Pyrrolizidine alkaloids derivatization

A number of recent studies of the pyrrolizidine alkaloids in various Symphytum species have succeeded in characterizing twelve mono- and di-ester alkaloids of retronecine and hellotridine (31, 95-104). We have examined twelve samples each of comfrey root and leaf sold as herbs in the U.S. As determined by nmr, the total alkaloid content of the leaf samples was < 0.005% the roots, on the other hand, contained from 0.14-0.42% (130). Examination of the root alkaloid mixture by capillary gc-ms after derivatization allowed identification of seven alkaloids (Figures 4 and 7) in all of the samples the first four peaks, lycopsamine, intermedlne, and their 7-acetyl derivatives, accounted for 75% or more of the total alkaloids. The same seven alkaloids have been found in Russian comfrey, a cross between Symphytum officinale and asperum, sometimes called Symphytum X uplandIcum (31,96,104). 

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