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Hui Ming Ge Dr. Wen Hao Yang Yan Shen Dr. Nan Jiang Dr. Zhi Kai Guo Qiong Luo Qiang Xu Prof. Jing Ma Prof. Ren Xiang Tan Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(21):6338-6345
Two novel resveratrol aneuploids, hopeachinols A ( 1 ) and B ( 2 ), as well as a potent immunosuppressive polyphenol diptoindonesin G ( 3 ) were characterized from the ethanol extract of Hopea chinensis stem barks. The structure of the polyphenols was accommodated by comprehensive spectroscopic analysis with the absolute stereochemistry determined by the CD approach coupled with theoretical ECD spectra computer‐generated through the Gaussian 03 program. The distinct structure and biological profile of 3 recommended it as a starting molecule for the relevant drug discovery. 相似文献
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Siphonazole, an unusual metabolite from Herpetosiphon sp 总被引:2,自引:0,他引:2
Nett M Erol O Kehraus S Köck M Krick A Eguereva E Neu E König GM 《Angewandte Chemie (International ed. in English)》2006,45(23):3863-3867
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Cruz PG Fernández JJ Norte M Daranas AH 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(23):6948-6956
Belizeanic acid (BA), a novel metabolite belonging to the okadaic acid class of protein phosphatase inhibitors, was isolated from artificial cultures of the dinoflagellate Prorocentrum belizeanum. The structure and conformational behaviour of BA was elucidated by a combination of NMR spectroscopy and conformational analysis. The isolation of this metabolite, which possesses a simplified version of the okadaic acid skeleton, supports the biogenetic pathway previously reported for this class of compounds. BA showed potent inhibitory activity against protein phosphatase 1 (PP1) within the nM range. A plausible model for the interaction of BA with the PP1 binding pocket was derived from computational docking studies. 相似文献
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Three novel alkaloids, macropodumines A-C (1-3), were isolated from the stem of Daphniphyllum macropodum Miq. Interestingly, the structure of macropodumine A (1) was characterized as having a fused pentacyclic system including an unusual eleven-membered macrolactone ring, whereas macropodumine B (2) contains a rare cyclopentadienyl carbanion, which is stabilized as a zwitterion by an internal iminium cation. The structures of these new metabolites were established on the basis of their detailed spectroscopic analysis. In particular, the unique structure of zwitterion 2 was further confirmed by using single-crystal X-ray diffraction analysis. 相似文献
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Aplysiasecosterol A: A 9,11‐Secosteroid with an Unprecedented Tricyclic γ‐Diketone Structure from the Sea Hare Aplysia kurodai
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Atsushi Kawamura Prof. Dr. Masaki Kita Prof. Dr. Hideo Kigoshi 《Angewandte Chemie (International ed. in English)》2015,54(24):7073-7076
A new 9,11‐secosteroid having an unprecedented tricyclic γ‐diketone structure, aplysiasecosterol A ( 1 ), was isolated from the sea hare Aplysia kurodai. The structure was determined by one‐ and two‐dimensional NMR spectroscopic analysis, molecular modeling studies, a comparison of experimental and calculated ECD spectra, and a modified Mosher′s method. Aplysiasecosterol A ( 1 ) exhibited cytotoxicity against human myelocytic leukemia HL‐60 cells. A biosynthetic pathway for 1 from a known cholesterol was proposed and includes twice α‐ketol rearrangements and an intramolecular acetalization. 相似文献
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Bringmann G Mutanyatta-Comar J Maksimenka K Wanjohi JM Heydenreich M Brun R Müller WE Peter MG Midiwo JO Yenesew A 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(5):1420-1429
From the roots of the African plant Bulbine frutescens (Asphodelaceae), two unprecedented novel dimeric phenylanthraquinones, named joziknipholones A and B, possessing axial and centrochirality, were isolated, together with six known compounds. Structural elucidation of the new metabolites was achieved by spectroscopic and chiroptical methods, by reductive cleavage of the central bond between the monomeric phenylanthraquinone and -anthrone portions with sodium dithionite, and by quantum chemical CD calculations. Based on the recently revised absolute axial configuration of the parent phenylanthraquinones, knipholone and knipholone anthrone, the new dimers were attributed to possess the P-configuration (i.e., with the acetyl portions below the anthraquinone plane) at both axes in the case of joziknipholone A, whereas in joziknipholone B, the knipholone part was found to be M-configured. Joziknipholones A and B are active against the chloroquine resistant strain K1 of the malaria pathogen, Plasmodium falciparum, and show moderate activity against murine leukemic lymphoma L5178y cells. 相似文献
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Suffrutines A and B: A Pair of Z/E Isomeric Indolizidine Alkaloids from the Roots of Flueggea suffruticosa
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Zhen‐Long Wu Dr. Bing‐Xin Zhao Dr. Xiao‐Jun Huang Gen‐Yun Tang Dr. Lei Shi Prof. Dr. Ren‐Wang Jiang Xin Liu Dr. Ying Wang Prof. Dr. Wen‐Cai Ye 《Angewandte Chemie (International ed. in English)》2014,53(23):5796-5799
Suffrutines A ( 1 ) and B ( 2 ), a pair of novel photochemical Z/E isomeric indolizidine alkaloids, with a unique and highly conjugated C20 skeleton, were isolated from the roots of Flueggea suffruticosa. The structures were elucidated by extensive analysis of NMR spectra and single‐crystal X‐ray diffraction. The light‐induced isomerization and hypothetical biogenetic pathway to 1 and 2 , as well as their activity for regulating the morphology of Neuro‐2a cells are also discussed. 相似文献
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Dr. Ryuichi Sawa Dr. Yoshiaki Takahashi Dr. Hideki Hashizume Dr. Kazushige Sasaki Dr. Yoshimasa Ishizaki Maya Umekita Dr. Masaki Hatano Hikaru Abe Dr. Takumi Watanabe Naoko Kinoshita Yoshiko Homma Chigusa Hayashi Kunio Inoue Syunichi Ohba Toru Masuda Dr. Masayuki Arakawa Dr. Yoshihiko Kobayashi Dr. Masa Hamada Dr. Masayuki Igarashi Dr. Hayamitsu Adachi Dr. Yoshio Nishimura Dr. Yuzuru Akamatsu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15772-15781
The abuse of antibacterial drugs imposes a selection pressure on bacteria that has driven the evolution of multidrug resistance in many pathogens. Our efforts to discover novel classes of antibiotics to combat these pathogens resulted in the discovery of amycolamicin (AMM). The absolute structure of AMM was determined by NMR spectroscopy, X‐ray analysis, chemical degradation, and modification of its functional groups. AMM consists of trans‐decalin, tetramic acid, two unusual sugars (amycolose and amykitanose), and dichloropyrrole carboxylic acid. The pyranose ring named as amykitanose undergoes anomerization in methanol. AMM is a potent and broad‐spectrum antibiotic against Gram‐positive pathogenic bacteria by inhibiting DNA gyrase and bacterial topoisomerase IV. The target of AMM has been proved to be the DNA gyrase B subunit and its binding mode to DNA gyrase is different from those of novobiocin and coumermycin, the known DNA gyrase inhibitors. 相似文献
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Qiuqin Zhou Florian Grundmann Marcel Kaiser Matthias Schiell Dr. Sophie Gaudriault Dr. Andreas Batzer Dr. Michael Kurz Prof. Dr. Helge B. Bode 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(49):16772-16779
During the search for novel natural products from entomopathogenic Xenorhabdus doucetiae DSM17909 and X. mauleonii DSM17908 novel peptides named xenoamicins were identified in addition to the already known antibiotics xenocoumacin and xenorhabdin. Xenoamicins are acylated tridecadepsipeptides consisting of mainly hydrophobic amino acids. The main derivative xenoamicin A ( 1 ) was isolated from X. mauleonii DSM17908, and its structure elucidated by detailed 1 D and 2 D NMR experiments. Detailed MS experiments, also in combination with labeling experiments, confirmed the determined structure and allowed structure elucidation of additional derivatives. Moreover, the xenoamicin biosynthesis gene cluster was identified and analyzed in X. doucetiae DSM17909, and its participation in xenoamicin biosynthesis was confirmed by mutagenesis. Advanced Marfey’s analysis of 1 showed that the absolute configuration of the amino acids is in agreement with the predicted stereochemistry deduced from the nonribosomal peptide synthetase XabABCD. Biological testing revealed activity of 1 against Plasmodium falciparum and other neglected tropical diseases but no antibacterial activity. 相似文献
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Daldionin,an Unprecedented Binaphthyl Derivative,and Diverse Polyketide Congeners from a Fungal Orchid Endophyte
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Dr. Emma C. Barnes Dr. Juangjun Jumpathong Prof. Saisamorn Lumyong Priv.‐Doz. Dr. Kerstin Voigt Prof. Dr. Christian Hertweck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(13):4551-4555
Thailand possesses a rich diversity of orchid species that, in turn, live in symbiosis with a wide variety of fungi. Such endophytes have the potential to produce secondary metabolites with bioactivity against orchid and/or human pathogens. The orchid‐associated fungal strain Daldinia eschscholtzii was found to produce a diverse range of aromatic polyketides including the new naphthalene derivatives daldionin, nodulones B and C, and daldinones F and G along with eight known compounds. Daldionin possesses an unprecedented oxane‐linked binaphthyl ring system. These compounds demonstrate the high diversity of structural variations that are constructed during fungal biosynthesis, and the results include important observations concerning the biosynthesis of binaphthyl derivatives. Daldionin was found to have weak antiproliferative activity against HUVEC and K‐562 cell lines. All but one of the isolated compounds showed moderate antimicrobial activity towards at least one of the four tested microbial strains. 相似文献
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Ippei Kagiyama Dr. Hikaru Kato Dr. Tatsuo Nehira Prof. Jens C. Frisvad Prof. David H. Sherman Prof. Robert M. Williams Prof. Sachiko Tsukamoto 《Angewandte Chemie (International ed. in English)》2016,55(3):1128-1132
Seven new prenylated indole alkaloids, taichunamides A–G, were isolated from the fungus Aspergillus taichungensis (IBT 19404). Taichunamides A and B contained an azetidine and 4‐pyridone units, respectively, and are likely biosynthesized from notoamide S via (+)‐6‐epi‐stephacidin A. Taichunamides C and D contain endoperoxide and methylsulfonyl units, respectively. This fungus produced indole alkaloids containing an anti‐bicyclo[2.2.2]diazaoctane core, whereas A. protuberus and A. amoenus produced congeners with a syn‐bicyclo[2.2.2]diazaoctane core. Plausible biosynthetic pathways to access these cores within the three species likely arise from an intramolecular hetero Diels–Alder reaction. 相似文献