Sesquiterpenoids with PPARδ agonistic effect from a Korean marine sponge Ircinia sp.

One monocyclofarnesol-derived sesquiterpenoid (1), four new meroterpenoids (2–5) as well as two isolation artifacts (6–7) and a known sesquiterpenoid (8) were isolated from the marine sponge Ircinia sp. Their chemical structures were elucidated via analyses of spectroscopic data, which included NMR and HRMS data. Two terpenoids, 1 and 4, showed PPARδ agonistic activities, with EC₅₀ values of 18 and 30 μg/mL, respectively.     

Penilactones A and B, two novel polyketides from Antarctic deep-sea derived fungus Penicillium crustosum PRB-2

Two highly oxygenated polyketides, penilactones A and B (1 and 2), containing a new carbon skeleton formed from two 3,5-dimethyl-2,4-diol-acetophenone units and a γ-butyrolactone moiety, together with five known compounds (3-7) were isolated from an Antarctic deep-sea derived fungus Penicillium crustosum PRB-2. Penilactones A and B possess antipodal absolute stereochemistries. Their structures were elucidated by spectroscopic methods, and their absolute configurations were assigned by single-crystal X-ray diffraction and CD analyses. A plausible biogenetic pathway for 1-2 is proposed.     

Two new biscembranes with unprecedented carbon skeleton and their probable biogenetic precursor from the Hainan soft coral Sarcophyton latum

A new cembranolide diterpene, isosarcophytonolide D (1), and two biscembranes with an unprecedented fused carbon skeleton, bislatumlides A (3) and B (4), were isolated from the Hainan soft coral Sarcophyton latum. Their structures and relative stereochemistry were established by 1D and 2D NMR spectroscopic techniques. Compounds 3 and 4 should be obtained by Diels-Alder addition of two cembranoid units. Compound 1 could be one of the biosynthetic precursors. Both 3 and 4 showed mild cytotoxicity toward A549, HT-29, and P388 cell lines.     

Alkaloids and citrinins from marine-derived fungus Nigrospora oryzae SCSGAF 0111

A new pyrrolidinone, nigrospine (1), a new indole alkaloid, nigrospin A (2) and two new citrinins, nigrospins B and C (3-4) were isolated from a culture broth of the marine-derived fungal strain Nigrospora oryzae SCSGAF 0111. Their structures were determined by spectroscopic analysis, and the absolute configurations of 1 and 2 were determined by the Mosher ester technique. Compound 1 contains a rare 2,3-dihydro-benzofuran[2,3-c]2-pyrrolidone skeleton.     

Complanadine B, obscurumines A and B, new alkaloids from two species of Lycopodium

A new dimer of C₁₆N₂ type alkaloid, complanadine B (1), and two new C₁₆N type alkaloids, obscurumines A (2) and B (3), have been isolated from the club moss Lycopodium complanatum and L. obscurum, respectively. The structures and stereochemistry of 1-3 were elucidated by combination of 2D NMR spectra and chemical transformation. Complanadine A (4) isolated together with 1 induced secretion of neurotrophic factors from human astrocytoma cells.     

Bioactive meroterpenoids and alkaloids from the fungus Eurotium chevalieri

Five new meroterpenoids, chevalones A-D (1-4), aszonapyrone B (8), and a new sequiterpene alkaloid, eurochevalierine (5), together with four known compounds, sequiterpene (6), terpenoid pyrrolobenzoxazine named CJ-12662 (7), meroterpenoid, aszonapyrone A (9), and ergosterol were isolated from the fungus Eurotium chevalieri. The structures were established on the basis of spectroscopic evidence. The configurations of 1 and 5 were determined by X-ray analysis. The biosynthetic pathway of 1-3, 8, and 9 were proposed. Chemical transformation of aszonapyrone A (9) was also studied. Compounds 4, 5, and 7 exhibited antimalarial activity against Plasmodium falciparum, while 3, 5, and 7 showed antimycobacterial activity against Mycobacterium tuberculosis. In addition, compounds 2-7 showed cytotoxicity against cancer cell lines.     

Excavatoids A-D, new polyoxygenated briaranes from the octocoral Briareum excavatum

Three polyoxygenated briaranes, including two new compounds, excavatoids A (1) and B (2), and a known metabolite, briaexcavatin I (3), were isolated from the cultured octocoral Briareum excavatum. Moreover, the wild type B. excavatum, collected off southern Taiwan coast, yielded two new 5,6-epoxybriaranes, excavatoids C (4) and D (5). The structures of new compounds 1, 2, 4, and 5 were determined by spectroscopic methods and the structure of 1 was further confirmed by X-ray diffraction data analysis. The X-ray structure for briaexcavatin I (3) was also reported for the first time. Excavatoid A (1) is the first briarane which possesses six hydroxy groups and a 17-methoxy group. Excavatoid C (4) is the first 12,13-secobriarane which possesses a novel pentacyclic skeleton with an ?-lactone. Excavatoid D (5) displayed moderate inhibitory effects on superoxide anion generation and elastase release by human neutrophils.     

Five novel norcembranoids from Sinularia leptoclados and S. parva

Three new norcembrane-based diterpenoids, leptocladolides A (1), B (4) and C (5), along with five known metabolites 6-10, have been isolated from the dichloromethane extract of a Taiwanese soft coral Sinularia leptoclados. Furthermore, a chemical investigation on the dichloromethane extract of S. parva has resulted in the isolation of two new related isomers, 1-epi-leptocladolide A (2) and 7E-leptocladolide A (3), in addition to 1 and 7. The structures of new metabolites 1-5 were elucidated on the basis of extensive spectroscopic analyses and their relative stereochemistries were determined by NOESY experiments. The new metabolites 1 and 3 have been shown to exhibit significant cytotoxic activity against KB and Hepa59T/VGH cancer cell lines.     

Bisleuconins A-D: a pair of epimeric ent-kauranoid dimers and two new asymmetric analogues isolated from Isodonleucophyllus

A phytochemical investigation of Isodon leucophyllus led to the isolation of four novel ent-kauranoid dimers: bisleuconins A-D (1-4), and one known compound, rabdoloxin A (5). It was interesting that the structures of bisleuconins A (1) and B (2) were elucidated as a pair of epimeric ent-kauranoid dimers with unique linkage pattern C-16→C-17′ to connect two monomers. Bisleuconins C (3) and D (4) were two new asymmetric ent-kauranoid dimers. A possible biogenetic pathway of 1 and 2 was also proposed.     

Trypanocidal constituents of Dracocephalum komarovi

Trypanocidal constituents of Dracocephalum komarovi were investigated. Under guidance of the in vitro trypanocidal activity against epimastigotes of Trypanosoma cruzi, the causative agent of Chagas' disease, two new diterpenes, dracocequinones A (1) and B (2), and two known triterpene acids, ursonic acid and ursolic acid, were isolated as trypanocidal constituents, in addition to previously reported diterpenes, cyclocoulterone (4), komaroviquinone (5), dracocephalone A (6) and komarovispirone (7). Furthermore a new diterpene, komarovinone A (3), was isolated, together with four known terpenes. Among these compounds, komaroviquinone (5) showed the most potent activity with minimum lethal concentration of 0.4 μM. Structure elucidation of the new diterpenes 1-3 was described.     

Novel cyclopropyl diketones and 14-membered macrolides from the soil fungus Hamigera avellanea BCC 17816

Two novel cyclopropyl diketones, hamavellone A (1) and B (2), and two new 14-membered nonaketide macrolactones, hamigeromycin A (3) and B (4), together with six known compounds, 89-250904-F1 (radicicol analogue A, 5), pseurotin A (6), emodin (7), ω-hydroxyemodin (8), and emodin bianthrones (9 and 10) were isolated from the soil fungus Hamigera avellanea BCC 17816. The structures of the new compounds were defined by analysis of NMR and MS data. The absolute stereochemistry of 3 was addressed by chemical correlation to 5. Hamavellone B (2) exhibited antimalarial activity with an IC₅₀ of 5.2 μg/mL, whereas it also showed comparable cytotoxicity.     

Lyconadins C and F, new Lycopodium alkaloids from Lycopodium complanatum

New Lycopodium alkaloids, lyconadins C (1) and F (2), were isolated from the club moss Lycopodium complanatum. Lyconadin C (1) is a new C₁₆N₂-type Lycopodium alkaloid possessing unique fused-tetracyclic ring system consisting of a cycloheptene ring fused to a decahydroquinoline and pyridone rings. Lyconadin F (2) possesses a primary amide moiety in its molecular, which is the first example of Lycopodium alkaloids. Biogenetically, lyconadins C (1) and F (2) might be related to lyconadins A (4) and B (5). The structures and relative stereochemistry of 1 and 2 were elucidated on the basis of spectroscopic data. The absolute stereochemistry of 2 was elucidated by chemical correlations with lyconadin B (5) through hemiaminal form of lyconadin F (3).     

Feroniellides A and B, apotirucallane triterpenes with novel cyclic acetals from Feroniella lucida

The isolation and structure elucidation of two new triterpenes named feroniellides A (1) and B (2) from Feroniella lucida are described. Feroniellide A has a novel dioxabicyclic [3.2.1]octane moiety, and feroniellide B is the C-3 epimer of the known triterpenoid 3. Their overall structures and relative configurations were established by combined spectral data analysis. The cytotoxicity of 1 and 2 was also evaluated against human KB and HeLa carcinoma cells.     

Structural and stereochemical investigations into bromotyrosine-derived metabolites from southern Australian marine sponges, Pseudoceratina spp.

Chemical investigation of a southern Australian sponge, Pseudoceratina sp., resulted in the isolation of twelve bromotyrosine-derived alkaloids, comprising four new metabolites, aplysamine-7 (1), (−)-purealin B (2), purealin C (3) and purealin D (4); two new spiroisoxazole enantiomers, (−)-purealidin R (5) and (−)-aerophobin-2 (6); five known metabolites (−)-pseudoceratinine A (7), (−)-aeroplysinin-1 (8), aplysamine-2 (9), purpuramine G (10) and purpuramine J (11); and an artifact 12 derived from ethanolysis of 5. Structures for 1-12 were assigned on the basis of detailed spectroscopic analysis. A second southern Australian Pseudoceratina sp. afforded the first recorded account of a racemic bromotyrosine-derived spiroisoxazole, (±)-purealin (13b), together with the known achiral precursor purealidin A (15). A literature review of marine bromotyrosine-derived spiroisoxazoles reaffirmed the published dominance of (+)-spiroisoxazoles, acknowledging several accounts of (−)-spiroisoxazoles, while also revealing a wide range of chiroptical measurements suggestive of variable optical purity. The Pseudoceratina sp. metabolites 1-12, 13b and 15 were assessed for antibiotic properties, with the new metabolites 3 and 13b exhibiting broad spectrum activity against several Gram-positive bacteria.     

Arabidopsides A and B, two new oxylipins from Arabidopsis thaliana

Two new oxylipins, arabidopsides A (1) and B (2), were isolated from the aerial parts of Arabidopsis thaliana, and their structures and absolute stereochemistries were elucidated by spectroscopic data and chemical means. Arabidopsides A (1) and B (2) were rare monogalactosyl diacylglycerides containing 12-oxophytodienoic acid and/or dinor-oxophytodienoic acid.     

Bioactive meroditerpenes and indole alkaloids from the soil fungus Neosartorya fischeri (KUFC 6344), and the marine-derived fungi Neosartorya laciniosa (KUFC 7896) and Neosartorya tsunodae (KUFC 9213)

Two new metabolites including a new aszonalenin analogue (1c) and a new meroditerpene (3) were isolated, together with aszonalenin (1a), acetylaszonalenin (1b), 13-oxofumitremorgin B (2), aszonapyrone A (4b) and helvolic acid, from the culture of the soil fungus Neosartorya fischeri (KUFC 6344). While the ethyl acetate extract of the culture of the diseased coral-derived fungus Neosartorya laciniosa (KUFC 7896) furnished aszonapyrone B (4a), aszonapyrone A (4b), tryptoquivaline L and 3′-(4-oxoquinazolin-3-yl) spiro[1H-indole-3,5′-oxolane]-2,2′-dione, the ethyl acetate extract of the culture of the marine sponge-associated fungus Neosartorya tsunodae (KUFC 9213) yielded a new analogue of chevalone C (5) and helvolic acid. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis as well as HR-ESIMS. Compounds 1a–c, 2, 3, 4a, 4b and 5 were evaluated for their in vitro growth inhibitory activity on the MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (melanoma) cell lines by the protein binding dye SRB method.     

Daphcalycinosidines A and B, new iridoid-alkaloids from Daphniphyllum calycinum

Three new alkaloids, daphcalycinosidines A (1) and B (2) and daphcalycic acid (3) have been isolated from the seeds of Daphniphyllum calycinum. The structures and relative stereochemistries were determined on the basis of spectral studies including 2D NMR, mass spectrometry and chemical transformations. Structures 1 and 2 are characterized by an iridoid glucoside moiety linked to new Daphniphyllum alkaloid moieties.     

A novel chlorinated norsesquiterpenoid and two related new metabolites from the soft coral Paralemnalia thyrsoides

A structurally unique chlorinated norsesquiterpenoid, paralemnolin A (1), along with two new metabolites, paralemnolin B (2) and C (3), have been isolated from the soft coral Paralemnalia thyrsoides. Their structures were determined by extensive spectroscopic analyses. Single-crystal X-ray diffraction analysis of 1 further establish the absolute stereochemistry of 1.     

Pashinintide A,the first plant cyclopeptide from Rosaceae,included a sucrose,suggests a new natural receptor for saccharide

Pashinintide A (1), a new cyclic hexapeptide, included a saccharose, and a new cyclic heptapeptide named pashinintide B (2) were isolated from the branches and leaves of Pyrus pashia Buch.-Ham. ex D. Don. 1 and 2 present the first two plant cyclopeptides from Rosaceae. And the stable complex of cyclic hexapeptide and sucrose in 1 suggests that cyclic hexapeptide might be a new natural receptor for saccharide.     

Bioactive rearranged limonoids from the Chinese mangrove Xylocarpus granatum Koenig

Two new pyridine-containing limonoids, xylogranatopyridines A and B (1 and 2) and their formal precursor, prexylogranatopyridine (3) were isolated from the twigs and leaves of the Chinese mangrove, Xylocarpus granatum. Xylogranatopyridine B (2) possesses an unprecedented rearranged B-ring together with a seco-ring A, supporting the biogenetic connection of 1–2 with 3. The chemical structures were elucidated by means of detailed spectroscopic analysis and X-ray single-crystal diffraction. The absolute configurations were assigned using electronic solid-state circular dichroism (ECD) supported by time-dependent density functional theory (TDDFT) ECD calculations and X-ray analysis. Xylogranatopyridine A (1) exhibited a significant inhibitory activity against protein tyrosine phosphatase 1B (PTP1B) with an IC₅₀ value of 22.9 μM. This is the first report of PTP1B inhibitory activity of limonoids.