Isolation and Characterization of Anthocyanins from Hibiscus sabdariffa Flowers

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• 作者：Claudia Grajeda-Iglesias ; Maria C. Figueroa-Espinoza ; Nathalie Barouh ; Bruno Baréa ; Ana Fernandes ; Victor de Freitas ; Erika Salas
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：July 22, 2016
• 年：2016
• 卷：79
• 期：7
• 页码：1709-1718
• 全文大小：602K
• 年卷期：0
• ISSN：1520-6025

文摘

The intense red-colored Hibiscus sabdariffa flowers are an inexpensive source of anthocyanins with potential to be used as natural, innocuous, and health-beneficial colorants. An anthocyanin-rich extract from hibiscus flowers was obtained by ultrasound-assisted extraction. By a single-step process fractionation using a Sep-Pak C₁₈ cartridge, the main hibiscus anthocyanins, delphinidin-3-O-sambubioside (Dp-samb) and cyanidin-3-O-sambubioside (Cy-samb), were separated and then characterized via NMR and HPLC-ESIMS data. Since Dp-samb was the most abundant anthocyanin identified in the extract, its colorant properties were studied by the pH jumps method, which allowed the calculation of the single acid–base equilibrium (pK′_a 2.92), the acidity (pK_a 3.70), and the hydration constants (pK_h 3.02). Moreover, by using size-exclusion chromatography, new cyanidin-derived anthocyanins (with three or more sugar units) were successfully identified and reported for the first time in the hibiscus extract.