Cytoprotective dihydronaphthalenones from the wood of Catalpa ovata

Discovery of anti-inflammatory agents from 3, 4-dihydronaphthalene-1(2H)-one derivatives by inhibiting NLRP3 inflammasome activation

NLRP3 inflammatory vesicles are a polymer of cellular innate immunity composed of a pair of proteins. The continuous activation of NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammatory vesicles induces the occurrence and enhancement of inflammatory response. In this study, a series of 3, 4-dihydronaphthalene-1(2H)-one derivatives (DHNs, 6a-u, 7a-e, 8a-n) were synthesized and characterized by NMR and HRMS. We evaluated the cytotoxicity and anti-inflammatory activity of all compounds in vitro, and selected 7a substituted by 7-Br in A-ring and 2-pyridylaldehyde in C-ring as effective lead compounds. Specifically, 7a can block the assembly and activation of NLRP3 inflammasome by down-regulating the expression of NLPR3 and apoptosis-associated speck-like protein containing a CARD (ASC), and inhibiting the production of reactive oxygen species (ROS) and other inflammatory mediators. In addition, 7a inhibits the phosphorylation of inhibitor kappa B alpha (IκBα) and NF-κB/p65 and the nuclear translocation of p65, thereby inhibiting nuclear factor kappa-B (NF-κB) signaling. Molecular docking analysis confirmed that 7a could reasonably bind the active sites of NLRP3, ASC and p65 proteins. Therefore, 7a is predicted as a potential NLRP3 inflammatory vesicle inhibitor and deserves further research and development.

Iridoids and derivatives from Catalpa ovata with their antioxidant activities

Six new iridoid derivatives (1-6)，together with twelve known compounds (7-18), were isolated and identified from the dried fruits of Catalpa ovata G. Don. Their chemical structures were mainly established through the relative spectroscopic data, while the absolute configurations of compounds 2 and 3 were elucidated on the electronic circular dichroism calculations. Their antioxidant activities were evaluated by activating the Nrf2 transcriptional pathway in 293 T cells in vitro. Among them, Compounds 1, 3, 4, 6-8, 10-12, 14, 15, 17 and 18 showed significant Nrf2 agonistic effect compared with the control group at 25 μM. Finally, The hypothetical biosynthetic pathway for 1-13 was discussed.

Recent advances in natural phthalides: Distribution, chemistry, and biological activities

Phthalides, an important class of bioactive natural products, are widely distributed in plants, fungi, lichens, and liverworts. Amon them, n-butylphthalide, a phthalide monomer, has been approved to cure ischemic stroke. Owing to their good bioactivities in anti-microbial, anti-inflammatory, anti-tumor, anti-diabetic, and other aspects, a large number of researches have been conducted on phthalides from nature materials. In recent years, hundreds of novel natural phthalides were obtained. This review provides profiles of the advances in the distribution, chemistry, and biological activities of natural phthalides in 2016-2022.

Dissection of the Functional Mechanism of Human Gut Bacterial Strain AD16 by Secondary Metabolites' Identification, Network Pharmacology, and Experimental Validation

Gut microbiota plays important roles in several metabolic processes, such as appetite and food intake and absorption of nutrients from the gut. It is also of great importance in the maintenance of the health of the host. However, much remains unknown about the functional mechanisms of human gut microbiota itself. Here, we report the identification of one anticancer gut bacterial strain AD16, which exhibited potent suppressive effects on a broad range of solid and blood malignancies. The secondary metabolites of the strain were isolated and characterized by a bioactivity-guided isolation strategy. Five new compounds, streptonaphthalenes A and B (1-2), pestaloficins F and G (3-4), and eudesmanetetraiol A (5), together with nine previously known compounds, were isolated from the effective fractions of AD16. Structures of the new compounds were established by 1D and 2D NMR and MS analysis, and the absolute configurations were determined by the CD method. The analysis of network pharmacology suggested that 3, 2, and 13 could be the key components for the anti-NSCLC activity of AD16. In addition to the PI3K–Akt signaling pathway, the proteoglycans in cancer pathway could be involved in the anti-NSCLC action of AD16.

Total Synthesis of the Neuroprotective Agent Cudraisoflavone J

Cudraisoflavone J (1), isolated from Cudrania tricuspidata, is a potent neuroprotective compound with a chiral center. Herein, we report the first total synthesis of racemic cudraisoflavone J (1) using a Claisen rearrangement and a Suzuki coupling reaction as the key steps. Racemic secondary alcohol was kinetically resolved to give (+)- and (-)-cudraisoflavone J with up to 97 and 88% enantiomeric excess, respectively. The modified Mosher's method was used to elucidate the absolute configuration of naturally occurring cudraisoflavone J.

Furanocoumarins from the Roots of Angelica dahurica with Inhibitory Activity against Intracellular Reactive Oxygen Species Accumulation

Five new furanocoumarins, dahuribirin H (1), dahuribirin I (2), (2'S)-(+)-5-(2'-hydroxy-3'-methylbut-3'-enyloxy)-8-(3''-methylbut-2″-enyloxy)psoralen (3), (2'R)-(+)-5-(2',3'-epoxy-3'-methylbutoxy)-8-(3″-methylbut-2″-enyloxy)psoralen (4), and 5-methoxy-8-((Z)-4'-(3″-methylbutanoate)-3'-methylbut-2'-enyloxy)psoralen (5), along with 15 known compounds (6-20), were isolated from the roots of Angelica dahurica. The structures of the new compounds were elucidated by spectroscopic analysis, along with electronic circular dichroism calculations and Mosher ester analysis. Compounds 3, 4, 11, 13, and 16 reduced H₂O₂-induced cell death in HepG2 cells and attenuated reactive oxygen species (ROS) formation without showing cytotoxicity, suggesting that these compounds might have cytoprotective effects against H₂O₂-induced oxidative damage via ROS scavenging activities.

Anti-Inflammatory Effects of Catalpalactone Isolated from Catalpa ovata in LPS-Induced RAW264.7 Cells

Catalpa ovata (Bignoniaceae) is widely distributed throughout Korea, China, and Japan. This study investigated the anti-inflammatory effects of catalpalactone isolated from C. ovata in lipopolysaccharide (LPS)-induced RAW264.7 cells. Catalpalactone significantly inhibited nitric oxide (NO) production and inducible NO synthase (iNOS) expression in LPS-induced RAW264.7 cells. The levels of cytokines such as interleukin-6 and tumor necrosis factor-α were reduced under catalpalactone exposure in LPS-induced RAW264.7 cells. Additionally, catalpalactone suppressed signal transducer and activator of transcription 1 (STAT-1) protein expression and interferon-β (IFN-β) production. Treatment with catalpalactone prevented interferon regulatory factor 3 (IRF3) and nuclear factor-κB (NF-κB) activation. Taken together, these results suggest that the anti-inflammatory effects of catalpalactone are associated with the suppression of NO production and iNOS expression through the inhibition of IRF3, NF-κB, and IFN-β/STAT-1 activation.