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Natural product chemistry

Rongjie Hao, Yan Zhang, Tingting Du, Li Yang, Adeyemi S Adeleye, Yao Li
The relationship between the disinfection by-products (DBPs) formed with chlorination and chloramination techniques and the water chemistry of Haihe River was compared. Samples were collected at 28 different points within the mainstream and tributaries of the river. The DBPs investigated include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), and trichloronitromethane. THMs formed when the samples were chlorinated mostly exceeded 100 and 600 μg/L in the mainstream and tributaries and in the estuary, respectively...
December 8, 2016: Chemosphere
Robert A Hill, Andrew Sutherland
A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as hitorin A from Chloranthus japonicus.
January 12, 2017: Natural Product Reports
Spyridon A Petropoulos, Francesco Di Gioia, Georgia Ntatsi
BACKGROUND: Trends in modern pharmaceutical science show an increase in demand for new drugs and diet supplements derived from natural products, while during the last decades, great research is conducted regarding the natural compounds and their medicinal and bioactive properties. Organosulfur compounds are present in many plants and their bioactive properties have been used in folk and traditional medicine throughout the centuries. Not until recently, modern science confirmed and revealed the chemical compounds that are responsible for these properties, the chemistry involved in their biosynthesis and the main mechanisms of action...
January 10, 2017: Current Pharmaceutical Design
Christophe Leboulanger, Hélène Agogué, Cécile Bernard, Marc Bouvy, Claire Carré, Maria Cellamare, Charlotte Duval, Eric Fouilland, Patrice Got, Laurent Intertaglia, Céline Lavergne, Emilie Le Floc'h, Cécile Roques, Gérard Sarazin
This study describes, for the first time, the water chemistry and microbial diversity in Dziani Dzaha, a tropical crater lake located on Mayotte Island (Comoros archipelago, Western Indian Ocean). The lake water had a high level of dissolved matter and high alkalinity (10.6-14.5 g L-1 eq. CO32-, i.e. 160-220 mM compare to around 2-2.5 in seawater), with salinity up to 52 psu, 1.5 higher than seawater. Hierarchical clustering discriminated Dziani Dzaha water from other alkaline, saline lakes, highlighting its thalassohaline nature...
2017: PloS One
Awais Anwar, Emma Gould, Ryan Tinson, Murree Groom, Chris J Hamilton
Reactive sulfur species from garlic have long been renowned for their health benefits and antimicrobial properties. In agriculture the subject matter is now gathering momentum in the search for new bio-pesticides to addressing emerging environmental concerns and tighter restrictions on the use of many conventional chemical pesticides. Although the precise modes of action of these garlic-derived bioactives is complex, recent research has provided a number of new insights that deepen our understanding of garlic-derived products, such as garlic extracts and oils...
December 30, 2016: Antioxidants (Basel, Switzerland)
Suzanne M Adam, Isaac Garcia-Bosch, Andrew W Schaefer, Savita K Sharma, Maxime A Siegler, Edward I Solomon, Kenneth D Karlin
The 4H(+)/4e(-) reduction of O2 to water, a key fuel-cell reaction also carried out in biology by oxidase enzymes, includes the critical O-O bond reductive cleavage step. Mechanistic investigations on active-site model compounds, which are synthesized by rational design to incorporate systematic variations, can focus on and resolve answers to fundamental questions, including protonation and/or H-bonding aspects, which accompany electron transfer. Here, we describe the nature and comparative reactivity of two low-spin heme-peroxo-Cu complexes, LS-4DCHIm, [(DCHIm)F8Fe(III)-(O2(2-))-Cu(II)(DCHIm)4](+), and LS-3DCHIm, [(DCHIm)F8Fe(III)-(O2(2-))-Cu(II)(DCHIm)3](+) (F8 = tetrakis(2,6-difluorophenyl)-porphyrinate; DCHIm = 1,5-dicyclohexylimidazole), toward different proton (4-nitrophenol and [DMF·H(+)](CF3SO3(-))) (DMF = dimethyl-formamide) or electron (decamethylferrocene (Fc*)) sources...
December 28, 2016: Journal of the American Chemical Society
Nadia Berenstein
How did vanilla, once a rare luxury, become a global sensation? Rather than taking the vanilla flavor of vanilla beans as a pre-existing natural fact, this essay argues that the sensory experience that came to be recognized as vanilla was a hybrid artifact produced by an expanding global trade in a diverse set of pleasurable substances, including cured beans from artificially pollinated vanilla orchids, synthetic vanillin, sugar, and a far-flung miscellany of other botanical and chemical materials. Global trade and large-scale production resulted not in the production of a homogenous, stable commodity, but in a range of local vanillas, heterogeneous mixtures with a range of qualities and virtues...
December 2016: History of Science; An Annual Review of Literature, Research and Teaching
Kasi Pandima Devi, Dicson Sheeja Malar, Nady Braidy, Seyed Mohammad Nabavi, Seyed Fazel Nabavi
The plant milk thistle and silymarin has been traditionally used as a natural remedy for the treatment of various ailments including neurological disorders such Alzheimer's and Parkinson's Disease and cerebral ischemia for over 2000 years. The neuroprotective effects conferred by silymarin include modulation of various antioxidant mechanisms, and several kinases involved in cell signaling pathways, inhibition of the inflammatory response generated during neurodegeneration, neurotropic effects, regulation of neurotransmitters and inhibition of apoptosis...
December 27, 2016: Current Drug Targets
Shakeel Ahmed, Annu, Saif Ali Chaudhry, Saiqa Ikram
Nanotechnology is emerging as an important area of research with its tremendous applications in all fields of science, engineering, medicine, pharmacy, etc. It involves the materials and their applications having one dimension in the range of 1-100nm. Generally, various techniques are used for syntheses of nanoparticles (NPs) viz. laser ablation, chemical reduction, milling, sputtering, etc. These conventional techniques e.g. chemical reduction method, in which various hazardous chemicals are used for the synthesis of NPs later become liable for innumerable health risks due to their toxicity and endangering serious concerns for environment, while other approaches are expensive, need high energy for the synthesis of NPs...
January 2017: Journal of Photochemistry and Photobiology. B, Biology
Thien-Kim Le, Hyun-Hee Jang, Ha Thi Huong Nguyen, Tiep Thi My Doan, Ga-Young Lee, Ki Deok Park, Taeho Ahn, Young Hee Joung, Hyung-Sik Kang, Chul-Ho Yun
Enzymatic conversion of natural glycosides to their corresponding hydroxylated products using cytochromes P450 has significant advantages over synthetic chemistry and even enzyme-catalyzed glycosylation of chemicals. At present, the basic strategy for making glycosides of stilbenoid compounds is to use the glycosylation activity of enzymes, such as glycosyltransferases. Here, an efficient synthesis of a valuable (E)-astringin, a piceatannol glucoside, was developed using CYP102A1 via the highly regioselective C-3' hydroxylation of polydatin, a resveratrol glucoside...
February 2017: Enzyme and Microbial Technology
Maxim L Kuznetsov, Vadim Yu Kukushkin
Metal-bound isocyanides demonstrate a very rich chemistry towards 1,3-dipoles of the allyl anion type such as nitrones. Depending on the metal centre, dipole nature and substituent in isocyanides, cycloadducts, imine + isocyanates or metallacycles may be formed. In this work, the reasons for such diversity, intimate details of the reaction mechanism and main factors determining the chemoselectivity in the reaction between Au(iii)-bound isocyanides ([AuCl3(C[triple bond, length as m-dash]NR)]) and cyclic nitrones (-)O-N[combining low line](+)[double bond, length as m-dash]C(H)XXX[combining low line] (XXX = CH2CH2CMe2, CH2CH2CH2, OCH2CMe2, CH2OCMe2 and CH2CH2O) are analysed in detail by theoretical (DFT) methods...
December 21, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
Xiaohui Yan, Huiming Ge, Tingting Huang, Hindra, Dong Yang, Qihui Teng, Ivana Crnovčić, Xiuling Li, Jeffrey D Rudolf, Jeremy R Lohman, Yannick Gansemans, Xiangcheng Zhu, Yong Huang, Li-Xing Zhao, Yi Jiang, Filip Van Nieuwerburgh, Christoph Rader, Yanwen Duan, Ben Shen
: The enediyne family of natural products has had a profound impact on modern chemistry, biology, and medicine, and yet only 11 enediynes have been structurally characterized to date. Here we report a genome survey of 3,400 actinomycetes, identifying 81 strains that harbor genes encoding the enediyne polyketide synthase cassettes that could be grouped into 28 distinct clades based on phylogenetic analysis. Genome sequencing of 31 representative strains confirmed that each clade harbors a distinct enediyne biosynthetic gene cluster...
December 20, 2016: MBio
Garima Priyadarshani, Anmada Nayak, Suyog M Amrutkar, Sarita Das, Sankar K Guchhait, Chanakya N Kundu, Uttam C Banerjee
Scaffold-hopping of bioactive natural product aurones has been studied for the first time. 2-Arylideneimidazo[1,2-a]pyridinones as potential topoisomerase IIα (hTopoIIα)-targeting anticancer compounds were considered. A multifunctional activator, polyphosphoric acid, enabled to realize a cascade reaction of 2-aminopyridine with 2,3-epoxyesters toward synthesis of 2-arylideneimidazo[1,2-a]pyridinones. Most of the compounds exhibited hTopoIIα-selective poison activity with efficiency more than etoposide and DNA-binding property, while not interacting with hTopo I...
December 8, 2016: ACS Medicinal Chemistry Letters
Yonghua Wang, Dongming Lan, Rabia Durrani, Frank Hollmann
Peroxygenases are promising catalysts for preparative oxyfunctionalization chemistry as they combine the versatility of P450 monooxygenases with simplicity of cofactor-independent enzymes. Though many interesting applications have been reported, today 'we have only scratched the surface' and significant efforts are necessary to solve issues related to selectivity of the wild type enzymes and low product titers. For this, further elucidation of the vast natural diversity as well as protein and reaction engineering approaches are discussed...
December 16, 2016: Current Opinion in Chemical Biology
Chunngai Hui, Fan Pu, Jing Xu
Asymmetric catalysis for chiral compound synthesis is a rapidly growing field in modern organic chemistry. Asymmetric catalytic processes have been indispensable for the synthesis of enantioselective materials to meet demands from various fields. Michael addition has been used extensively for the construction of C-C bonds under mild conditions. With the discovery and development of organo- and metal-catalyzed asymmetric Michael additions, the synthesis of enantioselective and/or diastereoselective Michael adducts has become possible and increasingly prevalent in the literature...
December 19, 2016: Chemistry: a European Journal
Dan W Reynolds, John M Campbell, Byron S Johnson, Biren K Joshi, Kevin L Facchine, Stacey Long, Thomas M O'Connell, Iris V Paulus, Scott L Sides, Eric S Kraft, Andrew M Wolters
The chemical degradation of farglitazar (1) was investigated using a series of controlled stress testing experiments. Farglitazar drug substance was stressed under acidic, natural pH, basic, and oxidative conditions in solution. In the solid state, the drug substance was stressed with heat, high humidity, and light. Farglitazar was found to be most labile towards oxidative stress. A series of mechanistic experiments are described in which the use of (18)O-labelled oxygen demonstrated that oxidative degradation of farglitazar is caused primarily by singlet oxygen formed under thermal conditions...
December 14, 2016: Journal of Pharmaceutical Sciences
Qiong Zeng, Yi-Ming Liu, Yan-Wei Jia, Li-Hong Wan, Xun Liao
Carbon nanotubes (CNTs) possess large potential as extraction absorbents in solid phase extraction. They have been widely applied in biomedicine research, while very rare application in natural product chemistry has been reported. In this work, methoxypolyethylene glycol amine (mPEG-NH2) is covalently coupled to CNTs-magnetic nanoparticles (CNTs-MNP) to prepare a novel magnetic nanocomposite (PEG-CNTs-MNP) for use as dispersive solid-phase extraction (DSPE) absorbent. The average particle size was 86nm, and the saturation magnetization was 52...
February 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
P M Allard, T Péresse, J Bisson, K Gindro, L Marcourt, V C Pham, F Roussi, M Litaudon, J L Wolfender
No abstract text is available yet for this article.
December 2016: Planta Medica
E C Barnes, P Yin, K Akter, I Jamie, C E Yaegl, S R Vemulpad, J F Jamie
No abstract text is available yet for this article.
December 2016: Planta Medica
B Nay
No abstract text is available yet for this article.
December 2016: Planta Medica
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