Optimizing process of extraction and antibacterial activities of antibacterial substance from Ilex centrochinensis S.Y.Hu leaf

The size of inhibition zone was the index, S. aureus and E. coli were the indicator bacteria, to determine the best extraction method by comparing the bacteriostatic effect of extracts from water extraction, ultrasonic extraction, reflux extraction.Basis on the single-factor experiment, orthogonal experiment was used to optimize the extraction process.The effect of extracts from the optimal process on S.aureus, E.coli, E.aerogenes, P.aeruginosa, S.sonnei, C.albicans was determined.The results showed that the best extraction process was the use of water as solvent, ultrasound extraction, ultrasonic power 250 W, at roomtemperature, material liquid ratio of 1∶ 25, extraction for 30 minutes, extracted 2 times. Under these condition of extraction, the diameter of bacteriostatic rings against S.aureus, E.coli were 24.67 mm and 15.67 mm, and the diameter of bacteriostatic rings against E.aerogenes, P.aeruginosa, S.sonnei were 13.67~ 17.33 mm, and the extraction had no inhibitory effect on C.albicans.