Fractionation of the ethanolic extract of the stem bark of Morus macroura resulted in the isolation of four new Diels-Alder type adducts, named guangsangons K--N (1, 2, 5, 6), together with two known compounds, mulberrofuran G (3) and K (4). Their structures were determined on the basis of spectroscopic analyses and chemical methods. Furthermore, by means of (1)H-NMR variable temperature experiments and the Cotton curves in the circular dichroism (CD) spectra, the stereochemistry of four new compounds was elucidated. The isolated new compounds showed good activity on anti-oxidant in vitro, with the inhibitory rates of MDA being from 91.8 to 100.0% at concentrations of 10(-5) mol/l.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1248/cpb.52.1190 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Streamlined Vitamin D Metabolite Fingerprinting Analysis Using Isotope-Coded Multiplexing MS with Cost-Effective One-Pot Double Derivatization.
ACS Omega
December 2024
Department of Chemistry, Humboldt Universität zu Berlin, Brook-Taylor-Str. 2, Berlin 12489, Germany.
In this study, we extended a previously developed one-pot double derivatization reaction to establish the first routine isotope-coded multiplex derivatization for vitamin D and its metabolites for application in clinical environments, using commercial reagents, without the need for specialized reagents and advanced synthesis requirements. The original derivatization process consisted of using both a Cookson-type reagent and derivatization of hydroxyl groups. Initially, the analytes are derivatized by a Diels-Alder reaction using 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD), followed by acetylation using acetic anhydride, catalyzed by 4-dimethylaminopyridine at room temperature.
View Article and Find Full Text PDFSelf-healing hyaluronic acid/polylysine hydrogel prepared by dual-click chemistry from polyrotaxane slidable crosslinkers.
J Colloid Interface Sci
February 2025
The Key Laboratory of Biomedical Material, School of Life Science and Technology, Xinxiang Medical University, Xinxiang, PR China.
A new type of pH-sensitive hydrogel containing supramolecular structures was fabricated from maleimide-functionalized polyrotaxane, ɛ-polylysine and furan-functionalized hyaluronic acid by Diels-Alder reaction and amino-maleimide reaction. Firstly, pseudo polyrotaxane was obtained through self-assembly of polyethylene glycol and α-cyclodextrin, and then capped with 1-adamantanecarboxylic acid to convert it into polyrotaxane. Secondly, a maleimide-functionalized slidable crosslinker was obtained by modifying the polyrotaxane with 3-maleimide propionic acid, and furan-functionalized hyaluronic acid was prepared by modifying it with 2-furanmethylamine.
View Article and Find Full Text PDFMesoporous Acridinium-Based Covalent Organic Framework for Long-lived Charge-Separated Exciton Mediated Photocatalytic [4+2] Annulation.
Adv Mater
January 2025
Center for Ordered Materials, Organometallics and Catalysis (COMOC), Department of Chemistry, Ghent University, Krijgslaan 281-S3, Ghent, 9000, Belgium.
Article Synopsis
- Covalent organic frameworks (COFs) can be customized for photocatalysis, but their effectiveness is hampered by rapid charge recombination.
- Researchers have developed a new design strategy that introduces trap states in COFs to stabilize long-lived charge-separated excitons, enhancing their photocatalytic activity.
- A specific COF modification using cationic acridinium functionality allows for efficient chemical reactions with high yields, while the COF’s large mesopores facilitate better mass flow and significantly improve catalytic performance compared to existing technologies.
All-In-One Epoxy/MXene Nanocomposites with Bead-Type Polymeric Imidazole Latent Curing Agent for Enhancing Storage Stability and Flame Retardancy.
Adv Mater
December 2024
School of Advanced Materials Science and Engineering, Sungkyunkwan University, Seobu-ro 2066, Jangan-gu, Suwon-si, Gyeonggi-do, 16419, Republic of Korea.
Developing a single-component epoxy system is challenging but crucial for advanced thermoset applications. Unfortunately, conventional latent curing agents using chemical or physical passivation do not provide satisfactory storage stability and the necessary property requirements. Here, it is demonstrated that all-in-one epoxy/MXene nanocomposite system, comprising epoxy resin, polymeric imidazole latent curing agent beads (PILCAB), and TiCT MXene, exhibits excellent storage stability, improved flame retardancy, and enhanced mechanical strength.
View Article and Find Full Text PDFTowards a switchable nanoparticle behavior using inverse electron-demand Diels-Alder chemistry and ectoenzyme-based ligand activation.
Eur J Pharm Sci
January 2025
Department of Pharmaceutical Technology, University of Regensburg, Regensburg, 93053, Germany. Electronic address:
Nanoparticles (NPs) as drug delivery platforms encounter numerous obstacles on their journey from administration to the target site. Often, diametrically opposing particle properties are desirable to overcome biological and physical barriers. Therefore, stimuli-responsive NPs have been developed to allow for specific particle adaptation.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!