Raw tubers of Aconitum japonicum and A. carmichaeli, which are the sources of processed aconite roots used widely as an Oriental medicine in Japan, have been assayed for the alkaloid content and composition. They have been found to contain mesaconitine or hypaconitine as the main poisonous principle and to be highly toxic. When they are processed at 120° for 40 min (to Kako-bushi), a greater part of the poisonous aconitines is hydrolyzed into the much less poisonous benzoylaconines and, together with the postulated co-occurrence of substances which reduce the toxicity of the aconitines, the tubers become essentially innocuous. It has been revealed that the processed aconite roots (Shirakawabushi), prepared by a variety of procedures (immersion into salt water, coating with lime or ash, and/or some heat treatment), show variation in the alkaloid content and composition, and still exhibit considerable toxicity. The processed aconite roots (Ho-bushi), prepared by immersion into salt water and heat treatment, have also been shown to be innoxious, since the poisonous alkaloids represented by hypaconitine have been largely converted.into benzoylaconines and further the alkaloid content has been significantly reduced. It is quite probable that, in the processed aconite roots (Ho-bushi), not only the poisonous alkaloids but also other active principles have been much decreased owing to chemical degradation by heat treatment as well as by physical loss due to extraction during processing, which is to be clarified by future pharmacological examinations. It has been shown that, when raw tubers are heated at 100° in the presence of water (conditions employed for decoction), the content of the aconitines is gradually diminished and the toxicity reduced rapidly, a fact which confirms that raw tubers become far less toxic by means of sufficient heating under these conditions.
