Abstract
The extracts of two species of Rhododendron leaves and their poisonous principles, grayanotoxin I and III, have been daily administered p.o. to mice and rats for 12 weeks. Behavior, general appearance, mortality, body weight, organ weight, hematology, blood biochemistry, as well as gross and microscopic findings have not revealed any significant effects from the extracts and the toxins in both animals, except for the following changes. Thus, the body weights and the liver weights have generally decreased in the treated mice and in the treated animals, respectively. Decrease of the spleen weights and increase of the serum glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) levels have been also found in the animals given the extracts and the toxins at a higher dose which, however, has been concluded to be within a normal range of function from pathological examinations. Accumulated data demonstrate that despite of the intense acute toxicity, grayanotoxin I and III exhibit rather weak subchronic toxicity as far as the parameters selected in this study concern, which is possibly due to rapid metabolism and/or excretion.
