Preventive Effects of Protocatechuic Acid on LPS-Induced Inflammatory Response in Human Gingival Fibroblasts via Activating PPAR-γ

The protective effects of protocatechuic acid against natural and chemical toxicants: cellular and molecular mechanisms

Protocatechuic acid (PCA) is a water-soluble polyphenol compound that is extracted from certain fruits and plants or obtained from glucose fermentation. Several in vivo and in vitro studies have determined that PCA has protective effects against the toxicity of natural and chemical toxicants. We searched these articles in PubMed, Google Scholar, and Scopus with appropriate keywords from inception up to August 2023. Forty-nine studies were found about protective effects of PCA against drug toxicity, metal toxicity, toxins, chemical toxicants, and some other miscellaneous toxicants. PCA indicates these protective effects by suppression of oxidative stress, inflammation, and apoptosis. PCA reduces reactive oxygen/nitrogen species (RONS) and enhances the level of antioxidant parameters mainly through the activation of the Nrf-2 signaling pathway. PCA also decreases the levels of inflammatory mediators via downregulating the TLR-4-mediated IKBKB/NF-κB and MAPK/Erk signaling pathways. In addition, PCA inhibits apoptosis by lowering the expression of Bax, caspase-3, and caspase-9 along with enhancing the level of the antiapoptotic protein Bcl-2. Further evaluation, especially in humans, is necessary to confirm PCA as a potential therapeutic approach to intervene in such toxicities.

Pharmacodynamic material basis and pharmacological mechanisms of Cortex Mori against diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

The application of Cortex Mori (CM) in the treatment of diabetes mellitus (DM) has been extensively documented in traditional medicine. In recent years, the chemical composition of CM has been gradually unraveled, and its therapeutic mechanism in treating DM, diabetic nephropathy, diabetic cardiomyopathy, and other related conditions has been highlighted in successive reports. However, there is no systematic study on the treatment of DM based on the chemical composition of CM.

AIM OF THE STUDY

This study was conducted to systematically explore the hypoglycemic activity mechanism of CM based on its chemical composition.

METHODS

The material basis of Cortex Mori extract (CME) was investigated through qualitative analyses based on liquid chromatography-mass spectrometry (LC-MS). The possible acting mechanism was simulated using network pharmacology and validated in streptozotocin (STZ) + high fat diet (HFD)-induced diabetic rats and glucosamine-induced IR-HepG2 model with the assistance of molecular docking techniques.

RESULTS

A total of 39 compounds were identified in CME by the LC-MS-based qualitative analysis. In diabetic rats, it was demonstrated that CME significantly ameliorated insulin resistance, blood lipid levels, and liver injury. The network pharmacology analysis predicted five major targets, including AKT1, PI3K, FoxO1, Gsk-3β, and PPARγ. Additionally, three key compounds (resveratrol, protocatechuic acid, and kaempferol) were selected based on their predicted contributions. The experimental results revealed that CME, resveratrol, protocatechuic acid, and kaempferol could promote the expression of AKT1, PI3K, and PPARγ, while inhibiting the expression of FoxO1 and Gsk-3β. The molecular docking results indicated a strong binding affinity between resveratrol/kaempferol and their respective targets.

CONCLUSIONS

CME contains a substantial amount of prenylated flavonoids, which may be the focal point of research on the efficacy of CM in the treatment of DM. Besides, CME is effective in controlling blood glucose and insulin resistance, improving lipid levels, and mitigating liver injury in patients with DM. Relevant mechanisms may be associated with the activation of the PI3K/Akt pathway, the inhibition of the expression of FoxO1 and Gsk-3β, and the enhancement of PPARγ activity. This study represents the first report on the role of CME in the treatment of DM through regulating PPARγ, FoxO1, and Gsk-3β.

MAT2A inhibition suppresses inflammation in Porphyromonas gingivalis-infected human gingival fibroblasts

Background

Methionine adenosyl transferase II alpha (MAT2A) is the key enzyme to transform methionine into S-adenosylmethionine (SAM), the main methylgroup donor involved in the methylation. The purpose of our study wasto explore whether MAT2A-mediated methionine metabolism affected theexpression of inflammatory cytokines in human gingival fibroblasts(hGFs).

Methods

Both healthy and inflamed human gingiva were collected. HGFs werecultured and treated with P. gingivalis, with or without MAT2Ainhibitor (PF9366), small interference RNA (siRNA), or extrinsic SAMpretreatment. The levels of inflammatory cytokines were detected byreal-time PCR, western blotting, and ELISA. SAM levels were detectedby ELISA. The nuclear factor-kappa B (NF-κB) and mitogen-activatedprotein kinase (MAPK) pathway was explored by western blotting.

Results

The expression of MAT2A was increased in the inflamed tissues. P.gingivalis infection promoted the expression of MAT2A and SAM inhGFs. Meanwhile, PF9366 and MAT2A-knockdown significantly decreasedexpression of inflammatory cytokines and SAM production. PF9366inhibited activation of NF-κB/MAPK pathway in P. gingivalis-treatedhGFs.

Conclusions

MAT2A-mediated methionine metabolism promoted P. gingivalis-inducedinflammation in hGFs. Targeting MAT2A may provide a novel therapeuticmethod for modulating periodontitis.

Protocatechuic acid inhibits LPS-induced mastitis in mice through activating the pregnane X receptor

Mastitis refers to the inflammation in the mammary gland caused by various reasons. Protocatechuic acid (PCA) exerts anti-inflammatory effect. However, no studies have shown the protective role of PCA on mastitis. We investigated the protective effect of PCA on LPS-induced mastitis in mice and elucidated its possible mechanism. LPS-induced mastitis model was established by injection of LPS into the mammary gland. The pathology of mammary gland, MPO activity and inflammatory cytokine production were detected to evaluate the effects of PCA on mastitis. In vivo, PCA significantly attenuated LPS-induced mammary pathological changes, MPO activity, TNF-α and IL-1β production. In vitro, the production of inflammatory cytokines TNF-α and IL-1β was significantly reduced by PCA. Furthermore, LPS-induced NF-κB activation was also inhibited by PCA. In addition, PCA was found to activate pregnane X receptor (PXR) transactivation and PCA dose-dependently increased the expression of PXR downstream molecule CYP3A4. In addition, the inhibitory effect of PCA on inflammatory cytokine production was also reversed when PXR was knocked down. In conclusion, the protective effects of PCA on LPS-induced mastitis in mice through regulating PXR.

Dietary Polyphenols as Prospective Natural-Compound Depression Treatment from the Perspective of Intestinal Microbiota Regulation

The broad beneficial effects of dietary polyphenols on human health have been confirmed. Current studies have shown that dietary polyphenols are important for maintaining the homeostasis of the intestinal microenvironment. Moreover, the corresponding metabolites of dietary polyphenols can effectively regulate intestinal micro-ecology and promote human health. Although the pathogenesis of depression has not been fully studied, it has been demonstrated that dysfunction of the microbiota-gut-brain axis may be its main pathological basis. This review discusses the interaction between dietary polyphenols and intestinal microbiota to allow us to better assess the potential preventive effects of dietary polyphenols on depression by modulating the host gut microbiota.

Tamquam alter idem: formal similarities in a subset of reports on anti-inflammatory compounds in the years 2008–2019

A literature search on the in vitro testing of anti-inflammatory compounds of natural origin revealed a considerable number of studies adopting a similar template for data reporting in the years up to 2019. Sixty-five such reports appear to have been published between the years 2008 and 2019. Interestingly, this format template was clearly recognizable by a few hallmarks, such as a precise way of plotting cell viability data, extremely consistent endpoints, and the way these were graphically represented. In some instances the similarities extended to some textual features, such as in the case of figure legends. The similarity was so high that chance can be excluded and these studies can be safely assumed to have intentionally followed a template. By 2020, however, no new reports following this format have been published. Although a consistent and reproducible formatting for data reporting may improve report readability, this phenomenon should also be closely scrutinized to assess the rationale why it occurred, the validity of the endpoints that were chosen and why it was then abandoned. The present report reviewed the mean features of this format, traced its origin and its evolution over time, while discussing the limitations of this model.

Exploration of the Specific Pathology of HXMM Tablet Against Retinal Injury Based on Drug Attack Model to Network Robustness

Retinal degenerative diseases are related to retinal injury because of the activation of the complement cascade, oxidative stress-induced cell death mechanisms, dysfunctional mitochondria, chronic neuroinflammation, and production of the vascular endothelial growth factor. Anti-VEGF therapy demonstrates remarkable clinical effects and benefits in retinal degenerative disease patients. Hence, new drug development is necessary to treat patients with severe visual loss. He xue ming mu (HXMM) tablet is a CFDA-approved traditional Chinese medicine (TCM) for retinal degenerative diseases, which can alleviate the symptoms of age-related macular degeneration (AMD) and diabetic retinopathy (DR) alone or in combination with anti-VEGF agents. To elucidate the mechanisms of HXMM, a quantitative evaluation algorithm for the prediction of the effect of multi-target drugs on the disturbance of the disease network has been used for exploring the specific pathology of HXMM and TCM precision positioning. Compared with anti-VEGF agents, the drug disturbance of HXMM on the functional subnetwork shows that HXMM reduces the network robustness on the oxidative stress subnetwork and inflammatory subnetwork to exhibit the anti-oxidation and anti-inflammation activity. HXMM provides better protection to ARPE-19 cells against retinal injury after H₂O₂ treatment. HXMM can elevate GSH and reduce LDH levels to exhibit antioxidant activity and suppress the expression of IL-6 and TNF-α for anti-inflammatory activity, which is different from the anti-VEGF agent with strong anti-VEGF activity. The experimental result confirmed the accuracy of the computational prediction. The combination of bioinformatics prediction based on the drug attack on network robustness and experimental validation provides a new strategy for precision application of TCM.

Protocatechuic acid protects mice from influenza A virus infection

Influenza A virus (IAV) H1N1 infection remains great challenge to public health and causes great burden over the world. Although there are anti-viral agents available, searching for effective agents to treat H1N1 infection is still in urgent because of the emergence of resistant strain. Protocatechuic acid (PCA) is a biological agent with multiple functions. In present study, we explored the effects of PCA on H1N1 infection. Mice infected with mouse adapted influenza strain A/Font Monmouth were administrated with PCA. The body weight change, mortality, lung index, viral titer, immune cell infiltration, and cytokine production in the lung were monitored. The activation of toll-like receptor 4 (TLR4) and nuclear factor kappa light chain enhancer of activated B cells (NF-κB) pathway was investigated. PCA treatment prevented H1N1 infection-induced mice body weight loss and death. PCA reduced the lung index, viral titer, infiltration of immune cells, and cytokine level in the lung, as well as suppressed H1N1-induced TLR4/NF-κB activation. PCA protects mice against H1N1 infection and could be a potential therapeutic agent to treat influenza.

Potential neuroprotective activity of Mentha longifolia L. in aluminum chloride-induced rat model of Alzheimer's disease

Alzheimer's disease (AD) is an irreversible neurodegenerative disorder manifested by cognitive deterioration where the available treatments failed to delay its progression. The objective of this study was to investigate the neuroprotective activity in an aluminum chloride (AlCl₃ )-induced AD in vivo model and phytochemical profile of the traditional Egyptian herb Mentha longifolia (Ml). Male albino rats were injected with Ml fractions and essential oil for 15 days followed by AlCl₃ for 30 days. Oxidative stress and neuroinflammatory markers were measured namely: malondialdehyde (MDA), reduced glutathione (GSH), nitric oxide (NO), and nuclear factor-κB (NF-κB). Furthermore, cholinesterase activity was tested and analysis of brain neurotransmitters using HPLC was performed. Results showed that methylene chloride and ethyl acetate fractions were able to reverse the AlCl₃ mediated MDA increase, GSH decrease and exhibited anticholinesterase activity. EaFr reversed the increased levels of NF-κB and NO. Ml fractions and oil counteracted the AlCl₃ effect on brain neurotransmitters. Forty metabolites were tentatively characterized in the bioactive fractions using UPLC-PDA-ESI-MS. 5,6,4'-trihydroxy-3',7,8-trimethoxy flavone was isolated from Ml as a first report, in addition to 5,6-dihydroxy-3',4',7,8-tetramethoxy flavone and rosmarinic acid. These findings suggest that Ml is a promising nutraceutical and source of lead compounds halting AD progression. PRACTICAL APPLICATIONS: The results presented in this paper unravels the neuroprotective effect of Mentha longifolia fractions and oil by acting as anti-inflammatory, antioxidant agents, and regulating the levels of neurotransmitters. This provides basic knowledge for the development of Ml as a source of lead compounds and a promising food supplement protective against Alzheimer's disease.

Anti‑inflammatory effects of leaf and branch extracts of honeyberry (Lonicera caerulea) on lipopolysaccharide‑stimulated RAW264.7 cells through ATF3 and Nrf2/HO‑1 activation

Honeyberry (Lonicera caerulea) has long been used as a traditional medicine in China, Japan and northern Russia. Functional studies of honeyberry have mainly focused on the fruits, which have been reported to exert various pharmacological activities, including anti-inflammatory activity, with limited or no studies on the other parts of the plant, such as the leaves and branches. In the present study, the anti-inflammatory effects of extracts of the leaves (HBL), branches (HBB) and fruit (HBF) of honeyberry plant were evaluated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. HBL and HBB significantly inhibited the production of pro-inflammatory mediators in LPS-stimulated RAW264.7 cells, and the inhibitory effects of HBL and HBB were stronger than those of HBF. HBL and HBB blocked the nuclear accumulation of p65 independently of IκB-α. HBL did not inhibit the phosphorylation of ERK1/2 or p38; however, HBB effectively inhibited the phosphorylation of p38 but not ERK1/2. HBL and HBB increased the expression of heme oxygenase-1 (HO-1) protein by inducing the nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) through the activation of the reactive oxygen species (ROS)/p38 pathway; the reduction in inducible nitric oxide synthase (iNOS) and interleukin-1β (IL-1β) expression by HBL and HBB was inhibited by HO-1 knockdown. In addition, HBL and HBB increased the expression of activating transcription factor-3 (ATF3), and the reduction in iNOS and IL-1β expression by HBL and HBB was inhibited by ATF3 knockdown. Collectively, HBL and HBB inhibited LPS-induced nuclear factor-κB activation by blocking the nuclear accumulation of p65, increasing HO-1 expression through activation of the ROS/p38/Nrf2 pathway, and increasing ATF3 expression. Furthermore, HBB inhibited LPS-induced p38 phosphorylation. These findings suggest that HBL and HBB may have great potential as natural products for the development of anti-inflammatory drugs.

Involvement of Gut Microbiota, Microbial Metabolites and Interaction with Polyphenol in Host Immunometabolism

Immunological and metabolic processes are inextricably linked and important for maintaining tissue and organismal health. Manipulation of cellular metabolism could be beneficial to immunity and prevent metabolic and degenerative diseases including obesity, diabetes, and cancer. Maintenance of a normal metabolism depends on symbiotic consortium of gut microbes. Gut microbiota contributes to certain xenobiotic metabolisms and bioactive metabolites production. Gut microbiota-derived metabolites have been shown to be involved in inflammatory activation of macrophages and contribute to metabolic diseases. Recent studies have focused on how nutrients affect immunometabolism. Polyphenols, the secondary metabolites of plants, are presented in many foods and beverages. Several studies have demonstrated the antioxidant and anti-inflammatory properties of polyphenols. Many clinical trials and epidemiological studies have also shown that long-term consumption of polyphenol-rich diet protects against chronic metabolic diseases. It is known that polyphenols can modulate the composition of core gut microbiota and interact with the immunometabolism. In the present article, we review the mechanisms of gut microbiota and its metabolites on immunometabolism, summarize recent findings on how the interaction between microbiota and polyphenol modulates host immunometabolism, and discuss future research directions.

Protocatechuic acid mitigates cadmium-induced neurotoxicity in rats: Role of oxidative stress, inflammation and apoptosis

Environmental and occupational exposure to heavy metals, including cadmium (Cd), is associated with extremely adverse impacts to living systems. Antioxidant agents are suggested to eliminate Cd intoxication. In this paper, we investigated the potential neuroprotective effect of protocatechuic acid (PCA) against Cd-induced neuronal damage in rats. Adult male Wistar rats were randomly divided into control, PCA (100 mg/kg)-treated, CdCl₂ (6.5 mg/kg)-treated, and PCA and Cd treatment groups. Pre-treatment with PCA significantly reduced Cd concentrations and increased cortical acetylcholinesterase activity and brain derived neurotrophic factor. Additionally, PCA also prevented CdCl₂-induced oxidative stress in the cortical tissue by preventing lipid peroxidation and the formation of nitric oxide (NO), and significantly enhancing antioxidant enzymes. Molecularly, PCA significantly up-regulated the antioxidant gene expression (Sod2, Cat, Gpx1, and Gsr) that was down-regulated by Cd. It should be noted that this effect was achieved by targeting the nuclear-related factor 2 (Nfe2l2) mRNA expression. PCA also prevented the Cd-induced inflammation by reducing the pro-inflammatory cytokines, including tumor necrosis factor-α and interleukin-1β. Moreover, PCA supplementation relieved the Cd-induced neuronal death by increasing Bcl-2 and decreasing Bax and Cas-3 levels in the cortical tissue. The improvement of the cortical tissue histopathology by PCA confirmed the biochemical and molecular data. Collectively, our findings indicate that PCA can counteract Cd-induced cortical toxicity by enhancing the antioxidant defense system and suppressing inflammation and apoptosis.

Between Innovation and Standardization, Is There Still a Room for Scientific Reports? The Rise of a Formatting Tradition in Periodontal Research

Everybody, regardless of their role, is aware that biomedical research is rapidly evolving, and the demand for reproducibility is increasing together with the amount of novel information. “Before reproducibility must come pre-producibility” “Checklists work to improve science”, just to quote some of the articles querying how to find a new bridge between ethics in science and the urgency for publishing. Looking for papers on anti-inflammatory compounds in periodontics, we came across a significant number of articles that could be considered a prototype of a consistent study format. The literature on the testing of active compounds on lipopolysaccharides- (LPS)-induced inflammation in gingival fibroblasts was searched to identify studies that followed a consistent format, to better understand their similarities and assess the appropriateness of their methods. Several studies were identified with a degree of similarity in their methods and formatting that was so high that it was possible to rule out that it was due to chance, and a format template common to these studies was outlined. Although this was most likely beyond the intentions of their authors, these studies may pose the basis for an in-vitro testing standard for anti-inflammatory compounds; however, the dangers of acritical uniformity are also apparent.

Microbial Metabolites of Flavan-3-Ols and Their Biological Activity

Flavan-3-ols are the main contributors to polyphenol intake. Many varying beneficial health effects in humans have been attributed to them, including the prevention of cardiovascular disease and cancer. Nevertheless, the mechanisms by which these flavonoids could exert beneficial functions are not entirely known. Several in vitro studies and in vivo animal models have tried to elucidate the role of the specific colonic metabolites on the health properties that are attributed to the parent compounds since a larger number of ingested flavan-3-ols reach the colon and undergo there microbial metabolism. Many new studies about this topic have been performed over the last few years and, to the best of our knowledge, no scientific literature review regarding the bioactivity of all identified microbial metabolites of flavan-3-ols has been recently published. Therefore, the aim of this review is to present the current status of knowledge on the potential health benefits of flavan-3-ol microbial metabolites in humans while using the latest evidence on their biological activity.

Polyphenols in the management of brain disorders: Modulation of the microbiota-gut-brain axis

The modulation of the microbiota-gut-brain axis with a view to preventing and treating brain disorders became recently a hot topic for the scientific community. Dietary polyphenols are multifaceted compounds that have demonstrated to be highly advantageous to counteract inflammation, oxidative stress, and neurodegeneration, among other pathological conditions, being useful in the prevention and treatment of several chronic disorders. The potential of these compounds to prevent and treat brain disorders has not been only related to their capacity to reach the brain, depending on their chemical structure, and interact directly with brain cells, but also to their ability to modulate the communication between the brain and the gut, interfering with multiple branches of this axis. Preclinical studies have demonstrated the potential of these food bioactive compounds in brain diseases, namely, neurodevelopmental, such as Down's syndrome and Autism spectrum disorder, neurodegenerative, such as Parkinson's disease and Alzheimer's disease, and psychiatric disorders, such as depression and anxiety. Until now, dietary polyphenols have been recognized as promising nutraceuticals to combat brain disorders. However, the impact of these compounds on the gut-brain interconnection remains poorly elucidated. Also, clinical assays are crucial to further support the beneficial effects of these compounds as demonstrated in preclinical research.

Oridonin inhibits LPS-induced inflammation in human gingival fibroblasts by activating PPARγ

Oridonin, the major terpene isolated from Rabdosia rubescens, has been used as dietary supplement. Recently, it has been known to exhibit anti-inflammatory effect. This study we employed an in vitro model of LPS-stimulated human gingival fibroblasts to investigate the anti-inflammatory effects and mechanism of oridonin. Oridonin (10-30 μg/mL) was administrated 1 h before LPS treatment. The results showed that oridonin significantly inhibited inflammatory mediators PGE₂, NO, IL-6, and IL-8 production. Immunoblotting experiments revealed that oridonin reduced the expression of phosphorylation levels of NF-κB p65 and IκBα. Furthermore, the expression of PPARγ was up-regulated by the treatment of oridonin. Further studies showed that PPARγ inhibitor GW9662 could reverse the inhibition of oridonin on PGE₂, NO, IL-6, and IL-8 production. In conclusion, oridonin inhibited LPS-induced microglia activation through activating PPARγ.

Protocatechuic acid inhibits TGF-β1-induced proliferation and migration of human airway smooth muscle cells

Protocatechuic acid (3, 4-dihydroxybenzoic acid, PCA) is a major metabolite of anthocyanins and was reported to possess anti-allergic response. However, the effects of PCA on airway smooth muscle cells (ASMCs) proliferation and migration remain unclear. Therefore, this study aims to investigate the effects of PCA on proliferation and migration of ASMCs. ASMCs were pre-incubated with various concentrations of PCA for 30 min before stimulation with transforming growth factor-β1 (TGF-β1) for different times. Cell proliferation was determined using the colony formation assay. Cell migration was detected using the Transwell chamber assay. The levels of type I collagen, fibronectin, phosphorylated Smad2, Smad2, phosphorylated Smad3 and Smad3 were detected by western blot analysis. Our results demonstrated that PCA inhibited the proliferation and migration of ASMCs, as well as suppressed the expression levels of type I collagen and fibronectin in ASMCs induced by TGF-β1. Furthermore, PCA obviously down-regulated the phosphorylation levels of Smad2/3 in ASMCs exposed to TGF-β1. Taken together, the present results have revealed that PCA inhibits asthma airway remodeling by suppressing proliferation and extracellular matrix (ECM) protein deposition in TGF-β1-mediated ASMCs via the inactivation of Smad2/3 signaling pathway. Therefore, PCA may be useful for the prevention or treatment of asthma airway remodeling.

Inhibitory effects of Euphorbia supina on Propionibacterium acnes-induced skin inflammation in vitro and in vivo

Background

Euphorbia supina (ES) plant has been used as treatment for inflammatory conditions. The antibacterial effect and the anti-inflammatory mechanism of ES for Propionibacterium (P.) acnes-induced inflammation in THP-1 cells and acne animal model remain unclear. Therefore, the objective of the present study was to determine the antibacterial and anti-inflammatory activities of ES against P. acnes, the etiologic agent of skin inflammation.

Method

The antibacterial activities of ES were tested with disc diffusion and broth dilution methods. Cytotoxicity of ES at different doses was evaluated by the MTT assay. THP-1 cells were stimulated by heat-killed P. acnes in the presence of ES. The pro-inflammatory cytokines and mRNA levels were measured by ELISA and real-time-PCR. MAPK expression was analyzed by Western blot. The living P. acnes was intradermally injected into the ear of BLBC/c mice. Subsequently, chemical composition of ES was analyzed by liquids chromatography-mass spectrometry (LC-MS).

Result

ES had stronger antibacterial activity against P. acnes and inhibitory activity on lipase. ES had no significant cytotoxicity on THP-1 cells. ES suppressed the mRNA levels and production of IL-8, TNF-a, IL-1β in vitro. ES inhibited the expression levels of pro-inflammatory cytokines and the MAPK signaling pathway. Ear thickness and inflammatory cells were markedly reduced by ES treatment. Protocatechuic acid, gallic acid, quercetin, and kaempferol were detected by LC-MS analysis in ES.

Conclusions

Our results demonstrate antibacterial and anti-inflammatory activities of ES extract against P. acnes. It is suggested that ES extract might be used to treatment anti-inflammatory skin disease.

Electronic supplementary material

The online version of this article (10.1186/s12906-018-2320-8) contains supplementary material, which is available to authorized users.

Anti-Inflammatory Effects of Schisandrin B on LPS-Stimulated BV2 Microglia via Activating PPAR-γ

Schisandrin B (Sch B), a dibenzocyclooctadiene lignan isolated from Schisandra chinensis (Turcz.) Baill, has been shown to have anti-inflammatory effect. The purpose of this study was to evaluate the effect of Sch B on LPS-induced inflammation in microglia and to investigate the molecular targets of Sch B. BV2 cells were stimulated by LPS in the presence or absence of Sch B. The results showed that the levels of TNF-α, IL-6, IL-1β, and PGE₂ upregulated by LPS were significantly suppressed by Sch B. LPS-induced NF-κB activation was also inhibited by Sch B. Furthermore, Sch B was found to upregulate the expression of PPAR-γ in a concentration-dependent manner. In addition, the inhibition of Sch B on TNF-α, IL-6, IL-1β, and PGE₂ production were reversed by PPAR-γ antagonist GW9662. In conclusion, these results suggested that Sch B inhibited LPS-induced inflammatory response by activating PPAR-γ.

Influence of the Periodontal Disease, the Most Prevalent Inflammatory Event, in Peroxisome Proliferator-Activated Receptors Linking Nutrition and Energy Metabolism

Periodontal disease is considered one of the main pathologic diseases occurring in humans. Its pathologic process involves inflammatory reactions producing periodontal bone resorption and the tooth loss. But some patients do not present an evident clinical inflammation with bone resorption, and in others, the inflammation is prominent without bone resorption. A key question could be to investigate a different way of responding to aggression. Inflammation requires a complex intracellular metabolic process, starting with the harmful recognition and activation of the inflammasome, continues the energy supply with the alteration of oxidative stress conditions, and finishes with the elimination of the aggression with autophagy/apoptosis mechanisms, then concludes with recovery. Peroxisome proliferator-activated receptors (PPARs) are essential molecules produced in inflammation, and its genes and its activation have been related to periodontal disease. Also, an important aspect is the influence of PPARs in bone metabolism; the main periodontitis symptom is bone loss and PPARγ activation that can downregulate the bone resorption in experimental periodontitis, PPARγ-coated titanium dental implant surfaces could carry the antiinflammatory gene and restrain inflammation. PPARs could be one of the meeting background points with atherosclerosis/cardiovascular disease, diabetes and metabolic syndrome showing a modified proinflammatory statement such as it is described in periodontitis.

Phytochemical Analysis on Quantification and the Inhibitory Effects on Inflammatory Responses from the Fruit of Xanthii fructus

Objective:

Xanthii fructus (Compositae) is a traditional herbal medicine used for treating headache, toothache, pruritus, empyema, and rhinitis. In this study of the quality control of X. fructus, we performed simultaneous analysis of nine marker compounds: Protocatechuic acid (1), chlorogenic acid (2), caffeic acid (3), 4,5-dicaffeoylquinic acid (4), ferulic acid (5), 3,5-dicaffeoylquinic acid (6), 1,3-dicaffeoylquinic acid (7), 1,4-dicaffeoylquinic acid (8), and 4,5-dicaffeoylquinic acid (9).

Materials and Methods:

Nine components were separated using reversed-phase SunFire™ C₁₈ analytical column and analyzed using high-performance liquid chromatography. We examined the biological effects of the nine marker compounds by determining their anti-inflammatory activities in the murine macrophage cell line RAW 264.7.

Results:

Among the nine marker compounds, eight significantly inhibited lipopolysaccharide (LPS)-stimulated tumor necrosis factor-alpha (TNF-α) production. 1, 3, 5 had significant inhibitory effects on LPS-induced prostaglandin E₂ (PGE₂) production in RAW 264.7 cells. None of the tested marker compounds had a significant effect on interleukin-6 production in LPS-treated RAW 264.7 cells. Our data demonstrated that each marker compound from X. fructus exerts anti-inflammatory activity by targeting different inflammation-related pathways such as the TNF-α or PGE₂ pathway.

Conclusion:

Further experiments using in vitro and in vivo models are needed to identify the mechanisms responsible for the anti-inflammatory properties of each marker compound.

SUMMARY

Simultaneous analysis of nine phenylpropanoids in the Xanthii fructus was established using HPLC-PDA system.

1,4-dicaffeoylquinic acid significantly inhibited LPS-stimulated TNF-a production.

Protocatechuic acid, caffeic acid and ferulic acid had significant inhibitory effects on LPS-induced PGE2 production in RAW 264.7 cells.

Therapeutic and Prophylactic Potential of Morama (Tylosema esculentum): A Review

Tylosema esculentum (morama) is a highly valued traditional food and source of medicine for the San and other indigenous populations that inhabit the arid to semi-arid parts of Southern Africa. Morama beans are a rich source of phenolic acids, flavonoids, certain fatty acids, non-essential amino acids, certain phytosterols, tannins and minerals. The plant's tuber contains griffonilide, behenic acid and starch. Concoctions of extracts from morama bean, tuber and other local plants are frequently used to treat diarrhoea and digestive disorders by the San and other indigenous populations. Information on composition and bioactivity of phytochemical components of T. esculentum suggests that the polyphenol-rich extracts of the bean testae and cotyledons have great potential as sources of chemicals that inhibit infectious microorganisms (viral, bacterial and fungal, including drug-resistant strains), offer protection against certain non-communicable diseases and promote wound healing and gut health. The potential antinutritional properties of a few morama components are also highlighted. More research is necessary to reveal the full prophylactic and therapeutic potential of the plant against diseases of the current century. Research on domestication and conservation of the plant offers new hope for sustainable utilisation of the plant.