STUDIES ON CHINESE RHUBARB X. METABOLIC TRANSFORMATIONS OF ANTHAQUINONE DERIVATIVES

The anthraquinone derivatives in Chinese rhubarb undergo metabolic oxidation and conjugation in the animal body. The metabolic pathways are probably as follows:The percentages of excretion of total anthraquinone derivatives in the 24-hour urine of mice after oral ingestion of rhein, aloe-emodin and chrysophanol are found to be 27%, 14% and 6% respectively of the ingested dose. The rate of urinary excretion of anthraquinone derivatives in human beings receiving oral dosages of chrysophanol is at the highest level during the period from 4 to 12 hours after administration.The possible relationships among (1) the metabolic transformations of anthraquinone derivatives, (2) the renal transport of these compounds and (3) their pharmacological potencies are discussed in some detail.