HPLC Separation of Fruit Diastereoisomeric Monoterpenyl Glycosides

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Abstract
The use of a β-cyclodextrin chemically bound phase allows the chromatographic separation of the two isomers of synthetic glycosidically bound tertiary monoterpenic alcohols: linalool, α-terpineol or citronellol. Analysis of grape, passion fruit and apricot monoterpenyl glucosides purified and separated by several chromatographic techniques was carried out by chromatography on a β-cyclodextrin chemically bound phase. The diastereoisomeric forms present in these fruits were identified using mixtures of linalyl and α-terpinyl β-D-glucosides obtained from linalool and α-terpineol of known configuration. The enantiomeric ratio of linalool bound as rutinoside and arabinoglucoside derivatives was determined after release of the terminal rhamnose or arabinose unit by partial enzymatic hydrolysis using the same standards. In apricot as well as in passion fruit, glycosidically bound linalool is present at 85% as (S)-(+) isomer and at 15% as (R)-(−) isomer whereas in grape the (S)-(+) isomer represents more than 95% of the mixture. On the other hand (S)-(−) α-terpineol bound as β-D-glucoside in apricot fruit is present at a higher concentration than the (R)-(+) isomer, 70% versus 30%.