Low-dose acute vanillin is beneficial against harmaline-induced tremors in rats

Ameliorative effects of vanillin against pentylenetetrazole-induced epilepsy and associated memory loss in mice: The role of Nrf2/HO-1/NQO1 and HMGB1/RAGE/TLR4/NFκB pathways

BACKGROUND

Epilepsy is a severe neurological disorder associated with substantial morbidity and mortality. Vanillin (Van) is a natural phenolic aldehyde with beneficial pharmacological properties. This study investigated the neuroprotective effects of Van in epilepsy and elucidated its mechanism of action.

METHODS

Swiss albino mice were divided into the following five groups: "normal group", 0.9 % saline; "pentylenetetrazole (PTZ) group", intraperitoneal administration of 35 mg/kg PTZ on alternate days up to 42 days; and "PTZ + Van 20", "PTZ + Van 40", and "PTZ + sodium valproate (Val)" groups received PTZ injections in conjunction withVan 20 mg, Van 40 mg/kg, and Val 300 mg/kg, respectively. Behavioural tests and hippocampal histopathological analysis were performed in all groups. The Nrf2/HO-1/NQO1 and HMGB1/RAGE/TLR4/NFκB pathways, oxidative stress, neuro-inflammation, and apoptotic markers were analysed. Furthermore, brain acetylcholinesterase (AChE) activity and levels of dopamine (DA), gamma-aminobutyric acid GABA, and serotonin 5-HT were assessed.

RESULTS

Van prolonged seizure manifestations and improved electroencephalogram (EEG)criteriain conjunction with 100 mg/kg PTZ once daily. Van administration increased Nrf2/HO-1/NQO1 levels, with subsequent attenuation of malondialdehyde (MDA) and nitric oxide (NO) levels with elevated glutathione (GSH) levels and intensified superoxide dismutase (SOD) and catalase activities. Van reduced the gene and protein expression of HMGB1/RAGE/TLR4/NFκB and decreased the levels of inflammatory and apoptotic markers. In addition, Van reduced AChE activity, and elevated glial fibrillary acidic proteins (GFAP) increased neurotransmitter and brain-derived neurotrophic factors (BDNF).

CONCLUSION

By increasing Nrf2/HO-1/NQO1 levels and downregulating the HMGB1/RAGE/TLR4/ NFκB pathway, Van offered protection in PTZ-kindled mice with subsequent attenuation in lipid peroxidation, upregulation in antioxidant enzyme activities, and reduction in inflammation and apoptosis.

Evaluation of Potential Neuroprotective Effects of Vanillin Against MPP+/MPTP-Induced Dysregulation of Dopaminergic Regulatory Mechanisms in SH-SY5Y Cells and a Mouse Model of Parkinson's Disease

Parkinson's disease (PD) is a progressive neurodegenerative condition. The pathogenesis of PD is still unknown, and drugs available for PD treatment either have side effects or have suboptimal efficacy. Flavonoids are potent antioxidants having little toxicity with extended use, suggesting they might hold promising therapeutic potential against PD. Vanillin (Van) is a phenolic compound that has exhibited neuroprotective properties in various neurological disorders, including PD. However, the neuroprotective role of Van in PD and its underlying mechanisms are scarce and therefore need more exploration. Here, we evaluated the neuroprotective potential of Van and its associated mechanisms against MPP⁺/MPTP-induced neuronal loss in differentiated human neuroblastoma (SH-SY5Y) cells and the mouse model of PD. In the present study, Van treatment significantly enhanced the cell viability and alleviated oxidative stress, mitochondrial membrane potential, and apoptosis in MPP⁺-intoxicated SH-SY5Y cells. Moreover, Van significantly ameliorated the MPP⁺-induced dysregulations in protein expression of tyrosine hydroxylase (TH) and mRNA expressions of GSK-3β, PARP1, p53, Bcl-2, Bax, and Caspase-3 genes in SH-SY5Y cells. Similar to our in vitro results, Van significantly alleviated MPTP-induced neurobehavioral dysregulations, oxidative stress, aberrant TH protein expressions, and immunoreactivity in SNpc of mice brains. Treatment of Van also prevented MPTP-mediated loss of TH-positive intrinsic dopaminergic neurons to SNpc and TH-fibers projecting to the striatum of mice. Thus, Van exhibited promising neuroprotective properties in the current study against MPP⁺/MPTP-intoxicated SH-SY5Y cells and mice, indicating its potential therapeutic properties against PD pathology.

Ameliorative effect of vanillin on scopolamine-induced dementia-like cognitive impairment in a mouse model

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, which is among the top five causes of death in the United States. It is a neurodegenerative disorder that causes permanent loss of memory and cognition. The current pharmacotherapy for AD is based on providing symptomatic relief only and has many side effects. There is a need for a safer, disease-modifying drug for the treatment of AD.

EXPERIMENTAL APPROACH

The PASS online software was used to screen phytoconstituents based on their predicted effects on various AD-related targets. Vanillin was selected as the compound of interest, as it has not been researched elaborately on any animal model of AD. The acetylcholinesterase inhibitory activity of vanillin was established in vitro. Thereafter, ameliorative effect of vanillin was evaluated using the exteroceptive memory model in scopolamine-induced cognitive impairment mice model.

RESULTS

Vanillin showed an acetylcholinesterase inhibitory activity in vitro, and the IC50 value was calculated to be 0.033 mM. Vanillin significantly reversed the memory and behavioral deficits caused by scopolamine as demonstrated by significant improvement in memory in negative reinforcement, elevated plus maze, and spatial learning paradigms. Vanillin also proved to have a nootropic effect. Also, vanillin proved to have significantly better antioxidant and acetylcholinesterase inhibitory effects in vivo than donepezil hydrochloride. The potential anti-AD activity of vanillin was also confirmed by the reduction in IL-6 levels and TNF-α levels.

CONCLUSION

Our results suggest that vanillin is a safe and effective natural drug candidate having a great potential for the treatment of AD. However, more research is required to evaluate its effect on A beta plaques and Tau neurofibrillary tangles in vivo.

An Update on the Neurochemistry of Essential Tremor

Background:

The pathophysiology and neurochemical mechanisms of essential tremor (ET) are not fully understood, because only a few post-mortem studies have been reported, and there is a lack of good experimental model for this disease.

Objective:

The main aim of this review is to update data regarding the neurochemical features of ET. Alterations of certain catecholamine systems, the dopaminergic, serotonergic, GABAergic, noradrenergic, and adrenergic systems have been described, and are the object of this revision.

Methods:

For this purpose, we performed a literature review on alterations of the neurotransmitter or neuromodulator systems (catecholamines, gammaaminobutyric acid or GABA, excitatory amino acids, adenosine, T-type calcium channels) in ET patients (both post-mortem or in vivo) or in experimental models resembling ET.

Results and Conclusion:

The most consistent data regarding neurochemistry of ET are related with the GABAergic and glutamatergic systems, with a lesser contribution of adenosine and dopaminergic and adrenergic systems, while there is not enough evidence of a definite role of other neurotransmitter systems in ET. The improvement of harmaline-induced tremor in rodent models achieved with T-type calcium channel antagonists, cannabinoid 1 receptor, sphingosine-1-phosphate receptor agonists, and gap-junction blockers, suggests a potential role of these structures in the pathogenesis of ET.

Current and Future Neuropharmacological Options for the Treatment of Essential Tremor

BACKGROUND

Essential Tremor (ET) is likely the most frequent movement disorder. In this review, we have summarized the current pharmacological options for the treatment of this disorder and discussed several future options derived from drugs tested in experimental models of ET or from neuropathological data.

METHODS

A literature search was performed on the pharmacology of essential tremors using PubMed Database from 1966 to July 31, 2019.

RESULTS

To date, the beta-blocker propranolol and the antiepileptic drug primidone are the drugs that have shown higher efficacy in the treatment of ET. Other drugs tested in ET patients have shown different degrees of efficacy or have not been useful.

CONCLUSION

Injections of botulinum toxin A could be useful in the treatment of some patients with ET refractory to pharmacotherapy. According to recent neurochemical data, drugs acting on the extrasynaptic GABAA receptors, the glutamatergic system or LINGO-1 could be interesting therapeutic options in the future.

Elucidation of The Anti-Inflammatory Effect of Vanillin In Lps-Activated THP-1 Cells

Vanillin, a kind of phenolic compound, is naturally found in food and beverage and widely used as a flavoring agent. In view of the safety and universality of vanillin, exploring the functions of vanillin on human is of great value. Thus, lipopolysaccharide (LPS)-activated THP-1 cells were selected as the cell model to evaluate the anti-inflammatory effect of vanillin in this study. On the basis of the results, vanillin markedly suppressed the expression of inflammatory cytokines (that is, TNF-α, IL-1β, IL-6, and IL-8), mediators (NO, iNOS, PGE2, and COX-2), and NLRP3 inflammasome (that is, NLRP3, ASC, and caspase-1), blocked the LPS-induced activation of the NF-κB/IκBα/AP-1 signaling pathway, and activated the gene expression of the Nrf2/HO-1 signaling pathway. In addition, it was confirmed that vanillin was unable to react with LPS due to the results of quantification by HS-SPME-GC-MS. Hence, vanillin could effectively attenuate LPS-induced inflammatory response by regulating the expression of intracellular signaling pathways in THP-1 cells. It is a potent anti-inflammatory component found in food and beverage. These findings might contribute to the overall understanding of the potential health benefits of vanillin for food application. PRACTICAL APPLICATION: In this study, the anti-inflammatory effect of vanillin (VA) was evaluated by ELISA, real-time PCR, and western blot in LPS-induced THP-1 cells. The hypothesis that VA could react with LPS was excluded due to the results of quantification by HS-SPME-GC-MS. On the basis of the result, vanillin could effectively attenuate LPS-induced inflammatory response in THP-1 cells and was a potent anti-inflammatory component natural in food and beverage. These findings might contribute to the overall understanding of the potential health benefits of vanillin for food application.

Intracellular antioxidant effect of vanillin, 4-methylguaiacol and 4-ethylguaiacol: three components in Chinese Baijiu

Vanillin, 4-methylguaiacol, and 4-ethylguaiacol can improve AAPH-induced alterations in oxidative stress biomarkers and antioxidant enzymes in HepG2 cells.