Abstract
Hibiscus sabdariffa (Roselle) is in high demand worldwide due to its beneficial health properties owing to the polyphenols content, mainly in the flower calyx. The objective of this study was to find the best conditions (time and liquid: solid ratio) to extract polyphenols from Roselle using Ultrasound-Assisted Extraction (UAE) (40 kHz, 180 W), with ethanol how solvent; as well as determine the yield of phenols, anthocyanin, flavonoids, tannins, antioxidant activity (DPPH) and antigenotoxic effect (comet assay). A traditional solid-liquid extraction was applied as a reference. Extraction times of 40 and 60 min resulted in the highest polyphenols (13.019 mg GAE/g dry weight (dw)), flavonoids (4.981 CE/g dw), anthocyanins (1.855 mg Cya3GE/g dw), and tannins (0.745 CE/g dw) recoveries and an antioxidant activity (DPPH) of 74.58%. Extracts from white calyces contained similar amounts of phenols and flavonoids, but very little condensed tannins (0.049 CE/g dw) and practically no anthocyanins. Extracts from red and white calyces, showed antigenotoxic activity and repaired capacity of damage caused by mutagens in human lymphocytes.
Highlights
Hibiscus sabdariffa (Roselle, Java, Jute), family malvaceae, is an autogamous plant, known in Mexico and Latin America as Jamaican, and in many parts of the world as Roselle or red sorrel [1]
As seen in the figure, yield of extracts is increased significantly until 1:20 solid: liquid ratio; after which, the yield remains almost constant, appreciating a plateau at 60 and 120 min of treatment. This solid-liquid ratio was chosen to measure the effect of sonication time on the extraction, which is discussed later
In the extraction of Nephelium lappaceum L., a fruit common in Southeast Asia, ultrasound assisted extraction at 20 W, the highest anthocyanin and polyphenols yield was attained at 50 ◦ C with 50 W power, a 1:18.6 g/mL solid: liquid optimum ratio and 20 min extraction time [27]
Summary
Hibiscus sabdariffa (Roselle, Java, Jute), family malvaceae, is an autogamous plant, known in Mexico and Latin America as Jamaican, and in many parts of the world as Roselle or red sorrel [1]. Its cultivation is used to obtain fibers and thick and fleshy green, red (the most common) or red dark calyxes [3] This plant has been used for ancestral times mainly in the preparation of hot and cold beverages with antioxidant properties and that helps in the treatment of chronic diseases [4], for its antihypertensive, antihyperlipidemic, anti-inflammatory, antibacterial and anticancer effect, among others [5].
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