Ferulic acid ameliorates chronic constriction injury induced painful neuropathy in rats

Efficacy assessment of novel methanimine derivatives in chronic constriction injury-induced neuropathic model: An in-vivo, ex-vivo and In-Silico approach

The multicomponent etiology, complex clinical implications, dose-based side effect and degree of pain mitigation associated with the current pharmacological therapy is incapable in complete resolution of chronic neuropathic pain patients which necessitates the perpetual requirement of novel medication therapy. Therefore, this study explored the ameliorative aptitude of two novel methanimine imitative like (E)-N-(4-nitrobenzylidene)-4‑chloro-2-iodobenzamine (KB 09) and (E)-N-(4-methylbenzylidene)-4‑chloro-2-iodobenzamine (KB 10) in chronic constriction injury (CCI) of sciatic nerve induced neuropathic pain in rat model. Standard behavioral tests like dynamic and static allodynia, cold, thermal and mechanical hyperalgesia along with rotarod activity were performed at various experimental days like 0, 3, 7, 14 and 21. Enzyme linked immunosorbent assay (ELISA) on spinal tissue and antioxidant assays on sciatic nerve were executed accompanied by molecular docking and simulation studies. Prolonged ligation of sciatic nerve expressively induced hyperalgesia as well as allodynia in rats. KB 09 and KB 10 substantially attenuated the CCI elicited hyperalgesia and allodynia. They significantly reduced the biomarkers of pain and inflammation like Interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in ELISA and while enhanced the GSH, SOD and CAT and diminished the MDA levels during antioxidant assays. KB 09 displayed -9.62 kcal/mol with TNF-α and -7.68 kcal/mol binding energy with IL-6 whereas KB 10 exhibited binding energy of -8.20 kcal/mol with IL-6 while -11.68 kcal/mol with TNF-α and hence both trial compounds ensured stable interaction with IL-6 and TNF-α during computational analysis. The results advocated that both methanimine derivatives might be novel candidates for attenuation of CCI-induced neuropathic pain prospects via anti-nociceptive, anti-inflammatory and antioxidant mechanisms.

Exploring the Therapeutic Potential of Berberine and Tocopherol in Managing Diabetic Neuropathy: A Comprehensive Approach towards Alleviating Chronic Neuropathic Pain

Diabetic neuropathy (DN) causes sensory dysfunction, such as numbness, tingling, or burning sensations. Traditional medication may not ease pain and discomfort, but natural remedies such as Berberine (BR) and vitamin E or Tocopherol (TOC) have therapeutic potential to reduce inflammation while improving nerve function. Novel substances offer a more potent alternative method for managing severe chronic neuropathic pain that does not react to standard drug therapy by targeting various pathways that regulate it. Rats with diabetic control received oral doses of BR + TOC that showed significant changes in serum insulin levels compared to DN controls after 90 days, suggesting a decrease in sensitivity to painful stimuli partly by modulating the oxidative stress of the inflammatory pathway such as TNF-α suppression or stimulation of TNF-α depending on the amount of dose consumed by them. NF-kB also played its role here. Administering doses of BR and TOC reduced heightened levels of NF-kB and AGEs, effectively counteracting inflammation-targeted key factors in diabetes, promising possibilities for the benefits of these molecules revealed through in vivo investigation. In summary, treating neuropathy pain with a more comprehensive and organic approach can involve harnessing the powerful capabilities of BR and TOC. These compounds have been found to not only considerably decrease inflammation but also provide effective nerve protection while enhancing overall nerve function. With their multifunctional impacts on various neuropathic pain pathways in the body, these naturally occurring substances offer an exciting possibility for those who encounter high levels of neuropathic distress that do not respond well to conventional medication-centred therapies.

Nutraceuticals: A Promising Approach Towards Diabetic Neuropathy

BACKGROUND

Various nutraceuticals from different sources have various beneficial actions and have been reported for many years. The important findings from the research conducted using various nutraceuticals exhibiting significant physiological and pharmacological activities have been summarized.

METHODS

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct, Google Scholar, etc. The entire manuscript is available in the English language that is used for our various compounds of interest. These databases were thoroughly reviewed and summarized.

RESULTS

Nutraceuticals obtained from various sources play a vital role in the management of peripheral neuropathy associated with diabetes. Treatment with nutraceuticals has been beneficial as an alternative in preventing the progression. In particular, in vitro and in vivo studies have revealed that a variety of nutraceuticals have significant antioxidant and anti-inflammatory properties that may inhibit the early diabetes-driven molecular mechanisms that induce DPN.

CONCLUSION

Nutraceuticals obtained from different sources like a plant, an animal, and marine have been properly utilized for the safety of health. In our opinion, this review could be of great interest to clinicians, as it offers a complementary perspective on the management of DPN. Trials with a well-defined patient and symptom selection have shown robust pharmacological design as pivotal points to let these promising compounds become better accepted by the medical community.

Antinociceptive effect of Mansoa alliacea polar extracts involves opioid receptors and nitric oxide in experimental nociception in mice

To evaluate the antinociceptive effect and the possible mechanism of action of two polar extracts of Mansoa alliacea, a medicinal plant used in Perú, Brazil, and Mexico to treat rheumatic pain, we used the formalin and hot-plate tests in mice. We found that ethanolic (MA-EtOH) and aqueous (MA-AQ) extracts of M. alliacea induced antinociceptive effects in both nociceptive tests. The antinociceptive efficacy of the highest dosage (300 mg/kg) of both extracts were also compared by using intraperitoneal and oral administration in the formalin test. Results showed that intraperitoneal injection of the two extracts produced better antinociceptive effects than that obtained by their oral administration. The mechanism of action involved in their antinociceptive activity was determined in the formalin test. Results showed that the presence of A784168 (TRPV1 antagonist) did not alter the antinociceptive effect induced by any of the M. alliacea extracts, whereas naltrexone (opioid antagonist) partially prevented the antinociceptive effect only of MA-EtOH in both phases of the formalin test. Furthermore, the effects of the extracts were diminished by L-NAME (inhibitor of nitric oxide synthase), but not by ODQ (inhibitor of the soluble guanylyl cyclase) or glibenclamide (blocker of K⁺_ATP channels) in the neurogenic phase. However, the effect of MA-AQ was diminished by all the inhibitors in the inflammatory phase. These results support the use of M. alliacea as a potential natural product with efficacy for pain relief depending on the form of preparation and the route of administration by involving opioid receptors and the production of nitric oxide.

Upregulation of ubiquitin conjugating enzyme E2B (Ube2b) ameliorates neuropathic pain by regulating Kcna2 (potassium voltage-gated channel subfamily A member 2) in primary afferent neurons

Neuropathic pain is a kind of pain caused by damage to somatosensory nervous system. Currently, neuropathic pain is still a medical problem for clinicians. Ubiquitin conjugating enzyme E2B (Ube2b) is validated to be implicated with nerve function, but whether Ube2b can play a role in neuropathic pain is still elusive. In this work, we constructed chronic constriction injury (CCI) rat model by ligating the left sciatic nerve, Ube2b protein expression was confirmed to be decreased in spinal cord tissues of CCI rats via Western blot analysis and immunofluorescence (IF) staining. Moreover, Ube2b elevation alleviated the thermal hyperalgesia and mechanical hyperalgesia in CCI rats according to paw withdrawal thermal latency (PWTL) and paw withdrawal mechanic threshold (PWMT). In addition, Hematoxylin-eosin staining revealed that Ube2b elevation suppressed chronic sciatic nerve injury. All these data suggested that Ube2b could ameliorate neuropathic pain in CCI rats. Mechanically, Ube2b upregulation elevated the protein level of Kcna2 (potassium voltage-gated channel subfamily A member 2) and decreased the protein level of DNMT3a (DNA methyltransferase 3 alpha). Ube2b elevation could increase Kcna2 expression via suppressing DNMT3a. Rescue assays unveiled that Ube2b overexpression modulated-mechanical hyperalgesia and thermal hyperalgesia were reversed by Kcna2 depletion, indicating that Ube2b alleviated neuropathic pain via mediating Kcna2 via the regulation of DNMT3a. In summary, we found that Ube2b elevation ameliorated neuropathic pain through regulating Kcna2, which might offer a novel biomarker for the therapies of neuropathic pain.

Plant Polyphenols for Aging Health: Implication from Their Autophagy Modulating Properties in Age-Associated Diseases

Polyphenols are a family of naturally occurring organic compounds, majorly present in fruits, vegetables, and cereals, characterised by multiple phenol units, including flavonoids, tannic acid, and ellagitannin. Some well-known polyphenols include resveratrol, quercetin, curcumin, epigallocatechin gallate, catechin, hesperetin, cyanidin, procyanidin, caffeic acid, and genistein. They can modulate different pathways inside the host, thereby inducing various health benefits. Autophagy is a conserved process that maintains cellular homeostasis by clearing the damaged cellular components and balancing cellular survival and overall health. Polyphenols could maintain autophagic equilibrium, thereby providing various health benefits in mediating neuroprotection and exhibiting anticancer and antidiabetic properties. They could limit brain damage by dismantling misfolded proteins and dysfunctional mitochondria, thereby activating autophagy and eliciting neuroprotection. An anticarcinogenic mechanism is stimulated by modulating canonical and non-canonical signalling pathways. Polyphenols could also decrease insulin resistance and inhibit loss of pancreatic islet β-cell mass and function from inducing antidiabetic activity. Polyphenols are usually included in the diet and may not cause significant side effects that could be effectively used to prevent and treat major diseases and ailments.

Neuroprotective effect of l-theanine in a rat model of chronic constriction injury of sciatic nerve-induced neuropathic pain

BACKGROUND/PURPOSE

We investigated the protective efficacy of _l-theanine (LT), the major amino acid components of green tea, on chronic constriction injury (CCI) of sciatic nerve-induced neuropathic pain (NP) development and neuronal functional changes in rats.

METHODS

Rats with NP induced by CCI of the left sciatic nerve and sham-operated rats received LT or saline solution, with pain sensitive tests of thermal hyperalgesia and mechanical allodynia. Motor and sensory nerve conduction velocities were measured after surgery. Subsequently, the rats were sacrificed; the sciatic nerve was excised, homogenized, prepared and subjected for estimation of nitric oxide (NO), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), myeloperoxidase (MPO), and caspase-3.

RESULTS

CCI produced a significant increase in hyperalgesia and allodynia, an increase in SFI, a decrease in nerve conduction velocity, increases in NO, MDA, TNF-α, IL-1β, IL-6, MPO, and caspase-3 levels, as well as reduction of GSH, SOD, and CAT in the rat sciatic nerve. LT treatment significantly and dose-dependently alleviated CCI-induced nociceptive pain thresholds and ameliorated abnormal nerve conduction and functional loss in rats with CCI. Moreover, LT treatment reduced NO and MDA levels, increased antioxidative strength, and markedly suppressed the levels of neuroinflammatory and apoptotic markers in injured sciatic nerves.

CONCLUSION

This is the first report on the ameliorative effect of LT in CCI-induced NP in rats. This effect might be attributed to its anti-oxidative, anti-inflammatory, anti-apoptotic, and neuroprotective, thus making it potentially useful as an adjuvant to conventional treatment.

Eruca sativa Meal against Diabetic Neuropathic Pain: An H2S-Mediated Effect of Glucoerucin

The management of pain in patients affected by diabetic neuropathy still represents an unmet therapeutic need. Recent data highlighted the pain-relieving efficacy of glucosinolates deriving from Brassicaceae. The purpose of this study was to evaluate the anti-hyperalgesic efficacy of Eruca sativa defatted seed meal, along with its main glucosinolate, glucoerucin (GER), on diabetic neuropathic pain induced in mice by streptozotocin (STZ). The mechanism of action was also investigated. Hypersensitivity was assessed by paw pressure and cold plate tests after the acute administration of the compounds. Once bio-activated by myrosinase, both E. sativa defatted meal (1 g kg⁻¹ p.o.) and GER (100 µmol kg⁻¹ p.o., equimolar to meal content) showed a dose-dependent pain-relieving effect in STZ-diabetic mice, but the meal was more effective than the glucosinolate. The co-administration with H₂S scavengers abolished the pain relief mediated by both E. sativa meal and GER. Their effect was also prevented by selectively blocking Kv7 potassium channels. Repeated treatments with E. sativa meal did not induce tolerance to the anti-hypersensitive effect. In conclusion, E. sativa meal can be suggested as a new nutraceutical tool for pain relief in patients with diabetic neuropathy.

Ferulic acid dimer as a non-opioid therapeutic for acute pain

Purpose

Search for alternate pain medications has gained more importance in the past few years due to adverse effects associated with currently prescribed drugs including nervous system dysfunction with opioids, gastrointestinal discomfort with nonsteroidal anti-inflammatory drugs, and cardiovascular anomalies with cyclooxygenase-2 (COX-2) inhibitors. Phytomedicine has been explored for the treatment of pain, as these have been used for generations in regional communities and tend to lack major side effects in general. One such phytomedicine, incarvillateine (INCA), derived from the Chinese herb Incarvillea sinensis has its primary antinociceptive action through the adenosine receptor, a novel pain target. We hypothesized that derivatives of cinnamic acid dimers, which are structurally similar to INCA, would show potent antinociceptive action and that their effect would be mediated through adenosine receptor action.

Materials and methods

Dimers of cinnamic acid (INCA analogs) were synthesized using cavitand-mediated photodimerization (CMP) method, which utilizes a macromolecule (γ-cyclodextrin) to control excited state reactivity of photoactive compounds. Acute pain response was assessed by using formalin-induced licking behavior in hind paw of mice, and neurologic function was monitored through locomotor activity, mechanical hyperalgesia, and thermal sensitivity upon administration of test compound. For mechanistic studies, binding to adenosine receptor was determined by using computer modeling.

Results

Ferulic acid dimer (FAD), which has the same chemical functionalities on the aromatic ring as INCA, showed significant suppression of formalin-induced acute pain. Antinociceptive effect was observed primarily in the inflammatory phase, and no apparent behavioral changes related to the nervous system were noticeable. Inhibition of opioid receptor did not reverse antinociceptive response, and modeling data suggest adenosine 3 receptor binding.

Conclusion

FAD (INCA analog) shows potent nonopioid antinociceptive action mediated predominantly through A₃AR - adenosine 3 receptor action. Further characterization and selection of such INCA analogs will help us generate a new class of antinociceptives with precise chemical modifications by using CMP methodology.

The Neuroprotective Effects of Phenolic Acids: Molecular Mechanism of Action

The neuroprotective role of phenolic acids from food has previously been reported by many authors. In this review, the role of phenolic acids in ameliorating depression, ischemia/reperfusion injury, neuroinflammation, apoptosis, glutamate-induced toxicity, epilepsy, imbalance after traumatic brain injury, hyperinsulinemia-induced memory impairment, hearing and vision disturbances, Parkinson’s disease, Huntington’s disease, anti-amyotrophic lateral sclerosis, Chagas disease and other less distributed diseases is discussed. This review covers the in vitro, ex vivo and in vivo studies concerning the prevention and treatment of neurological disorders (on the biochemical and gene expression levels) by phenolic acids.