The Anti-inflammatory Effect of Gnaphalium affine Through Inhibition of NF-κB and MAPK in Lipopolysaccharide-Stimulated RAW264.7 Cells and Analysis of Its Phytochemical Components

1,5-Dicaffeoylquinic acid from Pseudognaphalium affine ameliorates dry eye disease via suppression of inflammation and protection of the ocular surface

PURPOSE

Pseudognaphalium affine (P. affine), a medicinal plant, has long been used to treat various diseases due to its astringent and vulnerary effects. These therapeutic benefits are largely attributed to high contents of phytochemicals, such as flavonoids and polyphenols, that have anti-inflammatory and tissue-protective activities. Herein, we investigated the potential of dicaffeoylquinic acids (diCQAs), polyphenols from P. affine, as a novel treatment for dry eye disease (DED).

METHODS

We isolated 1,5-, 3,4-, 3,5- and 4,5-diCQAs from the P. affine methanol extract, and tested the effects of diCQA isomers in cultures of human corneal epithelial cells (CECs) under desiccating hyperosmolar stress and in two mouse models for DED: desiccating environmental stress-induced DED and the NOD.B10-H2b mouse model of ocular Sjögren's syndrome.

RESULTS

Initial screening showed that, among the diCQAs, 1,5-diCQA significantly inhibited apoptosis and enhanced viability in cultures of CECs under hyperosmolar stress. Moreover, 1,5-diCQA protected CECs by promoting proliferation and downregulating inflammatory activation. Subsequent studies with two mouse models of DED revealed that topical 1,5-diCQA administration dose-dependently decreased corneal epithelial defects and increased tear production while repressing inflammatory cytokines and T cell infiltration on the ocular surface and in the lacrimal gland. 1,5-diCQA was more effective in alleviating DED, as compared with two commercially-available dry eye treatments, 0.05% cyclosporine and 0.1% sodium hyaluronate eye drops.

CONCLUSIONS

Together, our results demonstrate that 1,5-diCQA isolated from P. affine ameliorates DED through protection of corneal epithelial cells and suppression of inflammation, thus suggesting a novel DED therapeutic strategy based on natural compounds.

Comparative MS- and NMR-Based Metabolome Mapping of Egyptian Red and White Squill Bulbs F. Liliaceae and in Relation to Their Cytotoxic Effect

Urginea maritima L. (squill) species is widely spread at the Mediterranean region as two main varieties, i.e., white squill (WS) and red squill (RS), that are recognized for several health potentials. The major secondary metabolite classes of the squill are cardiac glycosides, mainly, bufadienolides, flavonoids, and anthocyanins. Herein, a multiplex MS and NMR metabolomics approach targeting secondary and aroma compounds in WS and RS was employed for varieties classification. Solid-phase micro extraction-gas chromatography/mass spectroscopy (SPME-GC/MS), ultra-high-performance liquid chromatography/mass spectrometry (UPLC/MS), as well as nuclear magnetic resonance (NMR) provided fingerprinting and structural confirmation of the major metabolites for both types of the squill. For comparison of the different platforms' classification potential, multivariate data analysis was employed. While Bufadienolides, viz. "hydroxy-scilliglaucosidin-O-rhamnoside, desacetylscillirosidin-O-rhamnoside and bufotalidin-O-hexoside" as well as oxylipids, were enriched in WS, flavonoids, i.e., dihydro-kaempferol-O-hexoside and its aglycon, taxifolin derivative, were predominant in RS. A cytotoxicity screening against three cancer cell lines, including breast adenocarcinoma (MCF-7), lung (A-549), and ovarian (SKOV-3) cell lines was conducted. Results revealed that WS was more effective on A-549 and SKOV-3 cell lines (WS IC₅₀ 0.11 and 0.4 µg/mL, respectively) owing to its abundance of bufadienolides, while RS recorded IC₅₀ (MCF7 cell line) 0.17 µg/mL since is is rich inflavonoids.

Pseudognaphalium affine Extract Alleviates COPD by Inhibiting the Inflammatory Response via Downregulation of NF-κB

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease with limited therapeutic options. Pseudognaphalium affine (D. Don) Anderb. is a medicinal and edible plant used to treat cough, asthma, and COPD for a long time in folk medicine. The objective of this study is to evaluate the effect of Pseudognaphalium affine (D. Don) Anderb. extract (GAE) and investigate the possible underlying mechanism in vivo and in vitro. In vivo, the administration of GAE in a rat COPD model could significantly ameliorate lung damage and pulmonary function by inhibiting the production of pro-inflammatory cytokines. Western blot and real-time PCR results showed that GAE could suppress nuclear translocation of nuclear factor-kappa B (NF-κB), which indicated that GAE down-regulated the NF-κB pathway. Moreover, GAE protected against tumor necrosis factor (TNF)-α induced inflammatory response in BEAS-2B and inhibited the NF-κB pathway. All data suggested that GAE exhibited its anti-COPD effect by inhibiting pro-inflammatory cytokines, which may be associated with the inhibition of the NF-κB pathway.

Preparation of newly identified polysaccharide from Pleurotus eryngii and its anti-inflammation activities potential

The anti-inflammatory effects of two newly identified Pleurotus eryngii polysaccharides (WPEP, NPEP) were determined in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in this study. Characterization analysis revealed that molecular weights of WPEP and NPEP were 167 and 274 kDa, and were mainly composed of glucose with β-type glycosidic linkages. WPEP and NPEP could significantly inhibit LPS-induced inflammatory responses by regulating the production of NO, Protaglandin E2 (PGE₂ ), Interleukin-1β (IL-1β), Tumor necrosis factor-α (TNF-α), and Interleukin-6 (IL-6). This was through the blocking of the activation of Mitogen-activated protein kinase (MAPK) pathway by inhibiting phosphorylation of p38, extracellular regulation of protein kinases 1/2, and stress-activated protein kinase/jun aminoterminal kinase. Moreover, WPEP and NPEP inhibited NF-κB signaling by reducing nuclear translocation and phosphorylation of p65. Overall, our results, for the first time identified two P. eryngii polysaccharides and demonstrated the related anti-inflammatory effects, which indicated the favorable potential of P. eryngii polysaccharide as specific functional foods. PRACTICAL APPLICATION: This study prepared and characterized newly identified Pleurotus eryngii water-soluble polysaccharide fractions and elucidated the nutritional benefits, mainly the immune response related to anti-inflammatory activities by utilizing lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Collectively, results of this study suggested that the P. eryngii polysaccharide fractions could be considered as potential candidates for exploration in the development of new immunomodulatory agent or functional supplementary foods.

Design, synthesis and biological evaluation of novel desloratadine derivatives with anti-inflammatory and H1 antagonize activities

To improve the anti-inflammatory activity of desloratadine, we designed and synthesized a series of novel desloratadine derivatives. All compounds were evaluated for their anti-inflammatory and H₁ antagonistic activities. Among them, compound 2c showed the strongest H₁ antagonistic and anti-inflammatory activity. It also exhibited promising pharmacokinetic profiles and low toxicity. All these results suggest that compound 2c as a novel anti-allergic agent is worthy of further investigation.

Kaempferol‑3‑O‑β‑rutinoside suppresses the inflammatory responses in lipopolysaccharide‑stimulated RAW264.7 cells via the NF‑κB and MAPK pathways

Kaempferol‑3‑O‑β‑rutinoside is one of the compounds isolated from tartary buckwheat (Fagopyrum tatricum), and its biological effects have not been studied yet. The present study examined the anti‑inflammatory effects of kaempferol‑3‑O‑β‑rutinoside and explore its regulatory mechanisms in lipopolysaccharide (LPS)‑induced macrophage RAW264.7 cells. Kaempferol‑3‑O‑β‑rutinoside exhibited no cytotoxic effect in RAW 264.7 macrophage and 293 cell lines up to 300 µM. As the concentration of kaempferol‑3‑O‑β‑rutinoside was increased, the activity of nitric oxide was inhibited in LPS‑stimulated RAW264.7 cells. In addition, kaempferol‑3‑O‑β‑rutinoside treatment downregulated the expression of inflammation‑related cytokines tumor necrosis factor‑α and interleukin‑6 in LPS‑stimulated RAW264.7 cells. Furthermore, kaempferol‑3‑O‑β‑rutinoside treatment suppressed inflammatory‑mediated factors, such as inducible nitric oxide synthase and cyclooxyganse‑2. These inflammation‑related proteins are known to be regulated by NF‑κB and mitogen‑activated protein kinase (MAPK) signaling, therefore the effect of kaempferol‑3‑O‑β‑rutinoside on these pathways was investigated. The results demonstrated that kaempferol‑3‑O‑β‑rutinoside decreased the expression of inhibitor of κB (IκB) protein and IκB kinases; as a result, the nuclear translocation and expression of NF‑κB was inhibited in LPS‑stimulated RAW264.7 cells. Furthermore, kaempferol‑3‑O‑β‑rutinoside inhibited the phosphorylation of p38, extracellular signal‑regulated kinase and stress‑activated protein kinase in LPS‑stimulated RAW264.7 cells. Thus, the present data demonstrated that kaempferol‑3‑O‑β‑rutinoside suppressed inflammation‑related gene expression through the NF‑κB and MAPK pathways, and suggested that it may be a useful reagent in pharmacological research.

Identification of narciclasine from Lycoris radiata (L'Her.) Herb. and its inhibitory effect on LPS-induced inflammatory responses in macrophages

Lycoris radiata (L'Her.) Herb. (L. radiata) was traditionally used as a folk medicine in China for treatment of Alzheimer's disease. However, the specific component responsible for its considerable toxicity remained unclear thus restricting its clinical trials. Narciclasine (NCS) was isolated from L. radiata and treatment of NCS for 72 h exhibited significant antiproliferative effects against L02, Hep G2, HT-29 and RAW264.7 cells. However, what needs to be emphasized is that at safe working concentrations of 0.001-0.016 μM, administration of NCS for 24 h inhibited the mRNA expression of inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-ɑ), interleukin-1beta (IL-1β) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-induced macrophages thereby suppressing production of nitric oxide (NO), IL-6, TNF-ɑ and IL-1β. NCS supplementation also inhibited nuclear factor-kappa B (NF-κB) activation by suppressing NF-κB P65 phosphorylation and nuclear translocation, IκBɑ degradation and phosphorylation, and IκKɑ/β phosphorylation. The phosphorylation of c-Jun N-terminal kinase (JNK) and P38, and expression of COX-2 was also attenuated by NCS. These results suggested that NCS might exert anti-inflammatory effects through inhibiting NF-κB and mitogen-activated protein kinase (MAPK) pathways even at very low doses.

Anti-inflammatory effects of mulberry (Morus alba L.) root bark and its active compounds

Mulberry (Morus alba L.) root bark (MRB) was extracted using methanol and the extracts were subjected to tests of anti-inflammatory effects. The ethyl acetate fraction demonstrated the best anti-inflammatory effects. Purified compounds, sanggenon B, albanol B and sanggenon D, showed inhibitory effects on NO production in LPS-stimulated RAW264.7 cells and albanol B demonstrated the best anti-inflammatory effects. Regarding the underlying molecular mechanisms, further investigations showed that treatments with Albanol B reduced production of pro-inflammatory cytokines and decreased expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These results would contribute to development of novel anti-inflammatory drugs from MRB.

Extraction Process, Component Analysis, and In Vitro Antioxidant, Antibacterial, and Anti-Inflammatory Activities of Total Flavonoid Extracts from Abutilon theophrasti Medic. Leaves

The flavonoid fraction was extracted from the leaves of Abutilon theophrasti Medic., which are usually used as a traditional Chinese herbal medicine for the treatment of inflammation and joint pain. The current study focused on the extraction process, component analysis, and in vitro antioxidant, antibacterial, and anti-inflammatory activities of the flavonoid fraction as a part of ongoing research on bioactive substances from natural plant sources. This study evaluated the antioxidant activities via assays of DPPH radical scavenging capacity, ABTS radical scavenging capacity, and reducing power and investigated inhibitory activities against Escherichia coli, Salmonella, Staphylococcus aureus, and Streptococcus. Moreover, the inflammatory activity of the flavonoid fraction was estimated by measurement of the content of tumor necrosis factor alpha, interleukin-1-beta, interleukin-6, interleukin-10, nitric oxide, and cyclooxygenase-2 and the gene expression levels of several inflammation markers, such as inducible nitric oxide synthase and cyclooxygenase-2, in RAW 264.7 macrophages after LPS treatment. In addition, the underlying anti-inflammatory mechanisms, that is, the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, were also revealed from the gene and protein expression levels. Taken together, these results suggested that the flavonoid fraction might exert in vitro antioxidant, antibacterial, and anti-inflammatory effects on LPS-stimulated RAW 264.7 macrophages and will be potentially useful as an adjuvant treatment for oxidative stress and bacterial and inflammatory diseases.

Immunomodulatory Activity of Docosahexenoic Acid on RAW264.7 Cells Activation through GPR120-Mediated Signaling Pathway

In this study, we elucidated the immunomodulatory activity of docosahexaenoic acid (DHA) on protein expression in RAW264.7 cells and its molecular mechanism. The results showed that the proliferation index of RAW264.7 cells at 48 h was about 173.03 ± 7.82% after the treatment of 2.4 μM DHA. DHA could activate RAW264.7 cells by the G-protein coupled cell membrane receptor GPR120-C-Raf- mitogen-activated protein kinases (MAPKs)-nuclear factor κB (NF-κB) p65 pathway. In addition, 2.4 μM of DHA could significantly increase (P < 0.01) the mRNA and protein expression of inducible nitric oxide synthase (iNOS), which is consistent with the result of the NO release. ELISA results revealed that DHA could enhance the protein expression of cytokines IL-1β, IL-6, IL-10, IL-12, TNF-α, IFN-γ, and TGF-β. These results indicated that the immunomodulatory mechanism of RAW264.7 cells by DHA was associated with the release of NO and cytokines by stimulating the GPR120, C-Raf, and MAPKs to the NF-κB p65 pathway.

Methanol extract of Guettarda speciosa Linn. inhibits the production of inflammatory mediators through the inactivation of Syk and JNK in macrophages

Guettarda speciosa Linn. (G. speciosa, Rubiaceae) has been used as a traditional medicinal plant in Asia for the treatment of various inflammatory conditions, including cough, fever and maternal postpartum infection. However, the mechanisms underlying the anti‑inflammatory action of G. speciosa extracts have remained elusive. In the present study, the anti‑inflammatory effects of the methanol extract of G. speciosa (MGS) were investigated in murine macrophages by measuring the production of inflammatory mediators and the underlying mechanisms of action by performing immunoblotting analysis of proteins that are potentially involved. MGS reduced nitric oxide (NO) production through regulation of the expression of inducible NO synthase (iNOS) in lipopolysaccharide‑activated RAW 264.7 cells; however, cyclooxygenase‑2, the enzyme responsible for prostaglandin E2 production, was not affected at the mRNA or protein level. MGS reduced interleukin‑6 (IL‑6) production, but had no effect on tumor necrosis factor (TNF)‑α production. In addition, MGS suppressed the transcription of IL‑6, but not that of IL‑1β and TNF‑α. The effect of MGS on proinflammatory mediators resulted from the inhibition of the activation of spleen tyrosine kinase and c‑Jun N‑terminal kinase. In conclusion, the present study suggested that MGS may be a potential candidate for development as a therapeutic for alleviating inflammation.

Eburicoic acid from Laetiporus sulphureus (Bull.:Fr.) Murrill attenuates inflammatory responses through inhibiting LPS-induced activation of PI3K/Akt/mTOR/NF-κB pathways in RAW264.7 cells

Excessive activation of macrophages has been implicated in various types of inflammatory injury. Suppression of macrophage activation would have therapeutic benefits, leading to the alleviation of the progression of inflammatory diseases. Eburicoic acid (EA) is one of main bioactive components isolated from Laetiporus sulphureus (Bull.:Fr.) Murrill. In our previous study, we found that EA possessed anti-inflammatory activities. However, the cellular and molecular mechanisms underlying its anti-inflammatory activities remain to be poorly understood. The present study aimed to further evaluate its effect on lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 macrophage cells. We investigated the anti-inflammatory effect by modulating LPS-induced activation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/nuclear transcription factor-κB (NF-κB) pathway in RAW264.7 cells. The results showed that EA caused no obvious cytotoxicity, and its suitable concentrations on RAW264.7 cells were in the range from 0.02 to 0.08 μM. EA significantly inhibited the releases of inflammatory mediators, nitrite oxide (NO) and prostaglandin E2 (PGE₂); suppressed mRNA and protein expression levels of inducible nitrite oxide synthase (iNOS) and cyclooxygenase-2 COX-2 and pro-inflammatory cytokine TNF-α, IL-6, and IL-1β; and reduced levels of phosphorylated PI3K, Akt, mTOR, and NF-κBp65 in LPS-induced RAW264.7 cells in dose- and time-dependent manners. These aforementioned results indicated that EA executed anti-inflammatory effect on LPS-induced RAW264.7 cells, and this effect might be achieved via suppressing the PI3K/Akt/mTOR/NF-κB signaling pathway and inhibiting the LPS-induced productions of inflammatory mediators and pro-inflammatory cytokines.