(7R,8S)-Dehydrodiconiferyl Alcohol Suppresses Lipopolysaccharide-Induced Inflammatory Responses in BV2 Microglia by Inhibiting MAPK Signaling

New benzofuran neolignans with neuroprotective activity from Phyllanthodendron breynioides

A pair of undescribed dihydrobenzofuran neolignan enantiomers, (+/-)-phybrenan A (1a/1b), two new benzofuran neolignans, phybrenan B and C (2 and 3), along with four known neolignans (4 - 7) were obtained from the plants of Phyllanthodendron breynioides P. T. Li. The planar structures of all isolates were demonstrated by the analysis of detailed spectroscopic evidence (NMR, HRMS, and IR), and the absolute configurations of novel neolignans were elucidated by combined calculated and experimental ECD data analysis. The neuroprotective activities of all benzofuran neolignans against sodium nitroprusside (SNP)-induced cell death were examined in rat pheochromocytoma PC12 cells. The results exhibited that three compounds (4 - 6) possessed remarkable neuroprotective activities at 10 µM, better than the positive drug edaravone.

Exploration of the mechanism of luteolin against ischemic stroke based on network pharmacology, molecular docking and experimental verification

Stroke is a leading cause of morbidity and mortality worldwide. As the most common type of stroke cases, treatment effectiveness is still limited despite intensive research. Recently, traditional Chinese medicine has attracted attention because of potential benefits for stroke treatment. Among these, luteolin, a natural plant flavonoid compound, offers neuroprotection following against ischemic stroke, although the specific mechanisms are unknown. Here we used network pharmacology, molecular docking, and experimental verification to explore the mechanisms whereby luteolin can benefit stroke recovery. The pharmacological and molecular properties of luteolin were obtained from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform. The potential targets of luteolin and ischemic stroke were collected from interrogating public databases. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed by Funrich and Database for Annotation, Visualization and Integrated Discovery respectively, a luteolin-target-pathway network constructed using Cytoscape, Autodock vina was used for molecular docking simulation with Discovery Studio was used to visualize and analyze the docked conformations. Lastly, we employed an in vitro model of stroke injury to evaluate the effects of luteolin on cell survival and expression of the putative targets. From 95 candidate luteolin target genes, our analysis identified six core targets . KEGG analysis of the candidate targets identified that luteolin provides therapeutic effects on stroke through TNF signaling and other pathways. Our experimental analyses confirmed the conclusions analyzed above. In summary, the molecular and pharmacological mechanisms of luteolin against stroke are indicated in our study from a systematic perspective.

Network Pharmacology-Based and Molecular Docking-Based Analysis of Suanzaoren Decoction for the Treatment of Parkinson's Disease with Sleep Disorder

This study is aimed at exploring the possible mechanism of action of the Suanzaoren decoction (SZRD) in the treatment of Parkinson's disease with sleep disorder (PDSD) based on network pharmacology and molecular docking. Traditional Chinese Medicine Systems Pharmacology (TCMSP) was used to screen the bioactive components and targets of SZRD, and their targets were standardized using the UniProt platform. The disease targets of “Parkinson's disease (PD)” and “Sleep disorder (SD)” were collected by OMIM, GeneCards, and DisGeNET databases. Thereafter, the protein-protein interaction (PPI) network was constructed using the STRING platform and visualized by Cytoscape (3.7.2) software. Then, the DAVID platform was used to analyze the Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. Cytoscape (3.7.2) software was also used to construct the network of the “herb-component-target-pathway.” The core active ingredients and core action targets of the drug were verified by molecular docking using AutoDock software. A total of 135 Chinese herbal components and 41 corresponding targets were predicted for the treatment of PDSD using SZRD. Fifteen important signaling pathways were screened, such as the cancer pathway, TNF signaling pathway, PI3K-AKT signaling pathway, HIF-1 signaling pathway, and Toll-like receptor signaling pathway. The results of molecular docking showed that the main active compounds could bind to the representative targets and exhibit good affinity. This study revealed that SZRD has the characteristics and advantages of “multicomponent, multitarget, and multipathway” in the treatment of PDSD; among these, the combination of the main active components of quercetin and kaempferol with the key targets of AKT1, IL6, MAPK1, TP53, and VEGFA may be one of the important mechanisms. This study provides a theoretical basis for further study of the material basis and molecular mechanism of SZRD in the treatment of PDSD.

Inhibitory Effects of Myricetin on Lipopolysaccharide-Induced Neuroinflammation

Microglial activation elicits an immune response by producing proinflammatory modulators and cytokines that cause neurodegeneration. Therefore, a plausible strategy to prevent neurodegeneration is to inhibit neuroinflammation caused by microglial activation. Myricetin, a natural flavanol, induces neuroprotective effects by inhibiting inflammation and oxidative stress. However, whether myricetin inhibits lipopolysaccharide (LPS)-induced neuroinflammation in hippocampus and cortex regions is not known. To test this, we examined the effects of myricetin on LPS-induced neuroinflammation in a microglial BV2 cell line. We found that myricetin significantly downregulated several markers of the neuroinflammatory response in LPS-induced activated microglia, including inducible nitric oxide (NO) synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory modulators and cytokines such as prostaglandin E2 (PGE₂), interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α). Moreover, myricetin suppressed the expression of c-Jun NH2-terminal kinase (JNK), p38 MAPK, and extracellular signal-regulated kinase (ERK), which are components of the mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, myricetin inhibited LPS-induced macrophages and microglial activation in the hippocampus and cortex of mice. Based on our results, we suggest that myricetin inhibits neuroinflammation in BV2 microglia by inhibiting the MAPK signaling pathway and the production of proinflammatory modulators and cytokines. Therefore, this could potentially be used for the treatment of neuroinflammatory diseases.

Discovery and evaluation of novel synthetic 5-alkyl-4-oxo-4,5-dihydro-[1,2,4]triazolo[4,3-a]quinoxaline-1-carbox-amide derivatives as anti-inflammatory agents

To develop novel anti-inflammatory agents, a series of 5-alkyl-4-oxo-4,5-dihydro-[1, 2, 4]triazolo[4,3-a]quinoxaline-1-carboxamide derivatives were designed, synthesised, and evaluated for anti-inflammatory effects using RAW264.7 cells. Structures of the synthesised compounds were determined using ¹H NMR, ¹³C NMR, and HRMS. All the compounds were screened for anti-inflammatory activity based on their inhibitory effects against LPS-induced NO release. Among them, 5-(3,4,5-trimethoxybenzyl)-4-oxo-4,5-dihydro-[1, 2, 4]triazolo[4,3-a]quinoxaline-1-carboxamide (6p) showed the highest anti-inflammatory activity and inhibited NO release more potently than the lead compound D1. Further studies revealed that compound 6p reduced the levels of NO, TNF-α, and IL-6, and that its anti-inflammatory activity involves the inhibition of COX-2 and iNOS and downregulation of the mitogen-activated protein kinases (MAPK) signal pathway. Notably, compound 6p displayed more prominent anti-inflammatory activity than D1 and the positive control ibuprofen in the in vivo acute inflammatory model. Overall, these findings indicate that compound 6p is a therapeutic candidate for the treatment of inflammation.

Lignans and Neolignans: Plant secondary metabolites as a reservoir of biologically active substances

Lignans and neolignans are plant secondary metabolites derived from the oxidative coupling of phenylpropanoids. Biological activity of these phenolic compounds ranges from antioxidant, antitumor (terminaloside P, IC₅₀ = 10 nM), anti-inflammatory, anti-neurodegenerative (schibitubin B, IC₅₀ = 3.2 nM) and antiviral (patentiflorin A, IC₅₀ = 14-23 nM) to antimicrobial. In addition, it was observed that several members of this group, namely enterolactone and its biochemical precursors also known as phytoestrogens, possess important protective properties. Most of these lignans and neolignans are presented in reasonable amounts in one's diet and thus the protection they provide against the colon and breast cancer, to name a few, is even more important to note. Similarly, neuroprotective properties were observed (schisanwilsonin G, IC₅₀ = 3.2 nM) These structural motives also serve as an important starting point in the development of anticancer drugs. Presumably the most famous members of this family, etoposide and teniposide, synthetic derivatives of podophyllotoxin, are used in the clinical treatment of lymphocytic leukemia, certain brain tumors, and lung tumors already for nearly 20 years. This review describes 413 lignans and neolignans which have been isolated between 2016 and mid-2018 being reported in more than 300 peer-reviewed articles. It covers their source, structure elucidation, and bioactivity. Within the review, the structure-based overview of compounds as well as the bioactivity-based overview of compounds are described.

GABAB receptor activation attenuates inflammatory orofacial pain by modulating interleukin-1β in satellite glial cells: Role of NF-κB and MAPK signaling pathways

Orofacial inflammation could activate satellite glial cells (SGCs) in the trigeminal ganglion (TG) to produce interleukin 1β (IL-1β) which plays crucial roles in the development of inflammatory pain. Recent studies have shown that gamma-amino butyric acid-B (GABA_B) receptor could modulate the expression of inflammatory cytokines in microglia and astrocytes in the spinal cord. The objective of this study was to investigate whether GABA_B receptors in TG SGCs attenuate inflammatory facial pain via mediating IL-1β following inflammation and its mechanisms. Complete Freund's adjuvant (CFA) was injected into the whisker pad of rats to induce inflammation in vivo. Lipopolysaccharide (LPS) was added to culture medium to activate SGCs in vitro. Behavioral measures showed that microinjection of baclofen (a selective GABA_B receptor agonist) into the TG ameliorated the mechanical allodynia of CFA-treated rats. Interestingly, baclofen pretreatment inhibited SGC activation and IL-1β production, however, preserved the decreased expression of GABA_B receptors in SGCs activated by CFA in vivo and LPS in vitro. In addition, baclofen suppressed the increased expression of p-NF- κ B p65, p-I κ Bα, and p-p38 MAPK, while reversed the decreased production of I κ Bα, and further enhanced the increased expression of p-ERK(1/2) in LPS-treated SGCs in vitro. Finally, those effects of baclofen were abolished by saclofen (a specific GABA_B receptor antagonist) co-administration. Altogether, these results demonstrated for the first time that activation of GABA_B receptor might inhibit IL-1β production by suppressing NF- κ B and p38 MAPK signaling pathway activation and restore GABA_B receptor expression in SGCs to attenuate inflammatory facial pain.

Synthetic 3',4'-Dihydroxyflavone Exerts Anti-Neuroinflammatory Effects in BV2 Microglia and a Mouse Model

Neuroinflammation is an immune response within the central nervous system against various proinflammatory stimuli. Abnormal activation of this response contributes to neurodegenerative diseases such as Parkinson disease, Alzheimer’s disease, and Huntington disease. Therefore, pharmacologic modulation of abnormal neuroinflammation is thought to be a promising approach to amelioration of neurodegenerative diseases. In this study, we evaluated the synthetic flavone derivative 3′,4′-dihydroxyflavone, investigating its anti-neuroinflammatory activity in BV2 microglial cells and in a mouse model. In BV2 microglial cells, 3′,4′-dihydroxyflavone successfully inhibited production of chemokines such as nitric oxide and prostaglandin E₂ and proinflammatory cytokines such as tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 in BV2 microglia. It also inhibited phosphorylation of mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB activation. This indicates that the anti-inflammatory activities of 3′,4′-dihydroxyflavone might be related to suppression of the proinflammatory MAPK and NF-κB signaling pathways. Similar anti-neuroinflammatory activities of the compound were observed in the mouse model. These findings suggest that 3′,4′-dihydroxyflavone is a potential drug candidate for the treatment of microglia-related neuroinflammatory diseases.

Steppogenin Isolated from Cudrania tricuspidata Shows Antineuroinflammatory Effects via NF-κB and MAPK Pathways in LPS-Stimulated BV2 and Primary Rat Microglial Cells

Excessive microglial stimulation has been recognized in several neurodegenerative diseases, including Parkinson’s disease (PD), Alzheimer’s disease (AD), amyotropic lateral sclerosis (ALS), HIV-associated dementia (HAD), multiple sclerosis (MS), and stroke. When microglia are stimulated, they produce proinflammatory mediators and cytokines, including nitric oxide (NO) derived from inducible NO synthase (iNOS), prostaglandin E2 (PGE₂) derived from cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-12 (IL-12), and interleukin-6 (IL-6). These inflammatory reactions are related to the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Therefore, the modulation of NF-κB and MAPK is vital to prevent microglial activation and confer resistance against neuronal injury. In this study, steppogenin (1) isolated from Cudrania tricuspidata suppressed the neuroinflammatory responses to lipopolysaccharide (LPS). Steppogenin (1) inhibited the production of proinflammatory mediators and cytokines in LPS-challenged BV2 and rat primary microglial cells. Moreover, western blot analysis and immunofluorescence revealed that the nuclear translocation of NF-κB was inhibited in LPS-induced BV2 and rat primary microglial cells. The LPS-stimulated activation of BV2 and rat primary microglial cells was inhibited by steppogenin (1) through the suppression of c-Jun NH2-terminal kinase (JNK) and p38 MAPK signaling. These results suggested that steppogenin (1) exerted antineuroinflammatory effects against acute neuroinflammation in BV2 and rat primary microglial cells by suppressing the activation of NF-κB and MAPK signaling and the production of proinflammatory mediators and cytokines.