Authentication of senna extract from the eighteenth century and study of its composition by HPLC–MS

The historical relic of medicinal preparation of senna extract, over 200 years old, was analyzed using RP-HPLC connected with ESI⁻-MSⁿ. The conditions for extracting the compounds from the sample and separating them by HPLC were optimized. A broad spectrum of glycosides was identified. Both main senna anthraquinone glycosides, sennoside A and sennoside B, were not detected in the sample. Nevertheless, the found presence of other substances typical of senna allows the positive authentication of the sample. Three possible degradation products of sennosides were identified; rhein and two compounds with unresolved structure. Remarkable stability of some glycosides in the historical sample was found. Detailed ESI⁻-MSⁿ fragmentation mechanisms of sennoside A and B have been proposed. Graphic abstract: