Metabolism of α-ketol derivative of linolenic acid (KODA), a flowering-related compound, in Pharbitis nil

α-Ketol of octadecadienoic acid (KODA, 1) has been suggested to play a role in the photoperiod-regulated flowering in Pharbitis nil. The level of 1 in cotyledons is temporarily controlled during short-day conditions. The biosynthesis of 1 is well studied in plants; however, its in vivo conversion is less understood. We have investigated this issue by studying the metabolism of exogenously-applied [U-13C]-1, [1-14C]-1, and non-labeled 1 in P. nil seedlings by the spectroscopic methods and identified six major metabolites (4–9). We have also found that the enantiomers of 1 are differentially metabolized in P. nil seedlings.