Synephrine in Shiikuwasha (Citrus depressa Hayata): Change during Fruit Development, and Its Distribution in Citrus Varieties

摘要

The content of synephrine, an adrenergic phenethylamine, was determined by high performance liquid chromatography (HPLC) in Shiikuwasha (Citrus depressa, Hayata) plant material (flesh and peel) during fruit development, as well as in 45 species and cultivars of Citrus genus. HPLC conditions were as follows: column, Develosil ODS-5; mobile phase, acetonitrile-H_2O (2:98)-10 mM phosphoric acid and flow rate, 0.8 mL/min. In the extraction of synephrine from the sample citrus peel, a large quantity of synephrine was detected in water (100%) while no synephrine was found in the methanol extract (more than 60% concentration of methanol). Synephrine content in the peels during Shiikuwasha fruit development was gradually decreased to half the amount in January compared with that in August. Synephrine was detected in 30 of the 45 species and cultivars of Citrus genus, and was mainly found in the samples of Aurantium and Acrumen sections according to Tanaka's classification.