• Journal of Microbiology and Biotechnology
• /
• v.32 no.10
• /
• pp.1284-1291
• /
• 2022

The rise of methicillin-resistant Staphylococcus aureus (MRSA) has resulted in significant morbidity and mortality, and clinical treatment of MRSA infections has become extremely difficult. Sortase A (SrtA), a virulence determinant that anchors numerous virulence-related proteins to the cell wall, is a prime druggable target against S. aureus infection due to its crucial role in the pathogenicity of S. aureus. Here, we demonstrate that isovitexin, an active ingredient derived from a variety of traditional Chinese medicines, can reversibly inhibit SrtA activity in vitrowith a low dose (IC₅₀=24.72 ㎍/ml). Fluorescence quenching and molecular simulations proved the interaction between isovitexin and SrtA. Subsequent point mutation experiments further confirmed that the critical amino acid positions for SrtA binding to isovitexin were Ala-92, Ile-182, and Trp-197. In addition, isovitexin treatment dramatically reduced S. aureus invasion of A549 cells. This study shows that treatment with isovitexin could alleviate pathological injury and prolong the life span of mice in an S. aureus pneumonia model. According to our research, isovitexin represents a promising lead molecule for the creation of anti-S. aureus medicines or adjuncts.

• Journal of Life Science
• /
• v.29 no.2
• /
• pp.223-230
• /
• 2019

Ozone is a gaseous molecule able to kill microorganisms, such as yeast, fungi, bacteria, and protozoa. However, ozone gas is unstable and cannot be used easily. In order to utilize ozone properly and efficiently, plant oil can be employed. Ozone reacts with C-C double bonds of fatty acids, converting to ozonized oil. In this reaction, ozonide is produced within fatty acids and the resulting ozonized oil has various biological functions. In this study, we showed that ozonized oil has antimicrobial activity against fungi and bacteria. To test the antimicrobial activity of ozonized oil, we produced ozonized olive oil. Ozonized olive oil was applied to Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Antimicrobial activity was assayed using the disk diffusion method following the National Committee for Clinical Laboratory Standards. Minimal inhibitory concentrations (MIC) were 0.25 mg for S. aureus, 0.5 mg for S. epidermidis, 3.0 mg for P. aeruginosa, and 1.0 mg for E. coli. Gram positive bacteria were more susceptible than Gram negative bacteria. We compared growth inhibition zones against S. aureus and MRSA, showing that the ozonized olive oil was more effective on MRSA than S. aureus. Furthermore, the ozonized olive oil killed C. albicans within an hour. These data suggested that ozonized olive oil could be an alternative drug for MRSA infection and could be utilized as a potent antimicrobial and antifungal substance.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.42 no.3
• /
• pp.285-295
• /
• 2016

To investigate the effect of dietary fiber from mozuku, Cladosiphon novae-caledoniae kylin (C. novae-caledoniae kylin) on the skin care, we measured anti-oxidant activity, anti-microbial activities, tyrosinase activity inhibition and elastic activity. B16F10 melanoma cell (MTT assay) were used to measure cell viability. MC and MI exhibited in vitro antibacterial activity against Staphyloccus aureus (S. aureus) and MRSA without antifungal activity. Mozuku extract (MS) showed excellent tyrosinase inhibition effect compared to arbutin as a positive control (to 49% for tyrosine). The wrinkle-improving effect was relatively low. However, wrinkle-improving effect was relatively low. DPPH free radical scavenging activity was 89% in a concentrations at $500{\mu}g/mL$. These results indicate that the mozuku extracts may be an effective cosmetic ingredient for skin whitening.

• Archives of Pharmacal Research
• /
• v.28 no.9
• /
• pp.1031-1036
• /
• 2005

[ $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ ] (1) was isolated from an ethyl acetate extract of the root bark from Lycium chinense Miller, and its structure was determined using 1D and 2D NMR spectroscopy including DEPT, HMQC, and HMBC. $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ exhibited potent antimicrobial activity against antibiotic-resistant bacterial strains, methicillin-resistant Staphylococcus aureus (MRSA) isolated from patients, and human pathogenic fungi without having any hemolytic effect on human erythrocytes. In particular, compound 1 induced the accumulation of intracellular trehalose on C. albicans as stress response to the drug, and disrupted the dimorphic transition that forms pseudo-hyphae caused by the pathogenesis. This indicates that $(+)-Lyoniresinol-3{\alpha}-O-\beta-D-glucopyranoside$ has excellent potential as a lead compound for the development of antibiotic agents.

• Journal of Microbiology and Biotechnology
• /
• v.24 no.1
• /
• pp.44-47
• /
• 2014

A biotransformation approach using microbes as biocatalysts can be an efficient tool for the targeted modification of existing antibiotic chemical scaffolds to create previously uncharacterized therapeutic agents. By employing a recombinant Streptomyces venezuelae strain as a microbial catalyst, a reduced macrolide, 10,11-dihydrorosamicin, was created from rosamicin macrolide. Its chemical structure was spectroscopically elucidated, and the new rosamicin analog showed 2-4-fold higher antibacterial activity against two strains of methicillin-resistant Staphylococcus aureus compared with its parent rosamicin. This kind of biocatalytic approach is able to expand existing antibiotic entities and can also provide more diverse therapeutic resources.

• Korean Journal of Clinical Laboratory Science
• /
• v.47 no.3
• /
• pp.140-146
• /
• 2015

The increase in resistance by pathogenic bacteria to multiple antimicrobial agents has become a significant treat, as the effective antimicrobial agents available for the patients infected by such resistant bacteria are reduced, or even eliminated. Several natural plant extracts have exhibited antibacterial and synergistic activity against various resistant microorganisms. Houttuynia cordata is frequently used by many traditional medicine practicioners for its antimicrobial, antiviral, and anti-inflammatory properties. This study investigated the antibacterial effects of H. cordata extract against clinical multi-resistant bacteria, and compared the two methods used for the antimicrobial susceptibility testing. Thirty isolates of Methicillin-resistant Staphylococcus aureus (MRSA, 10), Vancomycin-resistant Enterococcus faecium (VRE, 10), Carbapenem-resistant Acinetobacter baumannii (CRAB, 10) were included in this study. The antibacterial effect of H. cordata was tested by disk diffusion and microbroth dilution methods as per CLSI guidelines. In disk diffusion, all isolates (30) showed no inhibition to 30,000 ug/mL of H. cordata. But in the microbroth dilution method, $MIC_{90}$ of H. cordata was 4,096 ug/mL, 8,192 ug/mL and 4,096 ug/mL in MRSA, VRE and CRAB, respectively. These results demonstrate that H. cordata exhibits antibacterial activity against MRSA, VRE and CRAB. Moreover, the microbroth dilution method is a more effective method than disk diffusion to evaluate the antibacterial activity of natural products. The Disk diffusion method used to evaluate the antibacterial activity of natural products required new standard guidelines including inoculum concentration of bacteria.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.12
• /
• pp.503-511
• /
• 2017

This study was conducted to evaluate the anti-inflammatory activity and clinical efficacy of a sample (A.C.C. extracts) obtained by distillation extraction of 14 herbal medicines including Phellodendron bark. To confirm this, the amount of nitric oxide (NO) produced by the cells in RAW 264.7 cells stimulated by lipopolysaccharide (LPS) and the changes in the production of inflammatory cytokines such as tumor necrosis factor (TNF)-${\alpha}$, interleukin(IL)-$1{\beta}$ and IL-6 were determined. The results showed that A.C.C. extracts strongly inhibited the production of NO and inflammatory cytokines increased by LPS without cytotoxicity. In addition, A.C.C. extracts showed strong bacterial reduction rates of 99.9% in Pseudomonas aeruginosa, Staphylococcus aureus, MRSA (Methicillin-resistant Staphylococcus aureus), Candida albicans and Streptococcus mutans. These findings indicate that A.C.C. extracts are effective ingredients with a strong antimicrobial effect together with an anti-inflammatory effect. In addition, when A.C.C. extracts were applied to infants and toddlers who were suffering from diaper rash, itching, and perspiration symptoms, symptoms of rash, atopy, rash, itching, and heat rash were improved. After the lapse of time, it was visually confirmed that it was considerably relaxed. These findings confirm that A.C.C. extracts comprise a clinically effective anti-inflammatory and anti-bacterial agent that alleviates symptoms such as diaper rash and fever and may therefore be an effective alternative to inflammatory diseases.

• Korean Journal of Pharmacognosy
• /
• v.47 no.2
• /
• pp.122-127
• /
• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• IMMUNE NETWORK
• /
• v.21 no.2
• /
• pp.13.1-13.19
• /
• 2021

Macrophages are important for the first line of defense against microbial pathogens. Integrin CD11b, which is encoded by Itgam, is expressed on the surface of macrophages and has been implicated in adhesion, migration, and cell-mediated cytotoxicity. However, the functional impact of CD11b on the inflammatory responses of macrophages upon microbial infection remains unclear. Here, we show that CD11b deficiency resulted in increased susceptibility to sepsis induced by methicillin-resistant Staphylococcus aureus (MRSA) infection by enhancing the pro-inflammatory activities of macrophages. Upon infection with MRSA, the mortality of Itgam knockout mice was significantly higher than that of control mice, which is associated with increased production of TNF-α and IL-6. In response to MRSA, both bone marrow-derived macrophages and peritoneal macrophages lacking CD11b produced elevated amounts of pro-inflammatory cytokines and nitric oxide. Moreover, CD11b deficiency upregulated IL-4-induced expression of anti-inflammatory mediators such as IL-10 and arginase-1, and an immunomodulatory function of macrophages to restrain T cell activation. Biochemical and confocal microscopy data revealed that CD11b deficiency augmented the activation of NF-κB signaling and phosphorylation of Akt, which promotes the functional activation of macrophages with pro-inflammatory and immunoregulatory phenotypes, respectively. Overall, our experimental evidence suggests that CD11b is a critical modulator of macrophages in response to microbial infection.

• Natural Product Sciences
• /
• v.23 no.1
• /
• pp.5-8
• /
• 2017

An antimicrobial compound has been isolated from the leaves of Glochidion superbum. The compound was determined as methyl 3, 4, 5-trihydroxybenzoate (methyl gallate), based on ultraviolet (UV), infrared (IR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS) analysis. The isolated compound exhibited potent antimicrobial activity against three clinical isolates of methicillin resistant Staphylococcus aureus (MRSA) by qualitative agar disc diffusion method and quantitative broth dilution method. Agar disc diffusion was done in a dose-dependent manner for each bacterial isolate at disc potencies of 25, 50, 100, and $150{\mu}g/disc$. The zones of inhibition were on average equal to 12.27, 14.20, 15.43, and 24.17 mm respectively. The inhibition zones were compared with that of vancomycin disc at $30{\mu}g$ as a reference standard. The MIC and MBC values were $50{\mu}g/ml$ and $100{\mu}g/ml$ respectively. The results of anti MRSA activity were analyzed using one-way ANOVA with Turkey's HSD and Duncan test. In conclusion, methyl gallate which was isolated from G. superbum showed the inhibition activity against methicillin resistant S. aureus.