Simultaneous determination of polymethoxyflavones in Citrus species, Kiyomi tangor and Satsuma mandarin, by high performance liquid chromatography.

The content of polymethoxyflavones (PMFs) in Kiyomi tangor (Citrus unshiu Marcov. forma miyagawa-wase×C. sinensis) and Satsuma mandarin (C. unshiu Marcov. forma miyagawa-wase) was determined by HPLC/UV. The major PMFs of Kiyomi tangor were determined as 3,6,7,4'-tetramethoxyflavone in the peels (10.1mg/g) and leaves (9.2mg/g), and 3-hydroxy-5,6,7,4'-tetramethoxyflavone in the stems (1.5mg/g). The major PMFs of Satsuma mandarin were determined as 5,6,7,8,4'-pentamethoxyflavone in the peels (2.2mg/g) and leaves (1.6 mg/g), and 5,6,7,3',4'-pentamethoxyflavone in the stems (1.4mg/g). Large amounts of Citrus by-products can ultimately provide a cheap and convenient source of PMFs.