6-Deoxotyphasterol and 3-Dehydro-6-deoxoteasterone, Possible Precursors to Brassinosteroidsin the Pollen ofCupressus arizonica

Bioscience, Biotechnology, and Biochemistry
1995.0

Abstract

Two new congeners (22R,23R,24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3α-ol 2 and (22R,23R, 24S)-22,23-dihydroxy-24-methyl-5α-cholestan-3-one 4 that are termed 6-deoxotyphasterol and 3-dehydro-6-deoxoteasterone, respectively, occur in relatively large amounts in the mature pollen of Cupressus arizonica. GC-MS, NMR spectroscopy, the reduction of 4 to 2, and the independent formation of 2 by the reduction of typhasterol were used to identify the new compounds. In the rice lamina bioassay, 2 showed weak activity. 6-Deoxocastasterone, castasterone, typhasterol, an epicastasterone-like compound, teasterone, 28-homocastasterone, 3-dehydroteasterone, brassinolide, and dolichosterone (or 24-epibrassinolide) were also present. These brassinosteroids were identified by co-chromatography with standards after being converted for an HPLC analysis of bioactive fractions. Six other peaks have not yet been assigned. 6-Deoxotyphasterol and 3-dehydro-6-deoxoteasterone should prove useful for exploring the early stages of the biosynthetic pathway(s) to brassinosteroids.

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