Survey of Phenolic Compounds Produced in Citrus
Flavonoid Composition of Citrus

Sour orange (Citrus aurantium), a pummelo × mandarin cross (Swingle and Reece 1967, Scora 1975a, Barrett and Rhodes 1976), contains neohesperidosyl flavanones. There has been some controversy over the flavanone composition of sour orange (Hattori et al. 1952, Albach and Redman 1969, Nishiura et al. 1969, Horowitz and Gentili 1977, Metzler 1977, Kamiya et al. 1979, Rousseff et al. 1987, Albach and Wutscher 1988). No hesperidin was detected in the sour orange cultivars examined in this study, although it has been reported in other studies of sour oranges (which probably examine sour orange hybrids) (Sarin and Seshadri 1960, Horowitz and Gentili 1977). There were small amounts of narirutin and eriocitrin in the cultivars examined in this study. Naringin is the predominant flavanone, followed closely by neoeriocitrin and neohesperidin. Others have found mainly neohesperidin to be the main flavanone in sour orange (Nishiura et al. 1969, 1971a,b, Metzler 1977, Albach and Wutscher 1988). Naringin–6"–malonate and poncerin are also present in some samples.

The leaf is the only sour orange tissue in which any of the four flavone/ols of this study are detectable. The neohesperidosyl flavone rhoifolin was found in the leaves of both cultivars studied. Rhoifolin has also been isolated from peel (Hattori et al. 1952) and has been reported to be a general component of sour orange (Horowitz and Gentili 1977). Other flavone glycosides, including neodiosmin, have also been isolated from sour orange (Sarin and Seshadri 1960, Horowitz and Gentili 1977).

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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.