Partition and water/oil adsorption of some surfactants.

Adsorption isotherms have been determined at the water/oil interface for five biphasic systems involving surfactants (non-ionic and ionic) present in both phases at partition equilibrium. The systems studied were polyoxyethylene(23)lauryl ether (Brij35) in water/hexane and four ionic surfactants, hexadecyltrimethylammonium bromide (CTAB), and a series of three tetraalkylammonium dodecylsulfate (TEADS, TPADS, and TBADS) in water/CH 2Cl 2. Interfacial tension measurements performed at the water/air and water/oil interfaces provided all the necessary information for the determination of the adsorption parameters by taking partition into account. These measurements also allowed the comparison of the adsorption properties at both interfaces which showed an increase of the adsorption equilibrium constant and a decrease of the maximum surface concentration at the water/oil interface compared to water/air. The values of the critical aggregation concentration showed, in all cases, that only the surfactant dissolved in the aqueous phase contribute to the decrease of the water/oil interfacial tension. In the case of the four ionic surfactants, the critical aggregation concentration obtained in biphasic conditions were lowered because of the formation of mixed surfactant-CH 2Cl 2 aggregates.

A lactosylated steroid contributes in vivo therapeutic benefits in experimental models of mouse lymphoma and human glioblastoma.

Various mono- and disaccharides were grafted onto a steroid backbone. Whereas in vitro these glycosylated steroids had no cytotoxic effects on six different human cancer cell lines, several of the glycosylated steroids under study did significantly modify the levels of in vitro migration of the human U373 glioblastoma, the A549 non-small-cell-lung cancer (NSCLC), and the PC-3 prostate cancer cells, with more pronounced effects in the case of a monosubstituted beta-L-fucopyranosyl-steroid (19), a monosubstituted beta-D-isomaltosyl-steroid (22), and a monosubstituted beta-D-lactosyl-steroid (24). These three compounds significantly increased the survival of conventional mice grafted subcutaneously with the P388 lymphoma, a lymphoma that metastasizes toward the liver. In vivo, the monosubstituted beta-D-lactosyl-steroid (24) also increased the antitumor effectiveness of cisplatin, a cytotoxic pro-apoptotic drug, in the case of the P388 lymphoma model. This compound also increased the survival of immunodeficient mice into whose brains human U373 glioblastoma cells had been orthotopically grafted.

Analysis of herbal dietary supplements for sexual performance enhancement: first characterization of propoxyphenyl-thiohydroxyhomosildenafil and identification of sildenafil, thiosildenafil, phentolamine and tetrahydropalmatine as adulterants.

Nine herbal dietary supplements intended to be beverages for enhancing sexual performance were analyzed before their possible launch on the market. Four of them contained a sildenafil analog reported for the first time as an adulterant. After isolation and characterization using NMR, MS, IR and UV, this analog was named propoxyphenyl-thiohydroxyhomosildenafil as the ethoxy chain on the phenyl ring of the already known analog thiohydroxyhomosildenafil was replaced by a propoxy moiety. One formulation was tainted with thiosildenafil, another unapproved PDE-5 inhibitor. Sildenafil along with the natural alkaloid tetrahydropalmatine that has no documented effect for enhancing erectile dysfunction were identified in two formulations. Another formulation was adulterated with phentolamine, a drug that is not approved for boosting male sexual performance when taken orally. The last formulation containing osthole, a bioactive natural coumarine improving sexual dysfunction, is most probably truly natural.

Identification of a novel sildenafil analogue in an adulterated herbal supplement.

iErect, a new dietary supplement marketed as "100% natural" and sold over the Internet, was analyzed. It contains thiosildenafil, a sildenafil analogue already reported as an adulterant in herbal formulations, and a new compound whose structure was elucidated after isolation using NMR, MS and IR. It was named depiperazinothiosildenafil as it results from the hydrolytic cleavage of the S-N bond of the sulfonamide group of thiosildenafil. A capsule of iErect contains a very high amount (≈220mg) of thiosildenafil and ≈30mg of depiperazinothiosildenafil, which places consumers at risk for potentially serious side-effects.

Synthesis of chiral ionic liquids by ion cross-metathesis: en route to enantioselective water-ionic liquid extraction (EWILE), an eco-friendly variant of the ELLE process.

From two initial ILs two other ILs are obtained by simultaneous ion exchange. The hydrophobic ions unite in the hydrophobic layer, whereas the hydrophilic ions gather in water. This protocol is explored as a variant of the ELLE process, in which an enantiomer of a racemic mixture is preferentially extracted with water.

Boron asymmetry in a BODIPY derivative.

A boradiazaindacene (BODIPY) fluorophore with a chirality held on the central boron has been synthesized and the racemate resolved. Dissymetrization of the BODIPY core was obtained by oxidation of the 3-methyl group to the corresponding carboxaldehyde. A hydrogen bond between the aldehyde proton and the fluorine on the boron atom was evidenced by both (1)H NMR and X-ray diffraction. Chiral high-performance liquid chromatography as well as circular dichroism confirm the persistence of both enantiomers.

Fe(II)-induced reduction of labelled endoperoxides. NMR degradation studies on G3 factor and its methyl ether.

The behavior of G3 factor and of its methylated or fluorinated analogues G3Me and G3F, was studied under Fe(II) conditions. Degradation products were isolated and characterized in each case. The use of labelled compounds allowed us to propose mechanisms in which a tertiary radical is involved. This radical rearranges by 5-exo-trig cyclization, or disproportionates in the case of G3Me. A correlation between antiplasmodial activity and stability of this radical is proposed.