Three new seco-labdane diterpenoids, named nudifloids W-Y (1-3), along with twelve known diterpenoids (4-15) and one sesquiterpenoid (16) were isolated from the stems and leaves of Callicarpa nudiflora. The chemical structures of compounds 1-3 were determined by 1D and 2D NMR, HR-ESI-MS, and electronic circular dichroism (ECD). The chemical structures of the remaining thirteen known compounds were determined by comparing their spectral data with those reported in the literature.
View Article and Find Full Text PDFTwo new nor-ent-halimane diterpenes and three previously unreported nor-clerodane diterpenes, designated callicaintides A-E (1-5), were isolated from Callicarpa integerrima. Compounds 1 and 2 feature a distinctive 5/6-membered ring system, while compounds 3-5 are characterized by progressively truncated carbon skeletons, containing 18, 17, and 16 carbons, respectively. In addition, four known compounds 6-9 were also identified.
View Article and Find Full Text PDFTwo new triterpenes mayteneri A (), mayteneri B (), and seven known compounds () were isolated from stems of Loes. The chemical structures of compounds and were established by 1D, 2D NMR, HRESIMS analysis, and calculating electronic circular dichroism (ECD). The structures of known compounds - were determined by comparison of their spectral with those reported.
View Article and Find Full Text PDFMarine natural products are considered to be valuable resources that are furnished with diverse chemical structures and various bioactivities. To date, there are seven compounds derived from marine natural products which have been approved as therapeutic drugs by the U.S.
View Article and Find Full Text PDFA new ruthenium(II) complex [Ru(Happip)(3)](ClO(4))(2) {Happip=2-(4-(β-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.
View Article and Find Full Text PDFA 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.
View Article and Find Full Text PDF