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Background and Objective: Today, a new β-coronavirus called SARS-CoV-2 has emerged and it is causing a global pandemic. Inter-human transmission studies have indicated a significant role of aerosols in the transmission of many respiratory viruses. Hence, it is very important to decrease the spread of the virus through disinfectant agents. This review aimed to provide an overview related to possible alternative inhibitory molecules against this virus. Method: The literature search was performed in the MEDLINE electronic database using the public access known as NCBI-PUBMED. Keywords "coronavirus" and “SARS-CoV-2” and “COVID19” were used. No specific time range was used. Results: We provide a review related to structure, anti-coronavirus activity and molecular mechanism of natural substances and semisynthetic derivatives such as glycopeptides, lipopeptides, probiotics, surfactants, terpenes and resveratrol. We also include the latest in vitro experiments with anti-SARSCoV- 2 activity. We also provide the theoretical basis for discussing the prospects of such natural molecules as possible alternative anti-Coronavirus products, so as to develop a complete screening for future applications. Conclusion: In summary, this review suggest to investigate deeper several molecules most of which belong to natural substances to fight COVID19 disease.

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. Higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases, the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to the presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

Nowadays, consumers have become increasingly attentive to human health and the use of more natural products. Consequently, the demand for natural preservatives in the food industry is more frequent. This has led to intense research to discover new antimicrobial compounds of natural origin that could effectively fight foodborne pathogens. This research aims to safeguard the health of consumers and, above all, to avoid potentially harmful chemical compounds. Lactobacillus is a bacterial genus belonging to the Lactic Acid Bacteria and many strains are defined GRAS, generally recognized as safe. These strains are able to produce substances with antibacterial activity against food spoilage bacteria and contaminating pathogens: the bacteriocins. The aim of this review was to focus on this genus and its capability to produce antibacterial peptides. The review collected all the information from the last few years about bacteriocins produced by Lactobacillus strains, isolated from clinical or food samples, with remarkable antimicrobial activities useful for being exploited in the food field. In addition, the advantages and disadvantages of their use and the possible ways of improvement for industrial applications were described.

Background: The class of fluoroquinolone antibiotics, due to its core chemical modifications, is considered as wide-spectrum antibacterial drugs with useful pharmacokinetic and pharmacodynamic properties. However, because of their poor solubility in water, they are used as salts (lactates or hydrochlorides). Fluoroquinolones, bacterial membranes and eukaryotic cell membranes interactions are well known and their permeation properties are well investigated. In fact, they are concentrated inside the cells and intracellular compartments. Nanotechnology in Drug Delivery has developed many supra-molecular structures that have been used to improve both pharmacokinetic and pharmacodynamic properties. The main results of the published papers showed reduction of toxicity, higher intracellular concentrations (both bacteria and eukaryotic), enhancement of antimicrobial activity, prolonged drug release, decreased mortality in animal model studies, improved water solubility and improved in vitro efficacy against intracellular pathogens. Methods: a literature search was performed in the NCBI-PUBMED database, with no time range, using the keywords "solid lipid nanoparticles" and ‘quinolones’ or the name of single antibiotics. Results: the most important aspects of lipid-based nanocarrier technology used for fluoroquinolones have been highlighted, with a focus on the latest formulation developments that have led to significant improvements of pharmacokinetics and pharmacodynamics. Both technological and microbiological aspects of published papers have been discussed. Conclusion: the potentiality of using lipid nanoparticles to improve the efficacy and potency of quinolone antibiotics has been supported by recent scientific publications, although some criticism appeared due to the microbiological investigative methods used and because of lack of systematic evaluation about the influence of technological approaches to the in vitro and in vivo drug activity.

ABSTRACTDifferent ofloxacin-loaded unilamellar vesicles were prepared by the extrusion technique, and their antimicrobial activities were determined in comparison to those of the free drug by means of MIC determinations with both American Type Culture Collection standards and wild-type bacterial strains (six strains of Enterococcus faecalis, seven strains of Escherichia coli, six strains of Staphylococcus aureus, and six strains ofPseudomonas aeruginosa). The accumulation of ofloxacin and liposome-ofloxacin was measured by determining the amount of the drug inside the bacteria as a function of time. Encapsulated fluoroquinolone yielded MICs which were at least twofold lower than those obtained with the free drug. In particular, liposomes made up of dimyristoylphosphatidylcholine-cholesterol-dipalmitoylphosphatidylserine and dimyristoylphosphatidylcholine-cholesterol-dihexadecylphosphate (4:3:4 molar ratio) provided the best improvement in antimicrobial activity against the various bacterial strains investigated. The liposome formulation produced higher intracellular fluoroquinolone concentrations than those achieved simultaneously with the free drug in both E. coliand P. aeruginosa.

The influence exerted by the antimicrobial and antimicotic nonapeptide Leucinostatin A (Leu A) on a biological membrane model made up of dipalmitoylphosphatidylcholine (DPPC) was investigated. Drug–membrane interactions, studied by means of differential scanning calorimetry and Fourier-transform infrared spectroscopy, depend on the behavior of the molecule which positions its hydrophilic part toward the bilayer phospholipid polar heads, while it inserts its hydrophobic portion into the membrane phospholipid acyl chain moiety. Calorimetric experiments showed that the peptide undergoes self-aggregation within the bilayer structure when present at molar fractions higher than 0.03. Peptide–membrane interactions as a function of time were analyzed as well. The latter demonstrated that Leu A inserts rapidly into the outer bilayers of DPPC membranes. 45Ca2+uptake by DPPC vesicles gave a reason for the ionophoric activity of Leu A against both mouse thymocytes and artificial membranes, which seems to be correlated to the self-assembling property of the peptide within the bilayers.

The entrapment of fluoroquinolones, perfloxacine mesilate (PFX) and ofloxacin (OFX), in polyalkylcyanoacrylate (PECA) nanoparticles could offer some advantages for their biological application; for examples, increasing their bioavailability, controlling the drug time-release in blood, and reducing the formation of bacterial resistance. To load these two drugs in PECA polymeric bulk, the incorporation or adsorption method was performed. These two methods were capable of influencing nanoparticle size, molecular weight, release profile, and drug–polymer association. The incorporation method, particularly for the OFX system, achieved PECA nanoparticle suspensions with a mean size value three times higher than that obtained in the absence of the drug. In contrast, negligible changes were observed for PFX systems. This preparation process also influenced the nanoparticle storage stability. The molecular weight values of the various nanoparticle preparations were also influenced; that is, the PFX-loaded systems showed an enhancement in the average molecular weight values, whereas a reduction was observed for OFX-loaded systems. The adsorption method showed no particular difference in particle size, molecular weight, and storage stability compared with nanoparticles prepared without the drugs. The nanoparticle loading capacity was higher for the colloidal systems obtained following the incorporation preparation procedure. The release of drug from the nanoparticles was biphasic for both preparation processes. The fluoro-quinolone-loaded nanoparticles showed an enhancement of the antimicrobial activity against standard bacteria strains from 2- to 50-fold compared with the free drugs.