Nuclear chemistry

Deep eutectic solvent

Choline chloride

Taguchi methods

Biology

Yield (engineering)

Metallurgy

Materials science

Chromatography

Solubility

Rutin

Orthogonal array

Solvent

Botany

Response surface methodology

Extraction (chemistry)

Organic chemistry

Alloy

Reagent

Eutectic system

Antioxidant

Flavonoid

Composite material

Hibiscus

Chemistry

Deep eutectic solvents (DESs) have been regarded as a substitute extraction solvent for conventional organic reagents due to their low toxicity and unique solubility. In this study, fifteen choline chloride-based DESs were prepared and successfully integrated with microwave-assisted extraction (MAE) technique for extracting Hibiscus manihot L. flowers natural antioxidants. The selected DES exhibited superior extraction performance than those by water and 60% ethanol. After statistical optimization by single-factor experiments, Taguchi orthogonal design and response surface methodology, the maximal extraction yields of ten natural antioxidants reached 0.880, 0.328, 0.176, 0.243, 5.143, 4.098, 4.852, 0.171, 0.509 and 0.303 mg/g, which was 1.42–1.94 folds to those by conventional extraction media and methods. In addition, ten natural antioxidants were enriched and recovered with a satisfactory recovery yield of 88.45%–92.02%, and the regenerative DES could be recycled at least four times. Overall, this study established a green, safe, high-efficiency and sustainable alternative for efficiently extracting bioactive ingredients from plant matrices.

Simultaneous extraction of natural organic acid and flavonoid antioxidants from Hibiscus manihot L. flower by tailor-made deep eutectic solvent