Abstract: Optimization of the extracting method of chlorogenic acid from Flos Lonicerae was studied by several different methods. Two different ways of Ultraviolet (UV) and Visible Spectrophotometr and High Performance Liquid Chromatography (HPLC) have been carried out for the quantitative and qualitative determination of chlorogenic acid in Flos Lonicerae. Inhibition test against pathogenic bacteria has been done with Flos Lonicerae ethanol and chlorogenic acid. The results of chlorogenic acid extraction showed that chlorogenic acid tiptop absorb-apex was 324nm, with ethanol of 70% concentration extraction was remarkably superior to other methods. The content of chlorogenic acid with 70% ethanol extraction was 43.35%, so the ethanol with 70% concentration extraction was the optimum condition. The antibacterial action of chlorogenic acid on Escherichia in vitro Coliand extracted with 70% ethanol from Flos Lonicerae showed that Flos Lonicerae had strong antimicrobial activity.

Key words: Flos Lonicerae, chlorogenic acid, extraction, examination, antimicrobial activity