Chlorine-containing polyacetoxybriarane diterpenoids from the octocoral Junceella fragilis.

The chemical screening of an octocoral identifed as Junceella fragilis has led to the isolation of five chlorinated briarane-type diterpenoids, including three known metabolites, gemmacolide X (1), frajunolide I (2), and fragilide F (3), along with two new analogs, 12α-acetoxyfragilide F (4) and 12α-acetoxyjunceellin (5). Single-crystal X-ray diffraction analysis was carried out to determine the absolute configurations of 1 and 2, while the structures of new compounds 4 and 5 were ascertained with 2D NMR experiments. Briaranes 1 and 3-5 were active in enhancing alkaline phosphatase (ALP) activity.

Immunomodulatory and anti-angiogenesis effects of excavatolide B and its derivatives in alleviating atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin condition primarily driven by T helper 2 (Th2) cytokines, resulting in skin barrier defects, angiogenesis, and inflammatory responses. The marine natural product excavatolide B (EXCB), isolated from the Formosan Gorgonian coral Briareum stechei, exhibits anti-inflammatory and analgesic properties. To enhance solubility, EXCB is chemically modified into the derivatives EXCB-61 salt and EXCB-79. The study aims to investigate the therapeutic effects of these compounds on dinitrochlorbenzene (DNCB)-induced skin damage and to elucidate the underlying anti-inflammatory and anti-angiogenesis mechanism. In vitro, using lipopolysaccharide (LPS)-induced RAW 264.7 cells, all compounds at 10 µM significantly inhibited expression of inflammatory proteins (inducible nitric oxide synthase and cyclooxygenase-2), vascular endothelial growth factor (VEGF), and cytokines (interleukin (IL)-1ß, IL-6, and IL-17A). In vivo, topical application of these compounds on DNCB-induced AD mice alleviated skin symptoms, reduced serum levels of IgE, IL-4, IL-13, IL-17, and interferon-γ, and moderated histological phenomena such as hyperplasia, inflammatory cell infiltration, and angiogenesis. The three compounds restored the expression of skin barrier-related proteins (loricrin, filaggrin, and claudin-1) and reduced the expression of angiogenesis-related proteins (VEGF and platelet endothelial cell adhesion molecule-CD31) in the tissues. This is the first study to indicate that EXCB, EXCB-61 salt, and EXCB-79 can treat AD disease by reducing inflammation and angiogenesis. Hence, they may be considered potential candidates for the development of new drugs for AD.

Prodigiosin Inhibits Transforming Growth Factor ß Signaling by Interfering Receptor Recycling and Subcellular Translocation in Epithelial Cells.

Prodigiosin (PG) is a naturally occurring polypyrrole red pigment produced by numerous microorganisms including some Serratia and Streptomyces strains. PG has exhibited promising anticancer activity; however, the molecular mechanisms of action of PG on malignant cells remain ambiguous. Transforming growth factor-ß (TGF-ß) is a multifunctional cytokine that governs a wide array of cellular processes in development and tissue homeostasis. Malfunctions of TGF-ß signaling are associated with numerous human cancers. Emerging evidence underscores the significance of internalized TGF-ß receptors and their intracellular trafficking in initiating signaling cascades. In this study, we identified PG as a potent inhibitor of the TGF-ß pathway. PG blocked TGF-ß signaling by targeting multiple sites of this pathway, including facilitating the sequestering of TGF-ß receptors in the cytoplasm by impeding the recycling of type II TGF-ß receptors to the cell surface. Additionally, PG prompts a reduction in the abundance of receptors on the cell surface through the disruption of the receptor glycosylation. In human Caucasian lung carcinoma cells and human hepatocellular cancer cell line cells, nanomolar concentrations of PG substantially diminish TGF-ß-triggered phosphorylation of Smad2 protein. This attenuation is further reflected in the suppression of downstream target gene expression, including those encoding fibronectin, plasminogen activator inhibitor-1, and N-cadherin. SIGNIFICANCE STATEMENT: Prodigiosin (PG) emerges from this study as a potent TGF-ß pathway inhibitor, disrupting receptor trafficking and glycosylation and reducing TGF-ß signaling and downstream gene expression. These findings not only shed light on PG's potential therapeutic role but also present a captivating avenue towards future anti-TGF-ß strategies.

Demethoxymurrapanine, an indole-naphthoquinone alkaloid, inhibits the proliferation of oral cancer cells without major side effects on normal cells.

Antioral cancer drugs need a greater antiproliferative impact on cancer than on normal cells. Demethoxymurrapanine (DEMU) inhibits proliferation in several cancer cells, but an in-depth investigation was necessary. This study evaluated the proliferation-modulating effects of DEMU, focusing on oral cancer and normal cells. DEMU (0, 2, 3, and 4 µg/mL) at 48 h treatments inhibited the proliferation of oral cancer cells (the cell viability (%) for Ca9-22 cells was 100.0 ± 2.2, 75.4 ± 5.6, 26.0 ± 3.8, and 15.4 ± 1.4, and for CAL 27 cells was 100.0 ± 9.4, 77.2 ± 5.9, 57.4 ± 10.7, and 27.1 ± 1.1) more strongly than that of normal cells (the cell viability (%) for S-G cells was 100.0 ± 6.6, 91.0 ± 4.6, 95.0 ± 2.6, and 95.8 ± 5.5), although this was blocked by the antioxidant N-acetylcysteine. The presence of oxidative stress was evidenced by the increase of reactive oxygen species and mitochondrial superoxide and the downregulation of the cellular antioxidant glutathione in oral cancer cells, but these changes were minor in normal cells. DEMU also caused greater induction of the subG1 phase, extrinsic and intrinsic apoptosis (annexin V and caspases 3, 8, and 9), and DNA damage (γH2AX and 8-hydroxy-2-deoxyguanosine) in oral cancer than in normal cells. N-acetylcysteine attenuated all these DEMU-induced changes. Together, these data demonstrate the preferential antiproliferative function of DEMU in oral cancer cells, with the preferential induction of oxidative stress, apoptosis, and DNA damage in these cancer cells, and low cytotoxicity toward normal cells.

Anti-Lymphangiogenic Terpenoids from the Heartwood of Taiwan Juniper, Juniperus chinensis var. tsukusiensis.

To look in-depth into the phytochemical and pharmacological properties of Taiwan juniper, this study investigated the chemical profiles and anti-lymphangiogenic activity of Juniperus chinensis var. tsukusiensis. In this study, four new sesquiterpenes, 12-acetoxywiddrol (1), cedrol-13-al (2), α-corocalen-15-oic acid (3), 1,3,5-bisaoltrien-10-hydroperoxy-11-ol (4), one new diterpene, 1ß,2ß-epoxy-9α-hydroxy-8(14),11-totaradiene-3,13-dione (5), and thirty-three known terpenoids were successfully isolated from the heartwood of J. chinensis var. tsukusiensis. The structures of all isolates were determined through the analysis of physical data (including appearance, UV, IR, and optical rotation) and spectroscopic data (including 1D, 2D NMR, and HRESIMS). Thirty-four compounds were evaluated for their anti-lymphangiogenic effects in human lymphatic endothelial cells (LECs). Among them, totarolone (6) displayed the most potent anti-lymphangiogenic activity by suppressing cell growth (IC50 = 6 ± 1 µM) of LECs. Moreover, 3ß-hydroxytotarol (7), 7-oxototarol (8), and 1-oxo-3ß-hydroxytotarol (9) showed moderate growth-inhibitory effects on LECs with IC50 values of 29 ± 1, 28 ± 1, and 45 ± 2 µM, respectively. Totarolone (6) also induced a significant concentration-dependent inhibition of LEC tube formation (IC50 = 9.3 ± 2.5 µM) without cytotoxicity. The structure-activity relationship discussion of aromatic totarane-type diterpenes against lymphangiogenesis of LECs is also included in this study. Altogether, our findings unveiled the promising potential of J. chinensis var. tsukusiensis in developing therapeutics targeting tumor lymphangiogenesis.

Nor-24-homoscalaranes, Neutrophilic Inflammatory Mediators from the Marine Sponge Lendenfeldia sp.

The marine sponge Lendenfeldia sp., collected from the Southern waters of Taiwan, was subjected to chemical composition screening, resulting in the isolation of four new 24-homoscalarane compounds, namely lendenfeldaranes R-U (1-4). The structures and relative stereochemistry of the new metabolites 1-4 were assigned based on NMR studies. The absolute configurations of compounds 1-4 were determined by comparing the calculated and experimental values of specific optical rotation. The antioxidant and anti-inflammatory activities of the isolated compounds were assayed using superoxide anion generation and elastase release assays. These assays are used to determine neutrophilic inflammatory responses of respiratory burst and degranulation. Compounds 2 and 4 inhibited superoxide anion generation by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB) with IC50: 3.98-4.46 µM. Compounds 2 and 4 inhibited fMLP/CB-induced elastase release, with IC50 values ranging from 4.73 to 5.24 µM. These findings suggested that these new 24-homoscalarane compounds possess unique structures and potential anti-inflammatory activity.

Marine diterpenoid targets STING palmitoylation in mammalian cells.

Natural products are important sources of therapeutic agents and useful drug discovery tools. The fused macrocycles and multiple stereocenters of briarane-type diterpenoids pose a major challenge to total synthesis and efforts to characterize their biological activities. Harnessing a scalable source of excavatolide B (excB) from cultured soft coral Briareum stechei, we generated analogs by late-stage diversification and performed structure-activity analysis, which was critical for the development of functional excB probes. We further used these probes in a chemoproteomic strategy to identify Stimulator of Interferon Genes (STING) as a direct target of excB in mammalian cells. We showed that the epoxylactone warhead of excB is required to covalently engage STING at its membrane-proximal Cys91, inhibiting STING palmitoylation and signaling. This study reveals a possible mechanism-of-action of excB, and expands the repertoire of covalent STING inhibitors.

Sinulariaone A: a novel diterpenoid with a 13-membered carbocyclic skeleton from an octocoral Sinularia species.

Chemical composition screening of an octocoral identified as Sinularia species led to the isolation of a novel diterpenoid, sinulariaone A (1), featuring a 13-membered carbocyclic skeleton. The structure of 1 was established by spectroscopic elucidation, computed calculation, and X-ray diffraction analysis. Moreover, a single-crystal X-ray diffraction analysis of chlorofurancembranoid B (2), obtained in our previous study from the same octocoral species, was reported for the first time to demonstrate the absolute configuration. Diterpenoid 1 showed cytotoxicity towards human promyelocytic leukemia HL-60 cells, with an IC50 value of 38.01 µM.

Targeting formyl peptide receptor 1 with anteiso-C13-surfactin for neutrophil-dominant acute respiratory distress syndrome.

BACKGROUND AND PURPOSE: Acute respiratory distress syndrome (ARDS) is a catastrophic pulmonary inflammatory dysfunction with a high mortality rate. An overwhelming immune response by neutrophils is a key feature in infective or sterile ARDS. The formyl peptide receptor 1 (FPR1) is a crucial damage-sensing receptor for inflammatory reactions in the initiation and progression of neutrophil-mediated ARDS. However, effective targets for controlling dysregulated neutrophilic inflammatory injuries in ARDS are limited. EXPERIMENTAL APPROACH: Human neutrophils were used to explore the anti-inflammatory effects of cyclic lipopeptide anteiso-C13-surfactin (IA-1) from marine Bacillus amyloliquefaciens. The lipopolysaccharide-induced model of ARDS in mice was used to determine the therapeutic potential of IA-1 in ARDS. Lung tissues were harvested for histology analyses. KEY RESULTS: The lipopeptide IA-1 inhibited immune responses of neutrophils, including respiratory burst, degranulation, and expression of adhesion molecules. IA-1 inhibited the binding of N-formyl peptides to FPR1 in human neutrophils and in hFPR1-transfected HEK293 cells. We identified IA-1 as a competitive FPR1 antagonist, thus diminishing the downstream signalling pathways involving calcium, mitogen-activated protein kinases and Akt. Furthermore, IA-1 ameliorated the inflammatory damage to lung tissue, by decreasing neutrophil infiltration, reducing elastase release and oxidative stress in endotoxemic mice. CONCLUSION AND IMPLICATIONS: The lipopeptide IA-1 could serve as a therapeutic option for ARDS by inhibiting FPR1-mediated neutrophilic injury.

Briastecholide M, a New Polyoxygenated Briarane from Briareum stechei.

A formerly unpublicized briarane diterpenoid, briastecholide M (1), and its established analogue, brianodin B (2), were purified from Briareum stechei, an octocoral collected from Okinawan waters. Using spectroscopic methods, the structure of 1 was established. Functional study showed that 1 can reducing the release of inducible nitric oxide synthase (iNOS) but enhancing cyclooxygenase-2 (COX-2) protein expression.

Antinociceptive Effects of Aaptamine, a Sponge Component, on Peripheral Neuropathy in Rats.

Aaptamine, a natural marine compound isolated from the sea sponge, has various biological activities, including delta-opioid agonist properties. However, the effects of aaptamine in neuropathic pain remain unclear. In the present study, we used a chronic constriction injury (CCI)-induced peripheral neuropathic rat model to explore the analgesic effects of intrathecal aaptamine administration. We also investigated cellular angiogenesis and lactate dehydrogenase A (LDHA) expression in the ipsilateral lumbar spinal cord after aaptamine administration in CCI rats by immunohistofluorescence. The results showed that aaptamine alleviates CCI-induced nociceptive sensitization, allodynia, and hyperalgesia. Moreover, aaptamine significantly downregulated CCI-induced vascular endothelial growth factor (VEGF), cluster of differentiation 31 (CD31), and LDHA expression in the spinal cord. Double immunofluorescent staining showed that the spinal VEGF and LDHA majorly expressed on astrocytes and neurons, respectively, in CCI rats and inhibited by aaptamine. Collectively, our results indicate aaptamine's potential as an analgesic agent for neuropathic pain. Furthermore, inhibition of astrocyte-derived angiogenesis and neuronal LDHA expression might be beneficial in neuropathy.

Briavioids E-G, Newly Isolated Briarane-Diterpenoids from a Cultured Octocoral Briareum violaceum.

The chemical screening of a cultured soft coral, Briareum violaceum, led to the isolation of eight natural, briarane-related diterpenoids, including three unreported metabolites, briavioids E-G (1-3), and five known briaranes, briacavatolides B (4) and C (5), briaexcavatin L (6), briaexcavatolide U (7) and briarenol K (8). The structures of briaranes 1-8 were established using spectroscopic methods. The absolute configuration of briavioid A (9), obtained in a previous study, was reported for the first time in this study by a single-crystal X-ray diffraction analysis using a copper radiation source. The anti-inflammatory activity of briaranes 1 and 2 and briaranes 4-8 was evaluated by screening their inhibitory ability against the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins in lipopolysaccharide (LPS)-induced RAW 264.7 macrophage cells.

Norsesquiterpenoids from the octocoral Paralemnalia thyrsoides (Ehrenberg 1834).

Three norsesquiterpenoids, pathyspirolactones A (1) and B (2), and napalilactone (3), featuring a γ-spirolactone moiety, were isolated from the cultured octocoral Paralemnalia thyrsoides. The structures of 1-3 were determined by analyzing spectroscopic data, DP4+ computation, specific optical rotation, and X-ray diffraction. In addition, we explored the absolute configurations of pathyspirolactone A (1) and its conformation of the cyclohexane ring to resolve the stereochemical confusion of those of norsesquiterpenoid compounds. Furthermore, we proved that pathyspirolactone B (2) was the first bromine-containing norsesquiterpenoid reported from octocorals.

Tyrosinase Inhibitors Derived from Chemical Constituents of Dianella ensifolia.

Dianella ensifolia is a perennial herb with thickened rhizome and is widely distributed in tropical and subtropical regions of Asia, Australia, and the Pacific islands. This plant has the potential to be used as a source of herbal medicine. This study investigated further phytochemistry and tyrosinase inhibitory effect of some constituents isolated from D. ensifolia. Four new flavans, (2S)-4'-hydroxy-6,7-dimethoxyflavan (1), (2S)-3',4'-dihydroxy-7-methoxy-8-methylflavan (2), (2S)-2'-hydroxy-7-methoxyflavan (3), and (2S,1'S)-4-hydroxy-4-(7-methoxy-8-methylchroman-2-yl)-cyclohex-2-enone (4), together with 67 known compounds, including 10 flavans (5−14), 5 flavanones (15−19), 3 flavone (20−22), 5 chalcones (23−27), 3 chromones (28−30), 15 aromatics (31−45), 7 phenylpropanoids (46−52), one lignan (53), 7 steroids (54−60), one monoterpene (61), one diterpene (62), 4 triterpenes (63−66), a carotenoid (67), 2 alkaloids (68 and 69), and 2 fatty acids (70 and 71) were isolated from D. ensifolia. Their structures were elucidated on the basis of physical and spectroscopic data analyses. Moreover, compounds 1−4, 8, 10−15, 20, 21, and 41 were evaluated for their mushroom tyrosinase inhibitory effect. Compounds 11 and 14 strongly inhibited mushroom tyrosinase activity with IC50 values of 8.6 and 14.5 µM, respectively.

Probing Anti-Leukemic Metabolites from Marine-Derived Streptomyces sp. LY1209.

The unmet need for specific anti-leukemic agents for the treatment of acute lymphoblastic leukemia led us to screen a variety of marine-derived bacteria. The fermentation broth extract of Streptomyces sp. LY1209 exhibited the most potent anti-proliferative effect against Molt 4 leukemia cells. A chromatographic anti-proliferative profiling approach was applied to characterize the metabolites with bioactive potential. Among all the metabolites, the major anti-leukemic constituents were staurosporine and a series of diketopiperazines (DKPs), including one novel and two known DKPs identified from nature for the first time. The structures of these compounds were identified using extensive spectroscopic analysis. The anti-proliferative potential of these metabolites against the Molt 4 cancer cell line was also determined. According to the in silico analysis utilizing a chemical global positioning system for natural products (ChemGPS-NP), it was suggested that these DKPs are potential anti-microtubule and alkylating agents, while staurosporine was proposed to be a tyrosine kinase inhibitor. Our findings not only identified a series of anti-proliferative metabolites, but also suggested a strategic workflow for the future discovery of natural product drug leads.

Antioxidant and Anti-α-Glucosidase Activities of Various Solvent Extracts and Major Bioactive Components from the Fruits of Crataegus pinnatifida.

Crataegus pinnatifida is used to treat various diseases, including indigestion, congestive heart failure, hypertension, atherosclerosis, and myocardial dysfunction. We evaluated antioxidant and anti-α-glucosidase activities of various solvent extracts and major bioactive components from the fruit of C. pinnatifida. Ethyl acetate extracts showed potent antioxidant activities with IC50 values of 23.26 ± 1.97 and 50.73 ± 8.03 µg/mL, respectively, in DPPH and ABTS radical scavenging assays. Acetone extract exhibited significant anti-α-glucosidase activity with IC50 values of 42.35 ± 2.48 µg/mL. HPLC analysis was used to examine and compare the content of active components in various solvent extracts. We isolated four active compounds and evaluated their antioxidant and anti-α-glucosidase properties. Among the isolated compounds, chlorogenic acid and hyperoside showed potential antioxidant activities in ABTS and superoxide radical scavenging assays. Moreover, hyperoside also displayed stronger anti-α-glucosidase activity than other isolates. The molecular docking model and the hydrophilic interactive mode of anti-α-glucosidase assay revealed that hyperoside might have a higher antagonistic effect than positive control acarbose. The present study suggests that C. pinnatifida and its active extracts and components are worth further investigation and might be expectantly developed as the candidates for the treatment or prevention of oxidative stress-related diseases and hyperglycemia.

Briarane-Related Diterpenoids from Octocoral Briareum stechei.

A known polyoxygenated briarane, briaexcavatolide P (1), was isolated from a Formosan octocoral Briareum stechei. Moreover, the same species B. stechei, collected from Okinawan waters, yielded three chlorine-containing briaranes, including two new compounds, briastecholides B (2) and C (3) as well as a known analogue, briarenol R (4). The structures of 1-4 were established using spectroscopic methods. In addition, briarane 1 demonstrated anti-inflammatory activity in lipo-polysaccharide-induced RAW 264.7 mouse macrophage cells by suppressing the expression of inducible nitric oxide synthase (iNOS) protein.

Scalarane-Type Sesterterpenoids from the Marine Sponge Lendenfeldia sp. Alleviate Inflammation in Human Neutrophils.

Sponge-derived scalaranes are remarkable sesterterpenoids previously found to exhibit profound inhibitory effects against neutrophilic inflammation. In our current work, we constructed the metabolomic profile of marine sponge Lendenfeldia sp. for the first time using a tandem mass spectrometry (MS/MS) molecular networking approach. The results highlighted the rich chemical diversity of these scalaranes, motivating us to conduct further research to discover novel scalaranes targeting neutrophilic inflammation. MS- and NMR-assisted isolation and elucidation led to the discovery of seven new homoscalaranes, lendenfeldaranes K-Q (1-7), characterized by methylation at C-24, together with five known derivatives, lendenfeldarane B (8), 25-nor-24-methyl-12,24-dioxoscalar-16-en-22-oic acid (9), 24-methyl-12,24,25-trioxoscalar-16-en-22-oic acid (10), felixin B (11), and 23-hydroxy-20-methyldeoxoscalarin (12). Scalaranes 1-4 and 6-12 were assayed against superoxide anion generation and elastase release, which represented the neutrophilic inflammatory responses of respiratory burst and degranulation, respectively. The results indicated that 1-3 and 6-12 exhibited potential anti-inflammatory activities (IC50 for superoxide anion scavenging: 0.87~6.57 µM; IC50 for elastase release: 1.12~6.97 µM).

Cembranoids from Octocoral Lobophytum crassum (von Marenzeller, 1886).

Two cembranoids, including a new compound, lobocrassin I (1), as well as a known analogue, lobohedleolide (2), were obtained by solvent extraction from octocoral Lobophytum crassum. This study employed a spectroscopic approach to establish the structures of these two cembranoids, and utilized single-crystal X-ray diffraction analysis to determine their absolute configurations. The results of biological activity assays demonstrated that cembranoid 2 exhibited bioactivity against the protein expressions of inducible nitric oxide synthase (iNOS) lipopolysaccharide (LPS)-treated RAW 264.7 mouse macrophage cells.

8-Hydroxybriaranes from Octocoral Briareum stechei (Briareidae) (Kükenthal, 1908).

Chemical investigation of the octocoral Briareum stechei, collected in the Ie Island, Okinawa, Japan, resulted in the isolation of a new briarane-type diterpenoid, briastecholide A (1), as well as the previously reported metabolites, solenolide C (2) and briarenolide S (3). The structures of briaranes 1-3 were characterized through spectroscopic analysis, and the absolute configuration of 2 was corroborated by a single-crystal X-ray diffraction analysis. Briarane 3 exhibited bioactivity against the protein expression of inducible nitric oxide synthase (iNOS).