Isolation and Characterization of Anthocyanins from Hibiscus sabdariffa Flowers.
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 (pKa 3.70), and the hydration constants (pKh 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.
Claudia
C
Grajeda-Iglesias
Maria C
MC
Figueroa-Espinoza
Nathalie
N
Barouh
Bruno
B
Baréa
REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
Ana
A
Fernandes
REQUIMTE - Laboratório Associado para a Química Verde, Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade do Porto , Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
Victor
V
de Freitas
Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua , Circuito Universitario s/n, Campus Universitario No. 2, CP 31125, Chihuahua, México.
Erika
E
Salas
D000872:Anthocyanins / Q000737:chemistry / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid; D035264:Flowers / Q000737:chemistry; D031584:Hibiscus / Q000737:chemistry*; D015394:Molecular Structure; D012822:Silicon Dioxide
D000872:Anthocyanins; C505011:delphinidin 3-sambubioside; D012822:Silicon Dioxide; C042953:octadecyl silane-bonded silica; C017154:cyanidin