Optimization of dynamic microwave-assisted extraction of Armillaria polysaccharides using RSM, and their biological activity

Abstract

We used the Box–Behnken design to optimize polysaccharide extraction from Armillaria luteo-virens (Alb. et Schw. Fr.) Sacc. The independent factors included extraction time (X1), microwave power (X2) and water to raw material ratio (X3). The experimental values were fitted to a second-order polynomial equation using multiple regression analysis and a statistical method. Analysis of Variance results indicated that all factors including X1 – X3 had an impact on Armillaria luteo-virens (Alb. et Schw. Fr.) Sacc. polysaccharide extraction. The optimal conditions for efficient yield of polysaccharide, giving a maximum yield of 8.43%, were: X1 = 30.24 min, X2 = 600.6 W and X3 = 40 mL/g. The model was verified by modifying the optimal conditions (X1 = 30 min, X2 = 601 W and X3 = 40 mL/g) for practical application. A pilot scale test was also carried out under optimal conditions. The obtained yields 8.40 ± 0.12% and 8.34 ± 0.25% were comparable with the optimized condition, which indicated that our model is accurate. Fourier transform infrared spectroscopy characterization revealed that the extracted polysaccharide produced typical absorption peaks. Oxygen radical absorbance capacity results showed the polysaccharides had good potential as an antioxidant. Moreover, the polysaccharide showed relatively strong inhibitory activity on the growth of NCI–H446 cells.