A total of 32 samples of commercial Coptidis Rhizoma derived from Coptis chinensis Franch, C. deltoidea C.Y. Cheng et Hsiao, C. japonica (Thumb.) Makino and C. japonica Makino var. dissecta Nakai were collected from herb markets in Taiwan and Japan. The contents of the eight quaternary alkaloids, namely coptisine, berberine, epiderberine, palmatine, columbamine, berberastine, jatrorrhizine and magnoflorine, in these samples were determined by capillary electrophoresis. It was found that the total alkaloid contents in C. chinensis (11.95 +/- 1.79%) and C. deltoidea (12.93 +/- 1.26%) were far higher than in C. japonica (8.17 +/- 0.41%) and C. japonica var. dissecta (7.90 +/- 1.36%). The quaternary alkaloids that had the highest contents in C. chinensis and C. deltoidea were berberine, coptisine, palmatine and epiberberin, whilst in C. japonica and C. japonica var. dissecta they were berberine, coptisine, jatrorrhizine and magnoflorine. Among these samples, those of C. japonica did not contain epiberberine and berberastine whilst those of C. japonica var. dissecta did not contain berberastine. The patterns of their capillary electrophoretograms were found to be very helpful in identifying the origins of the herbs.
