Inhibition of cancer growth by resveratrol (trans-3,5,4'-trihydroxystilbene; RESV), a phytoalexin present in many plant species, is limited by its low bioavailability. Pterostilbene (3,5-dimethoxy-4'-hydroxystilbene; PTER) and quercetin (3,3',4',5,6-pentahydroxyflavone; QUER), two structurally related and naturally occurring small polyphenols, show longer half-life in vivo. In vitro growth of highly malignant B16 melanoma F10 cells (B16M-F10) is inhibited (56%) by short-time exposure (60 min/day) to PTER (40 microm) and QUER (20 microm) (approximate mean values of plasma concentrations measured within the first hour after intravenous administration of 20 mg/kg each polyphenol). Intravenous administration of PTER and QUER (20 mg/kg per day) to mice inhibits (73%) metastatic growth of B16M-F10 cell in the liver, a common site for metastasis development. The anti-metastatic mechanism involves: 1) a PTER-induced inhibition of vascular adhesion molecule 1 expression in the hepatic sinusoidal endothelium, which consequently decreases B16M-F10 cell adhesion to the endothelium through very late activation antigen 4; and 2) a QUER- and PTER-induced inhibition of Bcl-2 expression in metastatic cells, which sensitizes them to vascular endothelium-induced cytotoxicity. Our findings demonstrate that the association of PTER and QUER inhibits metastatic melanoma growth and extends host survival.

The copper complex Tp (CF3)2,Br Cu(NCMe) (1, Tp (CF3)2,Br = hydrotris((3,5-bis(trifluoromethyl)-4-bromo)-pyrazol-1-yl)borate) catalyzes the insertion of the CHCO 2 Et group (from ethyl diazoacetate N 2 CHCO 2 Et, EDA) into the C-H bonds of methane, in a homogeneous process that uses supercritical carbon dioxide (scCO 2 ) as the reaction medium.Other light alkanes such as ethane, propane and butane have been also functionalized with this copper-based catalyst, in the first example of the derivatization of the series of C 1 -C 4 alkanes with this metal with a soluble catalyst.

No abstract

No abstract

Two simple and straightforward procedures for determining the organic content of hybrid silica materials by means of conventional NMR and GC/MS techniques are described. The methods involve dissolving the hybrid material either in a concentrated solution of sodium hydroxide in deuterated water containing a suitable reference or in a solution of hydrogen fluoride in water and extracting with methylene chloride. These methods constitute useful routine techniques for obtaining immediate information concerning both the amount and chemical composition of the organic compounds on the silica surface.