Cinnamaldehyde inhibits the NLRP3 inflammasome by preserving mitochondrial integrity and augmenting autophagy in Shigella sonnei-infected macrophages.

BACKGROUND: Worldwide, more than 125 million people are infected with Shigella each year and develop shigellosis. In our previous study, we provided evidence that Shigella sonnei infection triggers activation of the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome in macrophages. NLRP3 inflammasome is responsible for regulating the release of the proinflammatory cytokines interleukin (IL)-1ß and IL-18 through the protease caspase-1. Researchers and biotech companies have shown great interest in developing inhibitors of the NLRP3 inflammasome, recognizing it as a promising therapeutic target for several diseases. The leaves of Cinnamomum osmophloeum kaneh, an indigenous tree species in Taiwan, are rich in cinnamaldehyde (CA), a compound present in significant amounts. Our aim is to investigate how CA affects the activation of the NLRP3 inflammasome in S. sonnei-infected macrophages. METHODS: Macrophages were infected with S. sonnei, with or without CA. ELISA and Western blotting were employed to detect protein expression or phosphorylation levels. Flow cytometry was utilized to assess H2O2 production and mitochondrial damage. Fluorescent microscopy was used to detect cathepsin B activity and mitochondrial ROS production. Additionally, colony-forming units were employed to measure macrophage phagocytosis and bactericidal activity. RESULTS: CA inhibited the NLRP3 inflammasome in S. sonnei-infected macrophages by suppressing caspase-1 activation and reducing IL-1ß and IL-18 expression. CA also inhibited pyroptosis by decreasing caspase-11 and Gasdermin D activation. Mechanistically, CA reduced lysosomal damage and enhanced autophagy, while leaving mitochondrial damage, mitogen-activated protein kinase phosphorylation, and NF-κB activation unaffected. Furthermore, CA significantly boosted phagocytosis and the bactericidal activity of macrophages against S. sonnei, while reducing secretion of IL-6 and tumour necrosis factor following infection. CONCLUSION: CA shows promise as a nutraceutical for mitigating S. sonnei infection by diminishing inflammation and enhancing phagocytosis and the bactericidal activity of macrophages against S. sonnei.

Honokiol Exhibits Anti-NLRP3 Inflammasome and Antimicrobial Properties in Neisseria gonorrhoeae-Infected Macrophages.

Purpose: The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, crucial in infectious and inflammatory diseases by regulating IL-1ß, presents a target for disease management. Neisseria gonorrhoeae causes gonorrhea in over 87 million people annually, with previous research revealing NLRP3 inflammasome activation in infected macrophages. No natural products have been reported to counteract this activation. Exploring honokiol, a phenolic compound from Chinese herbal medicine, we investigated its impact on NLRP3 inflammasome activation in N. gonorrhoeae-infected macrophages. Methods: Honokiol's impact on the protein expression of pro-inflammatory mediators was analyzed using ELISA and Western blotting. The generation of intracellular H2O2 and mitochondrial reactive oxygen species (ROS) was detected through specific fluorescent probes (CM-H2DCFDA and MitoSOX, respectively) and analyzed by flow cytometry. Mitochondrial membrane integrity was assessed using specific fluorescent probes (MitoTracker and DiOC2(3)) and analyzed by flow cytometry. Additionally, the effect of honokiol on the viability of N. gonorrhoeae was examined through an in vitro colony-forming units assay. Results: Honokiol effectively inhibits caspase-1, caspase-11 and GSDMD activation and reduces the extracellular release of IL-1ß, NLRP3, and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in N. gonorrhoeae-infected macrophages. Detailed investigations have demonstrated that honokiol lowers the production of H2O2 and the phosphorylation of ERK1/2 in N. gonorrhoeae-infected macrophages. Importantly, the phosphorylation of JNK1/2 and p38 and the activation of NF-κB remain unaffected. Moreover, honokiol reduces the N. gonorrhoeae-mediated generation of reactive oxygen species within the mitochondria, preserving their integrity. Additionally, honokiol suppresses the expression of the pro-inflammatory mediator IL-6 and inducible nitric oxide synthase induced by N. gonorrhoeae independently of NLRP3. Impressively, honokiol exhibits in vitro anti-gonococcal activity against N. gonorrhoeae. Conclusion: Honokiol inhibits the NLRP3 inflammasome in N. gonorrhoeae-infected macrophages and holds great promise for further development as an active ingredient in the prevention and treatment of symptoms associated with gonorrhea.

Functional identification of specialized diterpene synthases from Chamaecyparis obtusa and C. obtusa var. formosana to illustrate the putative evolution of diterpene synthases in Cupressaceae.

Chamaecyparis obtusa and C. obtusa var. formosana of the Cupressaceae family are well known for their fragrance and excellent physical properties. To investigate the biosynthesis of unique diterpenoid compounds, diterpene synthase genes for specialized metabolite synthesis were cloned from C. obtusa and C. obtusa var. formosana. Using an Escherichia coli co-expression system, eight diterpene synthases (diTPSs) were characterized. CoCPS and CovfCPS are class II monofunctional (+)-copalyl diphosphate synthases [(+)-CPSs]. Class I monofunctional CoLS and CovfLS convert (+)-copalyl diphosphate [(+)-CPP] to levopimaradiene, CoBRS, CovfBRS1, and CovfBRS3 convert (+)-CPP to (-)-beyerene, and CovfSDS converts (+)-CPP to (-)-sandaracopimaradiene. These enzymes are all monofunctional diterpene syntheses in Cupressaceae family of gymnosperm, and differ from those in Pinaceae. The discovery of the enzyme responsible for the biosynthesis of tetracyclic diterpene (-)-beyerene was characterized for the first time. Diterpene synthases with different catalytic functions exist in closely related species within the Cupressaceae family, indicating that this group of monofunctional diterpene synthases is particularly prone to the evolution of new functions and development of species-specific specialized diterpenoid constituents.

The Angiotensin II Receptor Neprilysin Inhibitor LCZ696 Inhibits the NLRP3 Inflammasome By Reducing Mitochondrial Dysfunction in Macrophages and Alleviates Dextran Sulfate Sodium-induced Colitis in a Mouse Model.

The intracellular sensor protein complex known as the NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in regulating inflammatory diseases by overseeing the production of interleukin (IL)-1ß and IL-18. Targeting its abnormal activation with drugs holds significant promise for inflammation treatment. This study highlights LCZ696, an angiotensin receptor-neprilysin inhibitor, as an effective suppressor of NLRP3 inflammasome activation in macrophages stimulated by ATP, nigericin, and monosodium urate. LCZ696 also reduces caspase-11 and GSDMD activation, lactate dehydrogenase release, propidium iodide uptake, and the extracellular release of NLRP3 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) in ATP-activated macrophages, suggesting a potential mitigation of pyroptosis. Mechanistically, LCZ696 lowers mitochondrial reactive oxygen species and preserves mitochondrial integrity. Importantly, it does not significantly impact NLRP3, proIL-1ß, inducible nitric oxide synthase, cyclooxygenase-2 expression, or NF-κB activation in lipopolysaccharide-activated macrophages. LCZ696 partially inhibits the NLRP3 inflammasome through the induction of autophagy. In an in vivo context, LCZ696 alleviates NLRP3-associated colitis in a mouse model by reducing colonic expression of IL-1ß and tumor necrosis factor-α. Collectively, these findings suggest that LCZ696 holds significant promise as a therapeutic agent for ameliorating NLRP3 inflammasome activation in various inflammatory diseases, extending beyond its established use in hypertension and heart failure treatment.

Monoterpene synthases contribute to the volatile production in tana (Zanthoxylum ailanthoides) through indigenous cultivation practices.

Tana (Zanthoxylum ailanthoides), a perennial deciduous species in the Rutaceae family, possesses leaves with a unique fragrance that indigenous peoples incorporate into their traditional cuisine. In Kalibuan, the cultivated tana trees were pruned repeatedly to maintain a shorter height, which led to the growth of new leaves that were spicier and pricklier. Tana leaves contain a range of volatile terpenoids, and the pungent aroma may arise from the presence of monoterpenoids. To gain insight into the biosynthetic pathway, five candidate monoterpene synthase genes were cloned and characterized using a purified recombinant protein assay. The main product of Za_mTPS1, Za_mTPS2, and Za_mTPS5 is sabinene, geraniol, and (E)-ß-ocimene, respectively. The main product of Za_mTPS3 and Za_mTPS4 is linalool. Real-time PCR analysis revealed that Za_mTPS1 and Za_mTPS5 are expressed at higher levels in prickly leaves of cultivated tana, suggesting that they may contribute to the distinctive aroma of this plant.

Surfactin Containing Bacillus licheniformis-Fermented Products Alleviate Dextran Sulfate Sodium-Induced Colitis by Inhibiting Colonic Inflammation and the NLRP3 Inflammasome in Mice.

Inflammatory bowel disease (IBD) is a non-infectious disease characterized by chronic inflammation of the gastrointestinal tract. Currently, management of IBD is still a clinical challenge. The purpose of this study was to investigate the therapeutic potential of surfactin containing Bacillus licheniformis-fermented products (SBLF) and commercial surfactin (CS) on the treatment of dextran sulfate sodium (DSS)-induced colitis in a mouse model. We found that mice that received drinking water containing 3% DSS developed significant colitis symptoms, including increased disease activity index, body weight loss, shortening of the colon length, splenomegaly, colonic inflammation and colonic NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation. Notably, orally received SBLF, CS or clinical anti-inflammatory drug 5-aminosalicylic acid improved DSS-induced colitis symptoms in mice. These findings show that SBLF can improve IBD in mice by reducing colonic inflammation and inhibiting the NLRP3 inflammasome activation, suggesting that SBLF has the potential to be used as a nutraceutical in humans or a feed additive in economic and companion animals for preventing IBD.

The leaves of the seasoning plant Litsea cubeba inhibit the NLRP3 inflammasome and ameliorate dextran sulfate sodium-induced colitis in mice.

The intracellular sensor NACHT, LRR, and PYD domain-containing protein 3 (NLRP3) inflammasome controls caspase-1 activity and the maturation and release of the cytokines interleukin (IL)-1ß and IL-18. The NLRP3 inflammasome has attracted the attention of the pharmaceutical industry because it promotes the pathogenesis of many diseases, making it a promising target for drug development. Litsea cubeba (Lour.) is a plant traditionally used as a seasoning in Taiwan and in other Asian countries. In this study, we investigated the inhibitory activity of the leaves of L. cubeba against the NLRP3 inflammasome. We found that the ethanol extract of L. cubeba leaves (MLE) inhibited the NLRP3 inflammasome in macrophages by reducing caspase-1 activation and IL-1ß secretion. MLE reduced pyroptosis in macrophages and inhibited the release of NLRP3 and apoptosis-associated speck-like protein containing a CARD (ASC). In a mechanistic study, MLE reduced mitochondrial reactive oxygen species (ROS) production and preserved mitochondrial integrity, which led to reduced mitochondrial DNA release into the cytosol. MLE did not reduce the expression levels of NLRP3, IL-1ß precursor or TNF-α in lipopolysaccharide (LPS)-activated macrophages. These results indicated that MLE inhibited the NLRP3 inflammasome by suppressing the activation signals of the NLRP3 inflammasome but not by reducing the priming signal induced by LPS. In addition, oral administration of MLE (20-80 mg/kg) ameliorated dextran sulfate sodium (DSS)-induced colitis in a mouse model. Notably, mice that received MLE (1 and 2 g/kg) daily for 7 days did not exhibit visible side effects. Gas chromatography-mass spectrometry (GC-MS) analysis found that α-Terpinyl acetate (27.2%) and 1,8-Cineole (17.7%) were the major compounds in MLE. These results indicated that L. cubeba leaves have the potential to be a nutraceutical for preventing and improving NLRP3 inflammasome-related diseases.

Repositioning of the Angiotensin II Receptor Antagonist Candesartan as an Anti-Inflammatory Agent With NLRP3 Inflammasome Inhibitory Activity.

Aberrant activation of the NLRP3 inflammasome promotes the pathogenesis of many inflammatory diseases. The development of the NLRP3 inflammasome inhibitors from existing drugs for new therapeutic purposes is becoming more important. Candesartan is an angiotensin II receptor antagonist widely used as a blood pressure-lowering drug; however, the inhibitory potential of candesartan on the NLRP3 inflammasome has not yet been investigated. We demonstrated that candesartan significantly inhibited the NLRP3 inflammasome and pyroptosis in macrophages. Mechanistic analysis revealed that candesartan inhibited the expression of NLRP3 and proIL-1ß by suppressing NF-κB activation and reducing the phosphorylation of ERK1/2 and JNK1/2. Candesartan reduced mitochondrial damage and inhibited the NLRP3 inflammasome assembly by suppressing NLRP3 binding to PKR, NEK7 and ASC. In addition, candesartan inhibited IL-1ß secretion partially through autophagy induction. Furthermore, oral administration of candesartan reduced peritoneal neutrophil influx, NLRP3 and ASC expression in peritoneal cells, and lavage fluid concentrations of active caspase-1, IL-1ß, IL-6 and MCP-1 in uric acid crystal-injected mice. These results indicated that candesartan has board anti-inflammatory effects and has the potential to be repositioned to ameliorate inflammatory diseases or NLRP3-associated complications.

Immunomodulatory Properties of Polysaccharides from the Coral Pseudopterogorgia americana in Macrophages.

Polysaccharides from marine organisms produce an important regulatory effect on the mammalian immune system. In this study, the immunomodulatory properties of a polysaccharide that was isolated from the coral Pseudopterogorgia americana (PPA) were investigated. PPA increased the expression levels of tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and cyclooxygenase-2 (COX-2), but not inducible nitric oxide synthase and nitric oxide, in macrophages. A mechanistic study revealed that PPA activated macrophages through the toll-like receptor-4 and induced the generation of reactive oxygen species (ROS), increased the phosphorylation levels of protein kinase C (PKC)-α, PKC-δ and mitogen-activated protein kinases (MAPK), and activated NF-κB. The inhibition of ROS and knockdown of PKC-α reduced PPA-mediated TNF-α and IL-6 expression; however, the knockdown of PKC-δ significantly increased PPA-mediated TNF-α expression. In addition, the inhibition of c-Jun N-terminal kinase-1/2 and NF-κB reduced PPA-mediated TNF-α, IL-6 and COX-2 expression. Furthermore, the inhibition of ROS, MAPK and PKC-α/δ reduced PPA-mediated NF-κB activation, indicating that ROS, MAPK and PKC-α/δ function as upstream signals of NF-κB. Finally, PPA treatment decreased the phagocytosis activity of macrophages and reduced cytokine expression in bacteria-infected macrophages. Taken together, our current findings suggest that PPA can potentially play a role in the development of immune modulators in the future.

Sesquiterpene Synthases of Zanthoxylum ailanthoides: Sources of Unique Aromas of a Folklore Plant in Taiwan.

Zanthoxylum ailanthoides is a traditional spice crop in Taiwan with unique smells and tastes that differ between prickly (young) and nonprickly (mature) leaves. Different volatile terpenes between prickly young and nonprickly mature leaves were identified and considered to be one of the sources of their aromas. A transcriptome database was established to explore the biosynthesis of these compounds, and candidate terpene synthase genes were identified. The functions of these synthases were investigated using recombinant protein reactions in both purification and coexpression assays. ZaTPS1, ZaTPS2, and ZaTPS3 are germacrene D synthases, with different amino acid sequences. The main products of ZaTPS4 are trans-α-bergamotene and (E)-ß-farnesene, whereas ZaTPS5 forms multiple products, and ZaTPS6 produces ß-caryophyllene. ZaTPS7 forms monoterpene (E)-ß-ocimene and sesquiterpene (E,E)-α-farnesene. Reverse transcription PCR of ZaTPS gene expression in young and mature leaves revealed that ZaTPS1 was responsible for the mellow aroma in mature leaves. The expression of ZaTPS6 suggested that it plays a role in the background aromas of both types of leaves. Our findings deepened the understanding of the volatile compounds of Z. ailanthoides and revealed the source of its unique aromas by clarifying the biosynthesis of these compounds.

Inhibition of pro-inflammatory mediator expression in macrophages using wood vinegar from griffith's ash.

Macrophages are essential for host defense as they control foreign pathogens and induce acquired immune responses. Activated macrophages secrete pro-inflammatory reactive substances causing local cell and tissue inflammatory response, which helps an organism resist the invasion of foreign pathogens. Excessive or chronic inflammation can cause several diseases. Previous studies have reported that vinegar treatment decreases the levels of several inflammatory cytokines and biomarkers, including mitogen-activated protein kinases, cyclooxygenase-2, inducible nitric oxide synthase (iNOS), and nitric oxide (NO). However, the benefits of wood vinegar produced from Griffith's ash (Fraxinus formosana Hayata) in reducing inflammation have not been investigated yet. Thus, assuming that wood vinegar exerts anti-inflammatory effects in macrophages, in this study, we investigated the potential anti-inflammatory effects of the wood vinegar from Griffith's ash using a lipopolysaccharide (LPS)-induced inflammatory response model in RAW264.7 macrophages. We showed that the wood vinegar inhibited the production of iNOS, NO, and interleukin 6. In addition, we found that the wood vinegar reduced the phosphorylation levels of p38 and protein kinase C-α/δ in the LPS-stimulated RAW264.7 macrophages. Based on these results, we suggest that the produced wood vinegar can reduce inflammation in LPS-activated macrophages.

Corrigendum: A Synthetic Small Molecule F240B Decreases NLRP3 Inflammasome Activation by Autophagy Induction.

[This corrects the article DOI: 10.3389/fimmu.2020.607564.].

Ginsenoside M1 Induces Apoptosis and Inhibits the Migration of Human Oral Cancer Cells.

Oral squamous cell carcinoma (OSCC) accounts for 5.8% of all malignancies in Taiwan, and the incidence of OSCC is on the rise. OSCC is also a common malignancy worldwide, and the five-year survival rate remains poor. Therefore, new and effective treatments are needed to control OSCC. In the present study, we prepared ginsenoside M1 (20-O-beta-d-glucopyranosyl-20(S)-protopanaxadiol), a major deglycosylated metabolite of ginsenoside, through the biotransformation of Panax notoginseng leaves by the fungus SP-LSL-002. We investigated the anti-OSCC activity and associated mechanisms of ginsenoside M1 in vitro and in vivo. We demonstrated that ginsenoside M1 dose-dependently inhibited the viability of human OSCC SAS and OEC-M1 cells. To gain further insight into the mode of action of ginsenoside M1, we demonstrated that ginsenoside M1 increased the expression levels of Bak, Bad, and p53 and induced apoptotic DNA breaks, G1 phase arrest, PI/Annexin V double-positive staining, and caspase-3/9 activation. In addition, we demonstrated that ginsenoside M1 dose-dependently inhibited the colony formation and migration ability of SAS and OEC-M1 cells and reduced the expression of metastasis-related protein vimentin. Furthermore, oral administration or subcutaneous injection of ginsenoside M1 significantly reduced tumor growth in SAS xenograft mice. These results indicate that ginsenoside M1 can be translated into a potential therapeutic against OSCC.

Eucalyptus essential oils inhibit the lipopolysaccharide-induced inflammatory response in RAW264.7 macrophages through reducing MAPK and NF-κB pathways.

BACKGROUND: Eucalyptus essential oils have been used in traditional medicine for centuries. It was reported that Eucalyptus leaves possess antioxidant and antimicrobial effects. Here, we investigated the anti-inflammatory activity of the essential oils extracted from the leaves of four different Eucalyptus species in RAW264.7 macrophages. METHODS: Lipopolysaccharide (LPS)-activated RAW264.7 macrophages were used to evaluate the anti-inflammatory activity of the leaf essential oils of Eucalyptus. The cell survival was quantified by an Alamar Blue assay. Nitric oxide (NO) production was assessed by Griess reaction. TNF-α and IL-6 production were measured by enzyme-linked immunosorbent assay (ELISA). Nuclear factor-κB (NF-κB) transcriptional activity was measured by NF-κB reporter assay. Intracellular protein expression levels were determined by Western blot. The expression levels of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), mitogen-activated protein kinase (MAPK), protein kinase C (PKC) and NF-κB pathway were measured by western blot in LPS-activated RAW 264.7 macrophage. RESULTS: The essential oils extracted from Eucalyptus citriodora leaf exert the best NO inhibitory activity in LPS-activated RAW264.7 macrophages. The essential oils were fractionated into fractions A-H, and fraction F has been demonstrated to inhibit the expression levels of TNF-α, IL-6, NO, iNOS and COX-2 in LPS-activated RAW264.7 macrophages. Mechanistic analysis revealed that fraction F reduced the phosphorylation levels of ERK1/2, p38, PKC-α, PKC-ε and PKC-δ, and inhibited the NF-κB transcriptional activity. The chemical composition of Fraction F was determined by GC-MS. CONCLUSIONS: The discoveries made herein could help develop innovative nonsteroidal anti-inflammatory drugs with minimal side effects and strong efficacy. Clinical trials on these Eucalyptus leaf essential oils will help customize and optimize their therapeutic administration.

A Synthetic Small Molecule F240B Decreases NLRP3 Inflammasome Activation by Autophagy Induction.

Conjugated polyenes are a class of widely occurring natural products with various biological functions. We previously identified 4-hydroxy auxarconjugatin B (4-HAB) as anti-inflammatory agent with an IC50 of ~20 µM. In this study, we synthesized a new anti-inflammatory 4-HAB analogue, F240B, which has an IC50 of less than 1 µM. F240B dose-dependently induced autophagy by increasing autophagic flux, LC3 speck formation and acidic vesicular organelle formation. F240B inhibited NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome activation through autophagy induction. In a mechanistic study, F240B inhibited interleukin (IL)-1ß (IL-1ß) precursor expression, promoted degradation of NLRP3 and IL-1ß, and reduced mitochondrial membrane integrity loss in an autophagy-dependent manner. Additionally, F240B inhibited apoptosis-associated speck-like protein containing a CARD (ASC) oligomerization and speck formation without affecting the interaction between NLRP3 and ASC or NIMA-related kinase 7 (NEK7) and double-stranded RNA-dependent kinase (PKR). Furthermore, F240B exerted in vivo anti-inflammatory activity by reducing the intraperitoneal influx of neutrophils and the levels of IL-1ß, active caspase-1, IL-6 and monocyte chemoattractant protein-1 (MCP-1) in lavage fluids in a mouse model of uric acid crystal-induced peritonitis. In conclusion, F240B attenuated the NLRP3 inflammasome through autophagy induction and can be developed as an anti-inflammatory agent in the future.

Composition, in vitro Cytotoxicity, Anti-mildew and Anti-wood-decay Fungal Activities of the Fruit Essential Oil of Liquidambarformosana from Taiwan.

This study investigated the chemical composition, in vitro cytotoxicity, anti-mildew, and anti-wood-decay fungal activities of the essential oil isolated from the fruit of Liquidainbar formosana from Taiwan. The essential oil from the fresh fruit was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 45 compounds were identified, representing 98.5% of the essential oil. The main components identified were a-pinene (16.8%), ß-caryophyllene (10.1%), τ-muurolol (8.3%), τ-cadinol (7.6%), ß-pinene (6.7%), and sabinene (5.7%). The essential oil exhibited cytotoxic activity against human oral, liver, and lung cancer cells. The active source compounds were ß-caryophyllene, τ-cadinol, and τ-muurolol. The fruit essential oil was shown to have excellent anti-mildew and anti-wood-decay fungal activities, the active compounds being evaluated as τ-cadinol and τ-muurolol.

Composition of the Leaf Essential Oil of Phoebe formosana from Taiwan and its in vitro Cytotoxic, Antibacterial, and Antifungal Activities.

The essential oil from the leaves of Phoebe formosana from Taiwan was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Seventy-one compounds were identified, representing 100% of the oil. The main components identified were a-humulene (16.8%), τ-cadinol (8.9%), α-pinene (8.4%), α-cadinol (8.1%), ß-caryophyllene (8.0%), ß-phellandrene (6.0%), and ß-eudesmol (5.8%). The oil exhibited cytotoxic activity against human lung, liver and oral cancer cells. The active compounds were ß-caryophyllene, α-humulene, τ-cadinol, ß-eudesmol, and α-cadinol. The antibacterial activity of the oil was tested by the disc diffusion and micro-broth dilution methods against eight bacterial species. The oil exhibited moderate growth suppression against Gram-positive bacteria with inhibition zones of 28 to 36 mm, and MIC values of 250 to 375 µg/mL. The active antibacterial compounds were determined to be τ-cadinol, ß-eudesmol, and α-cadinol. The leaf oil displayed excellent antifungal activity with the active compounds determined as α-cadinol, ß-eudesmol, τ-cadinol, α-humulene, and ß-caryophyllene.

Essential Oil Compositions and Antimicrobial Activities of Various Parts of Litsea cubeba from Taiwan.

The essential oils of leaves, fruits, flowers, stems and twigs of Litsea cubeba were extracted by hydrodistillation. A total of 53, 50, 76, 94 and 90 compounds were identified from the leaf, fruit, flower, stem and twig oils, respectively, and their yields were 13.9 ± 0.09, 4.0 ± 0.03, 10.4 ± 0.05, 0.09 ± 0.01 and 0.4 ± 0.02 mL/100 g of the oven-dried (o.d.) materials, respectively. The main component in the leaf, flower and twig oils was 1,8-cineole, whereas in the fruit oil it was citral, and in the stem oil limonene, citronellal, and citronellol. When tested for their antibacterial activities using the paper disc diffusion method, oils from all parts showed excellent activities, particularly the fruit oil. When the oils were infused onto filter paper and tested for their antimicrobial paper capability according to the JIS L 1902 method, the fruit oil exhibited excellent antimicrobial activities. Citral was deemed the main cause of the antimicrobial activity. With the multiplicity of contagious diseases and their prevalence in hospitals, these essential oils present a potentially good choice as antibacterial agents. We think that the essential oils of this species are capable of multipurpose applications.

Composition, in vitro Anti-inflammatory, Antioxidant and Antimicrobial Activities of the Leaf Essential Oil of Machilus konishii from Taiwan.

The chemical composition and in vitro anti-inflammatory, antioxidant and antimicrobial activities of the leaf essential oil of Machils konishii has been investigated. The essential oil was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. Sixty-six compounds were identified, representing 100% of the oil. The main components identified were a-pinene (33.9%), α-pinene (13.9%), and thymol (12.0%); The leaf oil was able to reduce nitric oxide production by lipopolysaccharide-activated murine macrophages RAW 264.7 without reducing the cell viability. In addition, the leaf oil showed strong antioxidant and antimicrobial activities. The major ingredient of the oil that was responsible for the anti-inflammatory, antioxidant and antimicrobial activities was thymol.

Citral alleviates an accelerated and severe lupus nephritis model by inhibiting the activation signal of NLRP3 inflammasome and enhancing Nrf2 activation.

INTRODUCTION: Lupus nephritis (LN) is a major complication of systemic lupus erythematosus. NLRP3 inflammasome activation, reactive oxygen species (ROS) and mononuclear leukocyte infiltration in the kidney have been shown to provoke the acceleration and deterioration of LN, such as accelerated and severe LN (ASLN). Development of a novel therapeutic remedy based on these molecular events to prevent the progression of the disease is clinically warranted. METHODS: Citral (3,7-dimethyl-2,6-octadienal), a major active compound in a Chinese herbal medicine Litsea cubeba, was used to test its renoprotective effects in a lipopolysaccharide (LPS)-induced mouse ASLN model by examining NLRP3 inflammasome activation, ROS and COX-2 production as well as Nrf2 activation. The analysis of mechanisms of action of Citral also involved its effects on IL-1ß secretion and signaling pathways of NLRP3 inflammasome in LPS-primed peritoneal macrophages or J774A macrophages. RESULTS: Attenuated proteinuria, renal function impairment, and renal histopathology, the latter including intrinsic cell proliferation, cellular crescents, neutrophil influx, fibrinoid necrosis in the glomerulus, and peri-glomerular infiltration of mononuclear leukocytes as well as glomerulonephritis activity score were observed in Citral-treated ASLN mice. In addition, Citral inhibited NLRP3 inflammasome activation and levels of ROS, NAD(P)H oxidase subunit p47(phox), or COX-2, and it enhanced the activation of nuclear factor E2-related factor 2 (Nrf2). In LPS-primed macrophages, Citral reduced ATP-induced IL-1ß secretion and caspase-1 activation, but did not affect LPS-induced NLRP3 protein expression. CONCLUSION: Our data show that Citral alleviates the mouse ASLN model by inhibition of the activation signal, but not the priming signal, of NLRP3 inflammasome and enhanced activation of Nrf2 antioxidant signaling.