黄芩提取物对嗜水气单胞菌抑菌活性和机制的研究

Study on bacteriostatic activity and mechanism of scutellaria baicalensis against Aeromonas hydrophila

嗜水气单胞菌是我国淡水养殖重要病原菌,中草药因其天然安全性和良好的抑菌特性作为潜在抗生素替代品而成为水产养殖防治领域的研究热点.分别采用水提法和醇提法制备四种中草药(黄芩、乌梅、野菊花、凤尾草)的浸提液,通过滤纸片扩散法测定对嗜水气单胞菌的抑菌效果,筛选出对嗜水气单胞菌抑菌效果较明显的中草药,通过二倍稀释法测定其最低抑菌浓度,并对其抑菌机制进行研究.实验结果显示:四种中草药提取物对嗜水气单胞菌均具有一定抑菌效果,其中黄芩提取物抑菌效果最强.黄芩水提物MIC为0.125 g/mL,醇提物MIC为0.25 g/mL;经MIC浓度黄芩水提物处理之后,嗜水气单胞菌电导率上升,细胞膜通透性提高;胞内碱性磷酸酶外泄,细胞壁完整性受损;胞外蛋白质含量增加;可见黄芩提取物主要通过破坏细胞膜和细胞壁来实现对嗜水气单胞菌的抑菌作用.为新型嗜水气单胞菌抑菌剂的开发奠定理论基础.

Aeromonas hydrophila is an important pathogen in freshwater aquaculture in China.Chinese herbal medicine has become a research hotspot in the field of aquaculture control because of its natural safety and good bacteriostatic properties as potential antibiotic substitutes.The Chinese herbal medicine with strong antibacterial effects against Aeromonas hydrophila was screened from four candidates,including Scutellaria baicalensis,Fructus mume,Chrysanthemum indicum,and Pteris multifida Poir,by determining the sensitivity of water extract and alcohol extract from the candidates to Aeromonas hydrophila,with the method of filter paper diffusion method.The results showed that all the extracts from the four Chinese herbal medicines had certain antibacterial effects on Aeromonas hydrophila,among them the extracts from Scutellaria baicalensis had the best antibacterial activity.The MIC is 0.125 g/mL and 0.25 g/mL for water extract and alcohol extract from Scutellaria baicalensis,respectively.Aeromonas hydrophila treated with Scutellaria baicalensis water extract in MIC showed increasing conductivity,intracellular alkaline phosphatase leaks,and extracellular protein content,indicating the increasing cell membrane permeability and cell wall damage,and it can be seen that Scutellaria baicalensis extract inhibited Aeromonas hydrophila mainly by destroying cell membrane and cell wall.This study laid a theoretical foundation for the development of a new bacteriostatic agent for Aeromonas hydrophila.