Limonoids in seeds of Iyo tangor (Citrus iyo hort. ex Tanaka)

Abstract

Iyo tangor (Citrus iyo hort ex Tanaka) seeds contained limonin, nomilin, obacunone and deacetylnomilin, in order of decreasing concentration. They also contained the 17-β-D-glucopyranosides of nomilin, obacunone, limonin, deacetynomilin and nomilinic acid. Total limonoid aglycone concentration in the seeds was 873 mg per 100 g on a dry weight basis and total limonoid glucoside concentration was 446 mg. The composition and relative concentration of each limonoid aglycone and glucoside in Iyo tangor seeds were very similar to those of other citrus species distributed widely in western Japan such as Valencia orange (C. sinensis Osbeck), Sanbokan (C. sulcata hort, ex Tanaka) and Hyuganatsu (C. tamurana hort, ex Tanaka). These data reveal that Iyo tangor taxonomically belongs to the same group as those citrus species.