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Natural product chemistry

Jose G Maciá-Vicente, Yan-Ni Shi, Zakaria Cheikh-Ali, Peter Grün, Kyriaki Glynou, Sevda Haghi Kia, Meike Piepenbring, Helge B Bode
Fungi are prolific producers of natural products routinely screened for biotechnological applications, and those living endophytically within plants attract particular attention because of their purported chemical diversity. However, the harnessing of their biosynthetic potential is hampered by a large and often cryptic phylogenetic and ecological diversity, coupled with a lack of large-scale natural products' dereplication studies. To guide efforts to discover new chemistries among root-endophytic fungi, we analyzed the natural products produced by 822 strains using an untargeted UPLC-ESI-MS/MS-based approach and linked the patterns of chemical features to fungal lineages...
February 14, 2018: Environmental Microbiology
Chang Liu, Xiao-Tian Li, Rong-Rong Cheng, Zhu-Zhen Han, Li Yang, Zhong-Chen Song, Zheng-Tao Wang
Discovery of agents for oral infectious diseases is always encouraged in natural products chemistry. A bioassay-guided isolation led to the isolation of two new acetylenic acids (1, 2) along with seven known ones (3-9) from the ethanol extract of Thesium chinense Turcz, a commonly used oral anti-bacterial and anti-inflammatory herb. Their structures were elucidated on the basis of spectroscopic and chemical evidence. Exocarpic acid (3) demonstrated the most promising activity against three tested oral pathogenic bacterial strains, Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans, with minimum inhibitory concentration values of 0...
February 12, 2018: Journal of Natural Medicines
Bradley M Hover, Seong-Hwan Kim, Micah Katz, Zachary Charlop-Powers, Jeremy G Owen, Melinda A Ternei, Jeffrey Maniko, Andreia B Estrela, Henrik Molina, Steven Park, David S Perlin, Sean F Brady
Despite the wide availability of antibiotics, infectious diseases remain a leading cause of death worldwide 1 . In the absence of new therapies, mortality rates due to untreatable infections are predicted to rise more than tenfold by 2050. Natural products (NPs) made by cultured bacteria have been a major source of clinically useful antibiotics. In spite of decades of productivity, the use of bacteria in the search for new antibiotics was largely abandoned due to high rediscovery rates2,3. As only a fraction of bacterial diversity is regularly cultivated in the laboratory and just a fraction of the chemistries encoded by cultured bacteria are detected in fermentation experiments, most bacterial NPs remain hidden in the global microbiome...
February 12, 2018: Nature Microbiology
Emily C Gentry, Lydia J Rono, Martina E Hale, Rei Matsuura, Robert R Knowles
While interest in the synthetic chemistry of radical cations continues to grow, controlling enantioselectivity in the reactions of these intermediates remains a challenge. Based on recent insights into the oxidation of tryptophan in enzymatic systems, we report a photocatalytic method for the generation of indole radical cations as hydrogen-bonded adducts with chiral phosphate anions. These non-covalent open-shell complexes can be intercepted by the stable nitroxyl radical TEMPO• to form alkoxyamine-substituted pyrroloindolines with high levels of enantioselectivity...
February 12, 2018: Journal of the American Chemical Society
Changjian Xie, Xinguo Liu, Brendan C Sweeny, Thomas M Miller, Shaun G Ard, Nicholas S Shuman, Albert A Viggiano, Hua Guo
We report a joint experimental-theoretical study of the F- + HCl → HF + Cl- reaction kinetics. The experimental measurement of the rate coefficient at several temperatures was made using the selected ion flow tube method. Theoretical rate coefficients are calculated using the quasi-classical trajectory method on a newly developed global potential energy surface, obtained by fitting a large number of high-level ab initio points with augmentation of long-range electrostatic terms. In addition to good agreement between experiment and theory, analyses suggest that the ion-molecule reaction rate is significantly affected by shorter-range interactions, in addition to the traditionally recognized ion-dipole and ion-induced dipole terms...
March 13, 2018: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
Zhiqiang Ma, Chuo Chen
Natural products have played an important role in shaping modern synthetic organic chemistry. In particular, their complex molecular skeletons have stimulated the development of many new synthetic methods. We highlight in this article some recent examples of synthetic design inspired by the biosynthesis of natural products.
January 2018: Journal of the Chinese Chemical Society
Anna Stavrinides, Evangelos Tatsis, Thu-Thuy Dang, Lorenzo Caputi, Clare Stevenson, David Lawson, Bernd Schneider, Sarah O'Connor
Monoterpene indole alkaloids, a large class of plant natural products, derive from the biosynthetic intermediate strictosidine aglycone. Strictosidine aglycone, which can exist as a variety of isomers, can be reduced to form numerous different structures. We have discovered a short chain alcohol dehydrogenase (SDR) from monoterpene indole alkaloid producing plants (Catharanthus roseus and Rauvolfia serpentina) that reduce strictosidine aglycone and produce an alkaloid that does not correspond to any previously reported compound...
February 9, 2018: Chembiochem: a European Journal of Chemical Biology
Kevin Hung, Xirui Hu, Thomas J Maimone
Covering: 2011-2017Radical cyclizations have a rich history in organic chemistry and have been particularly generous to the field of natural product synthesis. Owing to their ability to operate in highly congested molecular quarters, and with significant functional group compatibility, these transformations have enabled the synthesis of numerous polycyclic terpenoid natural products over the past several decades. Moreover, when programmed accordingly into a synthetic plan, radical cascade processes can be used to rapidly assemble molecular complexity, much in the same way nature rapidly constructs terpene frameworks through cationic cyclization pathways...
February 8, 2018: Natural Product Reports
James J La Clair
Society suffers due to an inability to regulate matter. This study presents a practical tool for the encryption of materials by adjusting the levels of 13C at regiospecific atoms within a molecule to generate a stable-isotopically encoded signature. This system is demonstrated by securing a document by adapting natural product chemistry as an encryption device. This approach delivers a complex signal that would be difficult to intercept due to the need for access to extraction protocols, sophisticated NMR instrumentation and a vital level of prior knowledge...
February 8, 2018: Chemical Communications: Chem Comm
Eduardo A Silva-Junior, Antonio C Ruzzini, Camila R Paludo, Fabio S Nascimento, Cameron R Currie, Jon Clardy, Mônica T Pupo
Ants use pheromones to coordinate their communal activity. Volatile pyrazines, for instance, mediate food resource gathering and alarm behaviors in different ant species. Here we report that leaf-cutter ant-associated bacteria produce a family of pyrazines that includes members previously identified as ant trail and alarm pheromones. We found that L-threonine induces the bacterial production of the trail pheromone pyrazines, which are common for the host leaf-cutter ants. Isotope feeding experiments revealed that L-threonine along with sodium acetate were the biosynthetic precursors of these natural products and a biosynthetic pathway was proposed...
February 7, 2018: Scientific Reports
Xiaofang Zuo, Zhipeng Huo, Dongwei Kang, Gaochan Wu, Zhongxia Zhou, Xinyong Liu, Peng Zhan
To deal with the rapid emergence of drug resistance challenges, together with the difficulty to eradicate the virus, off-target effects and significant cumulative drug toxicities, it is still imperative to develop next-generation anti-HIV agents with novel chemical classes or new mechanisms of action. Areas covered: We primarily focused on current strategies to discover novel anti-HIV agents. Moreover, examples of anti-HIV lead compounds were mainly selected from recently patented publications (reported between 2014 and 2017)...
February 7, 2018: Expert Opinion on Therapeutic Patents
Sébastien Lacroix, Jasna Klicic Badoux, Marie-Pier Scott-Boyer, Silvia Parolo, Alice Matone, Corrado Priami, Melissa J Morine, Jim Kaput, Sofia Moco
Polyphenol-rich foods are part of many nutritional interventions aimed at improving health and preventing cardiometabolic diseases (CMDs). Polyphenols have oxidative, inflammatory, and/or metabolic effects. Research into the chemistry and biology of polyphenol bioactives is prolific but knowledge of their molecular interactions with proteins is limited. We mined public data to (i) identify proteins that interact with or metabolize polyphenols, (ii) mapped these proteins to pathways and networks, and (iii) annotated functions enriched within the resulting polyphenol-protein interactome...
February 2, 2018: Scientific Reports
Olga V Friese, Jacquelynn N Smith, Paul W Brown, Jason C Rouse
Antibody-drug conjugation strategies are continuously evolving as researchers work to improve the safety and efficacy of the molecules. However, as a part of process and product development, confirmation of the resulting innovative structures requires new, specialized mass spectrometry (MS) approaches and methods, as compared to those already established for antibody-drug conjugates (ADCs) and the heightened characterization practices used for monoclonal antibodies (mAbs), in order to accurately elucidate the resulting conjugate forms, which can sometimes have labile chemical bonds and more extreme chemical properties like hydrophobic patches...
February 2, 2018: MAbs
Artur Mardyukov, Peter R Schreiner
The large number and amounts of volatile organosulfur compounds emitted to the atmosphere and the enormous variety of their reactions in various oxidation states make experimental measurements of even a small fraction of them a daunting task. Dimethyl sulfide (DMS) is a product of biological processes involving marine phytoplankton, and it is estimated to account for approximately 60% of the total natural sulfur gases released to the atmosphere. Ocean-emitted DMS has been suggested to play a role in atmospheric aerosol formation and thereby cloud formation...
February 2, 2018: Accounts of Chemical Research
Jie Liu, Zhihong Wei, Haijun Jiao, Ralf Jackstell, Matthias Beller
Green Friedel-Crafts acylation reactions belong to the most desired transformations in organic chemistry. The resulting ketones constitute important intermediates, building blocks, and functional molecules in organic synthesis as well as for the chemical industry. Over the past 60 years, advances in this topic have focused on how to make this reaction more economically and environmentally friendly by using green acylating conditions, such as stoichiometric acylations and catalytic homogeneous and heterogeneous acylations...
January 24, 2018: ACS Central Science
Stephanie W Chun, Meagan E Hinze, Meredith A Skiba, Alison R Narayan
Like many complex natural products, the intricate architecture of saxitoxin (STX) has hindered full exploration of this scaffold's utility as a tool for studying voltage-gated sodium ion channels and as a pharmaceutical agent. Established chemical strategies can provide access to the natural product; however, a chemoenzymatic route to saxitoxin that could provide expedited access to related compounds has not been devised. The first step toward realizing a chemoenzymatic approach toward this class of molecules is the elucidation of the saxitoxin biosynthetic pathway...
February 1, 2018: Journal of the American Chemical Society
Jiachen Deng, Jingjing Wu, Hailong Tian, Jiajing Bao, Yong Shi, Weisheng Tian, Jinghan Gui
Furans are versatile synthons in organic chemistry. Herein we present a general method that transforms furans into alkynes via dual C-C double bond cleavage. The reaction is proposed to proceed by sequential [4+2] cycloaddition between furan and singlet oxygen and a formal retro-(3+2) fragmentation of the endoperoxide intermediate. A wide array of furans, including those derived from sapogenins, are amenable to this reaction, providing the corresponding alkynoic acids in up to 88% yields. The synthetic utility was demonstrated through a 7-step synthesis of the proposed structure of pregnane natural product aglatomin B from a known intermediate...
January 31, 2018: Angewandte Chemie
Panpan Li, Feng Yu, Naveed Altaf, Mingyuan Zhu, Jiangbing Li, Bin Dai, Qiang Wang
CH₄ as the paramount ingredient of natural gas plays an eminent role in C1 chemistry. CH₄ catalytically converted to syngas is a significant route to transmute methane into high value-added chemicals. Moreover, the CO/CO₂ methanation reaction is one of the potent technologies for CO₂ valorization and the coal-derived natural gas production process. Due to the high thermal stability and high extent of dispersion of metallic particles, two-dimensional mixed metal oxides through calcined layered double hydroxides (LDHs) precursors are considered as the suitable supports or catalysts for both the reaction of methanation and methane reforming...
January 31, 2018: Materials
Maximilian Kranz, Thomas Hofmann
The increasing demand for healthier food products, with reduced levels of table salt, sugar, and mono sodium glutamate, reinforce the need for novel taste enhancers prepared by means of food-grade kitchen-type chemistry. Although several taste modulating compounds have been discovered in processed foods, their Maillard-type ex food production is usually not exploited by industrial process reactions as the yields of target compounds typically do not exceed 1-2%. Natural deep eutectic solvents (NADES) are reported for the first time to significantly increase the yields of the taste enhancers 1-deoxy-ᴅ-fructosyl-N-β-alanyl-ʟ-histidine (49% yield), N-(1-methyl-4-oxoimidazolidin-2-ylidene) aminopropionic acid (54% yield) and N²-(1-carboxyethyl) guanosine 5'-monophosphate (22% yield) at low temperature (80-100 °C) within a maximum reaction time of 2 h...
January 28, 2018: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Marion Blocquet, Fangfang Guo, Maxence Mendez, Michael Ward, Sébastien Coudert, Sébastien Batut, Christophe Hecquet, Nadège Blond, Christa Fittschen, Coralie Schoemaecker
The characteristics of indoor light (intensity, spectral, spatial distribution) originating from outdoors have been studied using experimental and modeling tools. They are influenced by many parameters such as building location, meteorological conditions and the type of window. They have a direct impact on indoor air quality through a change in chemical processes by varying the photolysis rates of indoor pollutants. Transmittances of different windows have been measured and exhibit different wavelength cutoffs, thus influencing the potential of different species to be photolysed...
January 27, 2018: Indoor Air
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