Nobushige Nishimoto

The moulting hormone activity of ecdysterone and inokosterone isolated from Achyranthis Radix

Abstract The moulting hormone activity of ecdysterone (iso-inokosterone) and inokosterone isolated from Achyranthis Radix has been examined using the housefly, Musca domestica , and the silkworm, Bombyx mori . These chemicals showed a high activity as the hormone, although pupal-adult mixtures were induced indirectly by injecting large doses.

Pharmacology of Ecdysones in Vertebrates

There are many reports of ecdysones related to invertebrates, but studies applied to mammals are relatively few. We examined some pharmacological effects of ecdysterone and inokosterone (Matsuda et al., 1970) and found acute toxicities of both compounds to be very low. Oral administration of both compounds in a maximum permissible dose, 9.0 G./kg., in male mice did not give any fatal results. Therefore, the LD50 was not observed in practice. After intraperitoneal administration, the LD50 of ecdysterone is 6.4 G./kg. and that of inokosterone is 7.8 G./kg. respectively. Therefore, inokosterone has a somewhat lower toxicity than ecdysterone.

Source and Availability of Ecdysterones

Achyranthes radix, a source of the phytoecdysones, ecdysterone (I) and inokosterone (II), is an important crude drug that has been used for diuretic, tonic, and analgesic purposes in East Asia from ancient times. The components of this crude drug have been reported by many chemists to be a saponin with oleanolic acid as a sapogenin, achyrantin, inorganic salts, and a glucuronic acid-like substance. However, we thought that the effective principle of the crude drug might not be attributed to these compounds. Therefore a study was carried out in order to elucidate the effective principle under the direction of Professor Takemoto at Tohoku University. The roots used in the study were obtained from Achyranthes fauriei, one of the original plants from which the crude drugs has been obtained. It is seen everywhere in Japan along roadsides, in fields, and elsewhere.