Optimization of 1-Deoxynojirimycin Extraction from Mulberry Leaves by Using Response Surface Methodology

Abstract

Mulberry 1-deoxynojirimycin (DNJ, a potent α-glycosidase inhibitor) has therapeutic potency against diabetes mellitus. However, the amount of DNJ in mulberry leaves is low (about 0.1%), and a more effective extraction method is needed. Ultrasound-assisted extraction (UAE) was applied in this study for mulberry DNJ extraction, and five factors, the percentage of ethanol in the extraction solvent (x₁), ratio of the extraction solvent to mulberry sample (x₂), ultrasonic power (x₃), extraction temperature (x₄) and extraction time (x₅), were investigated by fractional factorial 2^(5-1) design (FFD) to obtain the optimum extraction efficiency (DNJ yield, Y₁) and extraction productivity (total yield, Y₂). The results showed that x₂, x₃ and x₅ had significant impact on Y₁ and Y₂, and were further optimized by response surface methodology (RSM). Under the optimized conditions (x₂, x₃ and x₅ of 7 ml/g, 180 W and 260 s, respectively), DNJ-enriched powder (0.8%) was produced with high extraction efficiency (98%) and productivity (20%), enabling this product to be used for nutraceutical purposes.