Optimization of Cellulase-Assisted Extraction of Total Flavonoids from Corn Bract and Evaluation of Antioxidant and Antibacterial Aactivities

Corn bract is a corn-based agricultural waste material that distributed worldwide. In present work, response surface methodology was applied to optimize the cellulase-assisted extraction of Total Flavonoids from Corn Bract (TFCB), the in vitro antioxidant and antibacterial as well as the in vivo antioxidant activities of TFCB were investigated. Results showed that the optimal conditions for TFCB extraction were as follows: Amount of cellulase, 0.4% (w/w); incubation time, 2 h; liquid-to-solid ratio, 35: 1 mL/g; ethanol concentration, 71% (v/v); TFCB yield was 1.284±0.01%, which was 25.39% higher than that of heat reflux extraction. In addition, when compared with vitamin C, TFCB showed weaker in vitro free radical-scavenging capacities, but stronger antioxidant activities in mice. Moreover, TFCB also exerted certain inhibitory effects against Gram-positive bacteria. This study will provide an evidence for the potential of comprehensive utilization of discarded corn bract.