Abstract:

A high performance liquid chromatographic (HPLC) method was developed for the determination of nucleotides. Meanwhile, a comparative analysis of nucleotides between fruiting body of Cordyceps militaris (L. ex Fr.) Link and cultured medium was conducted by the developed method. YMC-Polyamine column (5 μm, 250 mm × 4.6 mm) was used for the chromatographic separation. A mobile phase composed of acetonitrile and double distilled water at a flow rate of 1 mL/min was used for gradient elution and the elution program was as follows: acetonitrile/water (90:10, V/V) for 15 min → (86.5:13.5) for 20 min→(75:25) for 30 min → (70:30) for 35 min. Other chromatographic conditions were set as follows: column temperature 30 ℃, detection wavelength 259 nm, and injection volume 10 μL. Results showed that a good separation of thymine, cordycepin, uracil, adenosine, adenine, uridine, guanine and hypoxanthine was achieved. This method was stable, precise and reproducible and was successfully applied to the determination of nucleosides in commercial Cordyceps militaris (L. ex Fr.) Link samples. HPLC analysis revealed that a basic similarity of nucleotide kind was observed in various commercial samples of fruiting body of Cordyceps militaris (L. ex Fr.) Link. But the contents of nucleotides exhibited significant differences. A high content of cordycepin was found in cultured medium and solid fermentation products, but other nucleotides had a low content. These results demonstrate the excellence of cultured medium and solid fermentation products as a source of cordycepin.

Key words: Cordyceps sp., HPLC, nucleotides, cordycepin, solid fermentation products