Impact of extraction parameters and their optimization on the nutraceuticals and antioxidant properties of aqueous extract mulberry leaf

Abstract

An investigation into the efficient use of water as a solvent and the influence of extraction temperature, extraction time, water to leaf powder ratio, particle size, and extraction cycle on the nutraceutical and antioxidant profile of aqueous mulberry leaf extract were conducted using a single-factor experiment approach. All the assessed extracting parameters showed a significant effect on the nutraceutical compounds and antioxidant properties. The optimum extraction conditions were as follows: extraction temperature of 70°C, extraction time of 40 min, water to leaf powder ratio of 40:1 ml/g, particle size of 25 µm, and two extraction cycles. Based on these optimal conditions, chlorogenic acid (62.10 mg/g), caffeic acid (32.21 mg/g), kaempferol-7-O-gluco-side (19.30 mg/g), quercetin-3-rutinose (15.69 mg/g), quercetin-3-O-glucoside (32.38 mg/g), kaempferol-3-(6-rhamnosylglucoside) (42.52 mg/g), quercetin-3-(6-malonylglucoside) (65.19 mg/g), kaempferol-3-glucoside (66.27 mg/g), kaempferol-3-(6-malonylglucoside) (50.18 mg/g), 1-deoxynojirimycin (15.58 mg/g), and gamma-aminobutyric acid (5.05 mg/g) were obtained. The optimal aqueous extract had high antioxidant properties of 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (39.98 mM/g), cupric ion reducing capacity (58.93 mM/g), 1,1-diphenyl-2-picrylhydrazyl (101.33 mM/g), and ferric reducing antioxidant power capacity (233.77 mM/g) of dried mulberry leaf extract.