With the aid of multilayer coil countercurrent chromatography, subsequent acetylation, and liquid chromatographic purification of a glycosidic mixture obtained from lulo (Solanum quitoense L.) leaves, three C13-norisoprenoid glucoconjugates were isolated in pure form. Their structures were elucidated by NMR, MS, and CD analyses to be the novel (6R,9R)-13-hydroxy-3-oxo-α-ionol 9-O-β-D-glucopyranoside (4a), the uncommon (3S,5R,8R)-3,5-dihydroxy-6,7-megastigmadien-9-one 5-O-β-D-glucopyranoside (citroside A) (5a), and the known (6S,9R)-vomifoliol 9-O-β-D-glucopyranoside (6a). Enzymatic treatment of compound 5a showed the formation of 3-hydroxy-7,8-didehydro-β-ionone (7), an important lulo peeling volatile, which in its turn after chemical reduction and heated acid catalyzed rearrangement generates β-damascenone (9) and 3-hydroxy-β-damascone (10).
(6S, (3S, aroma precursors, β-damascenone, 3-hydroxy-7, lulo, Solanum quitoense, (6R, 9R)-13-hydroxy-3-oxo-α-ionol 9-O-D-d-glucopyranoside, new C13-norisoprenoid glucoconjugate, 5R, 8R)-3, 5-dihydroxy-6, 7-megastigmadien-9-one 5-O-β-D-glucopyranoside, 9R)-vomifoliol 9-O-β-D-glucopyranoside, 8-didehydro-β-ionone, 3-hydroxy-β-damascone
NCBI PubMed ID: 10564031Publication DOI: 10.1021/jf9807364Journal NLM ID: 0374755Publisher: American Chemical Society
Institutions: Departamento de Química, Universidad Nacional de Colombia, AA 14490, Bogotá, Colombia, Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
Methods: 13C NMR, 1H NMR, NOE, EI-MS, deacetylation, FAB-MS, GC-MS, TLC, enzymatic hydrolysis, GC, HPLC, UV, CI-MS, acetylation, CD, COSY, MLCCC
Found