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Advances in the Development of Antibacterial Composites
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Suping Wang, Haohao Wang, Xuedong Zhou, Jiyao Li, Libang He, Lei Cheng
The anti-biofilm mechanism of QAMs is that quaternary ammonium can lead to bacterial lysis by adhering to the cell membrane to produce cytoplasmic leakage (Beyth et al. 2006; Namba et al. 2009). Novel resin composites with QAMs were demonstrated to effectively hinder bacterial and biofilm growth, in that QAMs are covalently bonded with the resin polymer structure and immobilized in the resin, exerting contact inhibition against adherent bacteria (Imazato et al. 2012; Liu et al. 2016). Quaternary ammonium polyethyleneimine (QPEI) nanoparticles immobilized in resin-based materials were proven to have a strong antibacterial activity upon contact, without leaching-out of the nanoparticles and without compromising the mechanical properties (Beyth et al. 2006). QPEI incorporation resulted in 70% viable bacterial reduction in vivo. Furanone-containing composites revealed an increased antibacterial function against S. mutans viability when 5%–30% of furanone derivatives were added (Weng et al. 2012).
Infrared Spectroscopy
Published in Adorjan Aszalos, Modern Analysis of Antibiotics, 2020
Polymorphism is of importance because of the impact of this physical property on the bioavailability of solid dosage forms. Infrared spectroscopy, along with other tools, such as differential thermal analysis and x-ray diffraction, has been used to shed light on this property of some drug substances. Pelizza and coworkers [81] studied the polymorphism of rifampicin (Figure 12). Two crystalline modifications, one amorphous form, Hydrogen bonding in rifampicin. (Adapted from Reference 81.)and four solvates were studied. The infrared data on the major bands of these various forms are summarized in Table 10. That the functions that can be involved in the H bonding do not change in CDCI3 solution indicate that such H bonding is intramolecular. The C-21 hydroxyl is H bonded to the C-23 hydroxyl, which in turn is H bonded to the C-25 acetyl. The C- 8 hydroxyl is H bonded to the C-l hydroxyl, which in turn is bonded to the amide carbonyl. The C-4 hydroxyl is bonded to the furanone carbonyl and the amide NH to the imine nitrogen of the substituent at C-3. These interactions are indicated in Figure 9. The spectrum of form I indicates that, in this crystal, the C-23 hydroxyl is not H bonded to the acetyl group, as indicated by the acetyl frequency at 1725 cm−1 and the OH at 3550, although H bonding is seen at other possible sites. In form II, on the other hand, C-4 OH is not H bonded to the furanone carbonyl and the C-1 OH-amide carbonyl interaction is lacking. The IR spectrum of the amorphous form indicates that it is a mixture of that of form I and that found in CDCI3 solution. This implies two conformations of the acetyl group, which prevents formation of an ordered crystalline state.
Antibacterial Activity of Seaweeds and their Extracts
Published in Leonel Pereira, Therapeutic and Nutritional Uses of Algae, 2018
Lactones are a chemical class of cyclic esters, which includes furanones. The Australian red seaweed Delisea pulchra has been studied for its ability to remain free of surface bacterial colonization. Halogenated furanone extracts from D. pulchra have been used as effective surface sanitizers in the prevention of Pseudomonas aeruginosa biofilm formation. This halogenated furanone also inhibits quorum sensing mechanisms by interfering with bacterial inter-cell communication. In order for bacteria to express specific genes during quorum sensing, signaling molecules called acyl-homoserine lactones (AHLs) are required, as well as luminescence transcriptional activator (LuxR) regulatory proteins. The furanone extract frompulchra competes with AHL for the LuxR receptor site, thereby inhibiting virulence factor production and pathogenesis in Pseudomonas aeruginosa (Hentzer and Givskov 2003, Brameyer and Heermann 2015). Ren et al. (2004) found a similar inhibition of quorum sensing in Escherichia coli with a (5Z)4-bromo-5-(bromomethylene)-3-butyl-2(5H)-furanone extract from D. pulchra. Quorum sensing in Escherichia coli was inhibited by blocking S-ribosylhomocysteine lyase (LuxS) mediated AI-2 signaling. This influences genes and proteins involved in the normal production of flagellar synthesis, motility, and chemotaxis in the bacterium. Manefield et al. (2001) identified another mechanism of inhibition exerted by a halogenated furanone from D. pulchra. The bacterium, Erwinia carotovora, produces carbapenem as a virulence factor during quorum sensing. A commercially available 4-bromo-5-(bromomethylene)-3(1’-hydroxybutyl)-2(5H)-furanone was found to inhibit carbapenem production in Erwinia carotovora by disrupting the 3-oxo-C6-HSL dependent expression of the car ABCDEFG Hoperon. Castillo et al. (2015) also reported that a commercially produced furanone, similar to the D. pulchra extract, was effective against GramCampylobacter jejuni. When combined with epigallocatechin gallate from green tea and a citric acid extract, AI-2 activity, bacterial motility, and biofilm formation was significantly decreased.
Liver X receptor: a potential target in the treatment of atherosclerosis
Published in Expert Opinion on Therapeutic Targets, 2022
Shreya R. Savla, Kedar S Prabhavalkar, Lokesh K Bhatt
More recently, Li and team demonstrated the in vitro effects of furanone from a marine source against hyperlipidemia, which included lowering of ox-LDL, TGs, elevating expression of ABC transporters A1, G1, G5, G8, LDLR, and reducing the expression of SREBP-1c. Together, they concluded that furanone had anti-atherogenic effects by targeting LXRs [97]. The molecular mechanism for ABCA1/G1 expression in mouse macrophages by nobiletin, a functional component of citrus peel, was elucidated by Tsuboi et al. Their study reveals that AMPK activation by nobiletin causes LXRα transcription, which subsequently increases the transcription of ABCA1/G1 in HDL biosynthesis. This pathway, activated by nobiletin, for expression of ABCA1/G1 undergoes amplification by the PPARγ-LXRα loop [98].
Marine natural products as antifouling molecules – a mini-review (2014–2020)
Published in Biofouling, 2020
Ling-Li Liu, Chuan-Hai Wu, Pei-Yuan Qian
Nine structurally similar compounds (183–192, Figure S7) were tisolaed from Streptomyces strains and evaluated for their AF activity against major fouling organisms. Their potency is listed in Table 2. Analysis of structure-activity relationship suggested that the functional moiety responsible for AF activity lay in the 2-furanone ring and the lipophilicity of the compounds substantially affects their AF activities. On the basis of these findings, a compound with a straight alkyl side chain, butenolide (192, Figure S7), was synthesized and proven to be a very effective nontoxic, anti-larval settlement agent against three major fouling organisms (Table 3). Furthermore, 192 displayed potent AF activity when applied to marine paint, with around a 70% decrease in the coverage of biofoulers in comparison with the control. The strong AF activity, relatively low toxicity, and the simple structure of butenolide make it a promising candidate as a new AF additive (Xu et al. 2010).
Quorum sensing inhibitors: a patent review (2014–2018)
Published in Expert Opinion on Therapeutic Patents, 2018
Xin Chen, Likun Zhang, Mingxiang Zhang, Huayu Liu, Panrui Lu, Kejiang Lin
It was found that Delisea pulchra produces furanone compounds that bind to LuxR, thus suppressing the effect of AHLs [31]. Furanone 45 and furanone C-30 has been reported to be potent inhibitors against QS [32,33]. Recently, Sun et al. proposed that another furanone is a QSI and measured its activity against P. aeruginosa. It was found that compound 8, with the minimal inhibitory concentrations (MICs) of 32, 64 and 32 μg/mL against of ATCC27853, ATCC9027, and PAOA strains respectively, was the most potent inhibitor among the compounds synthesized, and more than 80% of the biofilm was inhibited in the three strains when the concentration of compound 8 is the quarter of the MIC (Figure 3) [34]. In addition, Kim et al. synthesized a series of brominated furanone derivatives and evaluated their inhibitory effects on Fusobacterium nucleatum. It was found that the QS of F. nucleatum was inhibited without significant cytotoxicity toward the host, making them possible candidate drugs for oral and dental infection [35]. Guo et al. synthesized five furanone derivatives and assessed their biological activities against P. aeruginosa and crop diseases. Compound 4 exhibited the greatest potency with a MIC value of 32 μg/mL against P. aeruginosa ATCC9027 (Figure 3) [36].