Stability control of senna leaves and senna extracts.

Powdered senna leaves and a commercial methanolic senna leaf extract were investigated for apparent degradation pathways of known constituents. Different defined storage conditions were chosen according to the guidelines of the international conference on harmonization. Analytical fingerprinting was carried out by HPLC with photodiode array detection. Differences in degradation pathways were observed between the powdered herbal drug material and the extract, depending on storage conditions and packaging materials. Within the crude plant material sennosides were shown to be degraded to sennidine monoglycosides, while rhein 8-O-glucoside was hydrolysed to rhein by enzymatic processes. Degradation of the anthranoid compounds was not due to the same pathways in the investigated commercial extracts. Only unspecific alterations of all compounds were observed. Forced decomposition of this herbal drug preparation under high temperature caused oxidative decomposition of the sennosides to rhein 8-O-glucoside. Furthermore flavonoid glycosides decomposition were observed with an apparent increase in the content of flavone aglyca.