diverse reported pharmacological activities along with its analytical techniques. Scientific data published on patuletin was collected from Scopus, Science Direct, Pubmed, Google, and Google Scholar. The collected data were analyzed and arranged as per specific pharmacological activities performed using in-vitro or in-vivo methods. Analytical methods of patuletin have been presented next to pharmacological activities Results: Available scientific literature indicates patuletin has anti-inflammatory, cytotoxic, genotoxic, hepatoprotective, antiproliferative, antiplatelet, antinociceptive, and antioxidant activity. In addition to these activities, its biological potential on breast cancer, rheumatoid arthritis, aldose reductase, and different types of microorganisms has been also presented in this work. Analytical data on patuletin signified the importance of patuletin for the standardization of herbal products and derived medicine. It may be concluded that patuletin with its diverse biological activities and readily available analytical methods, holds the potential to be translated into a new drug entity.