Decomposition of Methylazoxymethanol, the Aglycone of Cycasin, in D₂O

Abstract

CYCASIN, the toxic principle found in the nuts, roots, and leaves of Cycas circinalis L. and Cycas revoluta, is carcinogenic to rodents and has hepatotoxic, neurotoxic, teratogenic and radiomimetic properties^1,2. Convincing evidence has accumulated that the activity of cycasin, a β-glucoside of methylazoxymethanol (MAM), is due to the aglycone released by the action of β-glucosidases which are present in the plant or produced by the intestinal microflora of the test animal. Thus, MAM is toxic to rats when administered either by the parenteral or intraperitoneal route, while cycasin is toxic only when given orally³. Moreover, cycasin given orally to germ-free rats is well tolerated and is nearly quantitatively excreted unchanged, whereas the same treatment to conventional animals results in death⁴.