Cryptolide, a new brassinolide catabolite with a 23-oxo group from Japanese cedar pollen/anther and its synthesis

Based on the GC-MS direct comparison with synthetic candidates, a new brass inolide-related steroidal lactone detected in the pollen and anthers of Jap anese cedar (Cryptomeria japanica) was identified 22-trihydroxy-24-methyl-B -homo-7-oxa-5 alpha-cholestan-6,23-dione, being the first brassinolide cata bolite with 23-oxo function in the side chain and termed as cryptolide, and furthermore, the first occurrence of 28-homobrassinolide in plants was als o demonstrated by this work.