High Levels Of Antimicrobial Activity Research Articles

오배자, 우슬, 가자 및 감초를 포함하는 혼합추출물의 항산화 및 항균활성

In this study, antioxidant and antimicrobial activities of ethanolic crude extract and its five different solvent subfractions (namely, ethyl acetate fraction, n-butanol fraction, chloroform fraction, n-hexane fraction and the aqueous fraction) from a mixture of four different medicinal herbs (Galla rhois, Achyranthes japonica Nakai, Terminalia chebula Retz and Glycyrrhiza uralensis) were investigated. Among all the tested mixture combination of four medicinal herbs, 5:3:1:1 ratio of Galla:Achyranthes : Terminalia : Glycyrrhiza had the best antimicrobial effects against four strains of microorganisms (Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa and Escherichia coli) and exhibited the highest DPPH radical-scavenging activity. Further sub-fractions with solvents were screened for antioxidant and antimicrobial activities. Antioxidant activity in order was ethyl acetate fraction > n-butanol fraction > chloroform fraction > nhexane fraction > aqueous fraction. The n-butanol extracted fraction showed the highest level of antimicrobial activity in com- parison to other fractions. In addition, all those fractions did not show any cytotoxicity against human skin cell CCD-986sk. These results suggest that 5:3:1:1 combination extracts of medicinal herbs (Galla : Achyranthes : Terminalia : Glycyrrhiza) may be potentially used as a safe natural antimicrobial preservative.

Tri- and tetra-nuclear polypyridyl ruthenium(ii) complexes as antimicrobial agents

A series of inert tri- and tetra-nuclear polypyridylruthenium(II) complexes that are linked by the bis[4(4'-methyl-2,2'-bipyridyl)]-1,n-alkane ligand ("bb(n)" for n = 10, 12 and 16) have been synthesised and their potential as antimicrobial agents examined. Due to the modular nature of the synthesis of the oligonuclear complexes, it was possible to make both linear and non-linear tetranuclear ruthenium species. The minimum inhibitory concentrations (MIC) of the ruthenium(II) complexes were determined against four strains of bacteria--Gram positive Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), and Gram negative Escherichia coli (E. coli) and Pseudomonas aeruginosa (P. aeruginosa). In order to gain an understanding of the relative antimicrobial activities, the cellular uptake and water-octanol partition coefficients (log P) were determined for a selection of the ruthenium complexes. Although the trinuclear complexes were the most lipophilic based upon log P values and showed the greatest cellular uptake, the linear tetranuclear complexes were generally more active, with MIC values <1 μM against the Gram positive bacteria. Similarly, although the non-linear tetranuclear complexes were slightly more lipophilic and were taken up to a greater extent by the bacteria, they were consistently less active than their linear counterparts. Of particular note, the cellular accumulation of the oligonuclear ruthenium complexes was greater in the Gram negative strains compared to that in the Gram positive S. aureus and MRSA. The results demonstrate that the lower antimicrobial activity of polypyridylruthenium(II) complexes towards Gram negative bacteria, particularly P. aeruginosa, is not strongly correlated to the cellular accumulation but rather to a lower intrinsic ability to kill the Gram negative cells.

Brewery waste as a potential source of phenolic compounds: Optimisation of the extraction process and evaluation of antioxidant and antimicrobial activities

This paper reports the development of an extraction process that allows selective recovery of polyphenols from a brewery waste stream. The antioxidant activity of this extract (EC50=0.23–0.3g/L) was very high, similar to that of butylated hydroxyanisole (BHA) and higher than that of other synthetic antioxidants such as butylated hydroxytoluene (BHT). Crude extracts exhibited a high level of antimicrobial activity against Gram-positive and Gram-negative bacteria, when applied at concentrations of 1% and 3% (w/v). The antioxidant and antimicrobial activities can probably be attributed to the major phenolic compounds, such as protocatechuic, caffeic, p-coumaric and ferulic acids and catechin. With this procedure, the waste polyphenols could be used as cheap source of natural compounds, with potential applications in the food and health sectors. Substitution of synthetic additives with safe and effective natural additives may be of further benefit to the food industry.

Effect of the addition of plant extracts on the microbiota of minimally processed strawberry jam and its physicochemical and sensorial properties

Plant extract addition (pomegranate, rosemary, lemon and balsamic lemon) have been applied to strawberry jam obtained by osmotic dehydration in order to avoid its fast decline. Microbiological, physicochemical and sensorial parameters have been evaluated to compare product quality. Different doses of plant extract were tested to select those with the greatest antibacterial potential. Before determining its antimicrobial potential, the behaviour of the microbiota present in the strawberry jam was analysed using predictive microbiology. Moreover, the samples were analysed for moisture content, soluble solids, pH, water activity, colour and consistency. Strawberry jams were sensorially analysed. Pomegranate extract showed the highest level of antimicrobial activity. Jams with pomegranate showed significantly lower values in colour parameters than the control jam. However, there were no significant colour differences between jams with different doses of pomegranate extract. Jams without extracts were more consistent. In the sensory analysis, tasters found the studied samples to be very similar.

Preparative Isolation of Novel Antimicrobial Compounds from Pergidae sp. by Reversed-Phase High-Performance Liquid Chromatography

A novel macrocarpal (macrocarpal M) together with the grandinol (a known plant metabolite of Eucalptus spp.) were isolated from a methanolic extract of sawfly larvae sp. indet. (Australian sawfly, Hymenoptera:Symphyta) using the developed reversed-phase high-performance liquid chromatography (RP-HPLC) method. To the best of our knowledge, this macrocarpal M is found to have high levels of antimicrobial activity for the first time. The structures of two compounds were identified by ESI-MS, 1H NMR, 13C NMR, and 2D NMR.

사방오리나무 추출물의 항우식 및 항구취 효과

사방오리나무의 분획물과 분리화합물인 gallic acid의 항우식 작용과 항구취 활성을 조사하기 위해 구강병원균에 대한 항균활성, 부착능 그리고 산 생성을 조사하였다. 그리고 휘발성 황화합물의 측정은 oral chroma를 이용하여 구취억제 효과를 측정하였다. DCM 분획물은 넓은 항균스펙트럼을 가졌으며, EA 분획물은 Streptococcus mutans와 Porphyromons gingivalis에 대해 상대적으로 높은 항균활성을 가진 것으로 나타났다. 게다가 GA와 DCM 분획물은 각각 S. mutans와 S. salivarius에 대해 산 생성과 부착을 효과적으로 억제하였다. 사방오리나무의 2% MeOH 추출물은 구취유발 화합물인 황화수소, 메틸머캅탄, 황화디메틸을 억제하는 효과가 뛰어났으며(p<0.05), 2% GA 또한 황화수소를 억제시키는 효과가 있음이 확인되었다(p<0.05). 본 연구의 결과, 사방오리나무의 활성 분획물과 GA는 항균효능, 산생성 억제능, 부착 억제능 및 구취 억제효능을 가짐으로써 구강병원균에 대한 천연항균제제로써의 사용 가능성이 충분히 있는 것으로 판단된다. To investigate the antimicrobial and anti-halitosis effects of Alnus firma extracts and gallic acid (GA) isolated from A. firma, we measured their antimicrobial activities against oral pathogens and their inhibitory effects on the cell adhesiveness and acid production of oral pathogens. In addition, the levels of volatile sulfur compounds were determined by using oral chroma. The dichloromethane (DCM) fraction has broad antimicrobial activity, and the ethylacetate (EA) fraction showed a relatively high level of antimicrobial activity against Streptococcus mutans and Porphyromons gingivalis. Especially, the GA and DCM fractions had significant inhibitory effects on the attachment and acid production of S. mutans and Streptococcus salivarius, respectively. The 2% MeOH extract of A. firma showed a significant inhibitory effect on the production of volatile oral compounds, such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide, which can cause bad breath and halitosis. Two percent GA also had a significant inhibitory effect on the production of hydrogen sulfide. Our study showed that the active fractions and GA of A. firma could be suitable resources for development as a natural antibiotic agent for the treatment of infectious oral diseases.

Synthesis and antimicrobial evaluation of l-phenylalanine-derived C5-substituted rhodanine and chalcone derivatives containing thiobarbituric acid or 2-thioxo-4-thiazolidinone

Four novel series of compounds, including the l-phenylalanine-derived C5-substituted rhodanine (6a–q, 7a–j) and chalcone derivatives containing thiobarbituric acid or 2-thioxo-4-thiazolidinone (9a–e, 11a–e) have been designed, synthesized, characterized, and evaluated for their antibacterial activity. Some of these compounds showed significant antibacterial activity against Gram-positive bacterias, especially against the strains of multidrug-resistant clinical isolates, among which compounds 6c–e, 6g, 6i, 6j and 6q exhibiting high levels of antimicrobial activity against Staphylococcus aureus RN4220 with minimum inhibitory concentration (MIC) values of 2 μg/mL. Compound 6q showed the most potent activity of all of the compounds against all of the test multidrug-resistant clinical isolates tested. Unfortunately, however, none of the compounds were active against Gram-negative bacteria at 64 μg/mL.

Classification and Characterization of Manuka Honeys Based on Phenolic Compounds and Methylglyoxal

Manuka honey from New Zealand is often considered to be a medicinal product of special value due to its high level of antimicrobial activity. Therefore, the distinct authentication of its botanical origin is of great importance. Aside from the common pollen analysis, it is in this respect particularly the analysis of the phenolic acids, flavonoids, and norisoprenoids that is described as useful. In the present study, numerous manuka honeys were analyzed by UPLC-PDA-MS/MS after solid-phase extraction and compared to other kinds of honey to define marker substances characteristic for manuka honeys. The PDA profiles obtained differed markedly from each other so that the individual honey samples could be assigned to three groups. For the honeys of group 1 the comparably high concentrations of 4-hydroxybenzoic acid, dehydrovomifoliol, and benzoic acid proved to be typical, whereas the profiles of group 2 showed high kojic acid and 2-methoxybenzoic acid intensities. The manuka honeys of group 3, on the other hand, yielded high amounts of syringic acid, 4-methoxyphenyllactic acid, and methyl syringate. Furthermore, the comprehensive comparison of manuka honeys to other unifloral honeys revealed that especially kojic acid, 5-methyl-3-furancarboxylic acid, leptosin, unedone, 2-methoxybenzoic acid, 4-methoxyphenyllactic acid, 3-hydroxy-1-(2-methoxyphenyl)penta-1,4-dione, and methyl syringate were useful for distinguishing manuka honeys from the other kinds of investigated honeys. Moreover, kojic acid, unedone, 5-methyl-3-furancarboxylic acid, 3-hydroxy-1-(2-methoxyphenyl)penta-1,4-dione, and lumichrome were identified in manuka honey for the first time.

Coordinating antimicrobial activity and wound repair

Linking the high levels of antimicrobial activity and keratinocyte hyperproliferation in psoriatic skin lesions.

Development of intra-vaginal matrices from polycaprolactone for sustained release of antimicrobial agents

Microporous poly(ε-caprolactone) matrices were loaded with an antibacterial agent, ciprofloxacin and an antifungal agent, miconazole nitrate, respectively, for investigations of their potential as controlled vaginal delivery devices. Ciprofloxacin loadings up to 15% w/w could be obtained by increasing the drug content of the poly(ε-caprolactone) solution, while the actual loadings of miconazole were much lower (1-3% w/w) due to drug partition into methanol during the solvent extraction. The kinetics of ciprofloxacin release in simulated vaginal fluid at 37 were characterised by a small burst release phase in the first 24 h, low drug release up to 7 days (10%) and gradual release of up to 80% of the drug content by day 30. Meanwhile, the release kinetics of miconazole-loaded matrices could be effectively described by the Higuchi model with 100% drug release from the highest loaded matrices (3.2% w/w) in 13 days. Ciprofloxacin or miconazole released over 30 and 13 days, respectively, from poly(ε-caprolactone) matrices into simulated vaginal fluid retained high levels of antimicrobial activity in excess of 80% of the activity of the free drug. This study confirms the potential of poly(ε-caprolactone) matrices for delivering antimicrobial agents in the form of an intra-vaginal device.

Antimicrobial activity of Bacillus megaterium strains

A bacterial strain with a high level of antimicrobial activity was isolated from soil and identified as Bacillus megaterium. Production of antibiotics by nine strains of this species from the collection of the State Research Institute for Genetics and Selection of Industrial Microorganisms was investigated. In submerged cultures, nine out of ten B. megaterium strains were found to produce antibacterial antibiotics differing in their spectra of action. Physicochemical characteristics of five compounds were described. Three of them belonged to peptide antibiotics. All five compounds were active against the methicillin-resistant strain Staphylococcus aureus INA 00761. Three of them were shown to be the previously undescribed compounds. Antibiotics produced by various B. megaterium strains were also active against the Leuconostoc mesenteroides VKPM B-4177 strain resistant to glycopeptide antibiotics and against gram-negative bacteria Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922.

Synthesis and antimicrobial and antifungal activities of quaternary salts of adamantane-containing alkoxydialkylaminopropanols

A series of quaternary salts of adamantane-containing alkoxydialkylaminopropanols was synthesized. The structures of the reaction products were confirmed by IR and PMR spectroscopy. Some compounds were found to have high levels of antimicrobial activity.

Lantibiotics, Class I Bacteriocins from the Genus Bacillus

Antimicrobial peptides exhibit high levels of antimicrobial activity against a broad range of spoilage and pathogenic microorganisms. Compared with bacteriocins produced by lactic acid bacteria, antimicrobial peptides from the genus Bacillus have been relatively less recognized despite their broad antimicrobial spectra. These peptides can be classified into two different groups based on whether they are ribosomally (bacteriocins) or nonribosomally (polymyxins and iturins) synthesized. Because of their broad spectra and high activity, antimicrobial peptides from Bacillus spp. may have great potential for applications in the food, agricultural, and pharmaceutical industries to prevent or control spoilage and pathogenic microorganisms. In this review, we introduce ribosomally synthesized antimicrobial peptides, the lantibiotic bacteriocins produced by members of Bacillus. In addition, the biosynthesis, genetic organization, mode of action, and regulation of subtilin, a well-investigated lantibiotic from Bacillus subtilis, are discussed.

Promoter analysis of the pepper antimicrobial protein gene, CaAMP1, during bacterial infection and abiotic stress

In a previous study, we isolated and functionally characterized a novel antimicrobial protein gene with a high level of antimicrobial activity, CaAMP1, from pepper leaves infected with Xanthomonas campestris pv. vesicatoria. In this study, a series of 5′-deletions in the region −1190 bp upstream of the transcriptional start site of the CaAMP1 gene were analyzed in tobacco to determine the activity of the CaAMP1 promoter fused to the β-glucuronidase (GUS) reporter gene, using an Agrobacterium-mediated transient expression assay. The CaAMP1 gene and promoter were locally and systemically induced by microbial infection. Several biotic and abiotic stress-related cis-acting elements, including GT1 box, W box, MYB, RAV1, ERE, and LTRE, were localized in the upstream promoter region of the CaAMP1 gene. The −1190, −967 and −626 bp regions of the CaAMP1 promoter activated by Pseudomonas syringae pv. tabaci infection, were simultaneously activated by treatments with salicylic acid and methyl jasmonate. The −1190 bp CaAMP1 promoter was also activated by abscisic acid, NaCl, and low temperature. Expression of the pepper transcription factor, CARAV1, but not CAZFP1, contributed to the activation of the CaAMP1 promoter. Deletion analysis of the CaAMP1 promoter suggested that some novel cis-acting elements are necessary for the induction of CaAMP1 expression during pathogen exposure and that environmental stresses may reside in the genomic sequence upstream of the CaAMP1 gene between −626 bp and −425 bp.

Complexes of aminoglycoside antibiotics with copolymers of acrylamide with acrylic and methacrylic acids

Aminoglycoside antibiotics are structurally related substances with high levels of antimicrobial activity with wide spectra [1]. However, they are characterized by marked toxicity, particularly oto- and nephrotoxicity, when used therapeutically, and can produce neuromuscular blockade. The use of aminoglycoside antibiotics in clinical medicine therefore requires constant monitoring of blood peak and trough concentrations, which is a major hindrance. This raises the question of decreasing the toxicity of aminoglycoside antibiotics. One effective means of reducing the toxicity of ionogenic biologically active substances (BAS) without loss of biospecific activity is to complex them with nontoxic polyelectrolytes. The literature contains descriptions of water-soluble polymer complexes of kanamycin and gentamicin based on carboxymethyl and sulfopropyl esters of dextran which have high activity, though their toxicological characteristics were not reported [4]. The aim of the present work was to prepare and study the physicochemical, toxicological, and antimicrobial properties of complexes of aminoglycoside antibiotics with synthetic low molecular weight anionic copolymer carriers. Water-soluble copolymers of acrylamide (ACR) with acrylic (AA) and

Essential oil composition and antibacterial activity of Dichondra repens

Dichondra repens Forst is a Convolvulaceae plant. There are 5~8 species in the world and only one species in China. It is a traditional Chinese medicine, which has been known for a long time for its properties of heat-clearing, detoxicating, and damp elimination. It has been used in the treatment of diseases such as icterohepatitis, dysentery, and hydrops [1] in folk and clinical medicine. Extensive growth and cultivation of Dichondra repens Forst is now in progress and it has been exploited as a beverage food in China. Research [2] on the antibacterial activity of the decoction and tinctura from this plant against Bacillus diphtheriae and the antibacterial, anti-inflammation, and antinociceptive activity [3] of the n-butanol extract of Dichondra repens Forst has been conducted, and the chemical composition of Dichondra repens Forst has been reported [4, 5]. But there is not much attention devoted to the essential oil of Dichondra repens Forst and its antibacterial activities. Essential oils have demonstrated numerous biological actions, including antimicrobial activities [6, 7]. These properties are likely due to the many components of these complex mixtures and is facilitated by their ready dilusion across cell membranes. In this report, the chemical composition and antibacterial activities of the essential oil from Dichondra repens Forst is described. The essential oil was obtained from Dichondra repens Forst by steam distillation. The amount of components from the essential oil was calculated by the area normalization method. The separated components were identified by GC-MS. The antimicrobial activity of the essential oil has been tested by the method of disc-agar diffusion [8]. A total of 137 compounds were separated and 31 compounds were identified representing about 78.76% of the total oil. The chemical components and relative contents in the essential oil of Dichondra repens Forst are given in Table 1. The identified compounds mainly include 6-(methylamino)-phenanthren-3-ol (17.41%), (–)-trans-pinane (9.50%), ylangene (8.20%), isocaryophyllene (4.61%), phenol,2,6-dimethoxy(3.84%), 6-octadecenal (2.88%), 2-methyl-Z-4-tetradecene (2.56), 1H-cycloprop[e]azulene, decahydro-1,1,7-trimethyl-4-methylene (2.10%). The disc diameters of inhibition zones, minimum inhibitory concentrations (MIC), and minimum bactericidal concentrations (MBC) of Dichondra repens Forst essential oil for the microoganisms tested are shown in Table 2. The data obtained from the disc-agar diffusion method indicated that Bacillus diphtheriae had the strongest inhibition zone (23 mm), followed by β-hemolytic streptococci (22 mm), Enterococcus faecium (20 mm), and Escherichia coli (20 mm). Klebsiella pneumoniae exhibited a weak inhibition zone (8 mm). The results of MIC indicated the oil inhibited all microorganisms tested. Escherichia coli had the lowest MIC (0.80 μg/mL). The oil was demonstrated to have a strong bactericidal effect. The lowest MBC was 1.50 μL/mL for Escherichia coli. Escherichia coli presented the lowest MIC and MBC values. The strains that presented the biggest inhibition zones (diffusion method) are not always the most sensitive (values of MIC and MBC were lower) because the size of the inhibition zone does not reflect the antibacterial effectiveness of a compound, since it is affected by the solubility of the oil, the diffusion range in the agar, evaporation (it can affect the dose), etc. [9]. Some researchers reported that there is a relationship between the chemical structures of the most abundant compounds in the tested oil and the antimicrobial activity. The essential oils rich in phenolic compounds are widely reported to possess high levels of antimicrobial activity [10–15], which has been confirmed and extended in the present studies. The antimicrobial nature of the essential oil studied is apparently related to its phenolic components. The content of 6-(methylamino)phenanthren3-ol is the highest in the essential oil of Dichondra repens Forst (Table 1). The antimicrobial nature of the essential oil studied is apparently related to the 6-(methylamino)phenanthren-3-ol component.

Photocatalysts for reagentless disinfection on the basis of titanium dioxide films modified by silver nanoparticles

Using the test cultures of Pseudomonas fluorescens and Lactococcus lactis bacteria, photoinduced pathophysiological properties of film titanium dioxide photocatalysts modified by silver nanoparticles are investigated. It is shown that the deposition of silver leads to an increase in the adsorption of microorganisms from the solution and to a rise in the efficiency of photogeneration of hydroxyl radicals and superoxide ions, which provides the attainment of a high level of antimicrobial activity. In particular, the survival rate of P. fluorescens eubacteria under the UV irradiation in contact with the TiO2/Ag catalyst decreases by a factor of more than 70 compared with irradiation in the absence of the photocatalyst. The developed photocatalysts allow the manifold increase in the efficiency of the disinfection of aqueous media with the use of ultraviolet.

Synthesis and antimicrobial activity of 1-[4-(1-adamantyl)phenoxy]-3-amino-2-propanol

Reaction of 1-[4-(1-adamantyl)phenoxy]glycidyl ether with amines leads to the corresponding 1-[4-(1-adamantyl) phenoxy]-3-alkyl(dialkyl)amino-2-propanols. The proposed structures of the synthesized compounds are confirmed by IR and NMR spectroscopy. Substances tested by the serial dilution method exhibited a high level of antimicrobial activity.

Isolation and characterization of a protective bacterial culture isolated from honey active against American Foulbrood disease

Bacterial strains isolated from US domestic honey were screened for antibacterial activity against Paenibacillus larvae ssp. larvae, the causative agent of American Foulbrood (AFB) in apiaries. A bacterial isolate (TH13) showing a high level of antimicrobial activity against P. larvae ssp. larvae ATCC 9545 was selected and identified as Paenibacillus polymyxa by 16S rRNA gene sequencing. The antimicrobial compound was purified by 80% saturated ammonium sulfate precipitation followed by CM-sepharose chromatography and reverse-phase HPLC. The molecular mass of the compound was determined to be 1168.78 Da by ESI-qTOF MS, matching that of polymyxin E1. The producer strain showed a broad range of antibacterial activity against gram-positive and -negative bacteria including P. larvae ssp. larvae ATCC 25747 and foodborne pathogens such as Bacillus cereus F4552 and Escherichia coli O157:H7 ATCC 43895. The selection of antibiotic-producing bacterial strains indigenous to honey as protective cultures against AFB may lessen the use of antibiotics in apiaries.

Discovery of Medically Significant Lantibiotics

The emergence of drug-resistant pathogens such as staphylococci and enterococci in the hospital setting has long being recognized as a serious clinical problem. Staphylococcus aureus is the causative agent of many nosocomial infections from minor skin abscesses to serious, potentially life threatening diseases such as bone and soft tissue intra-surgical infections, sepsis and invasive endocarditis, while enterococci are responsible for nosocomial bacteraemia, surgical wound infections and endocarditis. The most infamous drug-resistant forms of these include MRSA (methicillin resistant S. aureus), VISA (vancomycin insensitive S. aureus), hVISA (heterogenous vancomycin insensitive S. aureus) and VRE (vancomycin resistant S. aureus). While enhanced hygiene awareness is essential to any solution, the identification of effective novel antimicrobial compounds remains a major goal in eradicating these and other infections caused by multi-drug resistant pathogens. In recent years a class of antimicrobial peptides, the Lantibiotics, have been the focus of an ever increasing level of attention. This interest has been prompted by an enhanced appreciation of the mode of action of these peptides (including, in many cases, the ability to bind lipid II) and their frequently high levels of antimicrobial activity. Here we review lantibiotic-related issues in drug discovery, outline the strategies that have been employed to identify these peptides and summarize the use of bioengineering to generate enhanced forms of these peptides as well as the application of the associated biological machinery to generate novel forms of existing pharmaceutical compounds. In so doing we highlight how some, or all, of these approaches have the potential to result in the development of clinically important drugs.