Seeking Optimal Extraction Method for Augmenting Hibiscus sabdariffa Bioactive Compounds and Antioxidant Activity

Abstract

The dried flowers of Hibiscus sabdariffa (HS), available worldwide, have various applications in both non-medicinal and medicinal fields. The growing global interest in the health benefits of HS is linked to its potential prevention or management of non-communicable diseases. The aim of this research was to find the optimal extraction method that ensures the maximum yield of multiple beneficial bioactive components, such as polyphenols, anthocyanins, vitamin C, β-carotene, antioxidant activity, free radical scavenging activity DPPH and ferric reducing antioxidant power (FRAP). To this end, stirring, pulsed electric field, and ultrasound-assisted extraction were evaluated, either alone or in combination. Under optimized extraction conditions, the obtained extract exhibited an elevated total polyphenol content (37.82 mg of gallic acid equivalents/g dry weight (dw)), total anthocyanin content (610.42 μg of cyanidin equivalents/g dw), total carotenoids content (921.84 μg of β-carotene equivalents/g dw), and ascorbic acid content (507.44 mg/100 g dw). Remarkably, the extracts exhibited strong antioxidant properties (487.51 μmol of ascorbic acid equivalents (AAE)/g dw and 243.42 μmol AAE/g dw as evidenced by FRAP and DPPH assays, respectively). This research advances the parameters that should be employed to produce the optimal and nutritionally enhanced HS flower extracts, that can be used in the commercial sector.