ABSTRACT

Flavonoids are secondary metabolites of plants sharing characteristic structural phenolic moieties present as glycosylated derivatives or as aglycones (Stafford 1990; Andersen and Markham 2006). The relatively large number of avonoids reported is a result of the many different combinations that are possible between polyhydroxylated aglycones with mono-and oligosaccharides. The most common sugar moieties include glucose, rhamnose, galactose, arabinose, xylose, and rutinose, or any combination of these. When the glycosylation site is on one of the hydroxyl groups

15.1 Flavonoids: Structure, Activity, and Availability .........................................405 15.2 The HMG-Flavonoids in Bergamot Tissue ..................................................407 15.3 Recently Developed Mass Spectrometric Methods in Analysis of

Flavonoids ..................................................................................................... 411 15.3.1 Paper Spray Mass Spectrometry (PS-MS)........................................ 411

15.3.1.1 PS-MS Determination of Flavonoids from Bergamot Juice ................................................................................... 412

15.3.2 Leaf Spray Mass Spectrometry (LS-MS) ......................................... 415 15.3.2.1 Analysis of Flavonoids from Bergamot Albedo by Leaf

Spray Mass Spectrometry .................................................. 417 15.4 Functional Food from Bergamot Waste Tissue ............................................ 417 Acknowledgment ................................................................................................... 422 References .............................................................................................................. 422

of aglycone, members are called O-glycosides. The most diffused members of this group are those with the sugar moiety bound to the aglycone hydroxyl group at C-7, or in some cases, at C-3. C-glycosides (compounds with sugar moieties bound at one of the C-atoms of the aglycon moiety) have also been reported in various plants (Caristi et al. 2006). Diglycosylated members are further distinguished between rutinosides (rhamnosyl-α-1,6 glucose linkage) and neohesperidosides (rhamnosyl-α-1,2 glucose linkage), based on the site where rhamnose is linked to glucose (see Figure 15.1). Another group of compounds classied as polymethoxy avonoids has also been reported in different plants (Bocco et al. 1998; Leuzzi et al. 2000).