Phytoecdysteroids, structures

Figure 3. Structural diversity of zoo- and phytoecdysteroids The diagrams represent the known structural variations. " " indicates not conclusively proven...

There are many well-established methods for separation and structure determination of ecdysteroids.20 27 A newly described method is two-dimensional thin-layer chromatography. It has been used to separate complex mixtures of phytoecdysteroids. Silica plates were developed first with toluene—acetone—ethanol—25% aqueous ammonia (100 140 32 9 v/v) and then developed in the other direction with chloroform—methanol—benzene (25 5 3 v/v)48... 

Figure 6.11 Structure and sites of biochemical modification of phytoecdysteroids. The structures of the most commonly reported phytoecdysteroid, 20-hydroxyecdysone, and a 24-alkylphytoecdysteroid, cyasterone. Some common sites of biochemical modifications reported for phytoecdysteroids. (From Adler and Grebenok, 1999.)...

The variability of structures among phytoecdysteroids led to the discrimination between true ecdysteroids and ecdysteroid-related compounds (6 see above). It should be pointed out that these definitions are based on chemical structures and do not discrimi-... 

Publication of the crystal structure of the Hdiothis viresence EcR (HvEcR) LBD heterodimerized with LBD of H. viresence ultraspiracle protein (HvUSP) with and without ponasterone A (phytoecdysteroid) or a BAH ecdysone agonist provided a more realistic conformation of the HvEcR LBD and the ligands in the LBD [21]. The most surprising result was that ponasterone A co-crystallized in the HvEcR LBD in an orientation opposite to that predicted by the CoMEA, 4D-QSAR and... 

Saatov Z, Usmanov BZ, Abubaldrov NK (1977) Phytoecdyzones of Ajuga turkestanica. IV. Chem Nat Compd 13(3) 359 Saatov Z, Gorovits MB, Abubaldrov NK (1990) Phytoecdysteroids of the plant Dianthus hoeltzeri. Chem Nat Compd 26(6) 717-718 Saatov Z, Syrov VN, Mamatkhanov AU, Abubaldrov NK (1994) Phytoecdysteroids of Ajuga and their biological activity. 1. Distribution tmd chemical structures of the compounds isolated. Chem Nat Compd, (30)2 138-145... 

Brassinolates (see above) are similar to phytoecdysteroids in structure (Camps, 1991). 

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