Metabolism of 2,5-Dimethyl-4-hydroxy-3(2H)-furanone in Detached Ripening Strawberry Fruits

The transformation of S -[ methyl - 14 C]adenosyl- l -methionine ( 14 C-SAM) and [2-(or 5-) methyl - 14 C]-2,5-dimethyl-4-hydroxy-3(2 H )-furanone ( 14 C- 1 ) was investigated in detached ripening strawberry fruits over a three-day period. Radiochemical analysis of the different fruit parts revealed that 46% and 51% of the applied 14 C remained in the stems for 14 C-SAM and 14 C- 1, respectively. In samples obtained by solid phase extraction, 1, 2,5-dimethyl-4-methoxy-3(2 H )-furanone ( 2 ), and glycosidically bound 1 were analyzed by reversed-phase high-performance liquid chromatography. Incorporation of 14 C-SAM and 14 C- 1 into 2 was observed with transformation rates of 0.4% and 0.3% of the applied 14 C, respectively. In addition, 0.7% of the applied 14 C- 1 was recovered as glycosidically bound 1 . The data support the conclusions that 14 C-SAM is the source of the methyl group in the 4-methoxy compound 2 and that 1 is the precursor of 2 and the glycosides studied.