New naphthoquinone and monoterpenoid from Plumbago zeylanica

New naphthoquinone 2 and new monoterpenoid 3 were isolated from the stems of Plumbago zeylanica, and their structures were determined on the basis of 2D NMR spectroscopy. Absolute configuration of 3 was established by synthesis of its enantiomer. The new naphthoquinone 2 showed potent inhibitory activity against nuclear factor κB (NF-κB), equivalent to that of parthenolide, a known potent inhibitor of NF-κB.     

Bieremoligularolide and eremoligularin, two novel sesquiterpenoids from Ligularia muliensis

From the roots of Ligularia muliensis, a novel bieremophilanolide and a new eremophilanolide have been isolated and their structures were elucidated by spectroscopic techniques, including HRMS, IR, UV, 1D-NMR, 2D-NMR, and CD spectra.     

Swiemahogins A and B, two novel limonoids from Swietenia mahogani

Two novel limonoids, swiemahogins A (1) and B (2) isolated from the twigs and leaves of Swietenia mahogany, are the first examples of andirobin and phragmalin types of limonoids, of which the D-ring δ-lactone is demolished and a rare γ-lactone is fused to the C-ring at C-8 and C-14. Their structures were elucidated by extensive spectroscopic means, and that of 1 was confirmed by single-crystal X-ray diffraction.     

Acutaxylines A and B, two novel triterpenes from Dysoxylum acutangulum

Two novel triterpenes, acutaxylines A (1) and B (2) consisting of a cyclopentenone side chain at C-17 and an oxepan-2-ol, were isolated from the leaves of Dysoxylum acutangulum. The relative stereochemistry of 1 and 2 was determined by NOESY correlations. Acutaxyline B showed moderate cytotoxicity against human blood premyelocytic leukemia cells.     

Barbatusin and cyclobutatusin,two novel diterpenoids from coleus barbatus bentham

The structure of three diterpenoids from Coleus barbatus, Bentham (Labiatae) having a spirocyclopropyl side chain have been determined: they are barbatusin (1a), 3β-hydroxy-3-deoxybarbatusin (2) and cyclobutatusin (3a). The structures of 1a and 3a were established by X-ray diffraction analysis, and the latter compound has been shown to have an unusual 4-membered ring produced by a bond across C(1) to C(11). Chemical transformations and interconversions are presented, together with spectroscopic studies.     

Angumycinones A and B,two new angucyclic quinones from Streptomyces sp. KMC004 isolated from acidic mine drainage

Two new angucyclic quinones, angumycinones A (1) and B (2) and six known angucyclinone analogues (3–8) were isolated from a liquid culture extract of the Streptomyces sp. KMC004 strain from acidic coal mine drainage. The structures of these compounds were established using extensive spectroscopic data analyses, including NMR, HRFABMS, UV, CD, and X-ray crystallography. Compounds 1–8 were tested for antimicrobial activity against ten pathogenic microbial or fungal strains. Angumycinone B (2) exhibited antimicrobial activity against Micrococcus luteus, Enterococcus hirae, and methicillin-resistant Staphylococcus aureus (MRSA) with minimum inhibitory concentration values of 0.78, 1.56, and 12.5 μg/mL, respectively.     

Rubiyunnanins A and B, two novel cyclic hexapeptides from Rubia yunnanensis

Two novel cyclic hexapeptides, named rubiyunnanins A (1) and B (2), were isolated from the roots of Rubia yunnanensis (Franch.) Diels. Their structures were elucidated extensively by spectroscopic analysis and theoretical computation. Possible biosynthetic pathways for RAs, 1, and 2 were proposed. Compound 2 showed moderate cytotoxicities against 11 cancer cell lines and inhibited nitric oxide (NO) production in LPS and IFN-γ-induced RAW 264.7 murine macrophages.     

Multistalides A and B, two novel sesquiterpenoid dimers from Chloranthus multistachys

Two novel sesquiterpenoid dimers, multistalides A and B (1-2), were isolated from the whole plant of Chloranthus multistachys. Their structures were established on the basis of spectroscopic analysis, and the absolute configuration of 1-2 was determined by CD exciton chirality method.     

Malayanines A and B, two novel limonoids from Chisocheton erythrocarpus Hiern

Two structurally interesting novel limonoids, malayanine A and malayanine B, were isolated from the bark of Chisocheton erythrocarpus Hiern. The structures were fully characterized through spectroscopic methods.     

Aminocadambines A and B, two novel indole alkaloids from Neolamarckia cadamba

Two novel monoterpenoid indole alkaloids, aminocadambines A (1) and B (2), characterized by tetrahydrofuran and 1,2,3,4-tetrahydropyridine rings, were isolated from the leaves of Neolamarckia cadamba. Their structures were elucidated on the basis of spectroscopic and computational methods. The absolute configuration of 1 was established by CD analysis. A plausible biosynthetic pathway for 1 and 2 is proposed.     

Nukiangendines A and B,two novel 13,14-seco-abietanes from Abies nukiangensis

From Abies nukiangensis, two novel 13,14-seco-abietane diterpenes, nukiangendines A (1) and B (2) were isolated. Their relative structures were determined by extensive NMR and HRMS spectroscopic analysis. The absolute configuration of 1 was established by ECD calculations. Compound 1 showed significant anti-hepatitis C virus (HCV) effects.     

Argeloside A and B, two novel 14,15-secopregnane glycosides from Solenostemma argel

Argeloside A and B, two novel 14,15-secopregnane glycosides characterized by the presence of two hemiketal functions involved in two five-membered rings, were isolated from Solenostemma argel fruits. Their structures have been established by ESIMS and NMR experiments. In particular the relative configuration of the molecules has been defined by combining the available NMR data with quantum chemical calculations of the geometries and ¹³C chemical shifts.     

Trigonoines A and B, two novel alkaloids from the leaves of Trigonostemon lii

Two novel alkaloids, trigonoine A containing a 2,8-diazabicyclo[3.3.1]nonane ring system and trigonoine B formed by a combination of a 2,3-dihydroquinolin-4-one and 3H-pyrrolo[2,3-c]quinoline rearranged from β-carboline skeleton were isolated from the leaves of Trigonostemon lii. Their structures were elucidated by 1D and 2D NMR spectroscopic methods.     

Daphlongeramine A, novel Daphniphyllum alkaloid from Daphniphyllum longeracemosum

A novel Daphyniphyllum alkaloid, Daphlongeramine A (1) with a unique fused octacyclic skeleton, together with a quite recently reported alkaloid Paxdaphnine A (2), were isolated from the fruits of Daphniphyllum longeracemosum. The structures were elucidated on the basis of spectroscopic data.     

Cinachyramine, the novel alkaloid possessing a hydrazone and two aminals from Cinachyrella sp.

The trifluoroacetate salt of cinachyramine (1) was isolated from the Okinawan sponge Cinachyrella sp. This structure was determined by the spectroscopic analysis and the degradation under acidic conditions. Cinachyramine (1) is a novel alkaloid with an unprecedented cage system possessing a hydrazone and two aminals.     

Calyciphylline C, a novel Daphniphyllum alkaloid from Daphniphyllum calycinum

Calyciphylline C (1), a novel Daphniphyllum alkaloid with unprecedented fused-hexacyclic ring system, has been isolated from the leaves of Daphniphyllum calycinum (Daphniphyllaceae), and the structure and relative stereochemistry were elucidated on the basis of spectroscopic data.     

Lonijaposides, novel cerebrosides from Lonicera japonica

Six novel cerebrosides, lonijaposides A₁-A₄, B₁ and B₂ (1-6) have been isolated from the flowers of Lonicera japonica. Their structures were established on the basis of 1D, 2D (DEPT, HMQC, HMBC and COSY) NMR, ESI-QTOF-MS/MS and chemical evidence.     

A novel neolignan, mansoxetane, and two new sesquiterpenes, mansonones R and S, from Mansonia gagei

Three new compounds, mansoxetane; 4′-(3-hydroxy-1,2-oxetanyl)-2′,2-dihydroxy-4-(2-formyl-1-ethyl)-6′,6-dimethoxy biphenyl, and mansonones R and S, together with two previously reported coumarins, mansorins A and C, and four known mansonones, mansonones C, E, G and H, were obtained from the methanolic extract of the heartwood from Mansonia gagei Drumm. Their structures were established by spectroscopic methods.     

Stipitatic acid: synthesis via cyclopropanated quinones

A new synthesis of stipitatic acid incorporating a cyclopropanated quinone intermediate is reported.     

Neoverataline A and B, two antifungal alkaloids with a novel carbon skeleton from Veratrum taliense

Bioassay-guided fractionation of the ethanol extract of the roots and rhizomes of Veratrum taliense yielded two new and thirteen known steroidal alkaloids. The structures of the two new compounds, neoverataline A and B, were established by extensive spectroscopic analyses to be 3,4-secocevane-4,9-olid-14,15,16,20-tetra-ol-3-oic acid and 3,4-secocevane-4,9-olid-7,14,15,16,20-penta-ol-3-oic acid, respectively, and are a novel carbon skelton. All of the fifteen alkaloids were subjected to in vitro antifungal assays, which showed that the verazine- (veramitaline, stenophylline B, stenophylline B-3-O-β-d-glucopyranoside, veramiline-3-O-β-d-glucopyranoside) and jerveratrum-type (jervine, jervine-3-O-β-d-glucopyranoside) alkaloids exhibited strong antifungal activities against the phytopathogenic fungus Phytophthora capisis with MICs of 160, 120, 160, 80, 80 and 120 μg·L⁻¹, respectively. Furthermore, the verazine-type alkaloids stenophylline B, stenophylline B 3-O-β-d-glucopyranoside and veramiline 3-O-β-d-glucopyranoside were shown to also inhibit the growth of another fungal phytopathogen Rhizoctonia cerealis with MICs of 160, 120 and 120 μg mL⁻¹. The MICs of triadimefon (an antifungal agrochemical used herein as a positive control) against P. capisis and R. cerealis were 120 and 80 μg mL⁻¹, respectively. A preliminary structure-activity relationship regarding these alkaloids has been formulated.