LIMONOIDS AND THEIR GLUCOSIDES IN VALENCIA ORANGE SEEDS DURING FRUIT-GROWTH AND DEVELOPMENT

The amounts of major citrus limonoids and their corresponding glucosides in Valencia orange seeds were measured during fruit growth and development. Limonin content, including limonoate A-ring lactone (LARL), increased steadily during the whole sampling period, July-December of the fruit-set year. Other limonoid aglycons also increased but not steadily. Limonoid glucosides began to appear in either September or October, and their contents steadily increased thereafter with the exception of obacunone 17-beta-D-glucopyranoside. Citrus seeds, demonstrated in Valencia orange, were shown to have no significant effect on the concentrations of LARL and total limonoid glucosides in fruit tissue. Data suggested that seeds possess limonoid biosynthetic systems independent from the biosynthesis occurring in the fruit tissue.