Antioxidant activity of Magnolol, honokiol, and related phenolic compounds

The antioxidant activity of 10 Japanese and Chinese crude drugs (Kampo drugs) was determined in vitro. Extract of Magnolia cortex, which had the highest antioxidant activity, contained phenolic compounds magnolol and honokiol. However, inhibitory effects of these compounds on lipid oxidation were weaker than that of α-tocopherol as measured by thiobarbituric acid assay. The structure-activity relationship of phenolic compounds showed that antioxidant activities were in the order 4-allyl-2,6-dimethoxyphenol ≥ p,p′-biphenol > eugenol > 2-allyl-6-methylphenol > honokiol > magnolol > caffeic acid > p-ethylphenol > guaiacol. As expected, these results showed that an electron donor and/or bulky groups at the ortho- or para-position of the phenol were required for inhibition of lipid oxidation. Electron spin resonance spin trapping experiments showed that phenol compounds with an allyl substituent on their aromatic rings directly scavenged superoxide (O ₂ ⁻ ), and that only eugenol trapped hydroxyl radicals. These findings suggest that phenolic compounds that contain allyl groups may be effective antioxidants because of the scavenging ability of O ₂ ⁻ or hydroxyl radical, whereas other phenols, without an allyl moiety such as α-tocopherol, may play a role in the termination of free radical chain reactions.     

Effects of different levels of dietarytrans-octadecenoate on steroid metabolism in rats

Rats were fed semipurified diets containing olive oil or partially hydrogenated corn oil at the 5 or 20% level for ca. 30 days. These fat diets contained the same amount of octadecenoate but differed in the geometry with respect to each fat level. Contents oft-18∶1 were 26% and 41% of total fatty acids, respectively. The linoleic acid content was also made equivalent (3.8 energy %). After feeding on cholesterol-free diets, rats ontrans fat, compared to those oncis fat, showed: (a) no changes in serum cholesterol and apolipoprotein levels, (b) no effects on the bile flow and concentrations of biliary cholesterol or bile acids, (c) a trend toward increased fecal excretion of neutral and acidic steroids, (d) a lesser extent of transformation of cholesterol to coprostanol in the gut, and (e) no changes in the composition of biliary and fecal bile acids. Observations (c) and (d) were more marked with a hightrans fat regimen. These observations, except for serum apolipoproteins and fecal steroid excretion, were practically reproducible even when rats were fed cholesterol-enriched diets. A preliminary part of this study was presented at the 74th annual AOCS meeting, Chicago, 1983.     

A Slurry Injection Method for the Fabrication of Multiple Microchannel SOFCs

A fabrication technology has been developed for a novel high-performance solid oxide fuel cells with honeycomb structure via the extrusion of a cathode-honeycomb monolith and subsequent channel surface coating with electrolyte/anode bilayers. A novel coating technique for the preparation of dense electrolyte films on the channel surfaces in cathode honeycomb supports is reported. When the dipping method is used, the high viscous resistance of the electrolyte slurry inhibited slurry penetration into the microchannels, which resulted in insufficient channel surface coating. By contrast, the newly developed channel coating technique, i.e. the slurry injection method , allowed the slurry to be injected into the honeycomb channels without the formation of any coating defects.     

Effects gap heat transfer on LWR fuel behavior during an RIA transient: In-pile experimental results with helium and xenon fillet rods

Gap heat transfer characteristics and their effects on LWR fuel behavior during an RIA have been studied through the in-pile experiment with UO₂ pellet fuel rods. The report describes the experimental results obtained in the NSRR tests in which PWR type test fuel rods of helium and xenon filled as the gap gas have been irradiated in the pulse reactor, NSRR, to simulate the prompt heat up of RIAs. The relation between the cladding temperature history and the gap heat transfer conditions, and the effects of gap gas composition on fuel behavior and on the fuel failure threshold are discussed based on the in-pile experimental data.     

Sm@C74: Computed Relative Isomeric Populations

Density-functional theory (DFT) calculations are reported for Sm@C₇₄, namely for Sm encapsulation in the IPR (isolated pentagon rule) C₇₄ cage and in two C₇₄ cages with a pentagon-pentagon junction. Their relative thermodynamic production yields are evaluated using the DFT calculated terms and it is shown that the IPR-based Sm@C₇₄ endohedral prevails at relevant temperatures in agreement with observation, however, isolation of a minor isomer could be possible.     

Calotropin: A Cardenolide from Calotropis gigantea that Inhibits Wnt Signaling by Increasing Casein Kinase 1α in Colon Cancer Cells

Wnt signaling plays key roles in embryonic development and various human diseases. Activity‐guided testing to isolate Wnt signaling inhibitors from the methanol extract of Calotropis gigantea (Asclepiadaceae) exudutes identified six Wnt inhibitory cardenolides ( 1 – 6 ), of which 1 , 3 , 5 , and 6 exhibited potent TCF/β‐catenin inhibitory activities (IC₅₀ 0.7–3.6 nM ). Calotropin ( 1 ) inhibited Wnt signaling by decreasing both nuclear and cytosolic β‐catenin in a dose‐dependent manner, and promoted degradation of β‐catenin by increasing the phosphorylation of β‐catenin at Ser45 through casein kinase 1α (CK1α). Moreover, 1 significantly increased CK1α protein and mRNA levels. The results suggest that 1 inhibits the Wnt signaling pathway by increasing CK1α protein levels. To the best of our knowledge, calotropin is the first small molecule to increase CK1α levels.     

Maintenance of hepatocyte functions by coculture with bone marrow stromal cells

Rat hepatocytes and bone marrow stromal cells (BMSCs) were cocultured with the aim of maintaining differentiated hepatocyte functions. After BMSCs were expanded to a confluent monolayer, freshly isolated hepatocytes were cultured with them, separated by a semipermeable membrane. The BMSCs significantly increased the urea synthesis and albumin secretion activities of the hepatocytes. Conditioned medium prepared from a BMSC monoculture had the same effect. Further study showed that interleukin-6 was involved in the maintenance of urea synthesis and another factor in the maintenance of albumin secretion.