五倍子提取物有效成分含量分析与体外抑菌活性比较

Quantitative analysis and comparison of the potential anti-bacterial active components of Galla chinensis extract in vitro

关键词:  五倍子提取物  抑菌活性成分  含量分析  抑菌活性比较

Key words:  Galla chinensis (GC)  active components  antibacterial activity

摘要:

传统中药五倍子(Galla chinensis, GC)被证明具有较好的抑菌效果,但其抑菌活性与活性成分之间的关联性不够明确。本研究采用大孔树脂从GC水提物(water extracts of GC, GCE)中分离五倍子单宁(gallotannins, GT)并收集大孔树脂脱GT后的剩余物(GTrE)；高效液相色谱法用于测定GCE中没食子酸(gallic acid, GA)和没食子酸甲酯(methyl gallate, MG)含量；然后通过最小抑菌浓度(minimum inhibitory concentration, MIC)法比较了GCE与其活性成分对耐药大肠杆菌(E. coli)和金黄色葡萄球菌(S. aureus)的抑菌活性,分析了活性成分含量与五倍子抑菌活性的关联性。结果表明,GCE对耐药E. coli和S. aureus具有显著的抑制作用。GT和GTrE与GCE的抑菌作用类似,两者在GCE中的含量分别为58.3%和22.8%,联合使用多呈现相加作用,对不同E. coli菌株的MIC范围为5-20 mg/mL；对不同S. aureus菌株的MIC范围为0.156-0.625 mg/mL。这提示GCE、GT和GTrE对S. aureus抑制的选择性更强。GA对上述两种菌的MIC范围为5-10 mg/mL,MG则为1.25-2.5 mg/mL,但GA和MG在GCE中的含量较低,分别为3.1665%和0.0899%。以上结果表明GCE具有显著的抑菌活性,GA和MG与其抑菌作用相似,但两者在GCE中的浓度远远低于它们的MICs。故推测含量较高的GT和GTrE或者未知组分的联合可能是五倍子发挥抑菌活性的主要成分。

Abstract:

Galla chinensis (GC) has been proved to have a good antibacterial effect, but the relationship between its antibacterial activity and active components is not clear. In this study, gallotannins (GT) were separated from GC water extracts of GC (GCE) by macroporous adsorption resin and GTRE was collected; The content of gallic acid (GA) and methyl gallate (MG) in GCE was determined by HPLC; Then, the inhibitory activity of GCE and its active components to E. coli and S. aureus was compared by the minimum inhibitory concentration (MIC) method, and the relationship between the content of active components and the antibacterial activity was analyzed. The results showed that GCE had significant inhibitory effects on drug resistant E. coli and S. aureus clinical isolates and its MIC was 8 mg/ml and 0.125 mg/mL, respectively. Their contents in GCE was 58.3% and 22.8%, and the combination of GCE and GCE to bacteria showed additive effect. The MICs of GT and GTrE to different E. coli strains range from 5 to 20 mg/mL, for different S. aureus strains, the range was 0.156-0.625 mg/mL indicating that GCE, GT and GTrE have stronger inhibiting selectivity for S. aureus. In addition, the MICs of GA to the two bacteria range from 5 to10 mg/mL, for MG, the range was 1.25-2.5 mg/mL, but the contents of GA and MG in GCE were only 3.1665% and 0.0899%, respectively. Therefore, the results suggested that GCE had significant antibacterial activity, GA and MG were similar to those of GCE, but their concentrations in GCE were far lower than their MICs. However, the high contents of GT and GTrE or unknown components and their combination may be the main components of gallnut to play antibacterial activity.