Ecdysones cyasterone

Ecdysones cyasterone Ajuga bracteosa, A. decumbens, A. pygmaea... 

Table 2< Effects of fl-ecdysone as compared to cyasterone and ponasterone A when orally Injected to 4th Instar B, mopi, 25 larvae were used per treatment.

Oral Injections >10 jig of fl-ecdysone also resulted In a promoted apolysls, but depending upon concentration and the exact age of the treated fourth Instar larvae, a variable number of the treated larvae were able to complete molting and essentially recover. Cyasterone Injections >10 yg, In general, caused a delay (antl-ecdysone) of molting of the treated fourth Instar larvae to the fifth Instar. This antlecdysone effect of cyasterone, at Its most severe, resulted In prothetely (precocious development) of a small % of the treated larvae. 

From Table 7 it can be seen that ajugasterone C is more than 10-fold more potent than 8-ecdysone, and more than 30-fold more potent than cyasterone, as a feeding deterrent to S- grcaninum when Incorporated into the artlflcal diet of this behavioral bio-assay. 

Ecdysone Itself and the phytoecdysones, inokosterone and maklsterone A, were much less effective as abortifacients than 20-0HE (Table I). Cyasterone and ponasterone A were inactive the implication being that the hydroxyl group on C25 is required for activity (10). 

Cyasterone a phytoecdysone (see Ecdysone), M, 520.67, m.p. 164-166 C. [a]D + 64.5 (pyridine). It has been isolated from various plants, including Cya-thula capitata (Amaranthaceae) and Ajuga decumbens (Labiatae). Unlike other ecdysones, C. has a stigmas-tane skeleton (see Steroids) and a y-lactone group in the side chain. 

Sterols are involved in the stabilization of cell membranes (E 2.2). Ergosterol is used in the technical preparation of vitamin Dg (D 6.4.9). Ecdysone and ecdy-sterone are molting hormones in insects and crustaceans (E 3.1). Similar compounds (ecdysteroids), e.g., ponasterone and cyasterone, which are widespread in higher plants, deter feeding insects (E 5.5.3). The hormone activity of certain ecdyste-roids in insects is up to 20 times that of ecdysone. Certain Drosophila species are... 

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