Anthraquinones, Anthrones and Dianthrones in Callus Cultures of Rhamnus frangula and Rhamnus purshiana.

Tissue cultures initiated from the cambial zone in branches of RHAMNUS FRANGULA L. and RHAMNUS PURSHIANA DC were grown on modified Murashige and Skoog medium with kinetin and 2,4-D as growth factors. To study the production of the genuine anthraquinone derivatives, the extraction of the fresh calli was performed in such a way that oxidation was prevented. In the fresh callus of RHAMNUS FRANGULA the glycosides of chrysophanoldianthrone and chrysophanolphys-ciondianthrone predominantly occurred, whereas in the freeze dried bark of RHAMNUS FRANGULA the glycosides of emodin and emodinanthrone were the main components. Aloe-emodin, which does not occur in the intact bark material of RHAMNUS FRANGULA, was proved to be present in the callus culture. In the fresh callus of RHAMNUS PURSHIANA the glycosides of chrysophanolanthrone and physcionanthrone dominated, while in the freeze dried bark of RHAMNUS PURSHIANA the glycosides of emodin, emodinanthrone and aloe-emodin were predominantly present. The total yields of the glycosidic bound aglycones produced in both cultures were approximately one third of the yields produced in the bark of the two intact species from which the cultures originated.