Absolute Configuration of Free and Bound 3-Hydroxy-β-Damascone and of 3-Oxo-α-Ionol β-D-Glucopyranoside in Tobacco

Abstract

The free and bound fractions of a sample of Oriental tobacco, Nicotania tabaccum L., were separated by selective retention on Amberh'te XAD-2 resin. Free forms of E-3-hydroxymegastigma-5,8-dien-7-one (3-hydroxy-β-damascone) and E-9-hydroxymegastigina-4,7-dien-3-one (3-oxo-α-ionol) outweighed the bound forms by respective ratios of 40:1 and 138:1. The absolute configuration of free and bound 3-hydroxy-β-damascone were shown to be 3R. Furthermore the aglycone of the β-D-glucopyranoside of (E)-9-hydroxymegastigma-4,7-dien-3-one(E-3-oxo-α-ionol) was assigned both (6R,9S) and (6R,9R) configurations. The ratio of these two epimers was found to be similar to their ratio in the whole glycosidic fraction, but it was quite different in the free fraction. Finally the elution order of the four diastereomeric trifluoroacetylated β-D-glucopyranosides of E-3-oxo-α-ionol was determined on a GC capillary column