植物提取物对龙眼主要致腐真菌的抑制作用

Plant extracts inhibiting rot-causing fungi of Dimocarpus longan fruits

从低温贮藏的腐烂龙眼果实中分离主要致腐真菌,并以丁香、甘草、花椒和高良姜4种常见药食两用植物为试验材料,对主要致腐真菌进行体外抑菌试验,从中筛选抑菌效果较好的植物提取物及有效的提取方法,然后用二倍稀释法测定其最小抑菌浓度和最小杀菌浓度。结果表明:低温条件下龙眼的致腐真菌主要是龙眼拟茎点霉菌,丁香提取物对该菌抑制效果最好;而且在室温下,用75%乙醇震荡提取48 h所得丁香提取物抑菌效果最佳;丁香提取液的最小抑菌浓度为6.25 mg·m L-1,最小杀菌浓度为12.50 mg·m L-1。

The rot-causing fungi of Dimocarpus longan Lour. fruits were isolated from D. longan stored at low temperature, then 4 kinds of Chinese herbs including Syzygium aromaticum L., Glycyrrhiza uralensis Fisch, Zanthoxylum bungeanum Maxim. and Alpinia officinarum Hance were tested against the main postharvest pathogen in vitro. The aim was to compare the antimicrobial effects of plant extracts so as to find the efficient method of extraction. Then the minimum inhibitory concentration（ MIC） and the minimum bactericidal concentration（MBC）were tested by the double dilution method .The results showed as follows. The main rot-causing fungus of Longan fruits stored at low temperature was Phomopsis longanae Chi. The inhibition effect of S. aromaticum extract was the best against Phomopsis longanae Chi. The extract had the highest inhibitory effect when extracted by 75%ethanol for 48 hours at room temperature. Its minimum inhibitory concentration was 6.25 mg·mL-1 and minimal bactericidal concentration was 12.50 mg·mL-1 .