Biosynthesis of 20-hydroxyecdysone in Ajuga hairy roots:: Fate of 6α- and 6α-hydrogens of lathosterol

The fate of 6 alpha- and 6 beta-hydrogens of lathosterol during the transformation into 20-hydroxyecdysone was chased by feeding [3 alpha,6 beta-H-2(2)]- and [3 alpha,6 alpha-H-2(2)]-lathosterols to hairy roots:of Ajuga reptans var. atropurpurea. The behavior of 6 beta-hydrogen, which mostly migrated to the C-5 position of 20-hydroxyecdysone, was in agreement with that of C-6 hydrogen of cholesterol. The results strongly supported the View that cholesterol and lathosterol are first metabolized into 7-dehydrocholesterol, which is then converted into 20-hydroxyecdysone via 7-dehydrocholesterol 5 alpha,6 alpha-epoxide in the hairy roots. (C) 1999 Elsevier Science Ltd. All rights reserved.