Quality Testing of Tacrolimus Ointment Mixed with Various Type of Ointments or Creams.

Tacrolimus ointment is used worldwide to treat atopic dermatitis. Although tacrolimus ointment is not suitable for clinical admixtures, it is often mixed with various ointments or creams, such as corticosteroids, antibacterial agents, and moisturizing agents. There is only one report of quality testing of admixtures of tacrolimus ointment with adaparene gel (Differin® Gel). In this study, we used HPLC to evaluate the pharmaceutical stability of tacrolimus mixed with eight different dermatologic ointments or creams. No decrease in the tacrolimus content was observed in any of the mixtures after 4 weeks of storage at room temperature, indicating that tacrolimus admixtures are stable.

Farnesol-Induced Disruption of the Staphylococcus aureus Cytoplasmic Membrane.

Farnesol, a sesquiterpene alcohol with an aliphatic carbon chain, inhibited the growth of Staphylococcus aureus and induced the leakage of potassium ions. We investigated the action of farnesol on the cytoplasmic membrane of S. aureus. No ion channels that would account for the loss of potassium ions were detected. Electron paramagnetic resonance measurements suggested that farnesol proceeds into the cytoplasmic membrane of S. aureus cells, where it induces the disordering and eventual disruption of the cytoplasmic membrane. This was supported by the result that the effects of farnesol decreased by the addition of carotenoid which was the stabilizing reagent for the lipid bilayer.

Effect of farnesol on mevalonate pathway of Staphylococcus aureus.

To investigate the mechanism of action by which farnesol functions as an antibacterial agent and inhibits Staphylococcus aureus growth, the growth rates of S. aureus cultured in farnesol versus S. aureus cultured in farnesol and supplemented with 3-hydroxy-3-methylglutaryl (HMG)-CoA or mevalonate were compared. The investigation was designed to observe whether farnesol affected on the mevalonate pathway by using the intermediate metabolites of the pathway. The resulting growth curves demonstrated that mevalonate reduced the antibacterial activity of farnesol, but HMG-CoA did not inhibit farnesol. These results suggest that farnesol affects the mevalonate pathway. Moreover, farnesol inhibited HMG-CoA reductase activity in an in vitro enzymatic assay.

Effects of two terpene alcohols on the antibacterial activity and the mode of action of farnesol against Staphylococcus aureus.

We have studied changes in the antibacterial activity and the mode of action of farnesol against Staphylococcus aureus when two terpene alcohols with an aliphatic carbon chain were added, individually, to a bacterial suspension that contained farnesol. Geraniol increased the growth-inhibitory activity of farnesol, but suppressed its ability to damage cell membranes, which is one of the predominant features of the growth-inhibitory activity of farnesol. Geranylgeraniol decreased the growth-inhibitory activity of farnesol and also suppressed its cell-damaging activity. It is possible that the presence of a terpene alcohol can both enhance and suppress the antibacterial activity of farnesol, and even change its mode of action. Thus, it is important to study not only the antibacterial activity of each constituent of an essential oil but also the interactions between them in efforts to characterize the antibacterial activity of the essential oil.

Light irradiation is a factor in the bactericidal activity of silver-loaded zeolite.

Silver loaded zeolite (Ag-Z) was previously found to have effective bactericidal activity against Escherichia coli. To understand the mechanisms of bactericidal activity of Ag-Z, role of light irradiation was focused and investigated in this study. In this study, we focused on light irradiation. Antibacterial assay and spectroscopic study revealed that light irradiation enabled Ag-Z to reduce dioxygen to form a reactive oxygen species, which led to bactericidal activity. These results indicate that the onset of bactericidal activity can be controlled by light irradiation.

Antibacterial activity of long-chain fatty alcohols against Staphylococcus aureus.

The antibacterial activity against Staphylococcus aureus of long-chain fatty alcohols was investigated, with a focus on normal alcohols. The antibacterial activity varied with the length of the aliphatic carbon chain and not with the water/octanol partition coefficient. 1-Nonanol, 1-decanol and 1-undecanol had bactericidal activity and membrane-damaging activity. 1-Dodecanol and 1-tridecanol had the highest antibacterial activity among the long-chain fatty alcohols tested, but had no membrane-damaging activity. Consequently, it appears that not only the antibacterial activity but also the mode of action of long-chain fatty alcohols might be determined by the length of the aliphatic carbon chain.

Biphasic effects of geranylgeraniol, teprenone, and phytol on the growth of Staphylococcus aureus.

We examined the antibacterial activities against Staphylococcus aureus of three diterpenes, namely, geranylgeraniol, teprenone, and phytol, by using a broth dilution with shaking method to identify the effects of diterpenes with long aliphatic carbon chains. We also performed time-kill assays and measured the leakage of K(+) ions from bacterial cells in response to these diterpenes. The diterpenes used inhibited the growth of S. aureus at concentrations of 0.15 microg/ml, as determined by damage to the cell membranes, and had clear bactericidal activity. However, the inhibitory effects of the diterpenes decreased when the concentration of each was raised above a certain level. The diterpenes tested in this study appeared to have both growth-inhibitory and growth-accelerating effects, and the net effect of each depended on its concentration.

The antibacterial effects of terpene alcohols on Staphylococcus aureus and their mode of action.

The study was made of the antibacterial effects of three terpene alcohols on Staphylococcus aureus, focusing on the leakage of K+ ions and toxicity over time. The leakage of K+ ions was monitored continuously with a K+-electrode. Our results suggested that the terpene alcohols, namely, farnesol, nerolidol and plaunotol might act on cell membranes. The rank order of effectiveness, farnesol>nerolidol>plaunotol, was the same in the toxicity assay and in the examination of the leakage of K+ ions, when we considered the initial rate and the amount of leaked K+ ions. The rank order agreed with the results of a growth-inhibition assay reported previously. The antibacterial activity reflected the initial rate of leakage of K+ ions, suggesting that damage to cell membranes might be one of the major modes of action of these terpene alcohols. The results also demonstrated that the initial rate of leakage and the amount of leaked K+ ions are useful as indices of the antibacterial activities of hydrophobic compounds.

Diastereomeric selective effects for growth inhibition of synthesized mini parallel double-stranded peptides on Escherichia coli and Staphylococcus aureus.

The synthesis of a series of mini double-stranded peptides containing chiral-x-Phe-y-Phe-peptide residues and the diastereomeric selective effects of these compounds on Escherichia coli NIHJ JC-2 and Staphylococcus aureus FDA 209P growth are described. In the case of bis(y-Phe-x-Phe)-N,N-ethane-1,2-diamine, bis(y-Phe-x-Phe)-N,N-buthane-1,4-diamine, bis(y-Phe-x-Phe)-N,N-hexane-1,6-diamine, and bis(y-Phe-x-Phe)-N,N-dodecane-1,12-diamine, etc., the four configurations, (L-, L-), (D-, L-), (L-, D-) and (D-, D-), where the symbols x- and y- represent optical isomers with L- and D- forms, were used to investigate the relationship between chirality and antibacterial activity. The level of activity increased in the following order: (L-, L-)<(D-, D-)<(L-, D-)<(D-, L-). The data show that (D-, L-) chilarity is more potent than (L-, L-) chilarity. Then, these results suggest that the -y-Phe-x-Phe Phe-sequence in the double-stranded peptide has anti-bacterial activity and the chirality of -y-Phe-x-Phe affects the anti-bacterial activity. Our results show that the uptake by penetration through the membrane of bis(y-Phe-x-Phe)(2)-Spacers is a first step in the expression of anti-bacterial activity. This study provides new insights in the chirality-antibacterial activity relationships of a series of mini double-stranded peptides.

Leakage of K+ ions from Staphylococcus aureus in response to tea tree oil.

The leakage of K(+) ions from Staphylococcus aureus in response to tea tree oil (TTO) was investigated with an ion-selective electrode. The amount of leaked K(+) ions and the rate of leakage of K(+) ions induced by TTO were dependent on the concentration of TTO. Measurements of initial rates required less time than measurements of total amounts and provided an index of the interaction between TTO and the cell membrane. Thus, the initial rate of leakage might be a more useful measure of the antibacterial activity of TTO than the total amount.

Bactericidal activity of Ag-zeolite mediated by reactive oxygen species under aerated conditions.

The bactericidal activity induced by the introduction of silver ions into zeolite was studied. Escherichia coli was used as the test microorganism. Silver ions were loaded into zeolite by the ion-exchange method. Silver-loaded zeolite was demonstrated the strong bactericidal activity. Dissolved oxygen was an essential factor for the occurrence of the bactericidal activity because the activity was observed only under aerated condition. Superoxide anions, hydrogen peroxide, hydroxyl radicals and singlet oxygen were formed. Scavengers of these each reactive oxygen species (ROS) inhibited the bactericidal activity. This means that all ROS contributed to the activity.

Purification and characterization of 3,3-dihydroxyazetidine from culture medium of Bacillus mesentericus and B. subtilis.

A method is described for the purification of 3,3-dihydroxyazetidine (DHA), which accelerates the growth of Bifidobacterium spp., from the culture medium of Bacillus mesentericus (BM). Purification involved adsorption to an ion-exchange resin; it required less time and gave a higher yield than a previously reported method. Monitoring the inhibition of E. coli NIHJ JC-2, we searched for other strains that produced 3,3-dihydroxyazetidine. We found that not only B. mesentericus TO-A but also B. subtilis IFO13719 produced the compound of interest.

DNA topology: topological transformation of DNA by reaction of cisplatin-DNA-core histone complexes with human DNA topoisomerase.

Cis-diamminedichloroplatinium(II), an active antitumor agent binds to core-histone -SV40 DNA complexes prepared by reaction of DNA with core-histone, and alters the fiber-like structure into the loosened structure. In order to model the cisplatin-modified chromatin complexes in cell, the complexes were reacted with human DNA topo II. We found the generations of unique topologically isomers such as trefoil knot (and catenane) and pseudo catenane (and pseudo knot) by reaction of cis-DDP--linearDNA--core-histone complexes with DNA topo I. The results are discussed in relation with a possible recombinational role of topo II (or topo I) on the reaction with cis-DDP--DNA--core-histone complexes.