Penicisteckins A-F, Isochroman-Derived Atropisomeric Dimers from Penicillium steckii HNNU-5B18.

Penicisteckins A-D (1-4), two pairs of atropodiastereomeric biaryl-type hetero- and homodimeric bis-isochromans with 7,5'- and 7,7'-linkages and a pair of atropodiastereomeric 2-(isochroman-5-yl)-1,4-benzoquinone derivatives [penicisteckins E (5) and F (6)], were isolated from the Penicillium steckii HNNU-5B18. Their structures including the absolute configuration were determined by extensive spectroscopic and single-crystal X-ray diffraction analysis and TDDFT-ECD calculations. Both the bis-isochromans and the isochroman/1,4-benzoquinone conjugates represent novel biaryl scaffolds containing both central and axial chirality elements. The monomer anserinone B (8) exhibited potent antibacterial activities against Staphylococcus aureus ATCC 29213 and methicillin-resistant Staphylococcus aureus with minimal inhibition concentration values ranging from 2 to 8 µg mL-1. Plausible biosynthetic pathways of 1-6 are proposed, which suggest how the absolute configurations of the isolates were established during the biosynthetic scheme.

Endoplasmic reticulum stress mediated the xanthohumol induced murine melanoma B16-F10 cell death.

Xanthohumol (XN) exerts a specific cytotoxicity in B16-F10 melanoma cells with cytoplasmic vacuoles formation. Further investigation showed XN inhibited cell proliferation in a time- and dose-dependent manner along with down-regulation of mitogen-activated protein kinase and up-regulation of the endoplasmic reticulum (ER) stress marker Bip, CHOP and protein ubiquitination, which was relieved by the ER-stress inhibitor 4-PBA. Whereas no early apoptosis characteristics was identified during XN induced cell death. [Formula: see text].

Iridoid Derivatives with Cytotoxic Activity from Pedicularis uliginosa Bunge.

Three new iridoids, rel-(4aR,7S,7aS)-7-hydroxy-7-methyl-1,4a,5,6,7,7a-hexahydrocyclopenta[c]pyran-4-carbaldehyde (1), 1-methoxy-7-methyl-1,3,5,6-tetrahydrocyclopenta[c]pyran-4-carbaldehyde (2), and rel-(1R,4S,4aS,7R,7aR)-7-methylhexahydro-1,4-(epoxymethano)cyclopenta[c]pyran-3(1H)-one (3), together with seven known analogues, were isolated from the 95 % EtOH extract of the whole plants of Pedicularis uliginosa Bunge. Their structures were elucidated via extensive NMR spectroscopy and mass spectral data. In terms of inhibitory effects on human tumor cells, compounds 1, 2, 6, 7, and 8 exhibited better inhibitory activities against ACHN cells than the positive control (vinblastine).

Terpenoids from Euphorbia pekinensis.

Euphorpekone A (1) and euphorpekone B (2), two new diterpenoids, 3ß-hydroxy-25-methyloxylanosta-8,23-diene, a new triterpenoid (3), together with a known triterpenoid, 3ß,25-dihydroxylanosta-8,23-diene (4), were isolated from Euphorbia pekinensis Rupr. Their structures were elucidated on the basis of UV, IR, 1D ((1)H, (13)C, NOE) and 2D ((1)H-(1)H COSY, HSQC, HMBC) NMR, HR-ESI-MS, X-ray diffraction analysis, and CD method.

A novel flavonoid isolated from Sophora flavescens exhibited anti-angiogenesis activity, decreased VEGF expression and caused G0/G1 cell cycle arrest in vitro.

Kushen, the dried root of Sophora flavescens Ait, is a traditional Chinese herbal medicine. Kushen alkaloids have been developed in China as anticancer drugs, and more potent antitumor activities have been identified in kushen flavonoids than in kushen alkaloids. In this study, the anti-angiogenic properties of (2S)-7,2',4'-triihydroxy-5-methoxy-8-dimethylallyl flavanone (Compound 1, a novel flavonoid isolated from Kushen), were examined using the human umbilical vein endothelial cell line (ECV304) in vitro. The results indicated that compound 1 shows anti-angiogenesis activity via inhibitory effects on cell proliferation, cell migration, cell adhesion, and tube formation. Further studies indicated that compound 1 blocks cell cycles in the G0/G1 phase without inducing apoptosis, and down regulates vascular endothelial growth factor (VEGF) expression. The free radical scavenging activity of compound 1 was found through 2',7'-dichlorofluorescin diacetate (DCFH-DA) incubation assay in cells. The anti-angiogenic properties of compound 1 and its antiproliferative effect on endothelial cells without causing apoptosis make it a good candidate for development as a agent against development of tumors.

Tirucallane-type triterpenoids from Dysoxylum lenticellatum.

Ten new tirucallane-type triterpenoids, represented by a rearranged skeleton dysolenticin A (1), dysolenticin B (2), a rare trinortriterpenoid dysolenticin C (3), three tirucallane triterpenoid derivatives with a hemiketal moiety dysolenticins D-F (4-6), dysolenticins G-I (7, 9, 10), and the new alkaloid dysolenticin J (12), together with seven known analogues were isolated from the twigs and leaves of Dysoxylum lenticellatum. Their structures were elucidated by extensive spectroscopic methods, and those of compounds 1, 3, 4, 6, and 10 were confirmed by single-crystal X-ray diffraction experiments. Dysolenticin J (12) showed significant vasodilative effects on intact rat aortic rings with a diastolic degree of 87.4% at 10 µg/mL.

A tellura-Baeyer-Villiger oxidation: one-step transformation of tellurophene into chiral tellurinate lactone.

Baeyer-Villiger (BV) oxidation is a fundamental organic reaction, whereas the hetero-BV oxidation is uncharted. Herein, a tellura-BV oxidation is discovered. By oxidizing a tellurophene-embedded and electron-rich polycycle (1) with mCPBA or Oxone, an oxygen atom is inserted into the Te-C bond of the tellurophene to form tellurinate lactone mono-2. This reaction proceeds as follows: (i) 1 is oxidized to the tellurophene Te-oxide form (IM-1); (ii) IM-1 undergoes tellura-BV oxidation to give mono-2. Moreover, the hybrid trichalcogenasumanenes 7 and 8 are, respectively, converted to tellurinate lactones mono-9 and mono-10 under the same conditions, indicating that tellura-BV oxidation shows high chemoselectivity. Due to the strong secondary bonding interactions between the Te[double bond, length as m-dash]O groups on tellurinate lactones, mono-2, mono-9, and mono-10 are dimerized to form U-shaped polycycles 2, 9, and 10, respectively. Notably, mono-2, mono-9, mono-10, and their dimers show chirality. This work enables one-step transformation of tellurophene into tellurinate lactone and construction of intricate polycycles.

Two novel nornemoralisin-type diterpenoids from Aphanamixis polystachya (Wall.) R. Parker.

Two novel heptanornemoralisin-type diterpenoids nornemoralisins A (1) and B (2), together with two known compounds nemoralisin (3) and nemoralisin A (4), were isolated from the stem bark and leaves of Aphanamixis polystachya (Wall.) R. Parker. Their structures were established through comprehensive analyses of NMR spectroscopic data and high resolution mass spectrometric (HR-ESI-MS) data. The absolute configurations of carbon stereocenters were elucidated by circular dichroism (CD) analyses. The four compounds were tested for their potential cytotoxic effects against ACHN, HeLa, SMMC-7721, and MCF-7 cell lines. Nornemoralisins A (1) and B (2) exhibited significant cytotoxicity on ACHN with an IC50 value of 13.9 ± 0.8 and 10.3 ± 0.4 µM, respectively, and other compounds failed to reveal obvious cytotoxicity on the tested cell lines, compared to positive control vinblastine (IC50, 28.0 ± 0.9 µM).

Chemical constituents from common vetch (Vicia sativa L.) and their antioxidant and cytotoxic activities.

Vicia sativa L. (common vetch) is a potential food source for both human beings and animals because of its abundant nutritional composition. There is a lack of phytochemical study on the whole plant, and thus the objective of this study was to investigate the isolation of phytochemicals and evaluate their biological activities. A new flavanol, (2R,3S)-3,3'-dihydroxy-4',7-dimethoxyflavanol (1), together with nine known compounds, two flavones (2-3), one coumarin (4), and six oleanane triterpenoids (5-10), was obtained from Vicia sativa L.. The structure of the new compound 1 was determined via its NMR spectra, IR and CD data. Compound 3 displayed the potential of the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging effect in antioxidant test. In terms of cytotoxic activities, compound 3 showed moderate cytotoxic activities against three human tumor cells, especially HeLa cells.

Isopimarane-type diterpenoids from Croton laevigatus.

A new isopimarane-type diterpenoid, crolaevinoid A, along with four known analogues was isolated from the twigs and leaves of Croton laevigatus. The structures of the isolated compounds were established on the basis of NMR and MS spectroscopic analyses. The isolated compounds were examined the antibacterial activities. Unfortunately, the compounds showed no antibacterial activity against Micrococcus luteus, Methicillin-resistant Staphylococcus aureus, Aeromonas hydrophila, Klebsiella pneumoniae ssp pneumoniae, Acinetobacter Baumanii, and Escherichia coli.

A novel trinorguaiane-type sesquiterpene from Dictamnus radicis.

A novel trinorguaiane-type sesquiterpene named radicol (1), together with a known sesquiterpene dictamnol (2), was isolated from the petroleum ether-EtOAc-MeOH extracts of the root of Dictamnus radicis Cortex. The structure of 1 was elucidated as 1 alpha,5 alpha-dimethyl-4 alpha,10 alpha-bicyclo[3.5.0]dec-8-en-1 beta,5 beta-diol (1) on the basis of IR, HRESIMS, 1H and 13C NMR, DEPT, 1H-1H COSY, HMQC, HMBC and NOESY.

Molecular basis of dimer formation during the biosynthesis of benzofluorene-containing atypical angucyclines.

Lomaiviticin A and difluostatin A are benzofluorene-containing aromatic polyketides in the atypical angucycline family. Although these dimeric compounds are potent antitumor agents, how nature constructs their complex structures remains poorly understood. Herein, we report the discovery of a number of fluostatin type dimeric aromatic polyketides with varied C-C and C-N coupling patterns. We also demonstrate that these dimers are not true secondary metabolites, but are instead derived from non-enzymatic deacylation of biosynthetic acyl fluostatins. The non-enzymatic deacylation proceeds via a transient quinone methide like intermediate which facilitates the subsequent C-C/C-N coupled dimerization. Characterization of this unusual property of acyl fluostatins explains how dimerization takes place, and suggests a strategy for the assembly of C-C and C-N coupled aromatic polyketide dimers. Additionally, a deacylase FlsH was identified which may help to prevent accumulation of toxic quinone methides by catalyzing hydrolysis of the acyl group.

A new iridoid and other chemical constituents from Pedicularis kansuensis forma albiflora Li.

A new iridoid (1) and thirteen known compounds 2-14 were isolated from Pedicularis kansuensis forma albiflora Li., and their structures were elucidated by spectroscopic methods including 2D-NMR techniques.

Pyrazolofluostatins A-C, Pyrazole-Fused Benzo[a]fluorenes from South China Sea-Derived Micromonospora rosaria SCSIO N160.

Pyrazolofluostatins A-C (1-3), three new benzo[a]fluorenes with an unprecedented carbon skeleton, were obtained from the South China Sea-derived Micromonospora rosaria SCSIO N160. Their structures were elucidated by extensive spectroscopic analyses. The structure of pyrazolofluostatin A (1) was confirmed by X-ray crystallographic analysis. Notably, 1-3 possessed a benzo[cd]indeno[2,1-f]indazol skeleton with a pyrazole-fused 6/5/6/6/5 pentacyclic ring system. Pyrazolofluostatin A (1) showed moderate antioxidation activity (EC50 48.6 µM).

Five new iridoids from Patrinia rupestris.

Five new iridoids, namely rupesin A-E (1-5, resp.), together with six known iridoids, 6-11, were isolated from the roots of Patrinia rupestris. Their structures were elucidated by spectroscopic methods including IR, UV, MS, and 1D- and 2D-NMR experiments, and comparison with data of known analogues. Compounds 4 and 11, compounds 1, 2, 5, 6, 8, 9, and 10, and compounds 3, 4, and 8 showed significant antibacterial activities against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus, respectively.

Sesquiterpenes from roots of Lingularia veitchiana.

Together with seven known sesquiterpenes, a new guaiane, a new furanoeremophilane, and a new eudesmane were isolated from the roots of Ligularia veitchiana. Their structures were elucidated by spectroscopic methods. The bioactivities of three known guaiane sesquiterpenes were determined.

Iridoids from Pedicularis kansuensis forma albiflora.

A new iridoid glycoside kansuenoside (1) and a new iridoid kansuenin (2), along with eight known compounds (3-10) were isolated from the whole plant of Pedicularis kansuensis forma albiflora Li. Their structures were elucidated by spectroscopic methods. Nine of them were assayed against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus.

Sesquiterpenes and other constituents from Cacalia deltophylla.

From the whole plant of Cacalia deltophylla (Maxim) Mattf, together with twelve known compounds (3-14), a new furanoeremophilane-type sesquiterpene named deltocacalone (1), and a new norsesquiterpene named deltonorcacalol (2) were isolated. Their structures were elucidated by spectroscopic methods including 2D-NMR techniques.

A new benzopyran derivative from Pseuduvaria indochinensis Merr.

From the twigs and leaves of Pseuduvaria indochinensis Merr., a new benzopyran derivative, pseudindochin (1), was isolated together with three known compounds, oligandrol (2), (6E,10E)-isopolycerasoidol (3) and polycerasoidol (4). The structure of compound 1 was elucidated on the basis of extensive spectroscopic data interpretation, including 1D, 2D NMR, HR-ESI-MS, UV and IR. Moreover, compounds 1-4 were evaluated in vitro for their cytotoxic activities against HL-60 and SMMC-7721 cell lines, but these compounds were essentially non-cytotoxic (IC50>30 µg/mL).

Pyrone derivatives from the endophytic fungus Alternaria tenuissima SP-07 of Chinese herbal medicine Salvia przewalskii.

Three new pyrones, solanapyrones P-R (1-3), were afforded by the extracts of the endophytic fungus Alternaria tenuissima SP-07 isolated from the fresh root of Chinese herbal medicine Salvia przewalskii, along with the known solanapyrones (4-6) and benzopyrones (7-9). Solanapyrones P (1) and Q (2) possess an unprecedented nor-solanapyrone skeleton as natural products. Their structures were determined on the basis of NMR and HR-ESI-MS analysis. The plausible biosynthetic pathways to those unknown compounds were discussed. All the isolated compounds were evaluated for their antibacterial activities against six bacteria.