ISOLATION OF 7-DEHYDROCHOLESTEROL FROM CELL-CULTURES OF SOLANUM MALACOXYLON

The presence of cholesterol, 7-dehydrocholesterol, cholecalciferol (vi tamin D-3) and its hydroxylated metabolites, 25-hydroxycholecalciferol (25-OH D-3) and 1 alpha,25-dihydroxycholecalciferol (1 alpha,25-diOH D-3), was demonstrated in cell cultures derived from sterile leaves of Solanum malacoxylon. When calli were grown in the dark, 7-dehydrochol esterol was found and identified on the basis of its chromatographic a nd spectroscopic properties. The analysis of calli grown in the light revealed the presence of vitamin D-3 and 25-OH D-3, where 7-dehydrocho lesterol was not detected. In suspended cells, maintained in the light , vitamin D-3, 25-OH D-3 and 1 alpha,25-diOH D-3 were found, but no 7- dehydrocholesterol was detected. Our results suggest that 7-dehydrocho lesterol may arise as an intermediate in the biosynthesis of vitamin D -3 in S. malaconylon. A photoreaction from 7-dehydrocholesterol may be operative in the biosynthesis of cholecalciferol, thus suggesting tha t in this plant there is a similar pathway to that in animals. Copyrig ht (C) 1996 Elsevier Science Ltd