FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRIC AND TANDEM MASS-SPECTROMETRIC STUDY OF (-)-MENTHOL-BETA-(D)-GLUCOPYRANOSIDE, NEOHESPERIDIN DIHYDROCHALCONE AND THEIR NONCOVALENT ASSOCIATION WITH BETA-CYCLODEXTRIN - 2 EXAMPLES OF INTERACTION OF A CARBOHYDRATE HOST WITH GLYCOCONJUGATE GUESTS

(-)-Menthol-beta-(D)-glucopyranoside 1 and neohesperidin dihydrochalco ne 2 are glycoconjugates of practical interest, Compound 1 releases (- )-menthol in foods by slow hydrolysis and 2 is a sweetener used as an alternative to sucrose for diet food and beverages, Their molecular en capsulation in beta-cyclodextrin (beta CD) is currently under investig ation with the purpose of obtaining long lasting properties in the fin al product, From a mass spectrometric point of view, the study of the protonated gaseous 1 : 1 host-guest complexes of 1 and 2 with beta CD is of particular interest, since the guest molecules possess an apolar aglycon, likely to interact with the lipophilic cavity of beta CD, an d a saccharidic part, whose capability of interaction with the polar e xternal surface of beta CD has not been investigated so far, We carrie d out a fast-atom bombardment (FAB) mass spectrometric and tandem mass spectrometric (MSIMS) study in thioglycerol on 1 and 2 and their gase ous protonated 1 : 1 association complexes with PCD, The FAB and tande m mass spectrometry results are later presented and discussed, Collisi onally-activated decomposition data from native 1 and 2 are compared w ith those of the complexes of 1 and 2 with PCD, The experimental data indicate that the presence of PCD may dramatically alter the fragmenta tion pattern of the two glycoconjugates. The observed fragmentation pa tterns are consistent with an attractive interaction between the polar external surface of PCD and the sugar residues of the guest molecules 1 and 2. The mass spectrometric data not only provide information on the nature of non-covalent interaction in controlling binding phenomen a, but also point out a role for carbohydrate-carbohydrate interaction s, possibly mediated via hydrogen bonding.