ABSTRACT
Two new triterpenes mayteneri A (1), mayteneri B (2), and seven known compounds (3-9) were isolated from stems of Maytenus hookeri Loes. The chemical structures of compounds 1 and 2 were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds 3-9 were determined by comparison of their spectral with those reported. Compounds 4-7 showed significant inhibitory activity for NLRP3 inflammasome, with the IC50 values of 2.36-3.44 µM.
Subject(s)
Maytenus , Oleanolic Acid , Molecular Structure , Oleanolic Acid/chemistry , Oleanolic Acid/analogs & derivatives , Oleanolic Acid/isolation & purification , Oleanolic Acid/pharmacology , Maytenus/chemistry , Triterpenes/chemistry , Triterpenes/pharmacology , Triterpenes/isolation & purification , Plant Stems/chemistry , Animals , Mice , Inflammasomes/drug effects , NLR Family, Pyrin Domain-Containing 3 Protein/antagonists & inhibitorsABSTRACT
A new ruthenium(II) complex [Ru(Happip)(3)](ClO(4))(2) {Happip=2-(4-(ß-D-allopyranoside)phenyl)imidazo[4,5-f][1,10]phenanthroline} was synthesized and characterized by elemental analysis, (1)H NMR and matrix-assisted laser desorption ionization mass spectrometry. Calf-thymus DNA-binding properties were studied by DNA viscosity measurements and spectroscopic methods of UV-visible (UV-vis) absorption and luminescence titrations, steady-state emission quenching, DNA competitive binding with ethidium bromide and DNA melting experiments, indicating that the complex partially intercalates into the DNA with a large binding constant greater than 10(6)M(-1). The pH effects on UV-vis absorption and emission spectra of the complex were studied, demonstrating that the complex acted as an excellent pH-induced "on-off-on" luminescence switch with large on-off intensity ratios of 88 and 50 with one of luminescence on/off switching actions occurring in near-physiological pH region (pK(a2)=7.33). The DNA photocleaving properties of [Ru(Happip)(3)](2+) were also studied and compared with those of [Ru(bpy)(2)(Happip)](2+) and [Ru(bpy)(2)(Hpip)](2+){bpy=2,2'-bipyridine, Hpip=2-(4-phenyl)imidazo[4,5-f][1,10]phenanthroline}.
Subject(s)
Coordination Complexes/chemical synthesis , Glycosides/chemistry , Intercalating Agents/chemical synthesis , Ruthenium/chemistry , 2,2'-Dipyridyl/analogs & derivatives , Binding, Competitive , DNA/chemistry , Ethidium/chemistry , Hydrogen-Ion Concentration , Kinetics , Luminescent Measurements , Magnetic Resonance Spectroscopy , Phenanthrolines/chemistry , Photolysis , Spectrometry, Fluorescence , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Ultraviolet RaysABSTRACT
A new ruthenium(II) complex grafted with beta-d-allopyranoside, Ru(bpy)(2)(Happip)(ClO(4))(2) (where bpy = 2,2'-bipyridine; Happip = 2-(4-(beta-d-allopyranoside)phenyl)imidazo[4,5-f][1,10]phenanthroline), has been synthesized and characterized by elemental analysis, (1)H NMR spectroscopy, and mass spectrometry. The acid-base properties of the complex have been studied by UV-visible and luminescence spectrophotometric pH titrations, and ground- and excited-state ionization constants have been derived. The Ru(II) complex functions as a DNA intercalator as revealed by UV-visible and emission titrations, salt effects, steady-state emission quenching by [Fe(CN)(6)](4-), DNA competitive binding with ethidium bromide, DNA melting experiment, and viscosity measurements.
