Research Of Antibacterial Activity Of Extracts From 35 Medicinal Plants

The Traditional Uygur Medicine records many Chinese herbs with bacteriostatic effects,and many of them still have not been systematically studied.This research assays the antibacterial capacities of 35 herbs extracts against 14 standard strains in vitro,as well as finding synergizing drug combinations,aiming to provide insights into the development of new kinds of medicine.The main contents of this research are listed as follow:1.The 90%minimum inhibitory concentrations(MIC₉₀)of 35 herbs extracts were measured by Methylthiazolyldiphenyl-tetrazolium bromide（MTT）based colorimetric micro-broth dilution method.Xinjiang-planted Gentiana macrophylla,Rosa rugosa and Hippophae rhamnoides has significant antibacterial ability.All of the 35 herb extracts has certain antibactrtial effects.Glycyrrhiza uralensis has strong bactericidal effect on Gram-positive bacteria.Arnebia euchroma、Mentha canadaensis can inhibit Candida albicans.2.Using 3k Da ultra filtration centrifuge tubes,10 effective extracts were sieved apart to evaluate the MIC₉₀s of their large and small molecules respectively and to obtain the molecular weight range of the antibacterial active ingredients of these herb extracts.It was found that the main antibacterial active substances of Gentiana macrophylla,Picrorhiza scrophulariiflora and Kummerowia striata are macromolecular components above 3000Da.The antibacterial activity of Achillea millefolia is mainly derived from small molecular components below 3000Da.The large and small molecular components within Rosa rugosa,Glycyrrhiza uralensis,Carthamus tinctorius,Peganum harmala and Bergenia purpurascens have synergistic antibacterial effects.The antibacterial effect of Hippophae rhamnoides extract has nothing to do with molecules size,both large and small molecules has the same antibacterial effect as the original extract liquid.3.Synergizing drug combinations against 5 common clinical strains（Staphyloccus aureus,Escherichia coli,Klebsiella Pneumoniae,Pseudomonas aeruginos,Acinetobacter baumannii）were screened out.Gentiana macrophylla can synergize with Ceftazidime to enhance its antibacterial effect on Escherichia coli,while Hippophae rhamnoides with chloramphenicol on Pseudomonas aeruginos.Achillea millefolium can synergize with a variety of antibiotics to inhibit Klebsiella Pneumoniae.4.By comparing self-made and market-bought Gentiana macrophylla,Rosa rugosa,and Glycyrrhiza uralensis extracts,it is founded that self-made extracts has a better anti-bacterial effect on Staphyloccus aureus、Bacillus subtillis、Klebsiella Pneumoniae、Acinetobacter baumannii、Streptococcus pyogenes.The antibacterial effects of 35 herbs extracts on 14 standard strains are comprehensively evaluated and the drug combinations that can inhibit 5 common clinical strains are generally summarized;The antibacterial effect of self-made and market-bought Gentiana macrophylla,Rosa rugosa,and Glycyrrhiza uralensis extracts are compared,which lays the foundation for the development of Xinjiang-planted herbal medicine.