Cinnamaldehyde, A Bioactive Compound from the Leaves of Cinnamomum osmophloeum Kaneh, Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mice by Inhibiting the NLRP3 Inflammasome.

Inflammatory bowel disease (IBD) comprises a group of idiopathic intestinal disorders, including ulcerative colitis and Crohn's disease, significantly impacting the quality of life for affected individuals. The effective management of these conditions remains a persistent challenge. The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a complex molecular structure, regulates the production of pro-inflammatory cytokines such as interleukin-1ß. Abnormal activation of the NLRP3 inflammasome plays a pivotal role in the development of IBD, making it a compelling target for therapeutic intervention. Our research revealed that cinnamaldehyde (CA), a major bioactive compound found in the leaves of Cinnamomum osmophloeum kaneh, demonstrated a remarkable ability to alleviate colitis induced by dextran sulfate sodium (DSS) in a mouse model. This effect was attributed to CA's ability to downregulate the activation of the NLRP3 inflammasome and reduce the expression of pro-inflammatory mediators in the colon. In the mechanism study, we observed that CA inhibited the NLRP3 inflammasome in macrophages, at least partially, by enhancing the autophagic response, without reducing mitochondrial damage. These findings collectively suggest that CA holds significant potential as a therapeutic agent for enhancing the management of IBD, offering a promising avenue for further research and development.

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.

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.

Composition and antimicrobial activities of the leaf essential oil of Machilus zuihoensis from Taiwan

This study investigated the chemical composition, and antimicrobial and anti-wood-decay fungal activities of the essential oil isolated from the leaf of endemic Machilus zuihoensis Hayata, Lauraceae, of Taiwan. The essential oil from the fresh leaves of M. zuihoensis was isolated using hydrodistillation in a Clevenger-type apparatus, and characterized by GC-FID and GC-MS. A total of 104 compounds were identified, representing 100% of the oil. The main components identified were n-dodecanal (23.8%) and (E)-nerolidol (10.5%). The antimicrobial activity of the oil was tested by the disc diffusion method and micro-broth dilution method against ten microbial species (Bacillus cereus, Staphylococcus aureus, S. epidermidis, Escherichia coli, Enterobacter aerogenes, Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio parahaemolyticus, Aspergillus niger, and Candida albicans), respectively. The oil exhibited strong growth suppression against Gram-positive bacteria and yeast with inhibition zones of 35~43 mm to MIC values of 125 µg mL-1, respectively. The anti-wood-decay fungal activity of the oil was also evaluated. Results showed that the oil demonstrated excellent activity against four wood-decay-fungi species (Trametes versicolor, Phaneochaete chrysosporium, Phaeolus schweintizii, and Lenzites sulphureu). For the antimicrobial and anti-wooddecay fungal activities of the oil, the active source compounds were determined to be τ-cadinol, β-eudesmol, and n-dodecanal.