title: Antibacterial Activities and Antibacterial Mechanism of Polygonum cuspidatum Extracts against Nosocomial Drug-Resistant Pathogens.
abstract: Recently, drug resistance due to the extensive abuse and over-use of antibiotics has become an increasingly serious problem, making the development of alternative antibiotics a very urgent issue. In this study, the Chinese herbal medicine, Polygonum cuspidatum, was extracted with 95% ethanol and the crude extracts were further purified by partition based on solvent polarity. The antimicrobial activities of the extracts and fractions were determined by the disk diffusion and minimum inhibitory concentration (MIC) methods. The results showed that the ethyl ether fraction (EE) of the ethanol extracts possesses a broader antimicrobial spectrum and greater antimicrobial activity against all of the tested clinical drug-resistant isolates, with a range of MIC values between 0.1-3.5 mg/mL. The active extract showed complete inhibition of pathogen growth and did not induce resistance to the active components. In addition, according to scanning electron microscope observations, EE resulted in greater cell morphological changes by degrading and disrupting the cell wall and cytoplasmic membrane, whereby ultimately this cell membrane integrity damage led to cell death. In conclusion, the EE extracts from Polygonum cuspidatum may provide a promising antimicrobial agent for therapeutic applications against nosocomial drug-resistant bacteria.
authors.affiliation: Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan. evangelion_0723@yahoo.com.tw.
authors.forename: Pai-Wei
authors.initials: PW
authors.lastname: Su
authors.affiliation: Department of Electronic Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan. chyang@cc.kuas.edu.tw.
authors.forename: Cheng-Hong
authors.initials: CH
authors.lastname: Yang
authors.affiliation: Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan. jfyang@isu.edu.tw.
authors.forename: Jyh-Ferng
authors.initials: JF
authors.lastname: Yang
authors.affiliation: Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan. evangelion_0723@yahoo.com.tw.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Su
authors.affiliation: Institute of Biotechnology and Chemical Engineering, I-Shou University, Kaohsiung 840, Taiwan. chuang@isu.edu.tw.
authors.forename: Li-Yeh
authors.initials: LY
authors.lastname: Chuang
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001424:Bacterial Infections / Q000188:drug therapy / Q000382:microbiology; D003428:Cross Infection; D052978:Disk Diffusion Antimicrobial Tests; D024881:Drug Resistance, Bacterial; D045468:Fallopia japonica / Q000737:chemistry*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts
keywords: Polygonum cuspidatum; antibacterial activity; clinical drug-resistant bacteria