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Journal of Natural Products

Muhammad Abbas, Sherif I Elshahawi, Xiachang Wang, Larissa V Ponomareva, Imran Sajid, Khaled A Shaaban, Jon S Thorson
The isolation and structure elucidation of four new naturally occurring amino-nucleoside [puromycins B-E (1-4)] metabolites from a Himalayan isolate ( Streptomyces sp. PU-14-G, isolated from the Bara Gali region of northern Pakistan) is reported. Consistent with prior reports, comparative antimicrobial assays revealed the need for the free 2″-amine for anti-Gram-positive bacteria and antimycobacterial activity. Similarly, comparative cancer cell line cytotoxicity assays highlighted the importance of the puromycin-free 2″-amine and the impact of 3'-nucleoside substitution...
November 12, 2018: Journal of Natural Products
Louise C Forster, Gregory K Pierens, Mary J Garson
A diterpene (1), previously isolated from a Japanese marine sponge, together with two undescribed (2, 3) diterpenes with highly rearranged carbon skeletons have been characterized from the Australian nudibranch species Goniobranchus geometricus. The structures and relative configuration were determined by spectroscopic analyses informed by detailed molecular modeling, as well as by DFT, DP4, and coupling constant predictions. A 13 R,14 R configuration was determined for secoshahamin (1) by chemical correlation with 12-desacetoxyshahamin C (4) and 12-desacetoxypolyrhaphin A (5); each metabolite (1, 4, and 5) was subjected to saponification and lactonization, yielding the same δ-lactone product (6)...
November 12, 2018: Journal of Natural Products
Yoshinosuke Usuki, Saho Ishii, Minako Ijiri, Ken-Ichi Yoshida, Tetsuya Satoh, Satoru Horigome, Izumi Yoshida, Takashi Mishima, Ken-Ichi Fujita
The inhibitory activities of the antimycin-class antibiotics UK-2A, antimycin A, and splenocin B against the production of anti-inflammatory cytokine IL-4, which is related to IgE-mediated allergic responses in rat basophilic leukemia (RBL-2H3) cells, were evaluated. Although antimycin A and splenocin B showed cytotoxicity at concentrations at which IL-4 release from the cells was restricted, UK-2A was found to restrict IL-4 release without cytotoxicity. Three UK-2A analogues (4-6) were then synthesized and assessed...
November 12, 2018: Journal of Natural Products
Norbert Kúsz, Péter Orvos, Laura Bereczki, Pierre Fertey, Petra Bombicz, Attila Csorba, László Tálosi, Gusztáv Jakab, Judit Hohmann, Dóra Rédei
Nine new (1-9) and two known (10, 11) jatrophane diterpenoids were isolated from the methanol extract of Euphorbia dulcis. The structure elucidation of the compounds was performed by means of extensive spectroscopic analysis, including HRESIMS, 1D (1 H, JMOD), and 2D (HSQC, HMBC, 1 H-1 H-COSY, NOESY) NMR experiments. The absolute configuration of compound 1 was determined by single-crystal X-ray diffraction. The electrophysiological effects of compounds 1-11 and the five diterpenoids (12-16) previously isolated from Euphorbia taurinensis were investigated on stable transfected HEK-GIRK1/4 (Kir3...
November 9, 2018: Journal of Natural Products
Thi Phuong Thuy Hoang, Catherine Roullier, Marie-Claude Boumard, Thibaut Robiou du Pont, Hassan Nazih, Jean-François Gallard, Yves François Pouchus, Mehdi A Beniddir, Olivier Grovel
Penicillium ubiquetum MMS330 isolated from the blue mussel Mytilus edulis collected on the Loire estuary in France was here investigated. As very few secondary metabolites have been documented for this species, its metabolome was studied following the OSMAC approach to enhance as many biosynthetic pathways as possible. Interestingly, HPLC-HRMS based hierarchical clustering analysis together with MS/MS molecular networking highlighted the selective overproduction of some structurally related compounds when the culture was performed on seawater CYA (Czapek Yeast extract Agar) medium...
November 8, 2018: Journal of Natural Products
Jianzhang Wu, Yiyuan Xi, Lili Huang, Ge Li, Qiqi Mao, Chengyan Fang, Tizhuang Shan, Wei Jiang, Min Zhao, Wenfei He, Jianyong Dong, Xiubao Li, Peihong Qiu, Pengcheng Yan
Four new steroids, named 7-dehydroerectasteroid F (1), 11α-acetoxyarmatinol A (2), 22,23-didehydroarmatinol A (3), and 3-O-acetylhyrtiosterol (4), together with 11 previously described analogues, were isolated from a South China Sea collection of the soft coral Dendronephthya gigantea. The structures of the new steroids were elucidated by comprehensive spectroscopic analysis and by comparison with previously reported data. Compound 1 showed potent protection against H2 O2 -induced oxidative damage in neuron-like PC12 cells by promoting nuclear translocation of Nrf2 and enhancing the expression of HO-1...
November 8, 2018: Journal of Natural Products
Victoria H Woolner, Rose M A Gordon, John H Miller, Matthias Lein, Peter T Northcote, Robert A Keyzers
A detailed examination of the red alga Callophycus serratus collected in Tonga led to the isolation of six new halogenated meroditerpenoids: callophycol C (1), callophycoic acid I (2), iodocallophycols E (3) and F (4), iodocallophycoic acid B (5), and callophycoic acid J (6). Of these, compounds 3-5 are new iodinated additions to the growing family of Callophycus meroditerpenoids. The relative configurations of compounds 1-6 were deduced by analyses of 1D NOE data and 1 H-1 H scalar coupling constants, and 3-6 are proposed to differ from the closely related compounds reported in the literature, iodocallophycoic acid A and iodocallophycols A-D...
November 8, 2018: Journal of Natural Products
Debananda Gogoi, Anirban Pal, Pronobesh Chattopadhyay, Subrata Paul, Ramesh C Deka, Ashis K Mukherjee
Inhibitors of thrombin, a key enzyme in the blood coagulation cascade, are of great interest because of their selective specificity and effectiveness in anticoagulation therapy against cardiovascular disorders. The natural soybean phytosterol, β-sitosterol (BSS) demonstrated anticoagulant activity by dose-dependent inhibition of thrombin in an uncompetitive manner with a Ki value of 0.267 μM as well as by partial inhibition of thrombin-catalyzed platelet aggregation with a half-maximal inhibitory concentration (IC50 ) value of 10...
November 8, 2018: Journal of Natural Products
Sarath P D Senadeera, Luke P Robertson, Sandra Duffy, Yun Wang, Vicky M Avery, Anthony R Carroll
Four new β-triketone monoterpene hybrids, intermediones A-D (1-4), have been identified from the flowers of the Australian eucalypt tree Corymbia intermedia. Intermediones A-D are β-triketones that incorporate a pinene moiety attached via a benzyl group to a syncarpic acid. The structures of 1-4, including relative configurations, were elucidated from the analysis of 1D/2D NMR and MS data. The absolute configurations of intermediones A and B were determined by comparison of experimental and predicted ECD spectra...
November 6, 2018: Journal of Natural Products
Wen-Jun Wei, Qiu-Yan Song, Zai-Qin Zheng, Xiaojun Yao, Ya Li, Kun Gao
Thirteen new ent-isopimarane-type diterpenoids, 1-10 and 14-16, and seven known diterpenoids, 11-13 and 17-20, were isolated from the roots of Euphorbia hylonoma. Among these compounds, four pairs of C-12 epimers (1 vs 2, 4 vs 5, 12 vs 13, and 14 vs 15) were identified. The structures of the new diterpenoids were elucidated using spectroscopic data analyses, electronic circular dichroism, and single-crystal X-ray diffraction data. The phytotoxic effects of compounds 1-20 on the growth of the roots and shoots of Poa annua and Festuca arundinacea seedlings were evaluated...
November 6, 2018: Journal of Natural Products
Kiwon Ko, Lilik D Wahyudi, Yong-Soo Kwon, Jung-Hwan Kim, Heejung Yang
Oxidative stress due to the presence of excess reactive oxygen species may cause cancers, aging, and many other conditions. Nuclear factor erythroid 2-related factor 2 (Nrf2) may control abnormal oxidative stress as a transcription factor by inducing antioxidant-related genes via antioxidant response elements (AREs) in the gene promoters. The 11 triterpenoid saponins (1-11) isolated from Camellia japonica roots were tested for ARE-luciferase activity and Nrf2 accumulation in human keratinocytes (HaCaT cells)...
November 5, 2018: Journal of Natural Products
Changwu Zheng, Xueying Wang, Wenwei Fu, Yue Lu, Hongsheng Tan, Hongxi Xu
The asymmetric total synthesis of five decarbonyl polycyclic polyprenylated acylphloroglucinols norsampsnes A (3) and B (4), garcinielliptones O (5) and N (6), and hyperscabrin A (7) is described. The synthesis to construct the core substituted cyclohexanone ring of these natural products was achieved by a key Dieckmann condensation. The chirality of the molecules was introduced by the stereoselective alkylation with Evans' oxazolidinones. The synthesis could be run on grams scale, and the Dieckmann condensation was investigated through the DFT calculations to help improve the yield of garcinielliptone O (5)...
November 5, 2018: Journal of Natural Products
Ria deGuzman, David J Midmore, Kerry B Walsh
Steviol glycosides (SG) (with stevioside and rebaudioside A predominating) are present in wild-type Stevia rebaudiana, at approximately 10% of dry weight (dw), prompting a consideration of the autoecological role played by these compounds in terms of energy (C) storage and/or osmoregulation. The leaf starch pool was observed to change diurnally with respect to the light cycle (from 3.29% to 0.73% of leaf dw between dusk and dawn) and also to increase under constant light treatment (from 1.53% to 6.25% of leaf dw), while SG pools were relatively constant (around 6% w/dw)...
November 2, 2018: Journal of Natural Products
Ploypat Niyomploy, Lai Yue Chan, Peta J Harvey, Aaron G Poth, Michelle L Colgrave, David J Craik
Cyclotides are macrocyclic cystine-knotted peptides most commonly found in the Violaceae plant family. Although Rinorea is the second-largest genera within the Violaceae family, few studies have examined whether or not they contain cyclotides. To further our understanding of cyclotide diversity and evolution, we examined the cyclotide content of two Rinorea species found in Southeast Asia: R. virgata and R. bengalensis. Seven cyclotides were isolated from R. virgata (named Rivi1-7), and a known cyclotide (cT10) was found in R...
November 2, 2018: Journal of Natural Products
Arihiro Iwasaki, Takato Tadenuma, Shimpe Sumimoto, Ikuma Shiota, Teruhiko Matsubara, Yumiko Saito-Nakano, Tomoyoshi Nozaki, Toshinori Sato, Kiyotake Suenaga
Hoshinoamides A (1) and B (2), new acyclic lipopeptides, were isolated from the marine cyanobacterium Caldora penicillata. Their structures were elucidated by spectroscopic analyses and degradation reactions. Hoshinoamides A (1) and B (2) did not exhibit any cytotoxicity against HeLa cells at 10 μM, but inhibited the in vitro growth of the malarial parasite Plasmodium falciparum (IC50 = 0.52 and 1.0 μM, respectively).
November 2, 2018: Journal of Natural Products
Ha Thanh Tung Pham, Thi Kim Quy Ha, Hyo Moon Cho, Ba Wool Lee, Jin Pyo An, Van On Tran, Won Keun Oh
As part of ongoing research to find new antidiabetic agents from medicinal plants, the chemical composition of Gynostemma longipes, an ethnomedicinal plant used to treat type 2 diabetes mellitus by local communities in Vietnam, was investigated. Ten new dammarane triterpenes, including two 3,4- seco-dammarane analogues, secolongipegenins S1 and S2 (1 and 2), a 3,4- seco-hexanordammarane, secolongipegenin S3 (3), two hexanordammarane glycosides, longipenosides ND1 and ND2 (4 and 5), and five other dammarane glycosides, longipenosides GL1-GL5 (6-10), were isolated from a 70% EtOH extract of the whole G...
November 2, 2018: Journal of Natural Products
Xiao-Li Ma, Jun Li, Jiao Zheng, Xiao-Pan Gu, Daneel Ferreira, Jordan K Zjawiony, Ming-Bo Zhao, Xiao-Yu Guo, Peng-Fei Tu, Yong Jiang
Fifteen new structurally unique monoterpenoid carbazole alkaloids, including two pairs of epimers (1/2 and 3/4), three pairs of enantiomers (6a/6b, 7a/7b, and 8a/8b), and five optically pure analogues (5, 9-12), were obtained from a 95% aqueous EtOH extract of Murraya microphylla by a combination of bioassay- and LC-MS-guided fractionation procedures. Their structures were established based on NMR and HRESIMS data interpretation. The absolute configuration of compound 1 was determined via X-ray crystallographic data analysis and for all compounds by comparison of experimental and calculated ECD data...
November 1, 2018: Journal of Natural Products
Jia-Wen Hu, Meng-Jiao Shi, Jia-Jia Wang, Li Li, Jian-Dong Jiang, Teng-Fei Ji
Hyperascyrins A-H (1-11) and four known compounds (12-15) were acquired from the air-dried aerial parts of Hypericum ascyron and were all identified as methylated polycyclic polyprenylated acylphloroglucinol derivatives. Their structures were established by NMR spectroscopy, experimental and calculated electronic circular dichroism (ECD) data, and comparison with established compounds. Compounds 8 and 9 showed protection against paracetamol-induced HepG2 cell damage at 10 μM. The neuroprotective activities of all compounds (10 μM) were evaluated, and compounds 1 and 8 exhibited mild neuroprotection against glutamate-induced toxicity in SK-N-SH cells...
October 31, 2018: Journal of Natural Products
Takatsugu Murata, Teppei Kuboki, Ryo Ishikawa, Takahiro Saito, Shotaro Taguchi, Kazuma Takeuchi, Emiko Hatano, Motoyuki Shimonaka, Isamu Shiina
The first total synthesis of violaceoid A, a cytotoxic agent, and the asymmetric total synthesis of (-)- and (+)-violaceoid B are reported. The precursor was accessed by desymmetrization of a substituted quinol moiety, and the racemic secondary alcohol was kinetically resolved using a chiral nucleophilic catalyst. The asymmetric synthesis of (-)- and (+)-violaceoid B elucidated the absolute configuration of the naturally occurring violaceoid B. Synthetic violaceoid A inhibited the growth of human breast cancer cell lines MCF-7 and Hs 578T at concentrations of less than 100 μM, while ( S)- and ( R)-violaceoid B were inactive...
October 30, 2018: Journal of Natural Products
Luisa Mattoli, Valentino Mercati, Michela Burico, Stella Bedont, Marina Porchia, Francesco Tisato, Sara D'Aronco, Sara Crotti, Marco Agostini, Pietro Traldi
A hypothesis on the peculiar pharmacological behavior of biologically active natural compounds is based on the occurrence of molecular interactions originating from the high complexity of the natural matrix, following the rules of supramolecular chemistry. In this context, some investigations were performed to establish unequivocally the presence of caffeine/catechin complexes in green tea extracts (GTEs). 1 H NMR spectroscopy was utilized to compare profiles from GTEs with caffeine/catechin mixtures in different molar ratios, showing that peaks related to caffeine in GTEs are generally upfield shifted compared to those of free caffeine...
October 29, 2018: Journal of Natural Products
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