Three lanostane triterpenoids with antitrypanosomal activity from the fruiting body of Hexagonia tenuis

During the search for new antitrypanosomal drug leads, three new antitrypanosomal compounds, hexatenuins A–C (1–3), were isolated from the fruiting body of Hexagonia tenuis. 1 and 3 possessed an unusual malonate half-ester functional group at C-3 position, and 1 and 2 had a spirostructure in the side-chain. Their structures were elucidated using MS analyses, extensive 2D-heteronuclear NMR data interpretation. Compounds 1–3 showed in vitro antitrypanosomal activity against Trypanosoma brucei brucei with IC₅₀ values of 0.57, 8.60 and 5.62 μg/ml, respectively.     

Ultrasonic-Combined Plasma Bubbling for Adherent Bacteria Disinfection on Medical Equipment

Plasma Chemistry and Plasma Processing - Atmospheric low-temperature plasma has received attention for application in disinfection methods. In this study, we develop a plasma bubbling method as a...     

Mineral Composition of Seawater Bittern Nigari Products and Their Effects on Changing of Browning and Antioxidant Activity in the Glucose/Lysine Maillard Reaction

Seawater bittern (nigari) is a concentrated solution remaining after the crystallization process of salt that has been used as a coagulant for tofu. Recently, various nigari products are distributed in the East Asia. To clarify the properties of nigari products, major mineral composition of six nigari products was determined. Then, effects of the nigari on the browning and antioxidant activity during the glucose/lysine Maillard reaction were investigated. Though the predominant cation was Mg²⁺, the content was varied by each product (0.88–6.49 mol/L). The other major ion contents were also varied. Each 0.5 mol/L of d-glucose and l-lysine were incubated with the nigari (5–50 % (v/v)) or nigari-related salts (1 or 2 mol/L). The browning (OD at 465 nm) and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging capacity and ferrous-reducing power) were increased remarkably by the nigari containing high Mg²⁺ content. The browning tended to be high with sulfates (Na₂SO₄, (NH₄)₂SO₄). On the other hand, high content of MgCl₂ decreased slightly the browning and antioxidant activity. These results suggest that the reaction and antioxidant activities were affected not only by salinity and cations but also by anions and other elements in the nigari.     

Protecting structure analyses of organic molecule-protected nanoscopic noble metal clusters

The stabilizing structure of cationic surfactant-protected platinum clusters in water and tertiary amine-protected rhodium clusters in chloroform, prepared by photo- and hydrogen-reduction, respectively, was investigated. These nanoscopic noble metal clusters present a narrow size distribution and are stable. The structural information of protective organic molecules on the surface of metal clusters was studied by transmission electron microscopy and hydrodynamic radius measurements according to the Taylor dispersion method. The size of the entire cluster with the protective layer surrounding the metal surface, obtained as Stokes' radii by the Taylor dispersion method, is considered to be fairly consistent with the sum of the naked particle size, obtained by transmission electron micrographs, and the size of the adsorbed protective layer, supporting the conformational information.     

XAFS spectra from X-ray fluorescence Kβ line using conventional energy-discriminating detector

X-ray fluorescence spectra of copper (Cu) metal, copper monoxide (CuO), and potassium chromate (K₂CrO₄) were recorded as a function of incident X-ray energy near the Cu K-edge and chromium (Cr) K-edge, respectively, using a conventional silicon drift detector. The spectra contained components due to elastic, inelastic, and multiple scattering, in addition to the Kα and Kβ lines. Cu and Cr K-edge X-ray absorption fine structure (XAFS) spectra of Cu, CuO, and K₂CrO₄ were obtained by an intensity analysis of the Kα and Kβ lines. The intensity of the Kβ line for the different incident photon energies was obtained by numerically removing the additional scattering components using the MUSCAT program. These spectra exhibited a jump near the K absorption edges, which reproduced the spectral features obtained in transmission mode for both Cu, CuO, and K₂CrO₄. A chemical shift was also clearly identified in the X-ray absorption near edges structure using the X-ray fluorescence Kβ line. In addition, the Cr K-edge extended XAFS spectrum of K₂CrO₄ was clearly observed using the Cr Kβ fluorescent line. The XAFS measurements on the Kα and Kβ lines are possible, and they carry equally valuable information.