Ecdysteroids are hormones controlling cell proliferation, growth and the developmental cycles of insects and other invertebrates. They are occasionally present in various unrelated plants for no apparent reason; no phytohormonal function has yet been identified. In certain cases, ecdysteroids are accumulated to high levels in leaves, roots or seeds. Some ecdysteroid-containing plants have been known as medicinal plants for centuries. One of them, Leuzea carthamoides Iljin (Asteraceae), growing in Central Asia, contains 0.4% ecdysteroid in dry roots and 2% in seeds. A pharmacological preparation from this plant, "Ecdisten', is already available as a commercial preparation for its anabolic, tonic and other effects, for medical use (review). It remained problematic, however, whether ecdysteroids were truly responsible for these effects, because Leuzea contains a number of other biologically active compounds in addition to ecdysteroids. We extracted and purified ecdysteroids from the seeds of Leuzea. With 6 g of 96% 20-hydroxyecdysone (20E), we made a large-scale feeding assay with Japanese quail to find out whether ecdysteroid alone could duplicate the anabolic effects of the seeds. We found that the 96% ecdysteroid increased the mass of the developing quails in a dose-dependent manner, with the rate of increase proportional to the ecdysteroid content in the seeds; there was a 115% increase in living mass with 100 mg kg-1 of pure 20E compared with 109.5% increase with 100-180 mg kg-1 20E equivalents in the seeds. We conclude that the plethora of growth-promoting, vitamin-like effects induced in vertebrates by Leuzea is mediated by ecdysteroids.

In the penultimate and last instar larvae of Schistocerca gregaria, 20‐hydroxyecdysone (20E) makes up 74–84% of detected ecdysteroids in the females, and 63–74% in the males. Remaining ecdysteroids include ecdysone, a compound with HPLC and TLC retention times of makisterone A, and highly polar metabolites. Except for the last instar females, the contents of ecdysone and the unknown compound are higher in the solitary phase, while that of polar metabolites is higher in the gregarious phase. The phases also differ in that the molt‐inducing ecdysteroid peaks last longer in the gregarious than in the solitary larvae. Peak concentrations reach 3.0–4.0 μg 20E equiv./ml in penultimate female instar, 2.5–3.0 μg/ml in penultimate male instar, and 1.5–2.0 μg/ml in the last larval instar of both sexes. © 1996 Wiley‐Liss, Inc.