Light-emitting-diode-induced fluorescence detection of fluorescent dyes for capillary electrophoresis microchip with cross-polarization method.

A cross-polarization scheme is presented to filter out the excitation light from the emission spectrum of fluorescent dyes using green light emitting diodes as a light source and a linear charge coupled device as an intensity detector. The excitation light was linearly polarized and was then used to illuminate the fluorescent dyes in the microchannels of a capillary electrophoresis microchip. The detector was shielded by the second polarizer, oriented perpendicular to the excitation light. The fluorescent signals from Rhodamine B dyes were measured in a dilution series with resulting emission signals and four different concentrations of fluorescent dyes were detected simultaneously with the same excitation source and detector. A limit-of-detection of 1 µM was demonstrated for Rhodamine B dye under the optimal conditions.

Synthesis of ring opening of evodiamine derivatives and evaluation on their biological activity.

As a main bioactive component extracted from Evodiae fructus, evodiamine has a variety of pharmacological activities. In this paper, evodiamine was chosen as starting material to react with different halides. Upon treatment of TFA, a series of novel ring-opening evodiamine derivatives 3a-o were successfully synthesized in a moderate to high yields. These obtained compounds exhibit a moderate to good antitumor activity against BGC803 and SW480 in vitro test by MTT assay. The results showed that hexyl substituted evodiamine derivative (3j, R=hexyl) has a strong antitumor activity against BGC803 and SW480.