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Flavonoids in Citrus and Related Genera

1971; Oxford University Press; Volume: 35; Issue: 11 Linguagem: Inglês

10.1080/00021369.1971.10860133

1881-1280

Masao NISHIURA, Shintaro Kamiya, Sachiko Esaki, Ito Fumiko,

Phytochemicals and Antioxidant Activities

Chemical structure of isonaringin (I), originally isolated from C. pseudogulgul and C. tengu, was studied. Permethylation of I followed by acid hydrolysis yielded 2,3,4-tri-O-methyl l-rhamnose and 2,3,4-tri-O-methyl d-glucose which were identified by comparing with authentic specimens by paper and thin-layer chromatographies. Partial methylation of I with dimethyl sulfate afforded didymin (II), 7-rutinoside of isosakuranetin, which could further be dehydrogenated to linarin (V), 7-rutinoside of acacetin. II and V were identified by mp, mixed mp, UV, IR, and comparison with authentic specimens, respectively. Thus I was proved to be identical with narirutin, 7-rutinoside of naringenin. Isolation of I from many species of citrus was also carried out. Neoeriocitrin, 7-neohes-peridoside of eriodictyol, was isolated from two Japanese miscellaneous varieties of citrus and a poncirus hybrid. The structure was assigned by degradative, spectral and thin-layer chromatographic evidences. The occurrence and distribution of flavanone glycosides in flowers, young and mature leaves, young and ripe fruits, dividing them into peels, segment membranes and juices, of many kinds of citrus were investigated. The occurrence of narirutin, eriocitrin and neoeriocitrin is fairly common to a number of species in genus citrus. Results also indicate that flavonoid patterns in citrus can be classified into eleven groups or more and further they can be summarized in two large groups: (a) those composed of flavanone rutinosides and (b) those composed of flavanone neohesperidosides. Thus the chemotaxonomic table of citrus was given as the results of our study in connection with the Tanaka's classification. Flavonoids in some artificial citrus hydrids were also studied.