Bioactive PKS–NRPS Alkaloids from the Plant-Derived Endophytic Fungus Xylaria arbuscula

A novel hybrid PKS–NRPS alkaloid, xylarialoid A (1), containing a 13-membered macrocyclic moiety and [5,5,6] fused tricarbocyclic rings, together with ten known cytochalasins (2–11), was isolated from a plant-derived endophytic fungus, Xylaria arbuscula. The chemical structures of all compounds were elucidated using 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculation. Compounds 1–3 and 10 exhibited significant antitumor activities against A549 and Hep G2 cell lines, with IC₅₀ values of 3.6–19.6 μM. In addition, compound 1 showed potent anti-inflammatory activity against LPS-induced nitric oxide (NO) production in macrophage RAW 264.7 cells (IC₅₀, 6.6 μM).     

Polyphenols from the Peels of Punica granatum L. and Their Bioactivity of Suppressing Lipopolysaccharide-Stimulated Inflammatory Cytokines and Mediators in RAW 264.7 Cells via Activating p38 MAPK and NF-κB Signaling Pathways

Punica granatum L. (Punicaceae) is a popular fruit all over the world. Owning to its enriched polyphenols, P. granatum has been widely used in treating inflammation-related diseases, such as cardiovascular diseases and cancer. Twenty polyphenols, containing nine unreported ones, named punicagranins A–I (1–9), along with eleven known isolates (10–20), were obtained from the peels. Their detailed structures were elucidated based on UV, IR, NMR, MS, optical rotation, ECD analyses and chemical evidence. The potential anti-inflammatory activities of all polyphenols were examined on a lipopolysaccharide (LPS)-induced inflammatory macrophages model, which indicated that enhancing nitric oxide (NO) production in response to inflammation stimulated in RAW 264.7 cells was controlled by compounds 1, 3, 5–8, 10, 11, 14 and 16–20 in a concentration-dependent manner. The investigation of structure–activity relationships for tannins 6–8 and 12–20 suggested that HHDP, flavogallonyl and/or gallagyl were key groups for NO production inhibitory activity. Western blotting indicated that compounds 6–8 could down-regulate the phosphorylation levels of proteins p38 MAPK, IKKα/β, IκBα and NF-κB p65 as well as inhibit the levels of inflammation-related cytokines and mediators, such as IL-6, TNF-α, iNOS and COX-2, at the concentration of 30 μM. In conclusion, polyphenols are proposed to be the potential anti-inflammatory active ingredients in P. granatum peels, and their molecular mechanism is likely related to the regulation of the p38 MAPK and NF-κB signaling pathways.     

Methylenedioxy Piperamide-Derived Compound D5 Regulates Inflammatory Cytokine Secretion in a Culture of Human Glial Cells

Neuroinflammation is the cornerstone of most neuronal disorders, particularly neurodegenerative diseases. During the inflammatory process, various pro-inflammatory cytokines, chemokines, and enzymes—such as interleukin 1-β (IL1-β), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), inducible nitric oxide synthases (iNOS), inhibitory kappa kinase (IKK), and inducible nitric oxide (NO)—are over-expressed in response to every stimulus. Methods: In the present study, we focused on the anti-neuroinflammatory efficacy of (2E,4E)-N,5-bis(benzo[d][1,3]dioxol-5-yl)penta-2,4-dienamide, encoded D5. We investigated the efficacy of D5 on the upstream and downstream products of inflammatory pathways in CHME3 and SVG cell lines corresponding to human microglia and astrocytes, respectively, using various in silico, in vitro, and in situ techniques. Results: The results showed that D5 significantly reduced the level of pro-inflammatory cytokines by up-regulating PPAR-γ expression and suppressing IKK-β, iNOS, NO production, and NF-κB activation in inflamed astrocytes (SVG) and microglia (CHME3) after 24 h of incubation. The data demonstrated remarkably higher efficacy of D5 compared to ASA (Aspirin) in reducing NF-κB-dependent neuroinflammation. Conclusions: We observed that the functional-group alteration had an extreme influence on the levels of druggability and the immunomodulatory properties of two analogs of piperamide, D5, and D4 ((2E,4E)-5-(benzo[d][1,3]dioxol-5-yl)-N-(4-(hydroxymethyl)phenyl)penta-2,4-dienamide)). The present study suggested D5 as a potential anti-neuroinflammatory agent for further in vitro, in vivo, and clinical investigations.     

Prunetin 4′-O-Phosphate,a Novel Compound,in RAW 264.7 Macrophages Exerts Anti-Inflammatory Activity via Suppression of MAP Kinases and the NFκB Pathway

Biorenovation, a microbial enzyme-assisted degradation process of precursor compounds, is an effective approach to unraveling the potential bioactive properties of the derived compounds. In this study, we obtained a new compound, prunetin 4′-O-phosphate (P4P), through the biorenovation of prunetin (PRN), and investigated its anti-inflammatory effects in lipopolysaccharide (LPS)-treated RAW 264.7 macrophage cells. The anti-inflammatory effect of P4P was evaluated by measuring the production of prostaglandin-E₂ (PGE₂), nitric oxide (NO), which is an inflammation-inducing factor, and related cytokines such as tumor necrosis factor-α (TNFα), interleukin-1β (IL1β), and interleukin-6 (IL6). The findings demonstrated that P4P was non-toxic to cells, and its inhibition of the secretion of NO—as well as pro-inflammatory cytokines—was concentration-dependent. A simultaneous reduction in the protein expression level of pro-inflammatory proteins such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) was observed. Moreover, the phosphorylation of mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), p38 MAPK (p38), and nuclear factor kappa B (NFκB) was downregulated. To conclude, we report that biorenovation-based phosphorylation of PRN improved its anti-inflammatory activity. Cell-based in vitro assays further confirmed that P4P could be applied in the development of anti-inflammatory therapeutics.     

Isoorientin Inhibits Amyloid β25–35-Induced Neuronal Inflammation in BV2 Cells by Blocking the NF-κB Signaling Pathway

Alzheimer’s disease (AD) is a severe neurodegenerative disorder. AD is pathologically characterized by the formation of intracellular neurofibrillary tangles, and extracellular amyloid plaques which were comprised of amyloid-beta (Aβ) peptides. Aβ induces neurodegeneration by activating microglia, which triggers neurotoxicity by releasing various inflammatory mediators and reactive oxygen species (ROS). Nuclear factor-kappa B (NF-κB) is expressed in human tissues including the brain and plays an important role in Aβ-mediated neuronal inflammation. Thus, the identification of molecules that inhibit the NF-κB pathway is considered an attractive strategy for the treatment and prevention of AD. Isoorientin (3′,4′,5,7-Tetrahydroxy-6-C-glucopyranosyl flavone; ISO), which can be extracted from several plant species, such as Philostachys and Patrinia is known to have various pharmacological activities such as anticancer, antioxidant, and antibacterial activity. However, the effect of ISO on Aβ-mediated inflammation and apoptosis in the brain has yet to be elucidated. In the present study, we investigated whether ISO regulated Aβ-induced neuroinflammation in microglial cells and further explored the underlying mechanisms. Our results showed that ISO inhibited the expression of iNOS and COX-2 induced by Aβ_25–35. And, it inhibited the secretion of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In addition, ISO reduced the ROS production in Aβ_25–35-induced BV2 cells and inhibited NF-κB activation. Furthermore, ISO blocked Aβ_25–35-induced apoptosis of BV2 cells. Based on these findings, we suggest that ISO represents a promising therapeutic drug candidate for the treatment and prevention of AD.     

Bioactive Polyketide and Diketopiperazine Derivatives from the Mangrove-Sediment-Derived Fungus Aspergillus sp. SCSIO41407

Ten polyketide derivatives (1–10), including a new natural product named (E)-2,4-dihydroxy-3-methyl-6-(2-oxopent-3-en-1-yl) benzaldehyde (1), and five known diketopiperazines (11–15), were isolated from the mangrove-sediment-derived fungus Aspergillus sp. SCSIO41407. The structures of 1–15 were determined via NMR and MS spectroscopic analysis. In a variety of bioactivity screening, 3 showed weak cytotoxicity against the A549 cell line, and 2 exhibited weak antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 3, 5, and 6 showed inhibition against acetylcholinesterase (AChE) with IC₅₀ values of 23.9, 39.9, and 18.6 μM. Compounds 11, 12, and 14 exhibited obvious inhibitory activities of lipopolysaccharide (LPS)-induced nuclear factor-κB (NF-κB) with IC₅₀ values of 19.2, 20.9, and 8.7 μM, and they also suppressed RANKL-induced osteoclast differentiation in bone marrow macrophages cells (BMMCs), with the concentration of 5 μM. In silico molecular docking with AChE and NF-κB p65 protein were also performed to understand the inhibitory activities, and 1, 11–14 showed obvious protein/ligand-binding effects to the NF-κB p65 protein.     

Luteolin-3′-O-Phosphate Inhibits Lipopolysaccharide-Induced Inflammatory Responses by Regulating NF-κB/MAPK Cascade Signaling in RAW 264.7 Cells

Luteolin (LT), present in most plants, has potent anti-inflammatory properties both in vitro and in vivo. Furthermore, some of its derivatives, such as luteolin-7-O-glucoside, also exhibit anti-inflammatory activity. However, the molecular mechanisms underlying luteolin-3′-O-phosphate (LTP)-mediated immune regulation are not fully understood. In this paper, we compared the anti-inflammatory properties of LT and LTP and analyzed their molecular mechanisms of action; we obtained LTP via the biorenovation of LT. We investigated the anti-inflammatory activities of LT and LTP in macrophage RAW 264.7 cells. We confirmed from previously reported literature that LT inhibits the production of nitric oxide and prostaglandin E₂, as well as the expression of inducible NO synthetase and cyclooxygenase-2. In addition, expressions of inflammatory genes and mediators, such as tumor necrosis factor-α, interleukin-6, and interleukin-1β, were suppressed. LTP showed anti-inflammatory activity similar to LT, but better anti-inflammatory activity in all the experiments, while also inhibiting mitogen-activated protein kinase and nuclear factor-kappa B more effectively than LT. At a concentration of 10 μM, LTP showed differences of 2.1 to 44.5% in the activity compared to LT; it also showed higher anti-inflammatory activity. Our findings suggest that LTP has stronger anti-inflammatory activity than LT.     

Ochraceopyronide,a Rare α-Pyrone-C-lyxofuranoside from a Soil-Derived Fungus Aspergillus ochraceopetaliformis

The fungal strain was isolated from a soil sample collected in Giza province, Egypt, and was identified as Aspergillus ochraceopetaliformis based on phenotypic and genotypic data. The ethyl acetate extract of the fungal strain exhibited promising activity levels against several pathogenic test organisms and through a series of ¹H NMR guided chromatographic separations, a new α-pyrone-C-lyxofuranoside (1) along with four known compounds (2–5) were isolated. The planar structure of the new metabolite was elucidated by detailed analysis of its 1D/2D NMR and HRMS/IR/UV spectroscopic data, while the relative configuration of the sugar moiety was determined by a combined study of NOESY and coupling constants data, with the aid of theoretical calculations. The structures of the known compounds—isolated for the first time from A. ochraceopetaliformis—were established by comparison of their spectroscopic data with those in the literature. All isolated fungal metabolites were evaluated for their antibacterial and antifungal activities against six Gram-positive and Gram-negative bacteria as well as against three human pathogenic fungi.     

New Cyclic Diarylheptanoids from Platycarya strobilacea

Five new cyclic diarylheptanoids (platycary A–E, compounds 1–5) and three previously identified analogues (i.e., phttyearynol (compound 6), myricatomentogenin (compound 7), and juglanin D (compound 8)) were isolated from the stem bark of Platycarya strobilacea. The structures of these compounds were determined using NMR, HRESIMS, and electronic circular dichroism (ECD) data. The cytotoxicity of compounds 1–5 and their ability to inhibit nitric oxide (NO) production, as well as protect against the corticosterone-induced apoptosis of Pheochromocytoma (PC12) cells, were evaluated in vitro using the appropriate bioassays. Compounds 1 and 2 significantly inhibited the corticosterone-induced apoptosis of PC12 cells at a concentration of 20 μΜ.     

Molecular Targets Implicated in the Antiparasitic and Anti-Inflammatory Activity of the Phytochemical Curcumin in Trichomoniasis

Trichomoniasis, is the most prevalent non-viral sexually transmitted disease worldwide. Although metronidazole (MDZ) is the recommended treatment, several strains of the parasite are resistant to MDZ, and new treatments are required. Curcumin (CUR) is a polyphenol with anti-inflammatory, antioxidant and antiparasitic properties. In this study, we evaluated the effects of CUR on two biochemical targets: on proteolytic activity and hydrogenosomal metabolism in Trichomonas vaginalis. We also investigated the role of CUR on pro-inflammatory responses induced in RAW 264.7 phagocytic cells by parasite proteinases on pro-inflammatory mediators such as the nitric oxide (NO), tumor necrosis factor α (TNFα), interleukin-1beta (IL-1β), chaperone heat shock protein 70 (Hsp70) and glucocorticoid receptor (mGR). CUR inhibited the growth of T. vaginalis trophozoites, with an IC₅₀ value between 117 ± 7 μM and 173 ± 15 μM, depending on the culture phase. CUR increased pyruvate:ferredoxin oxidoreductase (PfoD), hydrogenosomal enzyme expression and inhibited the proteolytic activity of parasite proteinases. CUR also inhibited NO production and decreased the expression of pro-inflammatory mediators in macrophages. The findings demonstrate the potential usefulness of CUR as an antiparasitic and anti-inflammatory treatment for trichomoniasis. It could be used to control the disease and mitigate the associated immunopathogenic effects.     

Anti-Inflammatory Effects of 6-Methylcoumarin in LPS-Stimulated RAW 264.7 Macrophages via Regulation of MAPK and NF-κB Signaling Pathways

Persistent inflammatory reactions promote mucosal damage and cause dysfunction, such as pain, swelling, seizures, and fever. Therefore, in this study, in order to explore the anti-inflammatory effect of 6-methylcoumarin (6-MC) and suggest its availability, macrophages were stimulated with lipopolysaccharide (LPS) to conduct an in vitro experiment. The effects of 6-MC on the production and levels of pro-inflammatory cytokines (interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α) and inflammatory mediators (nitric oxide (NO), prostaglandin E₂ (PGE₂)) in LPS-stimulated RAW 264.7 cells were examined. The results showed that 6-MC reduced the levels of NO and PGE₂ without being cytotoxic. In addition, it was demonstrated that the increase in the expression of pro-inflammatory cytokines caused by LPS stimulation, was decreased in a concentration-dependent manner with 6-MC treatment. Moreover, Western blot results showed that the protein levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), which increased with LPS treatment, were decreased by 6-MC treatment. Mechanistic studies revealed that 6-MC reduced the phosphorylation of the mitogen-activated protein kinase (MAPK) family and IκBα in the MAPK and nuclear factor-kappa B (NF-κB) pathways, respectively. These results suggest that 6-MC is a potential therapeutic agent for inflammatory diseases that inhibits inflammation via the MAPK and NF-κB pathways.     

Synthesis,Structure, Carbohydrate Enzyme Inhibition,Antioxidant Activity,In Silico Drug-Receptor Interactions and Drug-Like Profiling of the 5-Styryl-2-Aminochalcone Hybrids

The 2-amino-5-(3/4-fluorostyryl)acetophenones were prepared and reacted with benzaldehyde derivatives to afford the corresponding 5-styryl-2-aminochalcone hybrids. The trans geometry of the styryl and α,β-unsaturated carbonyl arms, and the presence of NH^…O intramolecular hydrogen bond were validated using ¹H-NMR and X-ray data. The 2-amino-5-styrylacetophenones and their 5-styryl-2-aminochalcone derivatives were screened in vitro for their capability to inhibit α-glucosidase and/or α-amylase activities. Their antioxidant properties were evaluated in vitro through the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and nitric oxide (NO) free radical scavenging assays. Kinetic studies of the most active derivatives from each series against α-glucosidase and/or α-amylase activities have been performed supported by molecular docking studies to determine plausible protein–ligand interactions on a molecular level. The key aspects of the pharmacokinetics of these compounds, i.e., absorption, distribution, metabolism, and excretion have also been simulated at theoretical level. The most active compounds from each series, namely, 2a and 3e, were evaluated for cytotoxicity against the normal monkey kidney cells (Vero cells) and the adenocarcinomic human epithelial (A549) cell line to establish their safety profile at least in vitro.     

Neuroinflammatory Markers: Key Indicators in the Pathology of Neurodegenerative Diseases

Neuroinflammation, a protective response of the central nervous system (CNS), is associated with the pathogenesis of neurodegenerative diseases. The CNS is composed of neurons and glial cells consisting of microglia, oligodendrocytes, and astrocytes. Entry of any foreign pathogen activates the glial cells (astrocytes and microglia) and overactivation of these cells triggers the release of various neuroinflammatory markers (NMs), such as the tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-1β (IL-10), nitric oxide (NO), and cyclooxygenase-2 (COX-2), among others. Various studies have shown the role of neuroinflammatory markers in the occurrence, diagnosis, and treatment of neurodegenerative diseases. These markers also trigger the formation of various other factors responsible for causing several neuronal diseases including Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), multiple sclerosis (MS), ischemia, and several others. This comprehensive review aims to reveal the mechanism of neuroinflammatory markers (NMs), which could cause different neurodegenerative disorders. Important NMs may represent pathophysiologic processes leading to the generation of neurodegenerative diseases. In addition, various molecular alterations related to neurodegenerative diseases are discussed. Identifying these NMs may assist in the early diagnosis and detection of therapeutic targets for treating various neurodegenerative diseases.     

Anti-Inflammatory Effects of Spiramycin in LPS-Activated RAW 264.7 Macrophages

Drug repurposing is a simple concept with a long history, and is a paradigm shift that can significantly reduce the costs and accelerate the process of bringing a new small-molecule drug into clinical practice. We attempted to uncover a new application of spiramycin, an old medication that was classically prescribed for toxoplasmosis and various other soft-tissue infections; specifically, we initiated a study on the anti-inflammatory capacity of spiramycin. For this purpose, we used murine macrophage RAW 264.7 as a model for this experiment and investigated the anti-inflammatory effects of spiramycin by inhibiting the production of pro-inflammatory mediators and cytokines. In the present study, we demonstrated that spiramycin significantly decreased nitric oxide (NO), interleukin (IL)-1β, and IL-6 levels in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Spiramycin also inhibited the expression of NO synthase (iNOS), potentially explaining the spiramycin-induced decrease in NO production. In addition, spiramycin inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs); extracellular signal-regulated kinase (ERK) and c-Jun N terminal kinase (JNK) as well as the inactivation and subsequent nuclear translocation of nuclear factor κB (NF-κB). This indicated that spiramycin attenuates macrophages’ secretion of IL-6, IL-1β, and NO, inducing iNOS expression via the inhibition of the NF-κB and MAPK signaling pathways. Finally, we tested the potential application of spiramycin as a topical material by human skin primary irritation tests. It was performed on the normal skin (upper back) of 31 volunteers to determine whether 100 μM and μM of spiramycin had irritation or sensitization potential. In these assays, spiramycin did not induce any adverse reactions. In conclusion, our results demonstrate that spiramycin can effectively attenuate the activation of macrophages, suggesting that spiramycin could be a potential candidate for drug repositioning as a topical anti-inflammatory agent.     

Diterpenoids Isolated from Podocarpus macrophyllus Inhibited the Inflammatory Mediators in LPS-Induced HT-29 and RAW 264.7 Cells

Species of Podocarpus are used traditionally in their native areas for the treatment of fevers, asthma, coughs, cholera, chest pain, arthritis, rheumatism, and sexually transmitted diseases. To identify natural products having efficacy against inflammatory bowel disease (IBD), we identified a new, 16-hydroxy-4β-carboxy-O-β-D-glucopyranosyl-19-nor-totarol (4) together with three known diterpenoids from P. macrophyllus. Furthermore, all the extracts, fractions, and isolates 1–4 were investigated for their anti-inflammatory effects by assessing the expression on nitric oxide (NO) production and proinflammatory cytokines in lipopolysaccharide (LPS)-stimulated RAW 264.7 and HT-29 cells. Among them, nagilactone B (2) exhibited a potent anti-inflammatory effect against NO production on RAW 264.7 cells; therefore, nagilactone B was further assessed for anti-inflammatory activity. Western blot analysis revealed that nagilactone B significantly decreased the expression of LPS-stimulated protein, inducible nitric oxide synthase (iNOS), cyclooxygenase (COX)-2, and phosphorylated extracellular regulated kinase (pERK)1/2. In addition, nagilactone B downregulated tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 levels in LPS-induced macrophages and colonic epithelial cells. To our best knowledge, this is the first report on the inhibitory effect of nagilactone B (pure state) and rakanmakilactone G against NO production in LPS-stimulated RAW 264.7 cells. Thus, diterpenoids isolated from P. macrophyllus could be employed as potential therapeutic phytochemicals for IBD.     

In Vitro Anti-Inflammatory Activity of Essential Oil and β-Bisabolol Derived from Cotton Gin Trash

Natural α-bisabolol has been widely used in cosmetics and is sourced mainly from the stems of Candeia trees that have become endangered due to over exploitation. The in vitro anti-inflammatory activity of cotton gin trash (CGT) essential oil and the major terpenoid (β-bisabolol) purified from the oil were investigated against lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages as well as the 3t3 and HS27 fibroblast cell lines. Nitric oxide (NO), prostaglandin E₂ (PGE₂), tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and interleukin 8 (IL-8) were measured using Greiss reagent, enzyme-linked immunosorbent assay (ELISA), and cytokine bead array (CBA)-flow cytometry. Non-toxic concentrations of CGT oil and β-bisabolol (1.6–50.0 µg/mL) significantly inhibited the production of the inflammatory mediators in a dose-dependent manner. Maximal inhibition by β-bisabolol was 55.5% for NO, 62.3% for PGE₂, and 45.3% for TNF-α production in RAW cells. β-Bisabolol induced a level of inhibition similar to an equal concentration of α-bisabolol (50.0 µg/mL), a known anti-inflammatory agent. These results suggest β-bisabolol exerts similar in vitro effects to known topical anti-inflammatory agents and could therefore be exploited for cosmetic and therapeutic uses. This is the first study to report the in vitro anti-inflammatory activity of β-bisabolol in CGT essential oil.     

Anti-Inflammatory Effects of Mitrephora sirikitiae Leaf Extract and Isolated Lignans in RAW 264.7 Cells

Mitrephora sirikitiae Weeras., Chalermglin & R.M.K. Saunders has been reported as a rich source of lignans that contribute to biological activities and health benefits. However, cellular anti-inflammatory effects of M. sirikitiae leaves and their lignan compounds have not been fully elucidated. Therefore, this study aimed to investigate the anti-inflammatory activities of methanol extract of M. sirikitiae leaves and their lignan constituents on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 mouse macrophage cells. Treatment of RAW 264.7 cells with the methanol extract of M. sirikitiae leaves and its isolated lignans, including (−)-phylligenin (2) and 3′,4-O-dimethylcedrusin (6) significantly decreased LPS-induced prostaglandin E₂ (PGE₂) and nitric oxide (NO) productions. These inhibitory effects of the extract and isolated lignans on LPS-induced upregulation of PGE₂ and NO productions were derived from the suppression of cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) production, respectively. In addition, treatment with 2-(3,4-dimethoxyphenyl)-6-(3,5-dimethoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane (3) and mitrephoran (5) was able to suppress LPS-induced tumor necrosis factor alpha (TNF-α) secretion and synthesis in RAW 264.7 cells. These results demonstrated that M. sirikitiae leaves and some isolated lignans exhibited potent anti-inflammatory activity through the inhibition of secretion and synthesis of PGE₂, NO, and TNF-α.     

Diterpenoid Compounds Isolated from Chloranthus oldhamii Solms Exert Anti-Inflammatory Effects by Inhibiting the IKK/NF-κB Pathway

Chloranthus oldhamii Solms (CO) is a folk medicine for treating infection and arthritis pain but its pharmacological activity and bioactive compounds remain mostly uncharacterized. In this study, the anti-inflammatory compounds of C. oldhamii were identified using an LPS-stimulated, NF-κB-responsive RAW 264.7 macrophage reporter line. Three diterpenoid compounds, 3α-hydroxy-ent-abieta-8,11,13-triene (CO-9), 3α, 7β-dihydroxy-ent-abieta-8,11,13-triene (CO-10), and decandrin B (CO-15) were found to inhibit NF-κB activity at nontoxic concentrations. Moreover, CO-9 and CO-10 suppressed the expression of IL-6 and TNF-α in LPS-stimulated RAW 264.7 cells. The inhibitory effect of CO-9 on TNF-α and IL-6 expression was further demonstrated using LPS-treated bone marrow-derived macrophages. Furthermore, CO-9, CO-10, and CO-15 suppressed LPS-triggered COX-2 expression and downstream PGE2 production in RAW 264.7 cells. CO-9 and CO-10 also reduced LPS-triggered iNOS expression and nitrogen oxide production in RAW 264.7 cells. The anti-inflammatory mechanism of the most effective compound, CO-9, was further investigated. CO-9 attenuated LPS-induced NF-κB activation by reducing the phosphorylation of IKKα/β (Ser176/180), IκBα (Ser32), and p65 (Ser534). Conversely, CO-9 did not affect the LPS-induced activation of MAPK signaling pathways. In summary, this study revealed new anti-inflammatory diterpenoid compounds from C. oldhamii and demonstrated that the IKK-mediated NK-κB pathway is the major target of these compounds.     

Anti-Neuroinflammatory Components from Clausena lenis Drake

Clausena lenis Drake (C. lenis) is a folk medicinal herb to treat influenza, colds, bronchitis, and malaria. The 95% and 50% ethanol extract of C. lenis showed significant nitric oxide (NO) inhibition activity in BV-2 microglial cells stimulated by lipopolysaccharide (LPS). Bio-guided isolation of the active extract afforded five new compounds, including a chlorine-containing furoquinoline racemate, (±)-claulenine A (1), an amide alkaloid, claulenine B (2), a prenylated coumarin, claulenin A (3), a furocoumarin glucoside, clauleside A (4), and a multi-prenylated p-hydroxybenzaldehyde, claulenin B (5), along with 33 known ones. Their structures were determined via spectroscopic methods, and the absolute configurations of new compounds were assigned via the electronic circular dichroism (ECD) calculations and single-crystal X-ray diffraction analysis. Compounds 2, 23, 27, 28, 33, and 34 showed potent anti-neuroinflammatory effects on LPS-induced NO production in BV-2 microglial cells, with IC₅₀ values in the range of 17.6–40.9 μM. The possible mechanism was deduced to interact with iNOS through molecular docking.