title: Thermochemical studies on the quantity-antibacterial effect relationship of four organic acids from Radix Isatidis on Escherichia coli growth.
abstract: In this report, we have investigated the inhibitory action of four organic acids from Radix Isatidis on Escherichia coli growth was investigated at 37 degrees C by using a microcalorimeter. The four organic acids were: syringic acid, 2-amino-benzoic acid, salicylic acid, benzoic acid. In accordance with thermokinetic model, the pertaining relationships of the drugs, such as growth inhibitory ratio vs. concentration, maximal power-output vs. growth rate constant, growth rate constant vs. concentration, were obtained. Half-inhibitory concentration of the drugs, IC(50), was obtained by quantitative analysis. From the view of thermodynamics and molecular structure, the relationship between quantity and effect of the four organic acids has been discussed. The functional groups on phenyl ring had important influence on the antibacterial activities. Our work suggests that microcalorimetry is a fast, simple and more sensitive method that can be easily performed and applied to study the anti-bacterial activities of organic acids from Radix Isatidis on microorganism compared to other biological methods.
authors.affiliation: Institute of Chinese Materia Medica, 302 Hospital of People's Liberation Army, Beijing, China.
authors.forename: Weijun
authors.initials: W
authors.lastname: Kong
authors.forename: Yanling
authors.initials: Y
authors.lastname: Zhao
authors.forename: Limei
authors.initials: L
authors.lastname: Shan
authors.forename: Xiaohe
authors.initials: X
authors.lastname: Xiao
authors.forename: Weiying
authors.initials: W
authors.lastname: Guo
mesh_terms: D000143:Acids / Q000737:chemistry / Q000494:pharmacology; D000465:Algorithms; D000900:Anti-Bacterial Agents; D002151:Calorimetry; D002701:Chloramphenicol / Q000494:pharmacology; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development*; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D000143:Acids; D000900:Anti-Bacterial Agents; D004365:Drugs, Chinese Herbal; D002701:Chloramphenicol