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Abstract:
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Asparagusic acid is a naturally occurring 1,2-dithiolane that has been isolated from both the roots and edible portions of Asparagus plants (Asparagus officinalis L.). The substance is a plant growth inhibitor exerting activity comparable to abscisic acid. Asparagusic acid also possesses potent nematicidal activity. The mode of biosynthesis of the 1,2-dithiolane ring of lipoic acid suggests that asparagusic acid may be biosynthesized from isobutyric acid. {1-('14)C}Isobutyric acid was administered and found to be specifically incorporated into asparagusic acid. Doubly labelled forms of isobutyric acid were administered and the results show that Asparagus officinalis does not biosynthesize sulfur containing compounds via the same mechanism that is available to bacteria and fungi. Several sulfur containing compounds, {2-('3)H, 1-('14)C}-sodium 3-mercaptoisobutyrate, {('35)S, 3-('3)H}-sodium 3-mercaptoisobutyrate and {('35)S, 3-('3)H}S-(2-carboxy-n-propyl)-L-cysteine were synthesized and administered and the biosynthesis of asparagusic acid in Asparagus officinalis was determined. |