Synthesis and characterization of new light emitter symmetrical phenoxazinium salt and its potential application as sensor for assessment of Hg2+.

The sensitization of the excited triplet state of a novel symmetrical Bis(dialkylamino)phenoxazinium salt was developed in the presence of Hg(2+). This effect was used to determine the concentration of Hg(2+) in different water samples. The phenoxazinium salt sensor was characterized by different spectroscopic tools such as: UV, FTIR, NMR and fluorescence spectra. The sensor has an emission band at 347 nm in DMSO. Hg(2+) in DMSO at pH 5.6 can remarkably quench the fluorescence intensity of the sensor at 347 nm and a new band was appeared at 436 nm due to the strong complex formation between Hg(2+) and sensor. The quenching of the band intensity at 347 and the enhancement of the intensity of the new band at 436 were used to determine the Hg(2+) in different waste water samples. The dynamic range found for the determination of Hg(2+) concentration is 8.7 × 10(-10) - 1.4 × 10(-6) mol L(-1) with a detection limit of 5.8 × 10(-10) mol L(-1) and quantification detection limit of 1.8 × 10(-9) mol L(-1).

Isolation and pharmacological activities of the Tecoma stans alkaloids.

Tecoma stans is a plant traditionally used in Mexico for the control of diabetes. Amongst the alkaloids isolated from the plant harvested in Egypt, Tecomine was shown to be one of the compounds responsible for the hypoglycemic action. Given the interest in substances able to treat type II diabetes, we isolated the main alkaloids present in the plant growing in Egypt and Brazil and tested them in vivo on db/db mice. Contrary to previous literature reports on different animal models, Tecomine was unable to modify glycemia; the only effect seen being a decrease in plasma cholesterol levels. On the contrary, when tested in vitro on glucose uptake in white adipocytes, the compound showed a marked effect. The two other alkaloids isolated, namely 5beta-Hydroxyskitanthine, early called Base C, and Boschniakine were inactive both in vivo and in vitro assays.