title: Comparative chemical and biochemical analysis of extracts of Hibiscus sabdariffa.
abstract: Hibiscus sabdariffa extracts have attracted attention because of potentially useful bioactivity. However, there have been no systematic studies of extraction efficiencies of H. sabdariffa. The nature of extracts used in different studies has varied considerably, making comparisons difficult. Therefore, a systematic study of extracts of H. sabdariffa made with different solvents was carried out using water, methanol, ethyl acetate and hexane in the presence/absence of formic acid, using different extraction times and temperatures. The extracts were analysed for total polyphenol content, antioxidant capacity using DPPH, FRAP and TEAC assays, and specific anthocyanins were determined using HPLC and LC-MS. The results showed the highest antioxidant capacities were obtained by extracting using water, with or without formic acid, for 10 min at 100°C. These extracts provided the highest concentrations of cyanidin 3-sambubioside and delphinidin 3-sambubioside. It will be important to use extraction conditions giving optimal extraction efficiencies for subsequent bioactivity experiments.
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Heba A
authors.initials: HA
authors.lastname: Sindi
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom. Electronic address: l.j.marshall@leeds.ac.uk.
authors.forename: Lisa J
authors.initials: LJ
authors.lastname: Marshall
authors.affiliation: School of Food Science and Nutrition, University of Leeds, Leeds LS2 9JT, United Kingdom.
authors.forename: Michael R A
authors.initials: MR
authors.lastname: Morgan
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D000975:Antioxidants / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D004187:Disaccharides / Q000032:analysis; D031584:Hibiscus / Q000737:chemistry*; D013058:Mass Spectrometry; D010936:Plant Extracts / Q000032:analysis*; D059808:Polyphenols / Q000032:analysis
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D004187:Disaccharides; D010936:Plant Extracts; D059808:Polyphenols; C505011:delphinidin 3-sambubioside; C546691:cyanidin 3-sambubioside
keywords: Anthocyanins; Antioxidant capacity; Cyanidin 3-sambubioside; DPPH; Delphinidin 3-sambubioside; FRAP; Hibiscus sabdariffa; Solvent extraction; TEAC; Total polyphenols