Abstract: This study was designed to obtain the optimized extracting process for the extraction of active substance from 3 traditional Chinese medicines with antibacterial activity against Actinobacillus pleuropneumoniae. The orthogonal array design was used with several factors,including solvent concentration,solid-liquid ratio,extraction frequency,extraction duration and extraction temperature.The extraction yield,MIC and MBC were selected as indexes.The results showed that the optimal extraction conditions for Rhizoma coptidis were as follows:1:8 as the ratio of raw material to liquid,70% as ethanol concentration,and 2 h as extraction duration;the optimal extraction conditions for Fructus mume were as follows:1:10 as the ratio of raw material to liquid,95% as ethanol concentration,90 ^oC as extraction temperature and 8 h as extraction duration;the optimal extraction conditions for PoLygonum cuspidatum were as follows:1:6 as the ratio of raw material to liquid,60% as ethanol concentration,90 ℃ as extraction temperature,2 h as extraction duration and reflux extraction for 3 times.Under the optimal extraction conditions,the MIC values of 3 traditional Chinese medicines were 15.60,10.20 and 15.60 mg/mL,respectively,and the MBC values were 26.00,18.20,15.60 mg/mL,respectively.

Key words: Fructus mume, extraction process;orthogonal array design;antibacterial activity