This book describes the manuscripts in the special issue of Antibiotics: "Natural Compounds as Antimicrobial Agents". This special issue contains two more papers on research into the use of natural compounds in animal production.
Efficacy and Mechanism of Traditional Medicinal Plants and Bioactive Compounds against Clinically
Introduction
These traditional medicinal plants or active compounds remain included as part of the common treatment of various diseases [9]. An electronic search was conducted using PubMed, Science Direct, and Google Scholar using the keywords “medicinal plant” AND “bioactive compounds” AND “antimicrobial activities” AND.
Traditional Medicinal Plants
21] Dichloromethane/ Metanol750–12,000μg/ml Dicomaanomala Sond.AsteraceaeTuberAqueous50–200μg/mLS.aureus,metisillienbestandeS.aureus, gentamisien–metisillienbestandeS.aureus,S. 21] Dichloromethane/ Metanol750–12,000μg/mL FicussurForssk.MoraceaeBark,LeavesAqueous,10–100mg/mLS.aureus,metisillienbestandS.aureus, gentamisien–metisillienbestand,S.
Bioactive Compounds (Bioactive Phytocomponents)
Emri BotanikFamilyExtractsPerformedBioactiveMIC*FrenuarOrganismsReferences Jatropha weddelliana BaillonEuphorbiaceaeHexanesGalicacid,kaemppherol,elagicacid,epikechin,vitexin,corilagin4–32µg/mLC.albicans 4-32µg/mLC. binoid,dronabinol,methyl-6-hydroxy1.25,1.5mg/mLS.aureus,E.coli,P. 100–800 µg/mL S.aureus,E.coli[99]Hexane8000µg/mL Acetone8000µg/mL n-butanol100–800µg/mL anine,Speciociliatine,Mytragine PaynantheineRhynchophylline128–256µg/mLS. Gries)WR Anderson.
Mechanism of Actions of Antibacterial Bioactive Compounds
Dihydrofolate reductase is a key enzyme for the synthesis of purine and pyrimidine rings of nucleic acid, resulting in reduced DNA, RNA and protein synthesis [156]. Such mechanisms include: (a) bacteria can share resistance genes by transformation, transduction and conjugation; (b) bacteria produce various enzymes to deactivate antibiotics by the process of phosphorylation, adenylation or acetylation; (c) damage or alteration of the active ingredient; (c) prevent the drug from interacting with the target; (d) secretion of the antibiotic from the cell [168–170].
Conclusions
The antibacterial activity of selected plants against resistant bacteria isolated from clinical samples. Asian Pac. Evaluation of the antimycobacterial activity of crude extracts and solvent fractions of selected Ethiopian medicinal plants.BMC complement.
Food Safety through Natural Antimicrobials
Natural Antimicrobials from Plants
These authors also investigated the effect of pH and different food ingredients on the activity of thyme and oregano against L. The anti-andidal activity of the main phenolic compounds of oregano (carvacrol at 0.1%) and clove (eugenol at 0.2%) essential oils was investigated by Chami et al. All strains were inhibited by concentrations of approx. 23-33 mM; concentrations of approx. 100 mM vanillic acid at pH>6.0 was not effective against the microorganisms, but with 10 mM at pH 5.0 the inhibition was complete.
108] and Gyawali and Ibrahim [2], “waste generated in the food processing industry could be incorporated into antimicrobial packaging or used as edible antimicrobial films”.
Natural Antimicrobials from Animals
Pleurocidin is a peptide with antimicrobial activity found in the skin secretions of winter flounder (Pleuronectes americanus) [112], and it is active against gram-positive and -negative bacteria such as E. The potential use of LPS in broth at 37◦C and minced meat preparations at 0, 6 and 12◦C was investigated by Kennedy et al. To study the role of the enzyme activity of lysozyme on its capacity against gram-positive bacteria (S. . aureus and Bacillus subtilis), Ibrahim et al.
Moreover, the mechanism of action also implies inhibition of enzymatic activity by the cell, impairment of nutrient uptake or peroxidation.
Natural Antimicrobials from Bacteria and Viruses: Biopreservation
Ming and Daeschel [234] evaluated gram-positive pathogenic and food spoilage bacteria for their resistance to aL-acquiring nisin. After pre-exposure of cells to the autoinducer and challenge with specific stresses, resistance to nisin and lactic acid was not mediated through quorum sensing. The resistance stability of Listeria monocytogenesmutant to LAB bacteriocins (mesenterocin, curvaticin and plantaricin) was evaluated by Rekhif et al.
Furthermore, the mutants resistant to one of the bacteriocins showed a cross-resistance to the other two bacteriocins, but not to nisin.
Natural Antimicrobials from Algae and Mushrooms
These authors observed changes in the expression of genes regulated by the LisRK system and the sigma factors SigB and SigL; Thus, a single exposure to a sublethal concentration of the bacteriocin initiates a response leading to resistance. First, they tested the antibacterial effects of essential oils of caraway, cinnamon, clove, coriander, caraway and basil against E. Next, the essential oils of basil, clove and cinnamon—the most potent against microorganisms—were incorporated into nanocomposite films made with alginate or clay and tested for 12 days.
Marjoram (1.5%) showed the highest activity against microorganisms in all matrices, reducing the populations of the three microorganisms up to 6.3, 4.5 and 5.8 log, respectively.
Future Perspectives
Microorganisms on the meat surface were not inhibited; however, a significant increase in the shelf life of the red dye was observed. 149] reported that chicken egg white lysozyme catalyzed the formation of silver nanoparticles that could sustain the hydrolase function of the enzyme; were effective against E. The MIC of the nanoparticles against both microorganisms was 320 UI/mL, which reduced their populations by more than 6 log CFU/mL after 48 and 72 h of incubation, respectively.
The anti-microsporidial activity of the bacteriocin was enhanced, showing a sustained reduction in faecal spore shedding and intestinal spore load.
Conclusions
In vitro antimicrobial activity of essential oils from Mediterranean Apiaceae, Verbenaceae and Lamiaceae against foodborne pathogens and spoilage bacteria. Antimicrobial activity of individual and mixed fractions of dill, coriander, coriander and eucalyptus essential oils. Int. Antimicrobial activity of two polysaccharide edible films incorporated with essential oils against three pathogenic bacteria.J.
Antimicrobial activity of alginate/clay nanocomposite films enriched with essential oils against three common foodborne pathogens. Food control.
Natural Product Type III Secretion System Inhibitors
Natural Products 1. Caminosides
Inhibition of the T3SS by piericidin A resulted in reduced formation of Ysc-type needle units on the surface of Y. Initial studies regarding the biological effects of butyric acid were performed prior to the knowledge of the T3SS (Figure 8). Sanguinaric chloride is a natural product isolated from extracts of the bloodroot plant Sanguinaria canadensis (Figure 11) [81].
They chose to monitor changes in expression of the T3SS via the two major regulatory pathways in D.
Conclusions
A small-molecule inhibitor of the bacterial type III secretion system protects against in vivo infection with Citrobacter rodentium.J. Design of small molecule inhibitors of type III secretion system ATPase EscN of enteropathogenic Escherichia coli. SepD/SepL-dependent secretion signals of the type III secretion system translocator proteins in enteropathogenic Escherichia coli.J.
Characterization of the mode of action of aurodox, a type III secretion system inhibitor from Streptomyces goldiniensis. Infect.
Actinobacteria Derived from Algerian Ecosystems as a Prominent Source of Antimicrobial Molecules
Algerian Sampling Sites Providing Culturable Actinobacteria
With an area of more than 2 million square kilometers, Algeria has an impressive climate diversity ranging from the snow-capped mountains in the northern regions overlooking the Mediterranean Sea to the hottest Sahara desert in the world. They cover different aspects, including the isolation and diversity of bacteria together with the investigation on secondary metabolite production aimed at a wide spectrum of biologic activities (mainly antimicrobial, but also cytotoxic agents and plant promoters) and with a look at potential biotechnological applications [54].
Biodiversity of Rare and Novel Genera and Species of Actinobateria
Figure 4a illustrates the percentage of new species, genera and rare Actinobacteria described since 2002 from different Algerian ecosystems. In summary, both the quantity and diversity of rare actinobacterial genera derived from the Sahara desert attest to the richness of this unique ecosystem. Sampling sites considered for the isolation and investigation of rare actinobacteria have mainly focused on Saharan soil and palm trees.
Secondary Metabolites Derived from Algerian Actinobacteria
PAL54A strain isolated from a Saharan soil in Ghardaïa produced the known chloramphenicol (20); therefore, this is the first production of this antibiotic by a Saccharothrix species. The new hydroxamic acid (31) was purified from the culture broth of StreptomycesWAB9, a strain isolated from the Saharan soil collected in the Bechar region. In particular, the stereochemistry of the known (-)-7-deoxy-8-O-methyltetrangomycin (35) was assigned by comparison with the polarimetric value obtained for the same molecule by stereoselective total synthesis [101].
A new Streptomyces strain isolated from Saharan soil produces di-(2-ethylhexyl)phthalate, a metabolite active against methicillin-resistant Staphylococcus aureus.Ann.
Do Global Regulators Hold the Key to Production of Bacterial Secondary Metabolites?
- Bioactive Secondary Metabolites 1. Malleilactone
- Global Regulators of Biosynthetic Gene Clusters 1. ScmR (Secondary Metabolite Regulator)
- Trimethoprim as an Inducer of Cryptic Biosynthetic Gene Clusters
- Conclusions and Future Outlook
It is one of the few gene clusters that includes both polyketide synthase (PKS)- and nonribosomal peptide synthetase (NRPS)-encoding genes (Figure 2B). We will focus on the role of ScmR in the regulation of some of the compounds discussed above. MftR was previously classified as a member of the MarR subfamily UrtR (Urate Responsive Transcriptional Regulator) [87,88].
ScmR represses expression of the local activator BhcM that is required for expression of thebhc gene cluster.
The Bactericidal Activity of Protein Extracts from Loranthus europaeus Berries: A Natural Resource of
Results
Therefore, according to the results obtained, the gram-positive bacteria were more sensitive to plant extract 2 than the gram-negative microorganisms, probably due to the different bacterial membrane structures. As shown in Figure 6B, a rapid reduction in the logarithm of the viable cells counted (−4 log CFU·mL−1) was detected with both. On the other hand, the SDS-PAGE analysis of all the gel filtration fractions revealed not only an enrichment of the active compounds (Fr 1 and Fr 2) (Figure 8B), but also a possible oligomeric nature of the antibacterial proteins considering the molecular mass determined under native conditions (Figure 7).
Calibration curve of the gel filtration YARRA™SEC-4000 column using protein standards of known molecular masses.
Materials and Methods 1. Collection of Plant Material
The antifungal activity was evaluated by measuring the diameter of the zone of inhibition on PCA plates. The MIC is defined as the lowest concentration of the extract at which no bacterial growth was detected. The antimicrobial activity of the partially purified samples (pellets 50% and 90% and gel filtration fractions) was determined according to Palmieri et al.
The extraction of the main pigments was carried out on the plant extract 2 before and after the dialysis with ethyl acetate as the solvent.
Conclusions
Quercus pubescens and its hemiparasite Loranthus europaeus: Nutrient dynamics of leaves and branches.Acta Physiol. Topical Loranthus europaeus ointment 40% as an alternative medicine in the treatment of acute cutaneous leishmaniasis versus 25%. Simple and robust determination of the activity signature of key enzymes of carbohydrate metabolism for physiological phenotyping in model and culture plants.J.
This article is an open access article distributed under the terms of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Antibacterial Activities, Phytochemical Screening and Metal Analysis of Medicinal Plants: Traditional
Recipes Used against Diarrhea
Discussion
The usefulness of these plants as well as the toxicity is due to their chemical nature, especially due to the presence of heavy metals such as zinc, manganese, cobalt, iron, copper, chromium and nickel. Lead (Pb) is a non-essential trace heavy metal that has no functions in both animals and plants. Copper (Cu) is an essential element for normal growth and development as well as for many enzymatic activities.
Due to harmful effects as well as antibiotic resistance to the synthetic drugs, researchers are trying to obtain antimicrobial drugs from medicinal plants due to their non-toxic nature.
Materials and Methods
Therefore, it has been concluded that the current research on the medicinal plants and their recipes used against diarrhea has shown them to be therapeutically active substances with enhanced activities. For this reason, the current research is useful to identify the bioactive substances obtained from the medicinal plants that are used against various antimicrobial activities. A selection of medicinal plants used for the treatment of diarrhea by Bangladeshi folk medicine.Am.
Shah, A.; Niaz, A.; Ullah, N.; Rehman, A.; Akhlaq, M.; Zakir, M.; Suleman Khan, M.; Comparative study of heavy metals in soil and selected medicinal plants.
In-Vitro Inhibition of Staphylococcal Pathogenesis by Witch-Hazel and Green Tea Extracts
Materials and Methods 1. Bacteria
Non-adherent cells (“cells”) were removed to another microtiter plate and the cell density was determined. The OD of each well was determined at 630 nm (BioTek Microplate Reader, Winooski, VT, USA). The plates were washed three times with PBST (PBS containing 0.05% Tween-20), and the same solution (100μL/well) was used to block unbound sites for 15 minutes at room temperature (RT).
One hundred microliters of each sample was added (in triplicate wells) and the plates were incubated for 2 hours at 37◦C.
Practical Applications
Specifically, sheep anti-SEA IgG (Toxin Technology, Sarasota, FL, USA) was used as the capture antibody, and sheep anti-SEA Horseradish peroxidase (HRPO) (Toxin Technology, Sarasota, FL, USA) was used as the detection antibody. To prepare test samples, the treated cells were removed by centrifugation, and the supernatants were collected. One hundred microliters of 3,3',5,5;-tetramethylbenzidine chromogen solution (Invitrogen, Carlsbad, CA, USA) substrate was added, and 0.3 HCl (50μL/well) was added to stop the reaction.
The significance of differences between treatment groups was calculated using a two-tailed Student's t-test. p<0.05 was considered significant.
