Microwave-assisted extraction of polyphenols from Eleutherine bulbosa Mill. Urb. bulbs using choline chloride-sorbitol based natural deep eutectic solvent

Eleutherine bulbosa Mill. Urb. is a potential plant to be developed as a raw pharmaceutical active ingredient. This plant can be utilized as raw materials for herbal medicine production. A green solvent is one of the innovative approaches to developing and utilizing natural products as a source of raw materials. This study aims to design and optimize the microwave-assisted extraction (MAE) of polyphenols from E. bulbosa bulbs using choline chloride- sorbitol-based natural deep eutectic solvent (NADES). The MAE method with choline chloride and sorbitol as the deep eutectic solvent composition was used to extract polyphenols content from E. bulbosa . Experimental design with some independent variables was involved, including NADES (choline chloride-sorbitol) ratio, liquid-solid ratio, microwave power, and extraction time. Response surface methodology with the Box-Behnken Design (using Design-Expert v12 program) was used to optimize the extraction condition based on the total polyphenols content (TPC) as a dependent variable. TPC value was determined using the Folin–Ciocalteu reagent and measured using a UV–Vis spectrophotometer at 761 nm. According to the study results, the optimum MAE condition was obtained at 1:1 g/g NADES (choline chloride-sorbitol) ratio, 5 minutes extraction time, 20%W microwave power, and 12:1 ml/g liquid-solid ratio. A 50 g sample was extracted under the ideal MAE conditions for the scale-up confirmation test, yielding a TPC value of 39.88 mgGAE/g sample. The MAE of polyphenols with choline chloride-sorbitol-based NADES produced a higher TPC as a target secondary metabolite and was conducted efficiently, rapidly, and in an environment-friendly way.