Inhibitory Effects of Extracts from Different Parts of Maize on α-Glucosidase and α-Amylase

Objective: To study the inhibitory effects of extracts from different parts of maize(whisker,straw skin,straw core)on the activities of α-glucosidase and α-amylase. Methods: The contents of total flavonoids,total saponins,total polysaccharides and total protein extracts in different parts of maize were determined by routine physical and chemical methods. The inhibitory activities of α-glucosidase and α-amylase were determined by enzyme substrate reaction and 3,5-dinitrosalicylic acid colorimetry. The effects of different pH,temperature and time on the activities of α-glucosidase and α-amylase were investigated. Results: the optimal conditions of α-glucosidase inhibition were pH6.8,temperature 37 ℃,time 20 min,and pH6.8,temperature 37 ℃,time 10 min. The content of total flavone(5.80%~18.23%),total saponin(7.87%~10.99%),total polysaccharide(24.48%~35.36%)and total protein(9.41%~13.02%)in different parts of maize were significantly different. The inhibitory effect of total flavone extract in different parts of maize on α-glucosidase was significant. The IC₅₀ of total flavone extract in whisker,straw core and straw skin was 0.63,0.35 and 0.13 mg/mL,respectively The maximum inhibition rates of α-amylase at 1,0.5 and 0.125 mg/mL were 36.41%±0.26%,21.46%±1.45% and 14.63%±0.62%. Conclusion: Total flavonoids are the main active components in different parts of maize,which can inhibit the activities of α-glucosidase and α-amylase.