Quantification of Aromatic Amino Acids in Cordyceps fungi by Micellar Electrokinetic Capillary Chromatography
WEI Xin1,2*, SU Yaxia1,2*, HU Hankun1†, LI Xiangtang2, XU Rui2, LIU Yiming21. Department of Pharmacy, Zhongnan Hospital of Wuhan University, Wuhan 430071, Hubei, China; 2. Department of Chemistry and Biochemistry, Jackson State University, Jackson, Mississippi 39217, USA
A facile micellar electrokinetic chromatography (MEKC) method was developed for quantification of aromatic amino acids in Cordyceps fungi. The proposed MEKC method had linear calibration curves and detection limits at the μmol/L level. Contents of aromatic amino acids in Cordyceps were found in the range from 0.004 9 % to 0.028 0% for tryptophan (Trp), 0.036 6% to 0.078 1% for tyrosine (Tyr), and 0.029 1% to 0.136 2% for phenylalanine (Phe). Levels of amino acids in cultivated Cordyceps militaris were found higher than those in natural Cordyceps sinensis. Interestingly, the ratio of Tyr to its precursor, Phe, in C. sinensis (1.20 ± 0.091, n=3) was significantly higher than that in cultivated C. militaris (0.54 ± 0.170, n=3). This is likely because the enzyme-catalyzed in vivo biotransformation of Phe to Tyr is much more effective in natural C. sinensis, a biological hybrid of larva and parasitic fungus, than in cultivated C. militaris.
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