[ Objective ] The aim was to research the antimicrobial effect of the extracts of Clerodendron bungei roots with different solvents on the common plant microbes. [ Method] The bacteria cake method was used to study the antimicrobial capability of Clerodendron bungei roots. [ Result ] The extracts have anti-bacterial action on Rhixoctonia cerealis V. Hoeven, Fusarium graminearum, Rhizoctonia solani and Setosphaeria turcica, especially the extract from distilled water has the strongest anti-bacterial action on Rhixoctonia cerealis V. Hoeven and Fusarium graminearum, the extract from ether has the strongest anti-bacterial action on Fusarium graminearum, the MIC all were 10 mg/ml. The extracts had different antimicrobial effect when pH value was from 5 to 8[ Conclusion] The extracts of Clerodendron bungei roots could inhibit the 4 pathogenic microorganism, and the antibacterial activity was affected by pH value greatly.
The test was undertaken to reveal the antifungal activity of extracts from Clerodendrum bungei leaves against Pestalotia and Rhizoctonia solani, the results showed that optimal condition for best antifungal activity of extracts against pestalotia and Rhizoctonia solani are as follows： material-liquid ratio of 1：6,75% ethanol as extracting solvent, reflux at 90℃ for 1.5 h. The substances with good dissolubility in ethanol and water solution such as organic acid, bioflavonoid and alkaloid are main antifungal bioactive substances in Clerodendrun bungei.
