• Journal of Microbiology and Biotechnology
• /
• v.26 no.2
• /
• pp.408-420
• /
• 2016

This study proposes an alternative approach for the use of chitosan silver-based dressing for the control of foot infection with multidrug-resistant bacteria. Sixty-five bacterial isolates were isolated from 40 diabetic patients. Staphylococcus aureus (37%) and Pseudomonas aeruginosa (18.5%) were the predominant isolates in the ulcer samples. Ten antibiotics were in vitro tested against diabetic foot clinical bacterial isolates. The most resistant S. aureus and P. aeruginosa isolates were then selected for further study. Three chitosan sources were tested individually for chelating silver nanoparticles. Squilla chitosan silver nanoparticles (Sq. Cs-Ag⁰) showed the maximum activity against the resistant bacteria when mixed with amikacin that showed the maximum synergetic index. This, in turn, resulted in the reduction of the amikacin MIC value by 95%. For evaluation of the effectiveness of the prepared dressing using Artemia salina as the toxicity biomarker, the LC₅₀ was found to be 549.5, 18,000, and 10,000 μg/ml for amikacin, Sq. Cs-Ag⁰, and dressing matrix, respectively. Loading the formula onto chitosan hydrogel dressing showed promising antibacterial activities, with responsive healing properties for the wounds in normal rats of those diabetic rats (polymicrobial infection). It is quite interesting to note that no emergence of any side effect on either kidney or liver biomedical functions was noticed.

• YAKHAK HOEJI
• /
• v.43 no.6
• /
• pp.716-728
• /
• 1999

Whole oil and ketonic fraction (KF) of Leptospermum scoparium have been tested for their antimicrobial activity and combination effect with several antibiotics against various bacterial strains and fungi by using microbiological assay methods. Antibacterial activities of KF against a number of test strains were 2-3 fold stronger than those of whole oil. MICs of the KF were $65~125{\;}{\mu\textrm{g}}/ml$ against seven gram positive bacterial strains, $65~250{\;}{\mu\textrm{g}}/ml$ against 19 methicillin resistance Staphylococcus aureus strains, and $65~50{\;}{\mu\textrm{g}}/ml$ against 14 quinolone resistance strains. However, KF showed little or no activity against gram negative bacteria. MICs of the KF were $16~250{\;}{\mu\textrm{g}}/ml$ against more than 50% of the anaerobic bacterial strains tested. KF showed the higher antibacterial activity than bacitracin against 10 strains of Bacteroids thetaiotaomicron, or three strains of Bacteroides ovatus, and the more active than ciprofloxacin against one strain of Bacteroides thetaiotaomicron and three strains of Bacteroids ovatus. The MICs of KF was 63 and $250{\;}{\mu\textrm{g}}/ml$ against Aspergillus niger and Candida albicans, respectively. Antibacterial activities of KF in combination with 19 antibiotics against 14 strains and with four antifungal agents against one fungal strain were determined by paper strip diffusion method. While most of combination showed additivity, KF showed synergism with bacitracin, exfadroxil, cephradin, and meropenem for 29~57% of the strains tested. However, ofloxacin, enoxacin, sparfloxacin showed antagonism with KF for 43~71% of the strains. KF alone and in combination with bacitracin, gentamycin, neomycin, itraconazole, fluconazole, terfinafine and ketoconazole against five bacterial strains or one fungus strain synergistic effect was demonstrated against 33% of strains examined with FIC index value below 0.5 by checkerboard study. Synergistic effect of KF with gentamicin against Staphylococcus epidermidis 329 (QRS) was found by time-kill study.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.21 no.6
• /
• pp.1564-1568
• /
• 2007

In this study fourteen ethanol extracts from Nepalese medicinal plants were screened for their in vitro antimicrobial and antiradical activity and their total phenolic content was evaluated. The antiradicalactivity was evaluated by free radical scavenging assay, using 2,2-diphenyl-1-picryl hydrazyl radical (DPPH). Plant extracts showed a wide range of radical scavenging activity, with $IC_50$ value ranging in between $5.38\; {\mu}g/\;mL$ - $429.61\;{\mu}g/mL$. Strong radical scavenging activity was shown by flower extract of Woodfordia fruticosa ($5.38\;{\mu}g/\;mL$) and stem bark extract of Azadirachta indica ($5.58 {\mu}g/\;mL$)that also contained high phenolic content. Most of the sample showed activity below the concentration of $100\; {\mu}g/mL$. For antimicrobial activity three test microorganisms namely Staphylococcus aureus, Streptococcus epidermidis, and Candida albicans were used. The minimum inhibitory concentration (MIC) of the plant extracts was determined. Most of the plant extracts were effective against bacterial strains only at higher concentration ($800\;-\;1,600\;{\mu}g/mL$) but none of these were effective against Candida albicans below $1,600\;{\mu}g/mL$.

• Journal of Integrative Natural Science
• /
• v.9 no.1
• /
• pp.72-79
• /
• 2016

Hexane, ethyl acetate and methanol extracts of whole plant of Boerhavia diffusa were screened for phytochemical and biological activities. Qualitative phytochemical screening via colorimetric method and the quantitative estimation of phenolic and flavonoid content were performed. Antioxidant assay using DPPH scavenging method was studied. Antimicrobial screening of plant extracts was done by cup diffusion technique. Cytotoxic activity of B. diffusa was studied by brine shrimp bioassay and anthelminthic activity was evaluated in vitro in Pheretima posthuma. This study revealed B. diffusa as a source of various phyto-constituents such as alkaloids, glycosides, saponins, tannins, carbohydrates, cardiac glycosides, flavonoids and terpenoids. Quantitative estimation of total phenol was found to be maximum in BEE i.e. $29.73{\pm}0.88$, BME $19.8{\pm}2.02$ and in BHE $9.15{\pm}0.304mgGAE/g$. Similarly, the total flavonoid content was found to be $17.44{\pm}0.75$ in BEE, $14.43{\pm}0.23$ in BHE and 3.678 mg QE/g in BME. Ethyl acetate extract showed its antibacterial activity against all tested pathogens except Escherichia coli whereas Staphylococcus aureus and Salmonella Typhi were resistant to methanol and hexane extract. The zone of inhibition (ZOI) of ethyl acetate extract against S. Typhi and B. cereus was found to be 18 mm and 14 mm respectively. The MIC value of BEE in S. Typhi was $3.125{\mu}g/ml$ and in B. cereus was $12.5{\mu}g/ml$. The preliminary screening of anticancer property of B. diffusa i.e. BSLT in methanol was found to be $165.19{\mu}g/ml$. B. diffusa was also found to contain anthelmintic property. The study helped in further exploration of medicinal properties of B. diffusa by phytochemical screening and biological activities paving the path for study and investigation in this plant.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.95-99
• /
• 2018

In insect defense system, antimicrobial peptides (AMPs) are one of important biological molecules to survive in a variety of environments. Insect can synthesize AMPs to protect against invading pathogens in humoral immune response. Taking more advantage of biological antimicrobial molecules, we report antibacterial activity of two cecropin type peptides, cecropin and moricin, isolated from the silkworm against four salmonella species. In this work, we purified antimicrobial candidate peptides (AMCP) from the extracts of immune challenged silkworm larval hemolymph by two-step chromatographic purification procedure, cation exchange and gel permeation chromatography. The molecular weights of purified peptides were estimated to be about 4 ~ 5 kDa by Tricin SDS-PAGE analysis, and identified as silkworm cecropin and moricin by NCBI BLAST homology search with their N-terminal amino acid sequences. As antibacterial activity assay, the purified peptides showed stronger antibacterial activity against Salmonella pathogens with an MIC value of $1{\sim}4{\mu}g/mL$. Therefore two cecropin type peptides purified from the silkworm will be valuable potential materials for development of new natural antibiotics.

• Journal of Microbiology and Biotechnology
• /
• v.34 no.7
• /
• pp.1452-1463
• /
• 2024

Fungi generate different metabolites some of which are intrinsically bioactive and could therefore serve as templates for drug development. In the current study, six endophytic fungi namely Aspergillus flavus, Aspergillus tubigenesis, Aspergillus oryzae, Penicillium oxalicum, Aspergillus niger, and Aspergillus brasiliensis were isolated and identified from the medicinal plant, Silybum marianum. These endophytic fungi were identified through intra transcribed sequence (ITS) gene sequencing. The bioactive potentials of fungal extracts were investigated using several bioassays such as antibacterial activity by well-diffusion, MIC, MBC, anti-biofilm, antioxidant, and haemolysis. The Pseudomonas aeruginosa PAO1 was used to determine the antibiofilm activity. The ethyl acetate extract of Aspergillus flavus showed strong to moderate efficacy against Staphylococcus aureus, Escherichia coli, P. aeruginosa, and Bacillus spizizenii. Aspergillus flavus and Aspergillus brasiliensis exhibited significant antibiofilm activity with IC₅₀ at 4.02 and 3.63 mg/ml, while A. flavus exhibited maximum antioxidant activity of 50.8%. Based on HPLC, LC-MS, and NMR experiments kojic acid (1) and carbamic acid (methylene-4, 1-phenylene) bis-dimethyl ester (2) were identified from A. flavus. Kojic acid exhibited DPPH free radical scavenging activity with an IC₅₀ value of 99.3 ㎍/ml and moderate activity against ovarian teratocarcinoma (CH1), colon carcinoma (SW480), and non-small cell lung cancer (A549) cell lines. These findings suggest that endophytic fungi are able to produce promising bioactive compounds which deserve further investigation.

• KSBB Journal
• /
• v.21 no.6 s.101
• /
• pp.422-427
• /
• 2006

The culture media from Fomitopsis pinicola were extracted by methanol and examined growth inhibition against Helicobacter pylori. The culture media from 8 days fermentation of F. pinicola showed maximum inhibition activity on H. pylori in 0.25 mg as MIC value. The highest activity against H. pylori by MHCS agar diffusion medium by Fp-P1 in 22.7 mm ID among 3 peaks from methanol fraction of 8 days culture media of Fomitopsis pinicola which purified by ion-exchange chromatography. The Fp-P1 from DEAE-Sephadex A-25 have been analysed by TLC as Fp-T1, Fp-T2 and Fp-T3 by ninhydrin staining. Fp-T3 (Rf value : 0.67) was higher activity against H. pylori in 14.4 mm ID. Fp-T3 was identified as single band by HPLC and TLC. It was assumed to aminosugar by BioLC analysis and TLC staining.

• Journal of Radiation Protection and Research
• /
• v.35 no.3
• /
• pp.117-123
• /
• 2010

Plutonium is by far the most important of the transuranic elements which have been released into the environment due to radio-toxicity and long term radiation effects on humans. And Pu isotope ratio ($^{240}Pu/^{239}Pu$) is of great interest because this ratio is used as a fingerprint for different sources. Mass spectrometry has been used as an useful atom counting technique with several advantages over decay counting techniques for the determination of Pu isotopes. It enables a determination of Pu isotope ratio in the environmental samples with a low detection limit and a short determination time. An ICP-MS is the representative mass spectrometry for Pu determination. In this study, the precision of $^{240}Pu/^{239}Pu$ isotope ratio was improved by using 4 multiple ion counters of MC-ICP-MS. The detection limit of $^{239}Pu$ and $^{240}Pu$ were $0.10\;fg\;ml^{-1}$ ($0.24\;{\mu}Bq\;ml^{-1}$), $0.12\;fg\;ml^{-1}$ ($0.97\;{\mu}Bq\;ml^{-1}$), respectively. The relative standard deviation of $^{240}Pu/^{239}Pu$ isotope ratio was less than 1 % in trace level. The various reference materials (seawater, soil and sediment) were analyzed to verify this method and their analytical results were in good agreement with the certified (or recommended value) value.

• Microbiology and Biotechnology Letters
• /
• v.39 no.1
• /
• pp.63-69
• /
• 2011

In this study, the antibacterial activity and the antioxidative effects, inhibitory effects on tyrosinase of Lespedeza cuneata G. Don extracts were investigated. MIC value of ethyl acetate fraction from L. cuneata G. Don on P. ovale (0.125%) showed that the antibacterial activity of the ethyl acetate fraction was higher than methyl paraben. The aglycone fraction of L. cuneata G. Don (14.63 ${\mu}g$/mL) showed the most prominent the free radical (1,1-diphenyl-2-picryl-hydrazyl, DPPH) scavenging activity ($FSC_{50}$). Reactive oxygen species (ROS) scavenging activities ($OSC_{50}$) of L. cuneata G. Don fraction on $Fe^{3+}$-EDTA/$H_2O_2$ system were investigated using the luminol-dependent chemiluminescence assay. The aglycone fraction of L. cuneata G. Don (0.07 ${\mu}g$/mL) showed the most prominent ROS scavenging activity. The protective effects of extract/fractions of L. cuneata G. Don on the rose-bengal sensitized photohemolysis of human erythrocytes were investigated. The L. cuneata G. Don extracts suppressed photohemolysis in a concentration dependent manner (1 ~ 50 ${\mu}g$/mL). The inhibitory effects ($IC_{50}$) of L. cuneata G. Don extracts on tyrosinase were determined with ethyl acetate fraction (104.83 ${\mu}g$/mL) and aglycone fraction (27.55 ${\mu}g$/mL) of L. cuneata G. Don extract. These results indicate that L. cuneata G. Don extract/fractions can function as high potential as bactericide against the pathogenic bacteria and antioxidant in biological systems, particularly skin exposed to UV radiation by scavenging $^1O_2$ and other ROS, and protect cellular membranes against ROS. Extract/fractions of L. cuneata G. Don could be applicable to new functional cosmetics for antiaging, antioxidant, and antibacterial activity.

• Korean Journal of Food Science and Technology
• /
• v.30 no.4
• /
• pp.957-963
• /
• 1998

Several medicinal herbs, which are nontoxic and have been used widely in traditional folk medicine, were extracted and antimicrobial activity of the extracts was investigated against various foodborne pathogens or food poisioning microorganisms. The ethanol extract of Sansa, Hwangryun, Cheukbaek, and Seokchangpo showed strong antimicrobial activities against Gram postive and Gram negative bacteria, whereas those of Sakunja, Sukjihwang and Baekji had little antimicrobial activities on microorganisms tested. Among medicinal herb extracts, ethanol extract of Coptis chinensis Franch (hwangryun) showed the strongest antimicrobial activity. Antimicrobial activity of ethanol extract of Coptis chinensis Franch was not destroyed by heating at $100^{\circ}C$ for 60 min and at $121^{\circ}C$ for 30 min, which is very stable over heat. The pH effect on minimal inhibitory concentrations (MIC) of the extract of Coptis chinensis Franch indicated that MIC was reduced with increasing the pH value of the medium. The inhibitory effect of partially purified substance from the ethanol extract of Coptis chinensis Franch on the growth of Listeria monocytogenes and Staphylococcus aureus was investigated. Growth of those strains occurred at the concentration of $100{\;}{\mu}g/mL$ and were inhibited at $500{\;}{\mu}g/mL$, whereas those strains was completely inactivated in the presence of $1000{\;}{\mu}g/mL$.