2,3-Epoxybrassinosteroids are intermediates in the biosynthesis of castasterone in seedlings of Secale cereale

• Published in: Phytochemistry (Oxford) 2005, Vol.66 (1), p.65-72
• Main Authors: Antonchick, Andrey, Svatoš, Aleš, Schneider, Bernd, Konstantinova, Olga V., Zhabinskii, Vladimir N., Khripach, Vladimir A.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Biosynthesis; Brassinosteroids; Castasterone; Cholestanols - metabolism; Deuterium; Deuterium labelling; Epoxides; Epoxysteroids; Fundamental and applied biological sciences. Psychology; Gramineae; Hydroxycholesterols - metabolism; Mass Spectrometry; Metabolism; Metabolism. Physicochemical requirements; Molecular Structure; Plant physiology and development; Secale - metabolism; Secale cereale; Secasterone; Seedlings - metabolism; Steroids
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/j.phytochem.2004.11.008

A brassinosteroid biosynthetic pathway from teasterone/typhasterol via 2,3-epoxybrassinosteroids to castasterone has been found in seedlings of Secale cereale. Epoxide hydrolysis resulting in stereoisomeric vicinal 2,3-diols followed by inversion of configuration at C-2 and C-3 was demonstrated by stepwise administration of deuterated precursors and HPLC–ESI-MS–SIM detection. The involvement of the 2,3-epoxybrassinosteroids secasterone and 2,3-diepisecasterone in the biosynthesis of castasterone has been demonstrated in seedlings of Secale cereale by LC–ESI-MS. Deuterated secasterone, upon administration to rye seedlings, was incorporated into castasterone and its 2β- and 3β-epimers. Administration of deuterated 2,3-diepisecasterone resulted in castasterone and 2-epicastasterone. A biosynthetic subpathway from typhasterol/teasterone via 2,3-epoxybrassinosteroid intermediates to castasterone is discussed.