Inhibition of potato sprout growth by carvone enantiomers and their bioconversion in sprouts.

The monoterpenes (R)-(−)-carvone and (S)-(+)-carvone inhibited sprout growth in a model system consisting of sprouts growing from potato eye pieces. The sprout tissue was not necrotic after carvone treatment and the inhibition was reversible, since after treatment the sprouts showed regrowth either by continued top growth or by branching. However, the effect of both isomers on sprout growth differed, and (S)-(+)-carvone inhibited the elongation of the sprouts sooner than did (R)-(−)-carvone. This might be explained by a faster uptake of the former, since the concentration of (S)-(+)-carvone and its derivatives was twice as high during the first 4 days compared with (R)-(−)-carvone-treated sprouts. The sprouts were able to reduce (R)-(−)-carvone mainly into neodihydrocarveol, and (S)-(+)-carvone into neoisodihydrocarveol; in addition hydroxylated compounds were also detected. [ABSTRACT FROM AUTHOR]