Iodide Enhances the Production of Pseurotin D over Pseurotin A by Inverting the Preference for the S2 versus the S2' Product in the Final Nonenzymatic Step.

Nonenzymatic reactions, though critical in natural product biosynthesis, are significantly challenging to control. Adding 3% NaI to the culture medium of significantly increased pseurotin D () production and decreased pseurotin A () production. Previously, and were suggested to be produced via a nonenzymatic reaction, where the epoxide at C-10 undergoes S2 () or S2' () reactions.

Biosynthesis-Encoded Lipogenic Acetyl-CoA Measurement Using NMR Reveals Glucose-Driven Lipogenesis and Glutamine's Alternative Roles in Kidney Cancer.

Fatty acid synthesis (FADNS) is a critical process in lipogenesis that is characteristically altered in clear cell renal cell carcinoma (ccRCC), which is the major type of kidney cancer. An important challenge in studying the FADNS process has been the accurate measurement of cytosolic lipogenic acetyl-CoA (AcCoA), the precursor in FADNS, due to its compartmentalization within cells. Here, we describe a novel NMR-based method to decode the isotopic enrichment of lipogenic AcCoA, which, as we demonstrated, is encoded in the simple signal ratios of the geminal methyl groups of lanosterol during its biosynthesis.

Photodynamic treatment increases the lifespan and oxidative stress resistance of Caenorhabditis elegans.

Photodynamic therapy is a noninvasive treatment in which specific photosensitizers and light are used to produce high amounts of reactive oxygen species (ROS), which can be employed for targeted tissue destruction in cancer treatment or antimicrobial therapy. However, it remains unknown whether lower amounts of ROS produced by mild photodynamic therapy increase lifespan and stress resistance at the organism level. Here, we introduce a novel photodynamic treatment (PDTr) that uses 20 μM hypericin, a photosensitizer that originates from Hypericum perforatum, and orange light (590 nm, 5.

A Single-Scan Ultraselective Heteronuclear Polarization Transfer Method for Unambiguous Complex Structure Assignment.

Complex nuclear magnetic resonance (NMR) signals of organic compounds containing multiple analogous substructures or mixtures pose a significant challenge to structural identification, thus resulting in frequent misassignment of structures. The GEMSTONE method, a single-scan technique that selectively excites a specific proton signal among the crowded NMR signals, was recently proposed as a solution. However, its extension to the polarization transfer method for heteronuclear spin systems was unsuccessful.

Facile Detection of Light-Controlled Radical Scavengers from Natural Products Using In Situ UV-LED NMR Spectroscopy.

With the recent development of chemical analysis technology, attention has been placed on natural light-sensitive compounds that exhibit photoreactivity to expand the structural diversity of natural product chemistry. Photochemical reactions that proceed via a free radical mechanism could be used to modulate the radical-scavenging ability of natural products as well as involve structural change. As the health benefits of radicals are also presented, there is a need for a controllable radical scavenging method for topical and selective application.

Discovery and Photoisomerization of New Pyrrolosesquiterpenoids Glaciapyrroles D and E, from Deep-Sea Sediment sp.

Two new pyrrolosesquiterpenes, glaciapyrroles D () and E () were discovered along with the previously reported glaciapyrrole A () from sp. GGS53 strain isolated from deep-sea sediment. This study elucidated the planar structures of and using nuclear magnetic resonance (NMR), mass spectrometry (MS), ultraviolet (UV), and infrared (IR) spectroscopic data.

Metabolic mechanisms of a drug revealed by distortion-free C tracer analysis.

Metabolomic isotopic tracing can provide flux information useful for understanding drug mechanisms. For that, NMR has the unique advantage of giving positional isotope enrichment information, but the current C 1D NMR approach suffers from low sensitivity and high overlaps. We developed a new 2D heteronuclear NMR experiment incorporating -scaling and distortion-free elements that allows for quantitative analysis of multiplets with high sensitivity and resolution.

Real-Time In-Organism NMR Metabolomics Reveals Different Roles of AMP-Activated Protein Kinase Catalytic Subunits.

AMP-activated protein kinase (AMPK in human and AAK in ) is a master regulator of metabolism. It has many isotypes, but its isotype-dependent functions are largely unknown. By developing real-time in-organism NMR metabolomics for , we were able to study different roles of the isotypic catalytic subunits of AAK/AMPK, AAK-1, and AAK-2 in live worms at the whole organism level.

Extraction of Individual Spectra from Mixture Data Based on High-Resolution C-C NMR Correlation Spectrum and DECODE Procedure.

In NMR analysis of complex organic molecules, low natural abundance of C and the low resolution of two-dimensional (2D) experiments are significant difficulties. Also challenging is the analysis of a mixture spectrum without separation, which has been limited to simple molecules. Through nonuniform sampling using modified heteronuclear multiple bond correlation combined with indirect covariance, a high-resolution C-C correlation spectrum was obtained with H sensitivity.

Supplementation with Chlorella vulgaris, Chlorella protothecoides, and Schizochytrium sp. increases propionate-producing bacteria in in vitro human gut fermentation.

Background: Gut microbiota are major contributors to host metabolism and are considered as potential targets of novel therapeutics. Microalgae have a strong potential for use as prebiotics because they are a rich source of proteins, fatty acids, fiber, and minerals for nutritional supplementation in humans. Nevertheless, there has been insufficient research into the effect of microalgae on gut microbiota.

Carbon Isotopomer Analysis with Non-Unifom Sampling HSQC NMR for Cell Extract and Live Cell Metabolomics Studies.

Isotopomer analysis using either C NMR or LC/GC-MS has been an invaluable tool for studying metabolic activities in a variety of systems. Traditional challenges are, however, that C-detected NMR is insensitive despite its high resolution, and that MS-based techniques cannot easily differentiate positional isotopomers. In addition, current C NMR or LC/GC-MS has limitations in detecting metabolites in living cells.

Specific Detection of Cellular Glutamine Hydrolysis in Live Cells Using HNCO Triple Resonance NMR.

Glutamine plays key roles as a biosynthetic precursor or an energy source in cancers, and interest in its metabolism is rapidly growing. However, the proper evaluation of glutamine hydrolysis, the very first reaction in the entire glutaminolysis, has been difficult. Here, we report a triple resonance NMR-based assay for specific detection of glutaminase activity carrying out this reaction using stable-isotope labeled glutamine.

Pontemazines A and B, phenazine derivatives containing a methylamine linkage from Streptomyces sp. UT1123 and their protective effect to HT-22 neuronal cells.

New phenazine derivatives with a methylamine linker, Pontemazines A (1) and B (2), were isolated from the culture broth of Streptomyces sp. UT1123. The structures of compounds 1 and 2 were determined by NMR spectroscopy and high-resolution mass spectrometry.

Salinazinones A and B: Pyrrolidinyl-Oxazinones from Solar Saltern-Derived Streptomyces sp. KMF-004.

Salinazinones A (1) and B (2), two unprecedented pyrrolidinyl-oxazinones, were isolated from the culture broth of Streptomyces sp. KMF-004 from a solar saltern at Aphae Island, Korea. The structures of these salinazinones, which are unusual and consist of 2-methylpropenyl-1,3-oxazin-6-one bearing 1-oxopyrrolidinyl substituents, were assigned by spectral and chemical analyses using Mosher's method, circular dichroism (CD), and calculated ECD.

Effect of Lycoris chejuensis and Its Active Components on Experimental Models of Alzheimer's Disease.

We found that an extract of Lycoris chejuensis and its three isolated active components, narciclasine, 7-deoxynarciclasine, and 7-deoxy-trans-dihydronarciclasine, each significantly reduced the formation of amyloid-β peptides in HeLa cells transfected with an amyloid precursor protein carrying the Swedish mutation up to 45 ± 3.6%. The extract down-regulated amyloid precursor protein, especially the mature form by up to 88%, and reduced the ability of secretases to generate toxic amyloid-β.

Neuroprotective effect of modified Chungsimyeolda-tang, a traditional Korean herbal formula, via autophagy induction in models of Parkinson's disease.

Aim Of The Study: Previous studies in our laboratory revealed the neuroprotective effect of modified Yeoldahanso-tang (MYH) in models of Parkinson׳s disease (PD). In this study, we investigated another traditional Korean herbal formula, modified Chungsimyeolda-tang (termed DG), as a potential treatment for PD. Chungsimyeolda-tang has been used in Korea to treat cerebrovascular diseases, such as stroke.

Pheophytin a and chlorophyll a identified from environmentally friendly cultivation of green pepper enhance interleukin-2 and interferon-γ in Peyer's patches ex vivo.

The oral consumption of capsicum has been reported to increase interleukin (IL)-2 and interferon (IFN)-γ production in Peyer's patches (PP); however, the active components responsible for these effects have not been completely identified. The beneficial biological effects of green peppers cultivated under environmentally friendly farming conditions (ECP), without the use of chemical pesticides, have rarely been compared with those of green peppers cultivated under conventional farming conditions (CCP). Oral administration of ECP extract significantly induced the production of IL-2 and IFN-γ in concanavalin A-treated cells from PP ex vivo; their levels were much higher than those in the CCP extract-treated group.

Structure assignment of lucentamycin E and revision of the olefin geometries of the marine-derived lucentamycins.

A new lucentamycin analogue, lucentamycin E (5), was isolated from the culture broth of the marine-derived actinomycete Nocardiopsis lucentensis, strain CNR-712. The absolute stereostructure of 5 was assigned by comprehensive analyses of NMR data and by application of the advanced Marfey's method. The planar structure of 5 was analogous to lucentamycins A-D, whereas the olefin geometry of the 3-methyl-4-ethylideneproline moiety was found to be E, opposite of that previously reported.

Hyperoside protects primary rat cortical neurons from neurotoxicity induced by amyloid β-protein via the PI3K/Akt/Bad/Bcl(XL)-regulated mitochondrial apoptotic pathway.

Amyloid β-protein (Aβ), which is deposited in neurons as neurofibrillary tangles, is known to exert cytotoxic effects by inducing mitochondrial dysfunction. Additionally, the PI3K/Akt-mediated interaction between Bad and Bcl(XL) plays an important role in maintaining mitochondrial integrity. However, the application of therapeutic drugs, especially natural products in Alzheimer's disease therapy via PI3K/Akt/Bad/Bcl(XL)-regulated mitochondrial apoptotic pathway has not aroused extensive attention.