Rutinosides, flavanone

Among aglycones, the best known are naringenin and hesperidin. Their glycosylated forms occur commonly as O- or C-glycosides, usually as rutinosides (6-O-a-L-rhamnosyl-D-glucosides) and neohesperidosides (2-O-a-L-rhamnosyl-D-glucosides) attached at position 7. Flavanones contribute to the flavour of citrus [19]. Table 12 reports the structures of some common flavanones. 

Narlngenln 7-B-rutinoslde 4 -B-D-glucoside (5,7,4 -trihydroxy-flavanone 7-B-rutinoside 4 -B-D-glucoside)... 

Eriocitrin (= 5,7,3, 4 - Tetrahydroxyflavanone-7-O- rutinoside) (flavanone O-glycoside) Mentha piperita (Lamiaceae), Myoporum tenuifolium (Myoporaceae), Citrus spp. (Rutaceae) ACE (28% inhibition at 300 pM) [76]... 

Figure 6.1. Flavonoids shown to be of nutritional significance are, for the most part, derivatives of either flavone or flavanone, e.g. quercetin (3,3,4,5,7-pentahydroxyflavone), rutin (quercetin-3-rutinoside), naringenin (4,5,7-trihydroxy flavanone), hesperetin (3,5,7-tri-hydroxy-4-methoxyflavanone) and hesperidin (hesperetin-7-rutinoside)...

Hesperidin hesperetin 7-rutinoside, a Flavanone (see) glycoside which makes up 8 % of the dry weight of orange peel. 

Because the flavonoid glycosides are non-volatile, GC has not routinely been used for flavonoid analysis. However, Greaser et al. (1992) have developed a method to analyze the hydrolyzed flavanone content by GC-MS. The method involves solvent extraction of the tissues, hydroylsis of the flavonoids to their respective aglycones, trimethylsilation, and analysis by GC-MS. While the method will accurately identify and quantify the flavonoid aglycones present in the sample, it cannot determine the relative amounts of the neohesperidosides and rutinosides, and would therefore only be able to give an estimation of the amount of bitter flavonoids in a sample. 

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