Isolation of a Glucosidic β-Damascenone Precursor from Rose Petals

The 9- O -β- d -glucopyranoside of 3-hydroxy-7,8-didehydro-β-ionol ( 1 ) has been isolated from a glycosidic XAD-2 extract obtained from rose petals. In addition to the β-damascenone-generating compound 1, the following glycoconjugates have been isolated and characterized as peracetates: 3-hydroxy-7,8-dihydro-β-ionol 9- O -β- d -glucopyranoside ( 2 ), 3-hydroxy-7,8-dihydro-β-ionol 3- O -β- d -glucopyranoside ( 3 ), 2-phenylethyl- O -β- d -glucopyranoside ( 4 ), 2-phenylethyl- O -β- d -galactopyranoside ( 5 ), benzyl- O -β- d -glucopyranoside ( 6 ), (2 E )-2,6-dimethyl-6-hydroxyocta-2,7-dienyl- O -β- d -glucopyranoside ( 7 ), (2 Z )-2,6-dimethyl-6-hydroxyocta-2,7-dienyl- O -β- d -glucopyranoside ( 8 ), and (2 E,6 E )-2,6-dimethyl-1-hydroxyocta-2,6-dien-8-yl- O -β- d -glucopyranoside ( 9 ). Keywords: Rosa damascena; Rosaceae; petals; aroma precursors; glycosides; β-damascenone; 3-hydroxy- 7,8-didehydro- β -ionol 9 -O- β - d - glucopyranoside; 3-hydroxy-7,8-dihydro- β -ionol 3 -O- β - d - glucopyranoside; 3-hydroxy-7,8-dihydro- β -ionol 9 -O- β - d - glucopyranoside; 2-phenylethyl -O- β - d - glucopyranoside; 2-phenylethyl -O- β - d - galactopyranoside; benzyl -O- β - d - glucopyranoside; (2E)-2,6-dimethyl-6-hydroxyocta-2,7-dienyl -O- β - d - glucopyranoside; (2Z)-2,6-dimethyl-6- hydroxyocta-2,7-dienyl -O- β - d - glucopyranoside; (2E,6E)-2,6-dimethyl-1-hydroxyocta-2,6-dien- 8-yl -O- β - d - glucopyranoside