Inhibitory effects of benzaldehyde derivatives from the marine fungus Eurotium sp. SF-5989 on inflammatory mediators via the induction of heme oxygenase-1 in lipopolysaccharide-stimulated RAW264.7 macrophages

Secondary Metabolites from the Genus Eurotium and Their Biological Activities

Eurotium is the teleomorph genus associated with the section Aspergillus. Eurotium comprises approximately 20 species, which are widely distributed in nature and human environments. Eurotium is usually the key microorganism for the fermentation of traditional food, such as Fuzhuan brick tea, Liupao tea, Meju, and Karebushi; thus, Eurotium is an important fungus in the food industry. Eurotium has been extensively studied because it contains a series of interesting, structurally diverse, and biologically important secondary metabolites, including anthraquinones, benzaldehyde derivatives, and indol diketopiperazine alkaloids. These secondary metabolites have shown multiple biological activities, including antioxidative, antimicrobial, cytotoxic, antitumor, insecticidal, antimalarial, and anti-inflammatory activities. This study presents an up-to-date review of the phytochemistry and biological activities of all Eurotium species. This review will provide recent advances on the secondary metabolites and their bioactivities in the genus Eurotium for the first time and serve as a database for future research and drug development from the genus Eurotium.

The Mechanism of Two Benzaldehydes from Aspergillus terreus C23-3 Improve Neuroinflammatory and Neuronal Damage to Delay the Progression of Alzheimer's Disease

Alzheimer's disease (AD), a neurodegenerative disease, is the most common cause of dementia in humans worldwide. Although more in-depth research has been carried out on AD, the therapeutic effect of AD is not as expected, and natural active substances are increasingly sought after by scientists. In the present study, we evaluated two benzaldehydes from a coral-derived Aspergillus terreus strain C23-3, their anti-neuroinflammatory activity in microglia (BV-2), and their neuroprotective activity and mechanisms in hippocampal neuronal cells (HT-22). These include the protein expression of iNOS, COX-2, MAPKs pathways, Tau protein-related pathways, caspases family-related signaling pathways. They also include the levels of TNF-α, IL-6, IL-18 and ROS, as well as the level of mitochondrial oxidative stress and neuronal cell apoptosis. The results showed that both benzaldehydes were effective in reducing the secretion of various inflammatory mediators, as well as pro-inflammatory factors. Among these, benzaldehyde 2 inhibited mitochondrial oxidative stress and blocked neuronal cell apoptosis through Tau protein-related pathways and caspases family-related signaling pathways, thereby inhibiting β-amyloid (Aβ)-induced neurological damage. This study reveals that benzaldehyde 2 has potential as a therapeutic agent for Alzheimer's disease, and offers a new approach to the high-value use of marine natural products.

Aesculetin exhibited anti-inflammatory activities through inhibiting NF-кB and MAPKs pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Aesculetin (6,7-dihydroxy-2H-1-benzopyran-2-one) has been reported to exhibit potent anti-inflammatory property both in vitro and in vivo.

AIMS OF THIS STUDY

In this study, we evaluated the anti-inflammatory effect and investigated underlying molecular mechanisms of aesculetin in LPS-induced RAW264.7 macrophages and DSS-induced colitis.

MATERIALS AND METHODS

In this study, the production of NO, TNF-α, and IL-6 were measured to identify the aesculetin with potent anti-inflammatory effect. Then, the underlying anti-inflammatory mechanisms were explored by western blotting in LPS-induced cells. Next, we verify the anti-inflammatory potential of aesculetin in DSS-induced colitis in vivo. The clinical symptoms of colitis, including weight loss, DAI, colon length and MPO activity, and the secretion of TNF-α and IL-6 were evaluated. Finally, Western blot analysis was applied to further investigate underlying mechanism in DSS-induced colitis model.

RESULTS

Our studies showed that aesculetin exhibited anti-inflammatory potential by inhibiting NO, TNF-α, and IL-6 production and reducing iNOS and NLRP3 expression in LPS-induced RAW264.7 cells. Mechanically, we found that aesculetin significantly inhibited LPS-induced activation of NF-κB and MAPKs signaling pathways. In DSS-induced mouse model, the colitis-related symptoms were relieved by treatment with aesculetin. Besides, aesculetin also inhibited the secretion of TNF-α and IL-6, and the activation of NF-κB and MAPKs signaling pathways in DSS-induced colitis.

CONCLUSIONS

The anti-inflammatory effect of aesculetin was connected with its inhibition on the activation of NF-κB and MAPKs signaling pathways both in vitro and in vivo. Therefore, aesculetin was expected to be developed as an anti-inflammatory drug.

A new benzaldehyde from the coral-derived fungus Aspergillus terreus C23-3 and its anti-inflammatory effects via suppression of MAPK signaling pathway in RAW264.7 cells

Marine fungi are important members of the marine microbiome, which have been paid growing attention by scientists in recent years. The secondary metabolites of marine fungi have been reported to contain rich and diverse compounds with novel structures (Chen et al., 2019). Aspergillus terreus, the higher level marine fungus of the Aspergillus genus (family of Trichocomaceae, order of Eurotiales, class of Eurotiomycetes, phylum of Ascomycota), is widely distributed in both sea and land. In our previous study, the coral-derived A. terreus strain C23-3 exhibited potential in producing other biologically active (with antioxidant, acetylcholinesterase inhibition, and anti-inflammatory activity) compounds like arylbutyrolactones, territrems, and isoflavones, and high sensitivity to the chemical regulation of secondary metabolism (Yang et al., 2019, 2020; Nie et al., 2020; Ma et al., 2021). Moreover, we have isolated two different benzaldehydes, including a benzaldehyde with a novel structure, from A. terreus C23-3 which was derived from Pectinia paeonia of Xuwen, Zhanjiang City, Guangdong Province, China.

Dihydroauroglaucin Isolated from the Mediterranean Sponge Grantia compressa Endophyte Marine Fungus Eurotium chevalieri Inhibits Migration of Human Neuroblastoma Cells

Cancer cell migration is a hallmark of the aggressiveness and progression of malignancies such as high-risk neuroblastoma. Given the lack of effective therapeutic solutions to counteract cancer progression, basic research aims to identify novel bioactive molecules with inhibitory potential on cancer cell migration. In this context, this work investigated the role of members of the salicylaldehyde secondary metabolite set from the sponge endophyte fungus Eurotium chevalieri MUT 2316 as potential inhibitors of human neuroblastoma SH-SY5Y cell migration. Since tetrahydroauroglaucin (TAG) and dihydroauroglaucin (DAG) were isolated in large amounts, both were evaluated for their anticancer properties towards SH-SY5Y cells. Both molecules were found to be non-cytotoxic by MTT assay and cytofluorimetric analysis. Moreover, DAG showed efficacy in inhibiting the highly migratory phenotype of SH-SY5Y cells by wound healing assay; whereas TAG, although structurally similar to DAG, showed no anti-migratory effect. Therefore, this work provides good reasons to conduct further in vitro and in vivo studies focusing on DAG as a potentially useful migrastatic natural marine molecule.

Biosynthesis of Viridicatol in Penicillium palitans Implies a Cytochrome P450-Mediated meta Hydroxylation at a Monoalkylated Benzene Ring

Cyclopenol (1) and viridicatol (6) with m-hydroxyl groups were isolated from a culture of Penicillium palitans. Genome mining and heterologous expression in Aspergillus nidulans led to the identification of their biosynthetic gene cluster and the cytochrome P450 enzyme VdoD responsible for the meta hydroxylation. Precursor feeding experiments into vdoD transformant proved the conversion of cyclopenin (2) to 1, which then undergoes a spontaneous or VdoA-catalyzed rearrangement to 6. A direct conversion of viridicatin (5) to 6 by VdoD was not detected.

Heme Oxygenase-1 Inhibits the Proliferation of Hepatic Stellate Cells by Activating PPARγ and Suppressing NF-κB

Background

Hepatic stellate cells (HSCs) are reported to play significant roles in the development of liver fibrosis. Heme oxygenase-1 (HO-1) is a key rate-limiting enzyme, which could decrease collagen synthesis and liver damage. Nevertheless, it was yet elusive towards the function and mechanism of HO-1.

Methods

An HO-1 inducer Hemin or an HO-1 inhibitor ZnPP-IX was used to treat the activated HSC-T6, respectively. MTT assay was adopted to detect cell proliferation. Immunocytochemical staining was employed to test the levels of alpha-smooth muscle actin (α-SMA), peroxisome proliferator-activated receptor-γ (PPARγ), and nuclear factor-kappa B (NF-kappa B) levels in HSC-T6. HO-1, PPARγ, and NF-κB expression levels were measured by qRT-PCR and Western blotting. ELISA was then used to detect the levels of transforming growth factor- (TGF-) beta 1 (TGF-β1), interleukin-6 (IL-6), serum hyaluronic acid (HA), and serum type III procollagen aminopeptide (PIIIP).

Results

HSC-T6 proliferation was inhibited in Hemin-treated HSCs. The levels of α-SMA, HA, and PIIIP and the production of ECM were lower in Hemin-treated HSCs, whereas those could be rescued by ZnPP-IX. NF-κB activation was decreased, but PPARγ expression was increased after HO-1 upregulation. Furthermore, the levels of TGF-β1 and IL-6, which were downstream of activated NF-κB in HSC-T6, were reduced. The PPAR-specific inhibitor GW9662 could block those mentioned effects.

Conclusions

Our data demonstrated that HO-1 induction could inhibit HSC proliferation and activation by regulating PPARγ expression and NF-κB activation directly or indirectly, which makes it a promising therapeutic target for liver fibrosis.

Bioactive Metabolites From Acid-Tolerant Fungi in a Thai Mangrove Sediment

Despite being potentially useful extremophile resources, there have been few reports on acid-tolerant fungi and their bioactive metabolites. Acidophilic/aciduric fungi (n = 237) were isolated from Thai mangrove sediments in an acidic medium. Using fungal identification technology (including morphologic observation, chemical screening, and sequence comparisons) all the isolates were identified and 41 representative isolates were selected for analysis of the phylogenetic relationships (ITS rDNA, β-tubulin, calmodulin, and actin gene sequences). There were seven genera identified – Penicillium; Aspergillus; Talaromyces; Cladosporium; Allophoma; Alternaria; and Trichoderma – in four taxonomic orders of the phylum Ascomycota, and Penicillium, Aspergillus, and Talaromyces were the dominant genera. Acidity tolerance was evaluated and 95% of the isolates could grow under extremely acidic conditions (pH 2). Six strains were classed as acidophilic fungi that cannot survive under pH 7, all of which had an extraordinarily close genetic relationship and belonged to the genus Talaromyces. This is the first report on the acidophilic characteristics of this genus. The antimicrobial, anti-tumor, and antiviral activities of the fermentation extracts were evaluated. Nearly three-quarters of the extracts showed cytotoxic activity, while less than a quarter showed antimicrobial or anti-H1N1 activity. The typical aciduric fungus Penicillium oxalicum OUCMDZ-5207 showed similar growth but completely different chemical diversity at pH 3 and 7. The metabolites of OUCMDZ-5207 that were obtained only at pH 3 were identified as tetrahydroauroglaucin (1), flavoglaucin (2), and auroglaucin (3), among which auroglaucin showed strong selective inhibition of A549 cells with an IC₅₀ value of 5.67 μM. These results suggest that acid stress can activate silent gene clusters to expand the diversity of secondary metabolites, and the bioprospecting of aciduric/acidophilic microorganism resources in Thai mangrove sediments may lead to the discovery of compounds with potential medicinal applications.

In vitro Anti-Inflammatory and Anti-Oxidative Stress Activities of Kushenol C Isolated from the Roots of Sophora flavescens

Kushenol C (KC) is a prenylated flavonoid isolated from the roots of Sophoraflavescens aiton. Little is known about its anti-inflammatory and anti-oxidative stress activities. Here, we investigated the anti-inflammatory and anti-oxidative stress effects of KC in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages, and tert-butyl hydroperoxide (tBHP)-induced oxidative stress in HaCaT cells. The results demonstrated that KC dose-dependently suppressed the production of inflammatory mediators, including NO, PGE₂, IL-6, IL1β, MCP-1, and IFN-β in LPS-stimulated RAW264.7 macrophages. The study demonstrated that the inhibition of STAT1, STAT6, and NF-κB activations by KC might have been responsible for the inhibition of NO, PGE₂, IL-6, IL1β, MCP-1, and IFN-β in the LPS-stimulated RAW264.7 macrophages. KC also upregulated the expression of HO-1 and its activities in the LPS-stimulated RAW264.7 macrophages. The upregulation of Nrf2 transcription activities by KC in the LPS-stimulated RAW264.7 macrophages was demonstrated to be responsible for the upregulation of HO-1 expression and its activity in LPS-stimulated RAW264.7 macrophages. In HaCaT cells, KC prevented DNA damage and cell death by upregulating the endogenous antioxidant defense system involving glutathione, superoxide dismutase, and catalase, which prevented reactive oxygen species production from tert-butyl hydroperoxide (tBHP)-induced oxidative stress in HaCaT cells. The upregulated activation of Nrf2 and Akt in the PI3K-Akt signaling pathway by KC was demonstrated to be responsible for the anti-oxidative stress activity of KC in HaCaT cells. Collectively, the study suggests that KC can be further investigated as a potential anti-inflammatory candidate for the treatment of inflammatory diseases.

Water-separated part of Chloranthus serratus alleviates lipopolysaccharide- induced RAW264.7 cell injury mainly by regulating the MAPK and Nrf2/HO-1 inflammatory pathways

Background

Chloranthus serratus (Chloranthaceae) has been used to treat bruises, rheumatoid and bone pain. However, the anti-inflammatory mechanisms of C. serratus in vitro have not been fully elucidated. The present study aimed to explore the anti-inflammatory activity and potential mechanisms of C. serratus’s separated part of water (CSSPW) in lipopolysaccharide (LPS)-induced RAW264.7 cells.

Methods

The concentrations of CSSPW were optimized by CCK-8 method. Nitric oxide (NO) content was detected by one-step method. The levels of inflammatory cytokines were determined by enzyme-linked immunosorbent assay (ELISA). Gene expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was detected by real-time quantitative PCR (qPCR). Immunofluorescence and DCFH-DA fluorescent probes were used to detect p65 nuclear translocation and reactive oxygen species (ROS) content, respectively. Western blotting was used to assay the protein expression of mitogen-activated protein kinases (MAPK), nuclear factor-kappa B (NF-κB) and nuclear transcription factor E2 related factor 2/haem oxygenase-1 (Nrf2/HO-1) pathways.

Results

The final concentrations of 15 ng/mL, 1.5 μg/mL and 150 μg/mL were selected as low, medium and high doses of CSSPW, respectively. CSSPW treatment significantly reduced the generation of NO, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), prostaglandinE₂ (PGE₂), iNOS mRNA and COX-2 mRNA in response to LPS stimulation. Furthermore, the protein expression of the MAPK and NF-κB pathways was suppressed by CSSPW treatment, as well as p65 nuclear translocation and ROS production. In contrast, the protein expression of the Nrf2/HO-1 pathway was markedly upregulated.

Conclusions

CSSPW exerts its anti-inflammatory effect via downregulating the production of pro-inflammatory mediators, inhibiting the activation of NF-κB and MAPK pathways, as well as activating Nrf2/HO-1 pathway in LPS-induced RAW264.7 cells.

A Review of Anti-Inflammatory Compounds from Marine Fungi, 2000-2018

Inflammation is a generalized, nonspecific, and beneficial host response of foreign challenge or tissue injury. However, prolonged inflammation is undesirable. It will cause loss function of involve organs, such as heat, pain redness, and swelling. Marine natural products have gained more and more attention due to their unique mechanism of anti-inflammatory action, and have considered a hotspot for anti-inflammatory drug development. Marine-derived fungi are promising sources of structurally unprecedented bioactive natural products. So far, a plethora of new secondary metabolites with anti-inflammatory activities from marine-derived fungi had been widely reported. This review covers 133 fungal metabolites described in the period of 2000 to 2018, including the structures and origins of these secondary metabolites.

Anti-inflammatory effects of chemical components from Ginkgo biloba L. male flowers on lipopolysaccharide-stimulated RAW264.7 macrophages

Ginkgo biloba L., well known as living fossil, have various pharmacological activities. Eighteen compounds were isolated from Ginkgo male flowers including a novel matsutake alcohol glycoside, Ginkgoside A (1), and 17 known compounds-calaliukiuenoside (2), benzylalcohol O-α-l-arabinopyranosyl-(1 → 6)-β-d-glucopyranoside (3), amentoflavone (4), sciadopitysin (5), bilobetin (6), isoginkgetin (7), olivil 4-O-β-d-glucopyranoside (8), dihydrodehydrodiconiferyl alcohol-4-O-β-d-glucoside (9), (+)-cyclo-olivil-6-O-β-d-glucopyranoside (10), (-)-isolariciresinol 4-O-β-d-glucopyranoside (11), coniferin (12), trans-cinnamic acid-4-O-β-d-glucopyranoside (13), p-coumaryl alchol glucoside (14), stroside B (15), methylconiferin (16), cis-p-coumaric acid 4-O-β-d-glucopyranoside (17), and cis-coniferin (18). Thirteen of these compounds had not previously found in Ginkgo. All extractive fractions and isolated compounds were evaluated for their anti-inflammatory ability in the lipopolysaccharide-induced RAW264.7 macrophages. The ethanol extract of Ginkgo flowers and the chloroform and ethyl acetate fractions can significantly decrease nitric oxide (NO), interleukin-6 (IL-6), and prostaglandin E₂ (PGE₂ ) production at 100 μg/ml. The most effective compounds, bilobetin (6) and isoginkgetin (7), elevated the NO inhibition ratios to 80.19% and 82.37% at 50 μM, respectively. They also exhibited significant dose-dependent inhibitory effects on tumor necrosis factor-α, IL-6, PGE₂ , inducible NO synthase mRNA, and cyclooxygenase-2 mRNA levels. So they can be promising candidates for the development of new anti-inflammatory agents.

Auroglaucin-related neuroprotective compounds from Vietnamese marine sediment-derived fungus Aspergillus niveoglaucus

Two new auroglaucin-derived compounds, niveoglaucins A (1) and B (2), together with four known related compounds were isolated from extract of the marine sediment-derived strain of Aspergillus niveoglaucus. The structures of these compounds were determined by 1D and 2D NMR spectroscopy and high resolution MS. The plausible biosynthetic pathway was proposed for new compounds 1 and 2. The neuroprotective activity in 6-OHDA-induced Parkinson's disease cell model was shown for niveoglaucin A (1).

Bioactive terpenoids from Santalum album derived endophytic fungus Fusarium sp. YD-2

Two new spiromeroterpenoids, namely fusariumin A (1) and B (2), along with four known terpenoids, asperterpenoid A (3), agathic acid (4), guignardone N (5), and trametenolic acid (6), were obtained from the endophytic fungus Fusarium sp. YD-2, derived from the twigs of Santalum album. Their structures were elucidated by a combination of spectroscopic analyses. The absolute configuration of 1 was determined by single-crystal X-ray diffraction using Cu Kα radiation, and that of 2 was elucidated on the basis of experimental and calculated electronic circular dichroism spectra. Compound 2 exhibited moderate anti-inflammatory activity in vitro by inhibiting nitric oxide (NO) production in lipopolysaccharide activated RAW264.7 cells with an IC₅₀ value of 50 μM, and compound 3 showed strong anti-inflammatory activity with an IC₅₀ value of 1.6 μM. In the antibacterial assay, compound 1 displayed significant activities against Staphylococcus aureus and Pseudomonas aeruginosa with an MIC value of 6.3 μg mL⁻¹, and compound 3 showed moderate activities against Salmonella enteritidis and Micrococcus luteus with MIC values of 6.3 and 25.2 μg mL⁻¹, respectively.

Two new spiromeroterpenoids, namely fusariumin A (1) and B (2), along with four known terpenoids, asperterpenoid A (3), agathic acid (4), guignardone N (5), and trametenolic acid (6), were obtained from the endophytic fungus Fusarium sp. YD-2, derived from the twigs of Santalum album.

N-Me-trichodermamide B isolated from Penicillium janthinellum, with antioxidant properties through Nrf2-mediated signaling pathway

A new trichodermamide-like alkaloid, N-Me-trichodermamide B (compound 1), was isolated from a marine fungus Penicillium janthinellum HDN13-309. The structure and absolute configuration of compound 1 were determined by extensive NMR analysis and the modified Mosher's method. This new alkaloid exhibited cellular protection from the H₂O₂-induced oxidative damage, and the mechanism study revealed that this antioxidant activity was regulated through Nrf2-mediated signaling pathway in HaCaT human keratinocytes. In addition, the inhibitor of p38 abrogated compound 1-induced phosphorylation of p38, up-expression of HO-1, and the nuclear localization of Nrf2. As a result, it suggested that this new alkaloid-induced antioxidant signaling pathway might be initiated through activation of p38.

Asperflavin, an Anti-Inflammatory Compound Produced by a Marine-Derived Fungus, Eurotium amstelodami

In the present study, 16 marine-derived fungi were isolated from four types of marine materials including float, algae, animals and drift woods along with the coast of Jeju Island, Korea and evaluated for anti-inflammatory effects in lipopolysaccharide (LPS)-stimulated RAW 24.7 cells. The broth and mycelium extracts from the 16 fungi were prepared and the broth extract (BE) of Eurotium amstelodami (015-2) inhibited nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells without cytotoxicity. By further bioassay-guided isolation, three compounds including asperflavin, neoechinulin A and preechinulin were successfully isolated from the BE of E. amstelodami. It was revealed that asperflavin showed no cytotoxicity up to 200 μM and significantly inhibited LPS-induced NO and PGE2 production in a dose-dependent manner. In the western blot results, asperflavin suppressed only inducible NOS (iNOS), but COX-2 were slightly down-regulated. Asperflavin was also observed to inhibit the production of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6. In conclusion, this study reports a potential use of asperflavin isolated from a marine fungus, E. amstelodami as an anti-inflammatory agent via suppression of iNOS and pro-inflammatory cytokines as well as no cytotoxicity.

Anti-Inflammatory Effects of Curvularin-Type Metabolites from a Marine-Derived Fungal Strain Penicillium sp. SF-5859 in Lipopolysaccharide-Induced RAW264.7 Macrophages

Chemical study on the extract of a marine-derived fungal strain Penicillium sp. SF-5859 yielded a new curvularin derivative (1), along with eight known curvularin-type polyketides (2–9). The structures of these metabolites (1–9) were established by comprehensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS). In vitro anti-inflammatory effects of these metabolites were evaluated in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Among these metabolites, 3–9 were shown to strongly inhibit LPS-induced overproduction of nitric oxide (NO) and prostaglandin E₂ (PGE₂) with IC₅₀ values ranging from 1.9 μM to 18.1 μM, and from 2.8 μM to 18.7 μM, respectively. In the further evaluation of signal pathways involved in these effects, the most active compound, (10E,15S)-10,11-dehydrocurvularin (8) attenuated the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW264.7 macrophages. Furthermore, compound 8 was shown to suppress the upregulation of pro-inflammatory mediators and cytokines via the inhibition of the nuclear factor-κB (NF-κB) signaling pathway, but not through the mitogen-activated protein kinase (MAPK) pathway. Based on the comparisons of the different magnitude of the anti-inflammatory effects of these structurally-related metabolites, it was suggested that the opening of the 12-membered lactone ring in curvularin-type metabolites and blocking the phenol functionality led to the significant decrease in their anti-inflammatory activity.

Discovery of the molecular mechanisms of the novel chalcone-based Magnaporthe oryzae inhibitor C1 using transcriptomic profiling and co-expression network analysis

Background

In our previous studies, we discovered a series of chalcone-based phytopathogenic fungus inhibitors. However, knowledge of their effects, detailed targets and molecular mechanisms in Magnaporthe oryzae (M. oryzae) remained limited.

Methods

To explore the expression and function of differentially expressed genes in M. oryzae after treatment with compound C1, we analyzed the expression profile of mRNAs using a microarray analysis and GO, KEGG and WGCNA analysis, followed by qRT-PCR and Western blots to validate our findings.

Results

A total of 1013 up-regulated and 995 down-regulated mRNAs were differentially expressed after M. oryzae was treated with C1 compared to those of the control samples. Among these, cytochrome P450, glycylpeptide N-myristoyltransferase (NMT) and peroxisomal membrane protein 4 were identified as the most significant DEGs and were validated by experiments.

Conclusion

In conclusion, our study suggests that the combination of transcriptomic microarray, bioinformatics analysis and weighted gene co-expression networks can be used to predict potential therapeutic targets and to map the pathways regulated by small molecular natural product-like drugs.

Electronic supplementary material

The online version of this article (doi:10.1186/s40064-016-3385-9) contains supplementary material, which is available to authorized users.

Moracin C, A Phenolic Compound Isolated from Artocarpus heterophyllus, Suppresses Lipopolysaccharide-Activated Inflammatory Responses in Murine Raw264.7 Macrophages

Artocarpus heterophyllus, a popular tropical fruit commonly known as the jackfruit tree, is normally planted in subtropical or tropical areas. Since a variety of phytochemicals isolated from A. heterophyllus have been found to possess potently anti-inflammatory, antiviral and antimalarial activities, researchers have devoted much interest to its potential pharmaceutical value. However, the exact mechanism underlying its anti-inflammatory activity is not well characterized. In this study, seven natural products isolated from A. heterophyllus, including 25-Hydroxycycloart-23-en-3-one (HY), Artocarpin (AR), Dadahol A (DA), Morachalcone A (MA), Artoheterophyllin B (AB), Cycloheterophyllin (CY) and Moracin C (MC) were collected. Lipopolysaccharide (LPS)-stimulated inflammatory response in RAW264.7 macrophages were used in this study. Among these compounds, MC significantly inhibited LPS-activated reactive oxygen species (ROS) and nitric oxide (NO) release without marked cytotoxicity. Furthermore, MC effectively reduced LPS stimulated up-regulation of mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and serval pro-inflammatory cytokines (interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α)). Mechanistic studies revealed that the anti-inflammatory effect of MC was associated with the activation of the mitogen activated protein kinases (MAPKs) (including p38, ERK and JNK) and nuclear factor-κB (NF-κB) pathways, especially reducing the nuclear translocation of NF-κB p65 subunit as revealed by nuclear separation experiment and confocal microscopy.

Anti-inflammatory activity of myricetin from Diospyros lotus through suppression of NF-κB and STAT1 activation and Nrf2-mediated HO-1 induction in lipopolysaccharide-stimulated RAW264.7 macrophages

Diospyros lotus is traditionally used for the treatment of diabetes, diarrhea, tumor, and hypertension. The purpose of this study was to investigate the anti-inflammatory effect and underlying molecular mechanisms of myricetin in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Myricetin dose-dependently suppressed the production of pro-inflammatory mediators (NO, iNOS, PGE2, and COX-2) in LPS-stimulated RAW264.7 macrophages. Myricetin administration decreased the production of NO, iNOS, TNF-α, IL-6, and IL-12 in mice. Myricetin decreased NF-κB activation by suppressing the degradation of IκBα, nuclear translocation of p65 subunit of NF-κB, and NF-κB DNA binding activity in LPS-stimulated RAW264.7 macrophages. Moreover, myricetin attenuated the phosphorylation of STAT1 and the production of IFN-β in LPS-stimulated RAW264.7 macrophages. Furthermore, myricetin induced the expression of HO-1 through Nrf2 translocation. In conclusion, these results suggest that myricetin inhibits the production of pro-inflammatory mediators through the suppression of NF-κB and STAT1 activation and induction of Nrf2-mediated HO-1 expression in LPS-stimulated RAW264.7 macrophages.

Marine natural products

This review covers the literature published in 2014 for marine natural products (MNPs), with 1116 citations (753 for the period January to December 2014) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1378 in 456 papers for 2014), together with the relevant biological activities, source organisms and country of origin. Reviews, biosynthetic studies, first syntheses, and syntheses that lead to the revision of structures or stereochemistries, have been included.

Dihydroisocoumarin Derivatives from Marine-Derived Fungal Isolates and Their Anti-inflammatory Effects in Lipopolysaccharide-Induced BV2 Microglia

Chemical investigation of the EtOAc extracts of marine-derived fungal isolates Aspergillus sp. SF-5974 and Aspergillus sp. SF-5976 yielded a new dihydroisocoumarin derivative (1) and 12 known metabolites. The structures of the isolated metabolites were established by extensive spectroscopic analyses, including 1D and 2D NMR spectra and MS data. Among the metabolites, the absolute configuration of 5'-hydroxyasperentin (6) was determined by single-crystal X-ray diffraction analysis. The in vitro antineuroinflammatory effects of the metabolites were also evaluated in lipopolysaccharide (LPS)-stimulated microglial cells. Among the isolated metabolites, dihydroisocoumarin derivatives 1-6 (10-80 μM) were shown to inhibit LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production by suppressing the expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), respectively, in LPS-stimulated BV2 microglia. Further, 1 (20-80 μM) was found to suppress the phosphorylation of the inhibitor of nuclear factor kappa B-α (IκB-α), interrupt the nuclear translocation of nuclear factor kappa B (NF-κB), and decrease the activation of p38 mitogen-activated protein kinase (MAPK).

Atomic force microscopy based investigations of anti-inflammatory effects in lipopolysaccharide-stimulated macrophages

A new method based on atomic force microscopy (AFM) was developed to investigate the anti-inflammatory effects of drugs on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The LPS-stimulated RAW264.7 macrophage cell line is a widely used in vitro cell model for the screening of anti-inflammatory drugs or the study of anti-inflammatory mechanisms. In this work, the inhibitory effects of dexamethasone and quercetin on LPS-CD14 receptor binding in RAW264.7 macrophages was probed by LPS-functionalized tips for the first time. Both dexamethasone and quercetin were found to inhibit LPS-induced NO production, iNOS expression, IκBα phosphorylation, and IKKα/β phosphorylation in RAW264.7 macrophages. The morphology and ultrastructure of RAW264.7 macrophages were determined by AFM, which indicated that dexamethasone and quercetin could inhibit LPS-induced cell surface particle size and roughness increase in RAW264.7 macrophages. The binding of LPS and its receptor in RAW264.7 macrophages was determined by LPS-functionalized AFM tips, which demonstrated that the binding force and binding probability between LPS and CD14 receptor on the surface of RAW264.7 macrophages were also inhibited by dexamethasone or quercetin treatment. The obtained results imply that AFM, which is very useful for the investigation of potential targets for anti-inflammatory drugs on native macrophages and the enhancement of our understanding of the anti-inflammatory effects of drugs, is expected to be developed into a promising tool for the study of anti-inflammatory drugs.