Xiumei Wu

Diarylheptanoids and a monoterpenoid from the rhizomes of Zingiber officinale: antioxidant and cytoprotective properties

Three new diarylheptanoids and one new monoterpenoid were isolated from the rhizomes of Zingiber officinale together with four known diarylheptanoids, 5-8. Their structures were elucidated mainly by spectroscopic methods, and they were deduced as 5-[4-hydroxy-6-(4-hydroxyphenethyl)tetrahydro-2 H-pyran-2-yl]-3-methoxybenzene-1,2-diol (1), sodium (E)-7-hydroxy-1,7-bis(4-hydroxyphenyl)hept-5-ene-3 S-sulfonate (2), sodium (E)-7-hydroxy-1,7-bis(4-hydroxyphenyl)hept-5-ene-3 R-sulfonate (3), and hydroxycineole-10-O-beta-D-glucopyranoside (4), respectively. Among the isolated compounds, compounds 1, 5, and 8 exhibited strong superoxide anion radical scavenging activities in a phenazine methosulfate-NADH system. In a more biological system, these compounds were demonstrated to exhibit potent protection against lipid peroxidation in mouse liver microsomes exposed to oxidative conditions. These compounds were subsequently tested on primary cultures of rat hepatocytes exposed to oxidative damage, and definitive cytoprotective actions were found.

Nanocrystalline tungsten carbide encapsulated in carbon shells

Abstract Nanocrystalline tungsten carbide with an average grain size of 12 nm was synthesized using the ion arc method. The characterization was carried out by means of XRD, TEM, and TGA. The experimental results indicate that the as-synthesized powders are mainly cubic WC 1 − x . Besides, a small amount of α-W 2 C is also observed. These tungsten carbide powders are encapsulated within crystalline graphite. Owing to the ultrafine sizes of the powers, oxidation of the graphite occurs at about 350 °C. The nanocrystalline tungsten carbide transforms into WO 3 at about 670 °C.

Effect of Laggera alata on hepatocyte damage induced by carbon tetrachloride in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCEnLaggera alata, as a traditional Chinese herbal medicine, has been widely used to ameliorate some ailments associated with inflammation including hepatitis in folk.nnnAIM OF THE STUDYnBased on anti-inflammatory activity of total phenolics from Laggera alata (TPLA), to further validate the remarkable curative effect Laggera alata in hepatitis, hepatoprotective effect of TPLA was examined.nnnMATERIALS AND METHODSnTPLA was prepared and its principle components were quantificationally analyzed. The hepatoprotective effects of TPLA were studied using a CCl(4)-induced injury model in primary cultured neonatal rat hepatocytes, and a CCl(4)-induced acute and chronic damage model in vivo.nnnRESULTSnTPLA significantly reduced cellular leakage of hepatocyte aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and improved cell viability in vitro. TPLA markedly decreased the serum AST and ALT levels of the mice, the levels of AST, ALT, total protein, albumin, and sialic acid in rat serum, and the hydroxyproline level in rat liver. Meanwhile, severe hepatic lesions induced by CCl(4) in mice/rats were remarkably improved by the administration of TPLA.nnnCONCLUSIONSnThis investigation verifies the hepatoprotective effect of TPLA in vitro/in vivo and clarifies its active components dicaffeoylquinic acids responsible for hepatoprotective potential.

Synthesis and Tensile Property of Nanocrystalline Metal Copper

A large disk-shaped specimen of nanocrystalline metal copper, with a diameter of 80 mm and thickness 5 mm, was synthesized by an inert gas condensation and insitu warm compacting technique. The grain size and density of the specimen are 36 nm and 94.3 % of standard density, respectively The positron lifetime and intensity were measured for monitoring the defects in the specimen. The results indicated that the size and amount of the vacancies and microvoids in the large specimen are close to that found in the small specimens of other nanostructured materials prepared by the same technique. The tensile stress-strain curve has been precisely measured by using the load cell and foil strain gauge. The results showed that the elastic modulus, yield stress, fracture strength, elongation and mirohardness are 0.65, 1.42, 1.82, 0.20 and 6 times of that for coarse-grained polycrystalline metal copper, respectively

Synthesis and antioxidant evaluation of novel silybin analogues

In this work, we evaluated the antioxidant properties of the eight novel silybin analogues for their capacity to scavenge free radicals including superoxide anion radicals and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals in vitro. Compound 7d demonstrated an excellent antioxidant effect in scavenging superoxide anion free radical with an IC50 value of 26.5 μM, while the IC50 of quercetin (the reference compound) was 38.1 μM. Compounds 7b, 7e, 7h showed certain scavenging activities for both types of free radicals.

Total synthesis and cytotoxicity evaluation of syrinenin-4-O-farnesylether and its analogues

First synthesis of natural product, syrinenin-4-O-farnesylether (1), was carried out via two different paths. Four of its derivatives (9–12) were also prepared. Cytotoxicity screening of the selected compounds were performed on six tumour cell lines. Compound 12 exhibited prominent IC50 values of 1.9 μM and 0.8 μM on CNE and PC-3 cells, respectively.