RP-HPLC Detection of 1-Deoxynojirimycin in Different Varieties and Sites of Mulberry Leaves

A method of pre-column derivatization with FMOC-Cl followed by RP-HPLC with UV detection was established for the determination of 1-deoxynojirimycin(DNJ) content in different varieties and sites of mulberry leaves.DNJ was extracted from mulberry leaves using 0.05 mol/L HCl and derivatized using FMOC-Cl in borate buffer solution(pH 8.50) prior to RP-HPLC detection.The chromatographic separation was achieved on a Waters X-Terra column using a mobile phase consisting of a mixture of acetonitrile and 0.1% aqueous acetic acid(55:45,V/V).There was a high positive correlation between the peak area and concentration of DNJ-FMOC with a correlation coefficient of 0.9852.The DNJ content was varied in different varieties of mulberry leaves.Among 15 varieties of mulberry,Qingyang Qing mulberry leaves contained the highest DNJ(0.1486%),while Pi mulberry leaves the lowest(0.04291%).Also,mulberry leaves in different sites contained different DNJ contents.It decreased from the top to bottom gradually,indicating DNJ content is reduced with the maturation of mulberry leaves.