• Advances in nano research
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• v.13 no.4
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• pp.325-339
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• 2022

Endophytes ascertain a symbiotic relationship with plants as promoters of growth, defense mechanism etc. This study is a first report to screen the endophytic population in Waltheria indica, a tropical medicinal plant. 5 bacterial and 3 fungal strains in leaves, 3 bacterial and 1 yeast species in stems were differentiated morphologically and identified by biochemical and molecular methods. The phylogenetic tree of the isolated endophytes was constructed using MEGA X. Silver nanoparticles were biosynthesized from a rare endophytic bacterium Cupriavidus metallidurans isolated from the leaf of W. indica. The formation of silver nanoparticles was confirmed by UV-Visible spectrophotometer that evidenced a strong absorption band at 408.5 nm of UV-Visible range with crystalline nature and average particle size of 16.4 nm by Particle size analyzer. The Fourier Transform Infra-Red spectrum displayed the presence of various functional groups that stabilized the nanoparticles. X-ray diffraction peaks were conferred to face centered cubic structure. Transmission Electron Microscope and Scanning Electron Microscope revealed the spherical-shaped, polycrystalline nature with the presence of elemental silver analyzed by Energy Dispersive of X-Ray spectrum. Selected area electron diffraction also confirmed the orientation of AgNPs at 111, 200, 220, 311 planes similar to X-ray diffraction analysis. The synthesized nanoparticles are evaluated for antimicrobial activity against 7 bacterial and 3 fungal pathogens. A good zone of inhibition was observed against pathogenic bacteria than fungal pathogens. Thus the study could hold a key aspect in drug discovery research and other pharmacological conducts of human clinical conditions.

• Journal of dental hygiene science
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• v.24 no.1
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• pp.54-61
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• 2024

Background: The Korean name for Angelica gigas Nakai (AGN) is Cham-dang-gui, which grows naturally or is cultivated, and its dried roots are used in traditional herbal medicines. The AGN root exert various pharmacological effects. Despite the various pharmacological effects of the AGN root, there are no reports on its anti-oral microbial effects. The purpose of this study was to reveal the anti-oral microbial effect and the microbial and biochemical changes in oral microorganisms according to the concentration of the ethanol extract of AGN (EAGN) root, and to confirm the possibility of using EAGN as a plant-derived functional substance for controlling oral infectious microorganisms. Methods: Disk diffusion test, growth measurement, biofilm formation assay, and measurements of acid production and buffering capacity were performed to confirm the antibacterial effect of EAGN. Results: EAGN showed anti-oral bacterial effects against Streptococcus mutans and Aggregatibacter actinomycetemcomitans at all concentrations, with S. mutans showing a more susceptible effect at concentrations above 5.0 mg/ml and A. actinomycetemcomitans at 3.75 mg/ml. EAGN treatment significantly reduced A. actinomycetemcomitans growth at all concentrations tested. Biofilm formation was significantly reduced at concentrations above 3.75 mg/ml for S. mutans and 2.5 mg/ml for A. actinomycetemcomitans. Acid production in S. mutans and A. actinomycetemcomitans was significantly increased by treatment with EAGN, and the buffering capacities of S. mutans and A. actinomycetemcomitans increased from an EAGN concentration of 3.75 mg/ml and above. Conclusion: EAGN showed anti-oral bacterial effects against both S. mutans and A. actinomycetemcomitans at concentrations above 3.75 mg/ml, which were thought to be related to the inhibition of their growth and biofilm formation. Therefore, EAGN can be used as a safe functional substance derived from medicinal plants owing to its antibacterial effects against S. mutans and A. actinomycetemcomitans.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.160-170
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• 2024

Erwinia amylovora is a plant pathogen that causes fire blight on apples and pears. Bacteriophages, which are viruses that selectively infect specific species of bacteria and are harmless to animal cells, have been considered as biological control agents for the prevention of bacterial pathogens. In this study, we aimed to use bacteriophages that infect E. amylovora as biocontrol agents against fire blight. We isolated bacteriophages Fifi044 and Fifi318 infecting E. amylovora, and characterized their morphology, plaque form, and genetic diversity to use as cocktails for disease control. The stabilities of the two phages were investigated at various temperatures and pH values and under sunlight, and long-term storage experiment was conducted for a year. To evaluate whether the two phages were suitable for use in cocktail form, growth curves of E. amylovora were prepared after treating the bacterial cells with single phages and a phage cocktail. In addition, a disease control test was conducted using immature apples and in vitro cultured apple plantlets to determine the biocontrol effects of the phage cocktail. The two phages were morphologically and genetically different, and highly stable up to 50℃ and pH value from 4 to 10. The phages showed synergistic effect when used as a cocktail in the inhibition of host bacterial growth and the disease control. This study demonstrated that the potential of the phage cocktail as a biocontrol agent for commercial use.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.610-616
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• 2002

The growth-inhibiting effects of Pinus densiflpora leaf-derived materials on nine human intestinal bacteria were investigated using the impregnated paper disk method, and their activities were compared with those of 13 commercially available terpenes. The biologically active constituent of the extract of P densiflora leaf was characterized as the monoterpene (1R)-(+)-$\alpha$-pinene by various spectroscopic analyses. Responses varied according to bacterial strain, chemicals, and dose. At 10 mg/disk, limonene and (1R)-(+)-$\alpha$-pinene strongly inhibited the growth of Clostridium perfringens, Staphylococcus aureus, and Escherichia coli, without adverse effects on the growth of five lactic acid-bacteria (Bifidobacterium adolescentis, B. bifidum, B. longum, Lactobacillus acidophilus, and L. casei). Little or no inhibition against seven bacteria was observed with anethole, borneol, camphor, caryophyllene, 1,8-cineole, estragole, linalool, and $\alpha$-terpineol. Structure-activity relationship revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S-(-)-$\alpha$-, and (1S-(-)-$\beta$-pinenes. Furthermore, the growth-inhibition against L. casei was much more pronounced in (1R)-(+)-$\beta$- and (In-(-)-$\beta$-pinenes than (1R)-(+)-$\alpha$- and (1S)-(-)-$\alpha$-pinenes. These results indicate that the (+)-$\alpha$ form seems to be required against C. perfringens and $\beta$ form against L. casei for growth-inhibiting activity. Morphologically, most strains of C. perfringens were damaged and disappeared at 5 and 2 mg/disk of (1R)-(+)-$\alpha$-pinene. Morphological study revealed that (1R)-(+)-$\alpha$-pinene had more growth-inhibiting activity against C. perfringens than (1R)-(+)-$\beta$-, (1S)-(-)-$\alpha$-, and (1S)-(-)-$\beta$-pinenes. As naturally occurring growth-inhibiting agents, the Pinus leaf-derived materials described above could be useful preventive agents against diseases caused by harmful intestinal bacteria such as clostridia.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.164-167
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• 2005

The growth responses of materials extracted from Juniperus virginiana leaves against Bifidobacterium bifidum, B. longum, Clostridium perfringens, Escherichia coli, Lactobacillus acidophilus, L. casei, and Streptococcus mutans were examined using impregnated paper disk agar diffusion. The biologically active constituent isolated from the J. virginiana extracts was characterized as ${\alpha}$-cedrene using various spectroscopic analyses including IR, EI-MS, and NMR. The responses varied according to the dose, chemicals, and bacterial strain tested. Methanol extracts of J. virginiana leaves exhibited a strong and moderate inhibitory activity against C. perfringens and E. coli at 5 mg/disk, respectively. However, in tests conducted with B. bifidum, B. longum, L. acidophilus, L. casei, and S. mutans, the methanol extracts showed no or weak inhibitory response. At 2 mg/disk, a-cedrene strongly inhibited the growth of C. perfringens and moderately inhibited the growth of E. coli and S. mutans, without any adverse effects on the growth of four lactic acid-bacteria. Of the commercially available compounds originating from J. virginiana leaves, cedrol and ${\alpha}$-pinene exhibited strong and moderate growth inhibition against C. perfringens, and ${\alpha}$-copaene revealed moderate growth inhibition against E. coli at 1 mg/disk. Furthermore, cedrol exhibited moderate and weak growth inhibition against S. mutans at 2 and 1 mg/disk, respectively. However, little or no activity was observed for camphene, (+)-2-carene, p-cymene, limonene, linalool, and a-phellandrene against B. bifidum, B. longum, C. perfringens, L. acidophilus, L. casei, and S. mutans at 2 mg/disk. The observed inhibitory activity of the J. virginiana leaf-extracted materials against C. perfringens, E. coli, and S. mutans may be an indication of at least one of the pharmacological actions of the J. virginiana leaf.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.1
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• pp.31-45
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• 2020

Objectives In this study, we investigated the antimicrobial activity of a 70% ethanol extract of Maneung-hwan (MEH), which is prescribed by practitioners of oriental medicine for use against methicillin-resistant Staphylococcus aureus (MRSA). Methods The antibacterial activity of MEH against MRSA strains was evaluated using the disc diffusion method, broth microdilution method (minimal inhibitory concentration, MIC), checkerboard dilution test, and time-kill test. The mechanism of action of MEH was investigated by bacteriolysis using detergents or ATPase inhibitors Additionally, mRNA and protein expression were investigated by quantitative reverse transcription-polymerase chain reaction and western blot assay, respectively. Results The MIC of MEH was 25~1,600 ㎍/mL against all the tested bacterial strains. We showed that MEH extract exerts strong antibacterial activity. In the checkerboard dilution test, the fractional inhibitory concentration index of MEH in combination with antibiotics indicated synergism or partial synergism against S. aureus. The time-kill study indicated that the growth of the tested bacteria was considerably inhibited after a 24-h treatment with MEH and selected antibiotics. To measure the cell membrane permeability, MEH (3.9 ㎍/mL) was combined with Triton X-100 (TX) at various concentrations N,N-dicyclohexylcarbodimide (DCCD) was also tested as an ATPase inhibitor. TX and DCCD cooperation against S. aureus exhibited synergistic action. Accordingly, the antimicrobial activity of MEH in the context of cell membrane rupture and ATPase inhibition was assessed. Additionally, the expression of genes and proteins associated with resistance was reduced after exposing MRSA to MEH. Conclusions These results suggest that MEH possesses antibacterial activity and acts as a potential natural antibiotic against MRSA.

• Archives of Pharmacal Research
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• v.28 no.10
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• pp.1114-1121
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• 2005

Flavonoids are polyphenols composed of two aromatic rings (A, B) and a heterocyclic ring (C). In order to determine the effects of the number of hydroxyl groups in the B-ring of the flavonoids on human cytochrome P450 (CYP) 1 family enzymes, we evaluated the inhibition of CYP1A-dependent 7-ethoxyresorufin O-deethylation activity by chrysin, apigenin and luteolin, using bacterial membranes that co-express human CYP1A1, CYP1A2, or CYP1B1 with human NADPH-cytochrome P450 reductase. Chrysin, which possesses no hydroxyl groups in its B-ring, exhibited the most pronounced inhibitory effects on CYP1A2-dependent EROD activity, followed by apigenin and luteolin. On the contrary, CYP1A1-mediated EROD activity was most potently inhibited by luteolin, which is characterized by two hydroxyl groups in its B-ring, followed by apigenin and chrysin. However, all of the 5,7-dihydroxyflavones were determined to similarly inhibit CYP1B1 activity. Chrysin, apigenin, and luteolin exhibited a mixed-type mode of inhibition with regard to CYP1A2, CYP1B1, and CYP1A1, with apparent Ki values of 2.4, 0.5, and 2.0 ${\mu}M$, respectively. These findings suggested that the number of hydroxyl groups in the B-ring of 5,7-dihydroxyflavone might have some influence on the degree to which CYP1A enzymes were inhibited, but not on the degree to which CYP1B1 enzymes were inhibited.

• Korean Journal of Human Ecology
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• v.20 no.6
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• pp.1213-1222
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• 2011

This research evaluated antibacterial and growth inhibition effects on three kinds of lactic acid bacteria and five kinds of food poisoning bacteria using Backryencho powder, hot water, 70% ethanol, and 95% ethanol extracts. Antibacterial activity was shown against Leu. mensenteroides for 8 and 10 mg/disc of the 95% ethanol extract solution and strong proliferation inhibition effects were displayed against B. subtilis, Stap. aureus, E. coli, and S. typhimurium. High antibacterial activity according to certain clear zone formations was shown especially for the 10 mg/disc. A 3% concentration of the 95% ethanol extract showed high growth inhibition effects against lactic acid bacteria, L. brevis, L. plantarum, and Leu. mesenteroids. The measurement of viable cell counts of S. aureus, E. coli, B. subtilis, and S. typhimurium indicated suppression effects by the 3% concentration of the 95% ethanol extract, at 49.60%, 41.54%, 35.95%, 28.82%, and 26.60% respectively. The antibacterial activities of the hot water, 70% ethanol, 95% ethanol extract of Backryencho against food poisoning bacteria and Kimchi fermentation lactic acid bacteria were confirmed through various methods of antibiotic measurement. Based on these results, Backryencho extract is considered a good source for a range of applications as a natural anti-bacterial agent for the storage ability of Kimchi and as a possible food preservative.

• Journal of Applied Biological Chemistry
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• v.42 no.4
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• pp.202-204
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• 1999

Methanol extracts of leaves from 15 Pinus species belonging to the family Pinaceae were tested for their in vitro growth-inhibiting activities against 10 bacteria commonly found in the gastrointestinal tracts of human, using impregnated paper disk methods. The inhibitory activities varied with both bacterial strain and Pinus species used. At a concentration of 10 mg/disk, a clear growth inhibition was produced from the extracts of Pinus armandii, P. banksiana, P. bungeana, P. densiflora, P. rigida, and P. thunbergii against Clostridium perfringens, whereas all Pinus samples revealed weak or little growth-inhibiting activity against Escherichia coli, Bacteroides fragilis, and Staphylococcus aureus. At 5 mg/disk, the extracts of P. banksiana and P. thunbergii exhibited potent growth inhibition toward C. perfringens. All the extracts except the one from P. densiflora did not adversely affect growth of Bifidobacterium adolescentis, B. longum, B. bifidum, B. breve, B. animalis, and Lactobacillus casei. The growth-inhibiting activity was more pronounced in C. perfringens, as compared to the lactic acid-producing bacteria. These results may be an indication of at least one of the pharmacological activities of these Pinus species.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.21-29
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• 2007

Paeonia lactiflora was stepwise extracted with hexane, chloroform, ethyl acetate, butanol and water. Anti-microbial activity of each extract was investigated. Methanol extract of P. lactiflora revealed anti-microbial activity against S. mutans, C. albicans, and S. aureus. Also, hexane fraction revealed anti-bacterial activity against S. mutans and ethyl acetate fraction acted as potent anti-microbial agent on C. albicans and S. aureus. The relative growth ratio(RGR) of hexane fraction of P. lactiflora against S. mutans were determined as 77.8% in concentration of 0.125 mg/ml, 98.46% in 0.25 mg/ml and 100% in 0.5 mg/ml. The ethyl acetate fraction of P. lactiflora revealed RGR against C. albicans as 52.5% in concentration of 0.125 mg/ml, 60.83% in 0.25 mg/ml and 78.33% in 0.5 mg/ml. It indicate that increasing concentration increase RGR. The measured minimal inhibitory concentration(MIC) of hexane fraction on S. mutans KCTC 5316 strain was 0.5 mg/ml and MIC of ethyl acetate fraction on C. albicans KCTC 7270 was 2.0 mg/ml. The experiment of inhibition to growth of KB roll(oral squamous cell carcinoma) result 61.9% in butanol, 76.7% in hexane extract of P. lactiflora. The hexane extract exhibit potent inhibition effect to the growth of KB cell. These results suggest that the hexane extract of Paeonia lactiflora has antimicrobial activity against S. mutans and has preventive effect to dental caries in addition to potent inhibition to KB cell growth.