A comprehensive study about Hibiscus sabdariffa leaves: antioxidant activity, polyphenol profile and macro- and micro-element content

Hibiscus sabdariffa leaves are generally consumed by people in cold drinks and herbal tea. The purpose of this study is to examine in terms of antioxidant activity, polyphenol profile and macro- and micro-element content of H. sabdariffa leaves. Firstly, antioxidant activity studies were carried out by applying antioxidant activity assays to different extracts of the plant leaves. It has been observed that the antioxidant activity results vary depending on the extraction solvent and that the result obtained for one extract in some tests could not be obtained for the same extract in the other tests when solvents are changed. Secondly, the polyphenol profile of this plant was identified with a high-performance liquid chromatography–diode array detector (HPLC–DAD). For this purpose, thirteen polyphenols were examined in leaves of this plant, but only caffeic acid, chlorogenic acid, ellagic acid, p-coumaric acid and quercetin were detected among the studied polyphenols. Finally, macro-element including calcium (Ca), potassium (K), magnesium (Mg), sodium (Na) and micro-element including copper (Cu), iron (Fe), zinc (Zn) analysis was carried out using flame atomic absorption spectrometry (FAAS).