Neuroprotective Effects of Methyl 3,4-Dihydroxybenzoate against TBHP-Induced Oxidative Damage in SH-SY5Y Cells

Differential eco-toxicological responses toward Eisenia fetida exposed to soil contaminated with naphthalene and typical metabolites

Naphthalene (NAP) was frequently detected in polycyclic aromatic hydrocarbons (PAHs)-contaminated soil, and its residues may pose an eco-toxicological threat to soil organisms. The toxic effects of NAP were closely tied to phenolic and quinone metabolites in biological metabolism. However, the present knowledge concerning the eco-toxicological impacts of NAP metabolites at the animal level is scanty. Here, we assessed the differences in the eco-toxicological responses of Eisenia fetida (E. fetida) in NAP, 1-naphthol (1-NAO) or 1,4-naphthoquinone (1,4-NQ) contaminated soils. NAP, 1-NAO, and 1,4-NQ exposure triggered the onset of oxidative stress as evidenced by the destruction of the antioxidant enzyme system. The lipid peroxidation and DNA oxidative damage levels induced by 1-NAO and 1,4-NQ were higher than those of NAP. The elevation of DNA damage varied considerably depending on differences in oxidative stress and the direct mode of action of NAP or its metabolites with DNA. All three toxicants induced different degrees of physiological damage to the body wall, but only 1, 4-NQ caused the shedding of intestinal epithelial cells. The integrated biomarker response for different exposure times illustrated that the comprehensive toxicity at the animal level was 1,4-NQ > 1-NAO > NAP, and the time-dependent trends of oxidative stress responses induced by the three toxicants were similar. At the initial stage, the antioxidant system of E. fetida responded positively to the provocation, but the ability of E. fetida to resist stimulation decreased with the prolongation of time resulting in provocation oxidative damage. This study would provide new insights into the toxicological effects and biohazard of PAHs on soil animals.

Methyl 3,4-dihydroxybenzoate alleviates oxidative damage in granulosa cells by activating Nrf2 antioxidant pathway

Oxidative damage induced granulosa cells (GCs) apoptosis was considered as a significant cause of compromised follicle quality, antioxidants therapy has emerged as a potential method for improving endometriosis pregnancy outcomes. Here, we found that GCs from endometriosis patients show increased oxidative stress level. Methyl 3,4-dihydroxybenzoate (MDHB), a small molecule compound that is extracted from natural plants, reversed tert-butyl hydroperoxide (TBHP) induced GCs oxidative damage. Therefore, the aim of this study was to assess the protective effect of MDHB for GCs and its potential mechanisms. TUNEL staining and immunoblotting of cleaved caspase-3/7/9 showed MDHB attenuated TBHP induced GCs apoptosis. Mechanistically, MDHB treatment decreased cellular and mitochondria ROS production, improved the mitochondrial function by rescuing the mitochondrial membrane potential (MMP) and ATP production. Meanwhile, MDHB protein upregulated the expression of vital antioxidant transcriptional factor Nrf2 and antioxidant enzymes SOD1, NQO1 and GCLC to inhibited oxidative stress state, further beneficial to oocytes and embryos quality. Therefore, MDHB may represent a potential drug candidate in protecting granulosa cells in endometriosis, which can improve pregnancy outcomes for endometriosis-associated infertility.

Effects of small molecules on neurogenesis: Neuronal proliferation and differentiation

Neurons are believed to be non-proliferating cells. However, neuronal stem cells are still present in certain areas of the adult brain, although their proliferation diminishes with age. Just as with other cells, their proliferation and differentiation are modulated by various mechanisms. These mechanisms are foundational to the strategies developed to induce neuronal proliferation and differentiation, with potential therapeutic applications for neurodegenerative diseases. The most common among these diseases are Parkinson's disease and Alzheimer's disease, associated with the formation of β -amyloid (Aβ ) aggregates which cause a reduction in the number of neurons. Compounds such as LiCl, 4-aminothiazoles, Pregnenolone, ACEA, harmine, D2AAK1, methyl 3,4-dihydroxybenzoate, and shikonin may induce neuronal proliferation/differentiation through the activation of pathways: MAPK ERK, PI3K/AKT, NFκ B, Wnt, BDNF, and NPAS3. Moreover, combinations of these compounds can potentially transform somatic cells into neurons. This transformation process involves the activation of neuron-specific transcription factors such as NEUROD1, NGN2, ASCL1, and SOX2, which subsequently leads to the transcription of downstream genes, culminating in the transformation of somatic cells into neurons. Neurodegenerative diseases are not the only conditions where inducing neuronal proliferation could be beneficial. Consequently, the impact of pro-proliferative compounds on neurons has also been researched in mouse models of Alzheimer's disease.

Gamma-mangostin Protects S16Y Schwann Cells Against tert-Butyl Hydroperoxide-induced Apoptotic Cell Death

BACKGROUND

Peripheral neuropathy is a common complication that affects individuals with diabetes. Its development involves an excessive presence of oxidative stress, which leads to cellular damage in various tissues. Schwann cells, which are vital for peripheral nerve conduction, are particularly susceptible to oxidative damage, resulting in cell death.

MATERIALS AND METHODS

Gamma-mangostin (γ-mangostin), a xanthone derived from Garcinia mangostana, possesses cytoprotective properties in various pathological conditions. In this study, we employed S16Y cells as a representative Schwann cell model to investigate the protective effects of γ-mangostin against the toxicity induced by tert-Butyl hydroperoxide (tBHP). Different concentrations of γ-mangostin and tBHP were used to determine non-toxic doses of γ-mangostin and toxic doses of tBHP for subsequent experiments. MTT cell viability assays, cell flow cytometry, and western blot analysis were used for evaluating the protective effects of γ-mangostin.

RESULTS

The results indicated that tBHP (50 μM) significantly reduced S16Y cell viability and induced apoptotic cell death by upregulating cleaved caspase-3 and cleaved PARP protein levels and reducing the Bcl- XL/Bax ratio. Notably, pretreatment with γ-mangostin (2.5 μM) significantly mitigated the decrease in cell viability caused by tBHP treatment. Furthermore, γ-mangostin effectively reduced cellular apoptosis induced by tBHP. Lastly, γ-mangostin significantly reverted tBHP-mediated caspase-3 and PARP cleavage and increased the Bcl-XL/Bax ratio.

CONCLUSION

Collectively, these findings highlight the ability of γ-mangostin to protect Schwann cells from apoptotic cell death induced by oxidative stress.

Methyl 3,4-dihydroxybenzoate inhibits RANKL-induced osteoclastogenesis via Nrf2 signaling in vitro and suppresses LPS-induced osteolysis and ovariectomy-induced osteoporosis in vivo

Osteoporosis deteriorates bone mass and biomechanical strength and is life-threatening to the elderly. In this study, we show that methyl 3,4-dihydroxybenzoate (MDHB), an antioxidant small-molecule compound extracted from natural plants, inhibits receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclastogenesis in vitro. Furthermore, MDHB attenuates the activation of mitogen-activated protein kinase (MAPK) and NF-κB pathways by reducing the levels of reactive oxygen species (ROS), which leads to downregulated protein expression of c-Fos and nuclear factor of activated T cells c1 (NFATc1). We also confirm that MDHB upregulates the protein expression of nuclear factor-erythroid 2-related factor 2 (Nrf2), an important transcription factor involved in ROS regulation, by inhibiting the ubiquitination-mediated proteasomal degradation of Nrf2. Next, animal experiments show that MDHB has an effective therapeutic effect on lipopolysaccharide (LPS)- and ovariectomized (OVX)-induced bone loss in mice. Our study demonstrates that MDHB can upregulate Nrf2 and suppress excessive osteoclast activity in mice to treat osteoporosis.

Ethnomedical, phytochemical and pharmacological insights on an Indian medicinal plant: The balloon vine (Cardiospermum halicacabum Linn.)

ETHNOPHARMACOLOGICAL RELEVANCE

Cardiospermum halicacabum Linn. (C. halicacabum) is one of the well-known leafy green vegetables in India. It is an herbaceous climber from the Sapindaceae family which is found in almost every Continent and Oceania. In the traditional Indian medicine systems, this plant is used for the treatment of rheumatism, abdominal pain, orchitis, dropsy, lumbago, skin diseases, cough, nervous disorders, and hyperthermia.

AIM OF THE REVIEW

This review presents the current information about ethnomedical uses and progress on geographical distribution, pharmacological activities, phytochemistry, micropropagation, and toxicity of C. halicacabum. Also, critically summarizes the relationship between the reported pharmacological activities and the traditional usages along with the future perspectives for research on this medicinal plant.

MATERIALS AND METHODS

The data on C. halicacabum were collected using multiple internet sources such as Google Scholar, Science Direct, Taylor & Francis, PubMed, Web of Science, Springer Link, Wiley online, and plant databases.

RESULTS

Chemical characterization using LC-MS/MS, HPLC, and NMR exposed the presence of chlorogenic acid, caffeic acid, coumaric acid, luteolin-7-o-glucuronide, apigenin-7-o-glucuronide, and chrysoeriol in different parts of C. halicacabum. Based on the outcomes of this review, the main bioactive compounds found in C. halicacabum include phenols, phenolic acids, flavonoids, flavonoid glycosides, and flavonoid glucuronides. Besides the above-mentioned constituents, palmitic acid, oleic acid, stearic acid, linolenic acid, eicosenoic acid, and arachidic acid are the compounds that constitute the fatty acid profile of C. halicacabum seeds. Specifically, Cardiospermin, a bioactive compound isolated from the root extract of C. halicacabum has been recognized for its anxiolytic activity. Moreover, C. halicacabum showed a broad spectrum of pharmacological activities including anti-inflammatory, anti-arthritic, anti-diabetic, anxiolytic activity, antiulcer, apoptotic activity, antibacterial, antiviral, anti-diarrheal, antioxidant, hepatoprotective, and nephroprotective properties. However, the bioactive compounds responsible for most of the above therapeutic properties have not been elucidated till now.

CONCLUSION

Phytochemicals from C. halicacabum showed noticeable pharmacological effects against plethora of health disorders. Some of the traditional applications were supported by modern scientific studies, however, more pharmacological evaluations should be conducted to validate other traditional uses of C. halicacabum. Despite C. halicacabum's vast pharmacological activity, additional human clinical trials are needed to determine the potent and safe dosages for the treatment of various health abnormalities. Besides, bioassay-guided isolation of active constituents, pharmacokinetic evaluations and identification of their mode of action are recommended for future investigations on C. halicacabum to unveil its therapeutic drug leads. Overall, this review suggests that C. halicacabum could be a new source of functional foods.

Oxidative stress-induced RAC autophagy can improve the HUVEC functions by releasing exosomes

Retinal neovascularization (RNV) is a common pathological feature in many kinds of fundus oculi diseases. Sometimes RNV can even lead to severe vision loss. Oxidative injury is one of the main predisposing factors for RNV occurrence and development. The specific mechanism may be closely related to the special structural tissues of the retina. Retinal astrocytes (RACs) are mesenchymal cells located in the retinal neuroepithelial layer. RACs have an intimate anatomical relationship with microvascular endothelial cells. They have a variety of functions, but little is known about the mechanisms by which RACs regulate the function of endothelial cells. The molecules secreted by RACs, such as exosomes, have recently received a lot of attention and may provide potential clues to address the RAC‐mediated modulation of endothelial cells. In this study, we aimed to preliminarily explore the mechanisms of how RAC exosomes generated under oxidative stress are involved in the regulation of endothelial function. Our results showed that the apoptosis and autophagy levels in RACs were positively correlated with the oxidative stress level, and the exosomes generated from RACs under normal and oxidative stress conditions had different effects on the proliferation and migration of endothelial cells. However, the effect of RACs on endothelial cell function could be markedly reversed by the autophagy inhibitor 3‐methyladenine or the exosome inhibitor GW4869. Therefore, oxidative stress can lead to increased autophagy in RACs and can further promote RACs to regulate endothelial cell function by releasing exosomes.

1.

tBHP‐induced oxidative stress can increase the level of autophagy in retinal (RAC) astrocytes.

2.

RAC with high‐autophagy level has a completely opposite effect on HUVEC functions when compared with normal RAC.

3.

RACs under different states have different effects on endothelial cell functions by releasing exosomes

Excretion, Metabolism and Cytochrome P450 Inhibition of Methyl 3,4-Dihydroxybenzoate (MDHB): A Potential Candidate to Treat Neurodegenerative Diseases

BACKGROUND AND OBJECTIVES

Methyl 3,4-dihydroxybenzoate (MDHB) has the potential to prevent neurodegenerative diseases (NDDs). The present work investigated its excretion, metabolism, and cytochrome P450-based drug-drug interactions (DDIs).

METHODS

After intragastric administration of MDHB, the parent drug was assayed in the urine and faeces of mice. Metabolites of MDHB in the urine, faeces, brain, plasma and liver were detected by liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). A cocktail approach was used to evaluate the inhibition of cytochrome P450 isoforms by MDHB.

RESULTS

The cumulative excretion permille of MDHB in the urine and faeces were found to be 0.67 ± 0.31 and 0.49 ± 0.44‰, respectively. A total of 96 metabolites of MDHB were identified, and all IC₅₀ (half-maximal inhibitory concentration) values of MDHB towards cytochrome P450 isoforms were > 100 μM.

CONCLUSIONS

The results suggest that MDHB has a low parent drug cumulative excretion percentage and that MDHB has multiple metabolites and is mainly metabolized through the loss of -CH₂ and -CO₂, the loss of -CH₂O, ester bond hydrolysis, the loss of -O and -CO₂, isomerization, methylation, sulfate conjugation, the loss of -CH₂O and -O and glycine conjugation, glycine conjugation, the loss of two -O groups and alanine conjugation, the loss of -CH₂O and -O and glucose conjugation, glucuronidation, glucose conjugation, etc., in vivo. Finally, MDHB has a low probability of cytochrome P450-based DDIs.

Methyl 3,4-dihydroxybenzoate protects against d-galN/LPS-induced acute liver injury by inhibiting inflammation and apoptosis in mice

Objectives

Aimed to investigate the effect and mechanism of methyl 3,4-dihydroxybenzoate (MDHB) on d-galactosamine/lipopolysaccharide (d-galN/LPS)-induced acute liver failure (ALF).

Methods

Confirmed the hepatoprotective effect and hepatotoxicity of MDHB by histopathological examination (HE) and examination of alanine aminotransferase (ALT) and aspartate aminotransferase (AST); the expression of serum tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6) was detected by ELISA; transcription levels of TNF-α, IL-1β, IL-6 and Toll-like receptor 4 (TLR4) were detected by qRT-PCR; and phosphorylation levels of p38 and p65 were analysed by Western blot.

Results

Histopathological examination and examination of ALT and AST confirmed that MDHB is a low toxicity drug that can resist d-galN/LPS-induced ALF; MDHB can effectively reduce high transcription and expression of TNF-α, IL-1β, IL-6 and TLR4 in d-galN/LPS-induced ALF; and Western blot showed that MDHB could down-regulate the expression of bax, up-regulate the expression of bcl-xl and bcl-2, and inhibit the phosphorylation of p38 and p65.

Conclusions

Methyl 3,4-dihydroxybenzoate can effectively resist d-galN/LPS-induced acute liver failure, which is related to the inhibition of inflammation and apoptosis.

Methyl 3,4-dihydroxybenzoate protects retina in a mouse model of acute ocular hypertension through multiple pathways

Methyl 3,4 dihydroxybenzoate (MDHB) is a small molecule that shows neuroprotective effects in vitro and in a photoreceptor-degenerative mouse model. Here we investigated whether MDHB protects retina in a mouse model of acute ocular hypertension (AOH) and explores the underlying mechanisms. AOH was induced in mice by increasing intraocular pressure to approximately 90 mmHg for 60 min, then MDHB or vehicle was intraperitoneally injected daily up to 7 days. Immunostaining and multi-electrode array recordings were performed to examine the structure and function of retinas receiving the treatments. Western-blotting was applied to test the expression of several proteins related to oxidative stress and brain-derived neurotrophic factor (BDNF)-initiated signaling. Results showed that AOH injury reduced the number of Brn3a-stained retinal ganglion cells (RGCs) and ChAT-amacrine cells; thinned the inner retinal layers and induced apoptosis. Physiologically, AOH decreased the response of OFF and ON-OFF RGCs. All of these changes were reversed by MDHB-treatment. Mechanistically, MDHB appeared to work on three parallel pathways: (1) MDHB decreased the production of reactive oxygen species, the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and cytosol heme oxygenase 1 (HO-1); (2) It upregulated the expression of BDNF and its receptor tropomyosin-related kinase B (TrkB), and activated the downstream AKT pathways; (3) It inhibited reactive gliosis by reducing GFAP and Iba-1 expression. Thus our results suggest that MDHB protects retina against AOH injury by inhibiting oxidative stress, activating the BDNF/AKT signaling and inhibiting inflammatory pathways. Therefore, MDHB may serve as a promising candidate to treat retinal ischemia.

Neuroprotective effects of chloroform and aqueous fractions of noni juice against t-Butyl hydroperoxide-induced oxidative damage in SH-SY5Y cells

Oxidative stress is more likely to cause damage to neuronal cells and mediates some neurodegenerative disorders. It is well known that natural antioxidants can prevent oxidative stress damage and become a potential therapeutic strategy. Noni juice obtained from the fruit of the tree Morinda citrifolia, as a folk medicine, has been used for over two thousand years. In the current study, the neuroprotective effect and mechanism of noni juice extracts against tert-Butyl hydroperoxide (TBHP)-induced SH-SY5Y cell damage were investigated. The results demonstrated that chloroform fraction (CF) and aqueous fraction (AF) of noni juice protected SH-SY5Y cells against TBHP-induced oxidative stress and the associated apoptosis effectively. CF and AF treatment significantly weakened the TBHP-induced cytotoxicity, reactive oxygen species generation, mitochondrial membrane depolarization, and apoptotic features. CF and AF restored cellular antioxidant enzyme activity; upregulated expression of heme oxygenase-1, catalase, and superoxide dismutase-1; and increased the nuclear accumulation of nuclear factor-erythroid 2 related factor 2 (Nrf2). The antioxidant and neuroprotection potential of CF may account for its high total phenolic and flavonoid content, while AF may be rich in polysaccharides. These results suggest that CF and AF exhibit antioxidant defense through the upregulation of Nrf2 along with endogenous antioxidants and reduce apoptosis via inhibiting the mitochondrial pathway to protect SH-SY5Y cells damaged by TBHP. CF and AF might be developed as agents for neurodegeneration prevention or therapy.

Methyl 3,4-Dihydroxybenzoate Induces Neural Stem Cells to Differentiate Into Cholinergic Neurons in vitro

Neural stem cells (NSCs) have been shown as a potential source for replacing degenerated neurons in neurodegenerative diseases. However, the therapeutic potential of these cells is limited by the lack of effective methodologies for controlling their differentiation. Inducing endogenous pools of NSCs by small molecule can be considered as a potential approach of generating the desired cell types in large numbers. Here, we reported the characterization of a small molecule (Methyl 3,4-dihydroxybenzoate; MDHB) that selectively induces hippocampal NSCs to differentiate into cholinergic motor neurons which expressed synapsin 1 (SYN1) and postsynaptic density protein 95 (PSD-95). Studies on the mechanisms revealed that MDHB induced the hippocampal NSCs differentiation into cholinergic motor neurons by inhibiting AKT phosphorylation and activating autophosphorylation of GSK3β at tyrosine 216. Furthermore, we found that MDHB enhanced β-catenin degradation and abolished its entering into the nucleus. Collectively, this report provides the strong evidence that MDHB promotes NSCs differentiation into cholinergic motor neurons by enhancing gene Isl1 expression and inhibiting cell cycle progression. It may provide a basis for pharmacological effects of MDHB directed on NSCs.

Determination of the Pharmacokinetics and Tissue Distribution of Methyl 3,4-Dihydroxybenzoate (MDHB) in Mice Using Liquid Chromatography-Tandem Mass Spectrometry

BACKGROUND AND OBJECTIVES

Methyl 3,4-dihydroxybenzoate (MDHB) has the potential to prevent neurodegenerative diseases (NDDs). The present work aims to reveal the pharmacokinetics and tissue distribution characteristics of MDHB.

METHODS

The pharmacokinetics and tissue distribution of MDHB were analyzed using LC-MS/MS after a single intragastric administration (50 to 450 mg/kg) in mice, and samples were collected from five animals at specific time points.

RESULTS

Pharmacokinetic parameters of MDHB following intragastric administrations were: the time to peak concentration (T_max) ranged from 0.033 to 0.07 h, the peak concentration (C_max) ranged from 12,379.158 to 109798.712 μg/l, the elimination half-life (t_1/2z) ranged from 0.153 to 1.291 h, the area under the curve (AUC_0-∞) ranged from 640.654 to 20,241.081 μg/l × h, the mean residence time (MRT_0-∞) ranged from 0.071 to 0.206 h, the apparent volume of distribution (V_z/F) ranged from 17.538 to 45.244 l/kg, and the systemic clearance (Cl_z/F) ranged from 22.541 to 80.807 l/h/kg. The oral bioavailability of MDHB was 23%. The maximum MDHB content was detected in the stomach, and the minimum content was observed in the testes; the peak content in the brain was 15,666.93 ng/g.

CONCLUSIONS

The pharmacokinetic characteristics of MDHB include fast absorption, high systemic clearance, a short half-life and an oral bioavailability of 23%. Additionally, MDHB permeates the blood-brain barrier (BBB) and is rapidly distributed to all organs. The identification of the pharmacokinetics of MDHB following its oral administration will contribute to further preclinical and clinical studies of its effects.

Methyl 3,4-Dihydroxybenzoate Enhances Resistance to Oxidative Stressors and Lifespan in C. elegans Partially via daf-2/daf-16

Genetic studies have elucidated mechanisms that regulate aging; however, there has been little progress in identifying drugs that retard ageing. Caenorhabditis elegans is among the classical model organisms in ageing research. Methyl 3,4-dihydroxybenzoate (MDHB) can prolong the life-span of C. elegans, but the underlying molecular mechanisms are not yet fully understood. Here, we report that MDHB prolongs the life-span of C. elegans and delays age-associated declines of physiological processes. Besides, MDHB can lengthen the life-span of eat-2 (ad1113) mutations, revealing that MDHB does not work via caloric restriction (CR). Surprisingly, the life-span–extending activity of MDHB is completely abolished in daf-2 (e1370) mutations, which suggests that daf-2 is crucial for a MDHB-induced pro-longevity effect in C. elegans. Moreover, MDHB enhances the nuclear localization of daf-16/FoxO, and then modulates the expressions of genes that positively correlate with defenses against stress and longevity in C. elegans. Therefore, our results indicate that MDHB at least partially acts as a modulator of the daf-2/daf-16 pathway to extend the lifespan of C. elegans, and MDHB might be a promising therapeutic agent for age-related diseases.