Abstract
Intermediacy of iridodial for the biosynthesis of iridoid glucosides in Lamium amplexicaule, Deutzia crenata, Patrinia gibbosa and Galium spurium var. echinospermon was established by the administration experiments of several labeled precursors to these plants.
Administration experiments of several substances to the cultured cells of Gardenia jasminoides f. grandiflora demonstraed that the glucosylation of the aglucone moieties of tarennoside and geniposide, iridoid glucosides occurring in the cultured cells, would take place probably at the stage of tarennogenin or genipin after progressive oxidation of the cyclopentane ring.
The results of the administration experiments of several substances including tritium–labeled 10–hydroxyloganin and 7–epi–10–hydroxyloganin prepared from geniposide to Lonicera morrowii strongly suggested that 10–hydroxyloganin is not the biosynthetic intermediate for secologanin. Thus, it is highly probable that loganin is directly cleaved to secologanin.
Biogenesis of oleoside–type secoiri–doidglucosides are also discussed.
Key Word Index
Iridoids - Biosynthesis - Lamium amplexicaule - Deutzia crenata - Patrinia gibbosa - Galium spurium - Callus of Gardenia jasminoides
