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Antibacterial activity

Sheng-Yuan Zhang, Wen Li, Hua Nie, Mei Liao, Bo Qiu, Ya-Li Yang, Yan-Fen Chen
Five new quinolizidine alkaloids, including three sparteine-type alkaloids (1-3) and two cytisine-type alkaloids (4-5), along with four known ones, were isolated from the roots of Sophora flavescens. Their structures were determined by extensive spectroscopic techniques including IR, UV, NMR and HR-ESI-MS. All the compounds were evaluated for their antibacterial activities against Staphylococcus aureus and Escherichia coli. This article is protected by copyright. All rights reserved.
January 22, 2018: Chemistry & Biodiversity
Han-Chi Tseng, Chun-Bing Chen, Ji-Chen Ho, Yu-Wen Cheng, Hsin-Wei Huang, Pei-Lun Sun, Chih-Hung Lee
BACKGROUND: Protothecosis is an uncommon infection caused by the achlorophyllic algae found more commonly in tropical areas. Only a limited number of cases have been reported. OBJECTIVE: We aimed to evaluate the clinicopathological features and treatment outcomes of cutaneous protothecosis. METHODS: We retrospectively identified 20 pathology-confirmed cases of cutaneous protothecosis based on skin biopsies in two tertiary medical centers in Taiwan from 1997 to 2015...
January 22, 2018: Journal of the European Academy of Dermatology and Venereology: JEADV
Kai-Bo Wang, Xu Hu, Sheng-Ge Li, Xin-Yu Li, Da-Hong Li, Jiao Bai, Yue-Hu Pei, Zhan-Lin Li, Hui-Ming Hua
Five pairs of new 2-oxoindole alkaloids, (±)-peganumalines A-E (1-5), and a new indole alkaloid, peganumaline F (6), along with two known analogues, were isolated from the seeds of Peganum harmala. Their structures and absolute configurations were elucidated through spectroscopic analyses and quantum chemistry calculations. Notably, (±)-peganumalines A (1) represent a pair of rare 2-oxoindole dimeric alkaloid enantiomer with the hitherto unknown carbon skeleton. All isolates were tested for antiproliferative and antibacterial activities...
January 17, 2018: Fitoterapia
Changxuan Shao, Haotian Tian, Tianyu Wang, Zhihua Wang, Shuli Chou, Anshan Shan, Baojing Cheng
Although membrane lytic antimicrobial peptides (AMPs) show enormous potential for addressing mounting global antibiotic resistance, therapeutic applications are hindered by their weak antimicrobial activity, high toxicity, salt sensitivity and poor understanding of structure-activity relationships. To investigate the effects of different parameters on the biological activities of AMPs, a rational approach was adopted to design a series of short cationic α-helical peptides comprising the Ac-WxKyWxzzyKxWyK-NH2 sequence, where x: cationic residues (Arg or Lys), y: hydrophobic residues (Ala, Val, Ile or Leu), and zz: β-turn (rigid D-Pro-Gly turn or flexible Gly-Gly turn)...
January 16, 2018: Acta Biomaterialia
Aleksandar Bijelic, Manuel Aureliano, Annette Rompel
Polyoxometalates (POMs) are, mostly anionic, metal oxide compounds that span a wide range of tunable physical and chemical features rendering them very interesting for biological purposes, an continuously emerging but little explored field. Due to their biological and biochemical effects, including antitumor, -viral and -bacterial properties, POMs and POM-based systems are considered as promising future metallodrugs. In this article, we focus on the antibacterial activity of POMs and their therapeutic potential in the battle against bacteria and their increasing resistance against pharmaceuticals...
January 22, 2018: Chemical Communications: Chem Comm
Yanli Niu, Tiantian Guo, Xiaoyan Yuan, Yunhui Zhao, Lixia Ren
Silver nanoparticles (AgNPs) show long-lasting and broad-spectrum antibacterial activity. Herein, PEGylated AgNPs were prepared in situ by complexing AgNO3 with the random copolymer of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and polyacrylic acid via electrostatic interaction followed by in situ reduction. AgNP hybrid supramolecular hydrogels were thus prepared through host-guest inclusion between PEGMA side chains and α-cyclodextrins in aqueous solution. The hydrogels were physically cross-linked by both pseudopolyrotaxane crystallization and AgNPs, which showed temperature responsiveness and self-healing properties...
January 22, 2018: Soft Matter
Afrah E Mohammed, Fadwa F Bin Baz, Jehan S Albrahim
In the current study, extracellular biosynthesis of silver nanoparticles (AgNPs) was carried out using aqueous extracts of green Calligonum comosum stem, besides Fusarium sp. Synthesized AgNPs were characterized using ultraviolet (UV)-Vis spectrophotometer, transmission electron microscopy (TEM) and zeta potential. Moreover, biosynthesized AgNPs were estimated for the scavenging ability on DPPH radical as well as tested for their antibacterial activity using well diffusion method against Gram-positive bacteria Staphylococcus aureus...
January 2018: 3 Biotech
Sha Liu, Li Jing, Zhu-Jun Yu, Chengyong Wu, Yongxiang Zheng, En Zhang, Qiang Chen, Yamei Yu, Li Guo, Yong Wu, Guo-Bo Li
The emergence and global spread of metallo-β-lactamase (MBL) mediated resistance to almost all β-lactam antibacterials poses a serious threat to public health. Since no clinically useful MBL inhibitors have been reported, there is an urgent need to develop new potent broad-spectrum MBL inhibitors effective against antibacterial resistance. Herein, we synthesized a set of 2-substituted ((S)-3-mercapto-2-methylpropanamido) acetic acid derivatives, some of which displayed potent inhibition with high ligand efficiency to the clinically relevant MBL subtypes, Verona Integron-encoded MBL (VIM)-2 and New Delhi MBL (NDM)-1...
January 11, 2018: European Journal of Medicinal Chemistry
Daniel Manoil, Norbert Lange, Serge Bouillaguet
Rose Bengal-acetate (RB-Ac) is a pro-photosensitizer claimed to diffuse into target cells, where the acetate groups are hydrolyzed and the photosensitizing properties of Rose Bengal (RB) are restored. Despite promising results on tumor cells, the interaction of RB-Ac with bacteria has never been investigated. This study aimed to assess the interaction of RB-Ac with Enterococcus faecalis and to evaluate its potential use in antimicrobial photodynamic therapy (aPDT). Spectrofluorometry was used to assess the ability of E...
January 11, 2018: Journal of Photochemistry and Photobiology. B, Biology
Ali Mohammadi Bardbari, Mohammad Reza Arabestani, Manoochehr Karami, Fariba Keramat, Hossein Aghazadeh, Mohammad Yousef Alikhani, Kamran Pooshang Bagheri
The rapid increase of drug resistance and failure of available antibiotics to treat biofilm-associated infections is of great health concern. Accordingly, our study aimed to evaluate the synergistic antibacterial, biofilm inhibitory, and biofilm removal activities of melittin in combination with colistin, imipenem, and ciprofloxacin against multidrug-resistant (MDR) strong biofilm producer Acinetobacter baumannii isolates. The kinetics of biofilm formation were evaluated for the isolates for 144 h. Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum biofilm inhibitory concentrations (MBICs), and biofilm removal activities for melittin and combinations with antibiotics were determined...
January 20, 2018: European Journal of Clinical Microbiology & Infectious Diseases
Debprasad Chattopadhyay, Durbadal Ojha, Hemanta Mukherjee, Paromita Bag, Shatrughna Prasad Vaidya, Shanta Dutta
Shorea robusta Gaertn has been used for skin and intestinal ailments in Indian Traditional medicine; while two tribal communities used its tender leaves in 'Meyadi-bukhar' or long-term fever. This prompted us to validate the aqueous and methanol extracts of Shorea robusta tender leaves against wild- and multidrug-resistant clinical isolates of Salmonella enterica Serovar Typhi (S. Typhi), the causative agent of typhoid fever. The antibacterial activity, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and growth inhibition were determined using disc diffusion, agar-and-broth dilution, dose- and time-response assays, along with the safety and protective efficacy in Balb/C mice, infected with S...
January 17, 2018: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
Yue Wang, Xiao-Wen Zhang, Hui Wang, Wen-Hong Fang, Hongyu Ma, Fengxia Zhang, Yuan Wang, Xin-Cang Li
Type I crustins are crucial effectors of crustacean immune system. Various type I crustins with high sequence diversity possess different antimicrobial activities. To date, the mechanism on how the sequence diversity of type I crustins affects their antimicrobial activities is largely unclear, and how different crustins function together against bacterial invasion still remains unknown. In this study, we identified two novel type I crustins, namely, SpCrus3 and SpCrus4, from an economically important crab, Scylla paramamosain...
January 15, 2018: Developmental and Comparative Immunology
Xiaoqing Cai, Lele Guo, Fei Pei, Xiaoyun Chang, Rui Zhang
Plant natural products have long been considered to be important sources of bioactive molecules. A large number of antimicrobial and anticancer agents have been isolated form plants. In the present study we evaluated the antimicrobial and anticancer activity of a plant derived secondery metabolite, Polyphyllin G. The results of antibacterial assays showed that Polyphyllin G prevented the growth of both Gram-positive and Gram-negative bacteria with minimum inhibitory concentrations (MICs) ranging from 13.1 to 78 μg/ml...
January 15, 2018: Archives of Biochemistry and Biophysics
Yuping Bao, Hao Zhang, Qian Luan, Mingming Zheng, Hu Tang, Fenghong Huang
Antibacterial and antioxidant chitosan-xylan/cellulose nanowhiskers (CNW) nanocomposite films were successfully prepared using CNW as nanofillers. The structure and morphology of the nanocomposite films were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), and scanning electron microscopy (SEM). The optical transmittance, thermal stability, mechanical property, and swelling property of the nanocomposite films were also evaluated. These results revealed the microstructure of the films and confirmed the good miscibility between chitosan-xylan and CNW...
March 15, 2018: Carbohydrate Polymers
Muhammad Salman Sarwar, Muhammad Bilal Khan Niazi, Zaib Jahan, Tahir Ahmad, Arshad Hussain
Antimicrobial packaging is an area of emerging interest and is rapidly expanding with application of nanotechnology. The present work investigates the effect of nanocellulose (NC) and Ag NPs on the physical, mechanical and thermal properties of PVA nanocomposite films. The tensile strength of PVA was improved from 5.52 ± 0.27 MPa to 12.32 ± 0.61 MPa when filled with 8 wt% of NC. Nanocomposite films exhibited strong antibacterial activity against both Staphylococcus aureus (MRSA) and Escherichia coli (DH5-alpha)...
March 15, 2018: Carbohydrate Polymers
Imran Khan, Charles Nkufi Tango, Sumaira Miskeen, Deog-Hwan Oh
Nisin-loaded chitosan-monomethyl fumaric acid (CM-N) nanoparticles were evaluated as a novel, direct food additive. Chitosan (CS) was modified with monomethyl fumaric acid (MFA) in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). CS-loaded nisin (CS-N) and CM-N nanoparticles were produced through ionic interactions between the positive amino group of CS and CS-MFA and negative tripolyphosphate ions. The resultant materials were characterized by TNBS assay, X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, and zeta potential analysis...
March 15, 2018: Carbohydrate Polymers
Honglei Chen, Guangqian Lan, Luoxiao Ran, Yang Xiao, Kun Yu, Bitao Lu, Fangying Dai, Dayang Wu, Fei Lu
A novel Konjac glucomannan/silver nanoparticle (KGM/AgNP) composite sponge was successfully prepared via a simple 2-step method for biomedical applications as wound-healing materials. First, AgNPs were prepared with green deoxidizer egg white. Then, KGM powder was added to the AgNP solution and stirred vigorously, and the composite sponge was obtained by freeze-drying. The KGM/AgNP composite sponge showed excellent water absorption and water retention, and considerable mechanical properties. KGM/AgNP composite sponges displayed good antibacterial activity against test microorganisms...
March 1, 2018: Carbohydrate Polymers
R Palankar, T P Kohler, K Krauel, J Wesche, S Hammerschmidt, A Greinacher
BACKGROUND: Activated platelets release the chemokine platelet factor 4 (PF4) stored in their granules. PF4 binds to polyanions (P) on bacteria, undergoes a conformational change and exposes neoepitopes. These neoepitopes induce production of anti-PF4/P antibodies. As PF4 binds to a variety of bacteria, anti-PF4/P IgG can bind and opsonize several bacterial species. OBJECTIVE: Here we investigated whether platelets are able to kill bacteria directly after recognizing anti-PF4/P IgG opsonized bacteria in the presence of PF4 via their FcγRIIA...
January 19, 2018: Journal of Thrombosis and Haemostasis: JTH
Grazia Totaro, Laura Sisti, Annamaria Celli, Irene Aloisio, Diana Di Gioia, Adam A Marek, Vincent Verney, Fabrice Leroux
Nanocomposites based on poly(butylene succinate) (PBS) and hydrotalcite-type anionic clays (HTs) organo-modified with biomolecules characterized by antibacterial and/or antioxidant activities, such as l-ascorbic acid (ASA), phloretic acid (HPP), l-tyrosine (TYR) and l-tryptophan (TRP), have been prepared by in situ polymerization. From XRD analysis and rheology experiments in a molten polymer state, intercalated HT hybrid platelets acting here as a hybrid filler are found to be well dispersed into polymers while providing a chain extension effect on PBS...
January 19, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
Felipe Viela, Iván Navarro-Baena, Jaime J Hernández, Manuel R Osorio, Isabel Rodriguez
The rapid emergence of antibiotic resistant bacteria has prompted the need for radically different approaches to combat bacterial infections. Among these, bioinspired surface topographies have emerged as an effective sustainable strategy to deter bacterial infection. This study demonstrates the bactericidal activity and cytocompatibility of the moth eye mimetic topography produced by thermal polymer nanoimprinting. The moth eye topography was found to have bactericidal capabilities against Gram negative and Gram positive bacteria...
January 19, 2018: Bioinspiration & Biomimetics
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