Identification of Brassinosteroids with Epimerized Substituents and/or the 23-Oxo Group in Pollen and Anthers of Japanese Cedar

Abstract

  Brassinosteroids in Japanese cedar (Cryptomeria japonica) were analyzed by GC-MS after being purified by reversed-phase HPLC. The occurrence of four stereoisomers of 23-dehydrobrassinolide, three stereoisomers of 28-homobrassinolide, and an isomer of homodolicholide was revealed. The stereochemical structures of these brassinosteroids remain undetermined. Among these, the 23-dehydrobrassinolide stereoisomers are the first brassinosteroids identified with an oxo group located at the C23 position. In addition, known brassinosteroids 3-dehydroteasterone, typhasterol and dolicholide were identified.