Abstract
The characteristics of flavonoids and coumarins in ten types of lemon (Lemon, Pink-lemonade, Meyer lemon, Ogasawarashima
lemon, Hachijyo fruit lemon, Alen-eureka lemon, Lisbon, Vilafranca, Sweet lemon, Ponderosa) were examined. Twelve
flavonoids and seven coumarins from the peel and juice of the different lemon types were analyzed using HPLC, and the
quantitative values were subjected to a multivariate statistics principal component analysis. The ten lemon types were separated
into four (I ～ IV) categories, corresponding to genus-species in plant classification (Citrus limon, Citrus meyeri, Citrus limetta,
Citrus pyriformis), based on the scatter diagram of the score plot from the principal component analysis. Lemon, Pink-lemonade,
Alen-eureka lemon, Lisbon, and Vilafranca were in category I: C. limon. Meyer lemon, Ogasawara-shima lemon, and Hachijyo
fruit lemon were in category II: C. meyeri. Sweet lemon (C. limetta) was in category III, and Ponderosa (C. pyriformis) was in
category IV. The characteristic flavonoids in the lemon types of category I were eriocitrin, diosmin, 6,8-C-diglucosylapigenin,
and 6,8-C-diglucosyldiosmetin. Those of category III were narirutin, nobiletin, and tangeretin, and those of category IV were
neoeriocitrin, neohesperidin, and naringin. Coumarins were not found in the juices but were found in the peels. The characteristic
coumarins in the category I lemon types were 8-geranyloxypsolaren, 5-geranyloxypsolaren (bergamottin), and 5-geranyloxy-7-
methoxycoumarin. That of the category II lemon types was 7-methoxy-5-prenyloxycoumarin, and that of the category IV types was
7-geranyloxycoumarin (auraptene). The antioxidative activity for the peel extract of the category I lemon types was the highest
activity of all categories (p < 0.05) suggesting a relationship to the eriocitrin and neoeriocitrin content.
