Search Results (463)

A chemical investigation of the EtOAc fraction from soft coral Clavularia viridis resulted in the isolation of 12 undescribed dolabellane-type diterpenoids, namely clavirolides W–Z (1–4), clavularols A–H (5–12), and three known analogs (13–15). Their structures were characterized by an extensive analysis of spectroscopic data, including X-ray diffraction and ECD calculations for the assignment of absolute configurations. The structures of 2 and 4–6 are feathered as peroxyl-substituted derivatives, while compounds 7–12 possess additional oxidative cyclization, including epoxide or furan that are rare in the dolabellane family. All these compounds were evaluated for activities on cytotoxic and anti-inflammatory models. Compound 10 exhibited most potential against NO production in the BV2 cell induced by LPS with an IC₅₀ value of 18.3 μM. Full article

Background: Rehmannia glutinosa, a traditional Chinese herb, is commonly used to treat vascular-related disorders. Sepsis-associated vascular endothelial dysfunction is closely associated with mitochondrial damage. This study investigated the protective effects of secondary metabolites from R. glutinosa against LPS-induced mitochondrial dysfunction in endothelial cells, providing potential therapeutic insights into sepsis-related vascular complications. Methods: Phytochemical profiling of fresh R. glutinosa roots was conducted, and the structures of new secondary metabolites (1 and 2) were elucidated through comprehensive spectroscopic analysis and ECD calculations. UPLC-Q-TOF-MS/MS characterized phenylethanoid glycosides. Mitochondrial function was assessed by measuring the membrane potential, ROS levels, and TOM20/DRP1 expression in LPS-injured HUVECs. Results: Two novel eremophilane-type sesquiterpenes, remophilanetriols J (1) and K (2), along with five known phenylethanoid glycosides (3–7), were isolated from the fresh roots of R. glutinosa. UPLC-Q-TOF-MS/MS analysis revealed unique fragmentation pathways for phenylethanoid glycosides (3–7). In LPS-injured HUVECs, all compounds collectively restored the mitochondrial membrane potential, attenuated ROS accumulation, and modulated TOM20/DRP1 expression. In particular, remophilanetriol K (2) exhibited potent protective effects at a low concentration (1.5625 μM). Conclusions: This study identifies R. glutinosa metabolites as potential therapeutics for sepsis-associated vascular dysfunction by preserving mitochondrial homeostasis. This study provides a mechanistic basis for the traditional use of R. glutinosa and offers valuable insights into the development of novel therapeutics targeting mitochondrial dysfunction in sepsis. Full article

Five new natural products, including two sorbicillinoids (1–2), one indolinone alkaloid (10), one tetracyclic steroid (11), and one α-pyrone derivative (14), were identified from the endophytic Penicillium sp. NX-S-6, together with thirteen known natural products. The structures of new compounds were unambiguously elucidated by comprehensive spectroscopic analyses (NMR, MS), as well as electronic circular dichroism (ECD) calculation. Notably, quinosorbicillinol (1) was identified as a rare hybrid sorbicillinoid incorporating a quinolone moiety, representing a unique structural scaffold in this natural product class. Biological evaluation revealed that Compounds 1, 4 and 8 potently inhibited the production of nitric oxide and interleukin 6 in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Mechanistic studies furthermore demonstrated that Compounds 4 and 8 effectively suppressed interleukin-1β secretion in LPS-induced immortalized mouse bone marrow-derived macrophages (iBMDMs) by blocking NLRP3 inflammasome activation. This inhibition was attributed to their ability to disrupt the assembly of the NLRP3-caspase-1 complex, a key event in the pathogenesis of inflammatory disorders. These findings not only expand the structural diversity of endophyte-derived natural products but also highlight their potential as lead compounds for developing anti-inflammatory therapeutics targeting the NLRP3 pathway. Full article

Marine organism-associated microbes are an important source of structurally diverse and biologically active secondary metabolites exhibiting antimicrobial, anticancer, and anti-inflammatory activities. In this study, we investigated Penicillium brevicompactum MSW10-1, isolated from Hydractinia echinata, a marine invertebrate adapted to extreme intertidal and subtidal environments with variable temperature, salinity, and oxygen conditions. Through a combination of LC/MS-guided chemical analysis and chromatographic purification, eight secondary metabolites were isolated, including brevicolactones A (1) and B (2). The absolute chemical structures of 1 and 2 were determined based on NMR spectroscopic experiments, HR-ESIMS data, and quantum chemical ECD calculations. The isolated compounds (1–8) were evaluated for their ability to inhibit hepatic lipogenesis, a key process in lipid metabolism that is dysregulated in metabolic-dysfunction-associated steatotic liver disease. Furthermore, the inhibitory effects of the isolated compounds on lipid accumulation were further evaluated in primary mouse hepatocytes, using Oil Red O staining. These findings suggested that the isolated compounds may serve as promising candidates for the treatment of metabolic liver diseases associated with lipid dysregulation. Full article

(−)-Patagonic acid (1) is a clerodane diterpene isolated from several plants from the Alismataceae, Asteraceae, Euphorbiaceae, Fabaceae, Lamiaceae, Salicaceae, Sapindaceae, and Velloziaceae families, and its biological potential as an inhibitor of butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) and as an anti-inflammatory compound has been described. Furthermore, the enantiomer (+)-1 is also described in Fabaceae and Verbenaceae. A lack of formal studies about the absolute configuration (AC) determination of 1 is emphasized. Thus, the present manuscript describes the AC determination of patagonic acid (1). The chemical correlation of (−)-1 from (−)-hardwickiic acid (2) was achieved by a simplistic oxidative process. The specific rotation value and electronic circular dichroism (ECD) analysis allowed for the AC determination of (−)-1 as (5R,8R,9S,10R)-(−)-patagonic acid. ECD revealed a positive exciton chirality (EC) phenomenon in both (−)-1 and (−)-2, which is directly associated with their configuration and conformational preferences, which were assessed by DFT calculations at the B3LYP/DGDZVP level of theory. Since the NMR data of (+)-1 are fully coincident with those from its enantiomer studied herein, the chirality of (5S,8S,9R,10S)-(+)-patagonic acid could also be determined. These experimental conclusions deeply complement the literature related to clerodane compounds biosynthesized in several families of plants of scientific interest. Full article

Two new racemic mixtures, including a polyketide, (±)-penilactone F (1), and a butenolide, (±) phenylbutyrolactone IIa (2), were isolated from the mangrove sediment-derived strain Aspergillus spelaeus SCSIO 41433. Additionally, 20 known compounds were isolated, including four penicillin-like compounds (11–14), three alkaloids (15–17), one sesquiterpene (18), and four phenolic acids (19–22). Their structures were elucidated through NMR spectroscopy, HRESIMS, X-ray diffraction, and ECD calculations. In the PDE4 inhibitory activity and anticancer cell activity assays, compounds 2, 3, 5, 8, 9, 11–14, and 16 exhibited weak PDE4 inhibitory activity at a concentration of 10 µM, Compound 11 demonstrated potent inhibitory effects against six cancer cell lines (MDA-MB-231, MDA-MB-435, HCT116, SNB-19, PC3, and A549), with IC₅₀ values ranging from 3.4 to 23.7 µM. Full article

Background/Objective: Avapritinib is an orally bioavailable tyrosine kinase inhibitor and was approved by the FDA in 2020 for gastrointestinal stromal tumor treatments. Although avapritinib is known to be chiral, its stereochemistry was initially established randomly. This study aims to develop a definitive method for determining avapritinib’s absolute configuration and propose a universal methodology for stereochemical characterization of flexible chiral drugs. Methods: The absolute configuration of avapritinib was determined through an integrated approach combining chiral resolution, chiroptical spectroscopy and synthetic validation. Enantiomeric separation was achieved via chiral liquid chromatography, followed by comprehensive chiroptical characterization including electronic circular dichroism (ECD), specific optical rotation and optical rotatory dispersion. Conformational analysis and density functional theory (DFT) calculations correlated experimental spectra with theoretical predictions, facilitating definitive configurational assignment. The stereochemical determination were further verified through ECD derivatization and chemical synthesis. Finally, the enantiomers’ kinase inhibition profiles against c-KIT D816V were quantitatively assessed. Results: Two enantiomers of avapritinib were resolved via chiral HPLC and a Chiralpak IG column. Through combined experimental ECD spectra and time-dependent DFT calculations employing the core extraction method, the levo-isomer was unambiguously determined as S configuration. This stereochemical assignment was confirmed by p-cyanobenzaldehyde derivatization and de novo synthesis. Biological evaluation revealed (S)-(−)-avapritinib exhibited superior c-KIT D816V inhibitory activity compared to its (R)-(+)-counterpart, a finding corroborated by molecular docking studies elucidating their differential target interactions. Conclusions: This study advances avapritinib stereochemical understanding and establishes a definitive protocol for its absolute configuration assignment, serving as a paradigm for flexible chiral drug characterization. Full article

Serratia marcescens is a common Gram-negative and facultative anaerobic bacillus that produces serratiochelins with several bioactivities. In this study, four catechol siderphores (1–4), including two new ones named serratiochelins E (1) and F (2), were obtained from the fermentation of a mangrove-derived bacterium, S. marcescens F2-2. The structures were elucidated with various spectroscopic methods such as NMR and HR-ESI-MS. Absolute and geometric configurations of the new compounds were established by employing quantum NMR calculations in conjunction with DP4+ probability analysis, ECD calculations, and the advanced Marfey’s method. The bioactivity test showed that serratiochelin B (3) displayed weak but selective cytotoxicity against HepG2 cancer cells with an IC₅₀ of 50.6 μmol/L and could trigger apoptosis through both Bcl-2/Bax/caspase-3 and Fas/FasL/caspase-8 signaling pathways. These findings deepen the understanding of siderophores of S. marcescens and provide a lead for research on anti-liver cancer drugs. Full article

Hemsleya chinensis tubers, abundantly produced in southwestern China, are commonly used as a folk medicine that excel in anti-inflammation to treat enteritis, bronchitis, and tonsillitis. In this study, three previously undescribed cucurbitane glycosides, hemchinins G–H (1–3), that were characterized by the presence of four glucose substitutions, as well as eleven ones with one to three β-glucoses, were isolated from the tubers of H. chinensis. The structures were confirmed using comprehensive UV, IR, HR-ESI-MS, and NMR analyses, and absolute configurations were determined through a comparison of calculated and experimental ECD after acid hydrolysis. Compounds 1–3 showed NO inhibition effects on LPS-induced RAW 264.7 cells. Finally, molecular docking analyses were conducted to obtain the affinities of the isolated cucurbitane glycosides and our previously reported 19 cucurbitane triterpenes, focusing on targets involved in anti-inflammatory effects. The results indicated that they showed high docking scores of affinities with the proteins in the NF-κB, AMPK, and Nrf2 signaling pathways. Among them, cucurbitane triterpenes with sugar moiety substitution at C-3 and C-26/27 showed better affinity ability. The findings can provide insights into the anti-inflammatory mechanisms of this species and facilitate the development of novel therapeutic agents. Full article

Background: Ten new sesquiterpenes, including eight eremophilane-type sesquiterpenes (1–8) and two compounds (9–10) with a cyclopentane ring, representing an undescribed subtype of sesquiterpene, along with a new abietane-type diterpenoid (11), were isolated and identified from a deep-sea-derived fungus: Eutypella sp. Methods: Their structures were elucidated on the basis of various spectroscopic analyses, mainly including nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectrometry (HRESIMS) data, ¹³C NMR calculations with DP4+ probability analyses, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction experiments. Results: Furthermore, compound 11 exhibited potent immunosuppressive activity with IC₅₀ values of 8.99 ± 1.08 μM in a lipopolysaccharide (LPS) model and 5.39 ± 0.20 μM in a concanavalin A (ConA) model. Full article

Heterologous expression of the G231L variant of VioA into 16 strains of marine-derived Streptomyces, combined with bioactivity tracking, leads to the activation of seven antibiotic streptogramins (1–7) in Streptomyces sp. OUC20-O. Among these, compound 1, named linstreptogramin, is a new compound with an unusual linear streptogramin skeleton. The planar structure and stereochemistry of compound 1 were established based on extensive MS and NMR spectroscopic analyses, together with ECD calculations. In the antibacterial activity evaluation, compounds 1–4 showed significant growth inhibition against the multidrug-resistant Enterococcus faecium CCARM 5203 with MIC values of 0.2–1.6 µg/mL, which are comparable to the positive control vancomycin. Full article

A total of 31 compounds were isolated from the ethyl acetate and n-butanol fractions of Anchusa italica Retz., which contained one ursane triterpenoid, 2α,3β,19α-trihydroxy-23-formyl-urs-12-en-28,21β-olide (1), and five norisoprenoids: (2R,6R,9S)-9-hydroxy-4-megastigmen-3-one-2-O-β-D-glucopyranoside (3); (2R,6S,9S)-9-hydroxy-megastigman-4,7-dien-3-one-2-O-β-D-glucopyranoside (4); (+)-isololiolide β-D-glucopyranoside (5); (2S,8R)-loliolide β-D-glucopyranoside (6a); and (2R,8S)-loliolide β-D-glucopyranoside (6b). It also contained 25 known compounds (2 and 7–30). The chemical structures of the compounds, inclusive of their absolute configurations, were ascertained using spectroscopic methods such as NMR, HR-MS, and quantum chemical calculations (computational NMR and ECD), in combination with relevant literature data. Moreover, the chemotaxonomic significance of the isolated substances was discussed, with compounds 1, 2, and 7–13 potentially broadening the application of triterpenes as taxonomic markers for the classification of the genus Anchusa. Full article

Platycladus orientalis, an evergreen tree belonging to the Cupressaceae family, has been traditionally used to treat various ailments, including fever, cough, diarrhea, diuresis, cold symptoms, and gastrointestinal disorders in folk medicine. As part of our ongoing investigation aimed at discovering bioactive natural products and elucidating their mechanisms of action from various natural sources, we investigated a methanol (MeOH) extract of P. orientalis leaves. This investigation led to the isolation and identification of a labdane-type diterpene, lambertianic acid (LA), via column chromatography and HPLC purification. The structure of LA was elucidated using LC/MS and NMR spectroscopic analyses, including HR-ESIMS, while its absolute configuration was confirmed through electronic circular dichroism (ECD) calculations. Recent studies have reported that labdane-type diterpenes exhibit diverse pharmacological activities, such as anticancer, anti-inflammatory, anti-obesity, and hypolipidemic effects. Notably, LA has been shown to modulate adipocyte metabolism via AMPK signaling; however, its role in skeletal muscle atrophy remains unexplored. Therefore, in this study, we investigated the effects of LA on dexamethasone (Dex)-induced muscle atrophy in C2C12 myotubes. Treatment with LA at concentrations of 25 µM and 50 µM significantly rescued myotube diameter and reduced the expression of atrophy-related proteins, including MuRF-1 and atrogin-1/MAFbx, without compromising cell viability at these moderate concentrations. These findings suggest that LA derived from P. orientalis exerts protective effects against skeletal muscle atrophy, highlighting its potential as a promising natural therapeutic candidate for muscle-wasting disorders. Full article

Three new structures named naphpyrone I–K (1–3) that contain a 6/6/6/6 oxaphenalene pyranone skeleton were isolated and purified from a marine-derived Streptomyces sp. HDN155000. Their chemical structures, including configurations, were elucidated by extensive NMR, MS, single-crystal X-ray diffraction, theoretical NMR calculations, DP4+ probability analysis, and ECD analyses. Naphpyrone K (3) showed cytotoxic activities against L-02, K562, NCI-H446/EP, MDA-MB-231, and NCI-H446 cancer cells with IC₅₀ values of 5.13, 3.34, 2.50, 2.61, and 2.20 μM, respectively. These findings highlight the potential for screening and developing therapeutic drugs from aromatic polyketides derived from marine actinobacteria. Full article

Chemical investigation on the whole herb of Peperomia heyneana Miq. resulted in the isolation of six lignans, including two previously undescribed compounds, named peperomianan A and B (1–2), and four known compounds, 1,2-cyclobutanedicarboxylic acid (3), (+)-medioresinol (4), (+)-pinoresinol (5), and (+)-yangambin (6). Their structures were established by extensive spectroscopic analyses. The absolute configuration of compound 1 was determined by comparison of the experimental and calculated electronic circular dichroism (ECD) spectra. Subsequently, the effects of all isolates on BPH-1 cells were evaluated in vitro by MTT assay. Full article