Research on the Extraction of Chlorogenic Acid from Sweet Potato Leaf and its Antibacterial Efficiency

[Objective] The extraction technology of chlorogenic acid from sweet potato leaf was optimized and its antibacterial activity was explored for the effective extraction and development of chlorogenic acid.[Method] The best extraction conditions of chlorogenic acid from sweet potato leaf was gotten through the orthogonal experiment and the minimal inhibitory concentration of chlorogenic acid to bacteria was determined according to the change of the absorbance value of liquid medium.[Results] The best extraction condition of the chlorogenic acid from sweet potato leaf was: the concentration of ethanol,60%; the ratio of solid-liquid,1:30; the time of ultrasonic treatment,50 minutes and the temperature of ultrasonic treatment,50℃.The extractive of the chlorogenic acid from sweet potato leaf had the antibacterial efficiency on Lactobacillus plantarum,Staphylococcus,Hansenula yeast,E.coli and Staphylococcus aureus; and the minimum inhibitory concentration were 1 000,1 000,500,250 and 200 μg/ml.[Conclusion] The chlorogenic acid,which had a strong antibacterial efficiency,was contained in sweet potato leaf and as a food additive the chlorogenic acid had good prospects for its development and application.