2026 Volume 95 Issue 2 Pages 307-317
This study examined relationships between petal color and flavonoid composition across eight Zinnia elegans Preciosa series cultivars by analyzing floral pigmentation and corresponding flavonoid profiles. Using the Royal Horticultural Society Color Chart (RHS.CC), the fresh petals of the eight Z. elegans cultivars were classified into six flower color groups: Red-purple, Red, Orange-red, Yellow-orange, Yellow, and Green-white. Crude extracts from each cultivar were analyzed using HPLC, and the main flavonoids were purified. Subsequent identifications were made using HPLC comparisons with authentic samples, nuclear magnetic resonance (NMR), and mass spectrometry (MS). Except for the petals of the green-white group’s ‘Preciosa White’, which did not show any UV–Vis spectra peaks in the visible range, each cultivar’s petals contained eight anthocyanins: 3-O-glucoside, 3,5-di-O-glucoside, 3-O-(6-O-acetylglucoside), and 3-O-(6-O-acetylglucoside)-5-O-glucoside of pelargonidin and cyanidin. Acetylated anthocyanins are major components of Z. elegans, and their precise structural determination was reported for the first time in Z. elegans cultivars. In flavones, in addition to the known substance apigenin 7-O-glucoside, luteolin 7-O-glucoside was identified for the first time in Z. elegans cultivars. In terms of flavonols, kaempferol 3-O-(2-O-glucosylglucuronide) is a newly identified flavonol glycoside. These flavones and flavonol were contained in petals of all cultivars used in this study. Furthermore, three caffeoylquinic acids, chlorogenic, neochlorogenic, and cryptochlorogenic acids, were present in all cultivars used in this study. In the Red-purple group, only anthocyanins contributed to the visible spectrum; in the Red and Orange-red groups, both anthocyanins and carotenoids were detected and in the Yellow-orange and Yellow groups, only carotenoids were detected. These findings indicate that differences in flower color among the eight Z. elegans Preciosa series cultivars are influenced by the cyanidin–pelargonidin derivative ratio and balance between anthocyanin and carotenoid contents. The findings on flavonoid pigments in Z. elegans cultivars containing the newly identified substances obtained in this study may be useful for future breeding of Z. elegans cultivars.
