Ecdysteroids chromophore

The term ecdysteroid was originally defined as "all compounds structurally related to ecdysone" [4], However, Lafont and Horn [5] differentiated between true ecdysteroids and ecdysteroid-related compounds. True ecdysteroids possess a steroid nucleus with an A/B-cis-ring junction and a 14a-hydroxy-7-en-6-one chromophore, irrespective of their biological activity, while ecdysteroid-related compounds do not fulfil all these criteria. 

The similarity of ecdysteroids and brassinosteroids may cause some difficulties in their definition. Ecdysteroids were initially defined as "all compounds structurally related to ecdysone" (3). This definition would include brassinosteroids. Recently an attempt has been made by Lafont and Horn to redefine ecdysteroids (6). According to their definition one may "distinguish between true ecdysteroids as compounds where the steroid bears a cis-fused A/B ring junction, a 7-ene-6-one chromophore and a 14a-OH (irrespective of activity in a moulting hormone assay) and ecdysteroid-related compounds which do not fulfil all the above criteria (either they lack the 14a-OH, or the 7-ene, or they present one additional 4- or 14-ene double bond, etc.)" (6). The latter group would include brassinosteroids. Unfortunately, comparable definitions of brassinosteroids are not available so far. 

Ecdysteroids have a common 7-en-6-one chromophore, sometimes a methyl group at C24 and several hydroxyl groups increasing their polarity. About 400 ecdysteroids have... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

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