The use of lobetyolin and HPLC-UV fingerprints for quality assessment of Radix Codonopsis

In 2005 edition of the Chinese Pharmacopoeia, lobetyolin was used as a marker for TLC identification of Radix Codonopsis, whose source plants are Codonopsis pilosula, C. pilosula var. modesta and C. tangshen. Quantification of lobetyolin in 44 samples derived from eight species of Codonopsis and another four genera of the same family Campanulaceae revealed that lobetyolin is present in all Codonopsis species and in Campanumoea javanica, Platycodon grandiflorum and Lobelia chinensis. In fact, the other five Codonopsis species are commonly used as the substitutes of Radix Codonopsis, and the roots of Campanumoeajavanica and Platycodon grandiflorum are sometimes found as the adulterants. Contents of lobetyolin were found variable among different samples, and some substitutes and adulterants actually had comparably high contents of lobetyolin. Therefore, lobetyolin should be taken only as a general but not a definitive marker for the identification of Radix Codonopsis. HPLC-UV fingerprints with seven characteristic peaks were established for discriminating Radix Codonopsis from its adulterants, but more specific and definitive markers remain to be identified for differentiating Radix Codonopsis from its substitutes.