Determination of nucleosides in natural Cordyceps sinensis and cultured Cordyceps mycelia by capillary electrophoresis

Cordyceps sinensis is a well-known traditional Chinese medicine, and some o f the active components are nucleosides. The analysis of nucleosides in Cor dyceps material has been performed by reversed-phase high-performance liqui d chromatography (HPLC) with gradient elution or by spectrometry. Here, we have explored the possibility of using capillary electrophoresis to determi ne the content of three major nucleosides (adenosine, guanosine and uridine ) in Cordyceps. Capillary electrophoresis needs no gradients, and it provid es a better separation due to its higher efficiency. In order to optimize t he resolution, the separation of adenosine, guanosine and uridine was deter mined in Cordyceps with respect to the variation of buffer concentration, p H, temperature, and voltage. By using the calibrated electrophoresis system , the separation was achieved for the three nucleosides in less than 10 min with a background electrolyte consisting of 0.2 M boric acid-sodium hydrox ide buffer, pH 8.5. The nucleoside contents of various types of natural Cor dyceps and cultured Cordyceps mycelia were determined and compared. There w as a great variation of nucleoside content in different sources of Cordycep s; the cultured Cordyceps mycelia, however, contains a much higher concentr ation than the natural Cordyceps.