Survey of Phenolic Compounds Produced in Citrus
Experimental Methods

Phenolic Compounds Studied

Citrus are a rich source of flavonoids (Robbins 1980). Determination of Citrus plant sources with high concentrations of individual flavonoids is desirable in order to study their biological properties. In this study, we determined the percentages of flavonoids, coumarins, and psoralins in different Citrus tissues. We have also quantified a number of specific flavonoids in these tissues. The high-pressure liquid chromatography patterns of phenolic compounds in members of the Citrus subtribe were evaluated using sensitive HPLC technology.

This survey quantitatively evaluates the following flavonoids

flavanone glycosides

eriocitrin (eriodictyol–7–O–rutinoside)

didymin (isosakuranetin–7–O–rutinoside)

hesperidin (hesperetin–7–O–rutinoside)

naringin (naringenin–7–O–neohesperidoside)

naringin–6"–malonate

naringin–4'–glucoside

narirutin (naringenin–7–O–rutinoside)

narirutin–4'–glucoside

neoeriocitrin (eriodictyol–7–O–neohesperidioside)

neohesperidin (hesperetin–7–O–neohesperidioside)

poncirin (isosakuranetin–7–O–neohesperidioside)

flavone glycosides

diosmin (diosmetin–7–O–rutinoside)

isorhoifolin (apiginin–7–O–rutinoside)

rhoifolin (apiginin–7–O–neohesperidoside)

flavonol glycoside

rutin (quercetin–3–O–rutinoside)

The flavonoid chemical structures are depicted in figure 4.

In this report, we compare the concentrations and percentages of these particular classes of phenolic compounds in various tissues for several members of the Citrus subtribe. For each cultivar studied, table 3 and table 4 provide estimates of the amounts of each phenolic compound in leaf, flavedo, albedo, and juice vesicle tissues based on identification by ultraviolet spectra. This information can be used to help differentiate citrus species, and it demonstrates that the tissues have different overall phenolic concentrations.

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United States Department of Agriculture
Agricultural Research Service

The material on this page is in the public domain.

Original posting: April 1, 1999.