臭牡丹根提取物的抑菌效果

[目的]研究臭牡丹根不同极性溶剂提取物对常见植物病原微生物的抑菌效果。[方法]制备了乙醇、乙醚、乙酸乙酯和蒸馏水4种臭牡丹提取物，采用菌饼法研究臭牡丹根的抑菌能力，包括抑菌圈直径（十字交叉法）、最小抑菌浓度（MIC）的测定。并以小麦赤霉为指示菌，观察了pH值为5～8范围内臭牡丹根提取物的抑菌活性。[结果]臭牡丹根的4种提取物对小麦纹枯病菌、小麦赤霉病菌、水稻纹枯病菌、玉米大斑病菌均具有不同程度的抑菌作用，其中，蒸馏水提取物的抑菌效果最好，其次为乙酸乙酯、乙醚，80％乙醇提取物的抑菌效果最差。4种溶剂提取物对小麦赤霉的抑制效果几乎都优于其他的菌种，而对玉米大斑的抑制效果最差，可能是其抑菌机理不同，导致对不同菌的抑菌能力产生差异。乙酸乙酯提取液对小麦赤霉、小麦纹枯、水稻纹枯和玉米大斑最小抑菌浓度分别为16、20、20、25mg／ml；80％乙醇提取液对水稻纹枯和小麦赤霉的最小抑菌浓度为30mg／ml，而对小麦纹枯和玉米大斑的最小抑菌浓度为35mg／ml；蒸馏水提取液对小麦纹枯和小麦赤霉的最小抑菌浓度为10mg／ml，水稻纹枯和玉米大斑的最小抑菌浓度分别为16、20mg／ml；乙醚提取液对小麦赤霉、小麦纹枯、水稻纹枯和玉米大斑最小抑制浓度分别为10、20、20、30mg／ml。总的看来，臭牡丹根提取物对这几种常见植物致病菌的MIC均在35mg／ml以下。臭牡丹根提取物在pH值5～8的范围内具有不同程度的抑菌作用。80％乙醇提取物和乙酸乙酯提取物在中性条件下，抑菌效果较好，然后，随着pH值增加或减小而变差；乙醚提取物在酸性条件下，对小麦赤霉的抑制作用大于在中性和碱性条件下；而蒸馏水的则与乙醚相反，表明其抑菌活性受pH值的影响较大。[结论]臭牡丹根对4种病原微生物具有较好的抑制效果，其抑菌活性受pH值影响较大。

Study on the Antimicrobial Effect of the Extracts of Clerodendron bungei Roots

[ 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.