Search results for "Biological Product"
showing 10 items of 126 documents
Making natural products from renewable feedstocks: back to the roots?
2019
Covering: up to mid-2019 This review highlights the utilization of biomass-derived building blocks in the total synthesis of natural products. An overview over several renewable feedstock classes, namely wood/lignin, cellulose, chitin and chitosan, fats and oils, as well as terpenes, is given, covering the time span from the initial beginning of natural product synthesis until today. The focus is put on the origin of the employed carbon atoms and on the nature of the complex structures that were assembled therefrom. The emerging trend of turning away from petrochemically derived starting materials back to bio-based resources, just as seen in the early days of total synthesis, shall be demon…
Total Synthesis of (-)-Hymenosetin.
2015
The 3-decalinoyltetramic acid (−)-hymenosetin and its N-methyl analogue were prepared in 11 and 8 steps, respectively, from (+)-citronellal using an intramolecular Diels–Alder reaction as the key step. This method represents the first example for the synthesis of a 3-decalinoyltetramic acid with a free NH moiety. The stereochemistry of the title compound, an unnatural diastereomer, and of a decalin building block was studied in detail using circular dichroism spectroscopy in the IR and UV/VIS freqeuncy range. This allowed to determine the absolute configuration of the natural product and to plan the synthetic route.
Lactones from the Sponge-Derived Fungus Talaromyces rugulosus.
2017
The marine-derived fungus Talaromyces rugulosus isolated from the Mediterranean sponge Axinella cannabina and cultured on solid rice medium yielded seventeen lactone derivatives including five butenolides (1–5), seven (3S)-resorcylide derivatives (6–12), two butenolide-resorcylide dimers (13 and 14), and three dihydroisocoumarins (15–17). Among them, fourteen compounds (1–3, 6–16) are new natural products. The structures of the isolated compounds were elucidated by 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy as well as by ESI-HRMS (ElectroSpray Ionization-High Resolution Mass Spectrometry). TDDFT-ECD (Time-Dependent Density Functional Theory-Electronic Circular Dichroism) calcul…
Azacoccones F-H, new flavipin-derived alkaloids from an endophytic fungus Epicoccum nigrum MK214079.
2020
Abstract Three new flavipin-derived alkaloids, azacoccones F-H (1–3), along with six known compounds (4–9) were isolated from the endophytic fungus Epicoccum nigrum MK214079 associated with leaves of Salix sp. The structures of the new compounds were established by analysis of their 1D/2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data. The absolute configuration of azacoccones F-H (1–3) was determined by comparison of experimental electronic circular dichroism (ECD) data with reported ones and biogenetic considerations. Epicocconigrone A (4), epipyrone A (5), and epicoccolide B (6) exhibited moderate antibacterial activity again…
Traditional Chinese medicines (TCMs) for molecular targeted therapies of tumours.
2009
Scientific progress in genetics, cell and molecular biology has greatly ameliorated our comprehensive understanding of the molecular mechanisms of neoplastic transformation and progression. The rapidly advancing identification of molecular targets in human cancers during the last decade has provided an excellent starting point for the development of novel therapeutics. A huge variety of potential molecular targets have been identified, many of which are already in the market for therapeutic purposes. It is now becoming possible to target pathways and/or molecules that are crucial in maintaining the malignant phenotype. Traditional Chinese medicine (TCM) is often considered as alternative or…
Arbutin synthase, a novel member of the NRD1β glycosyltransferase family, is a unique multifunctional enzyme converting various natural products and …
2002
Plant glucosyltransferases (GTs) play a crucial role in natural product biosynthesis and metabolization of xenobiotics. We expressed the arbutin synthase (AS) cDNA from Rauvolfia serpentina cell suspension cultures in Escherichia coli with a 6 x His tag and purified the active enzyme to homogeneity. The recombinant enzyme had a temperature optimum of 50 degrees C and showed two different pH optima (4.5 and 6.8 or 7.5, depending on the buffer). Out of 74 natural and synthetic phenols and two cinnamyl alcohols tested as substrates for the AS, 45 were accepted, covering a broad range of structural features. Converting rates comparable to hydroquinone were not achieved. In contrast to this broa…
Safety of the current drug treatments for vitiligo
2020
Introduction: Vitiligo is an acquired depigmenting skin disorder adversely affecting the patient's quality of life. Despite the presence of several treatment modalities, ranging from medical to physical to surgical options, none is curative. Each modality has its own drawbacks and side effects. Thus, the treatment modality needs to be tailored for each individual patient taking into consideration the disease characteristics and also its efficacy and safety to obtain a favorable risk-benefit ratio.Areas covered: This review highlights the different treatment modalities utilized in vitiligo up until 4 November 2019 along with their adverse effects and contraindications, if any.Expert opinion:…
Discovery of varlaxins, new aeruginosin-type inhibitors of human trypsins
2022
Low-molecular weight natural products display vast structural diversity and have played a key role in the development of novel therapeutics. Here we report the discovery of novel members of the aeruginosin family of natural products, which we named varlaxins. The chemical structures of varlaxins 1046A and 1022A were determined using a combination of mass spectrometry, analysis of one- and two-dimensional NMR spectra, and HPLC analysis of Marfey's derivatives. These analyses revealed that varlaxins 1046A and 1022A are composed of the following moieties: 2-O-methylglyceric acid 3-O-sulfate, isoleucine, 2-carboxy-6-hydroxyoctahydroindole (Choi), and a terminal arginine derivative. Varlaxins 10…
Modulation of Diabetes by Natural Products and Medicinal Plants via Incretins
2019
Incretins are metabolic hormones released after a meal that increase insulin secretion from pancreatic β-cells. The two main incretins are the intestinal peptides glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. Both induce a decrease in glycemia, slow down the absorption of nutrients, and are inactivated by the enzyme dipeptidyl peptidase-4. Recently, incretin-based therapies have become a useful tool to treat diabetic patients, and different studies have focused on the identification of glucagon-like peptide-1 receptor agonists, including those of natural origin. This review focuses on the new findings of medicinal plants and natural products as possible active ag…
Benzodiazines: recent synthetic advances.
2017
Benzodiazines (diazonaphthalenes with both nitrogens in the same ring) – cinnolines (1,2-benzodiazine), quinazolines (1,3-benzodiazine), phthalazines (2,3-benzodiazine) and quinoxalines (1,4-benzodiazine) – are important class of compounds with broad biological properties and wide application in pharmaceutical as well as agrochemical arenas. These diazaheterocycles are present in a wide variety of bioactive natural products as well as synthetic molecules that are good drug candidates constituting key structural units responsible for their pronounced therapeutic activities. Their rapidly growing uses and applications in medicinal and agrochemical arenas prompt the researchers for further stu…