Membrane active agents

V-acetyl-3-0-1 -carboxyethyl- membrane-active agents 178 anaphylaxis 135... 

Wagner E (1998) Effects of membrane-active agents in gene delivery. J Control Release 53 155-158... 

Rozema DB, Ekena K, Lewis DL, Loomis AG, Wolff JA (2003) Endosomolysis by masking of a membrane-active agent (EMMA) for cytoplasmic release of macromolecules. Bioconjug Chem 14 51-57... 

OTHER CELL WALL- OR MEMBRANE-ACTIVE AGENTS DAPTOMYCIN... 

Biocides probably have multiple target sites on viral particles and the overall damage caused results in loss of viral infectivity (Table 5.1). When compared to bacterial cells, however, viruses present only a few structural targets to biocides the envelope (when present), the glycoproteins, the capsid and the nucleic acid. The activity of biocides against the viral envelope has not been well documented but it can be expected that membrane-active agents such as phenolics and the cationic biocides (e.g. chlorhexidine and quaternary ammonium compounds — Q ACs) will act against the viral envelope, which is a typical unit membrane. The capsid is... 

Both spheroplasts and protoplasts are equally sensitive to lysis by membrane-active agents such as quaternary ammonium compounds (QACs), phenols and chlorhexidine. This demonstrates that the difference in sensitivities of whole cells to these agents is not due to a difference in sensitivity of the target cytoplasmic membrane but in the different permeability properties of the overlying wall or envelope structures. 

Ginsburg, I., Gibbs, D. F., Schuger, L., Johnson, K. J., Ryan, U.S., Ward, P. A., and Varani, J., Vascular endothelial cell killing by combination of membrane-active agents and hydrogen peroxide, Free Radicals Biol. Med., 7, 369, 1989. 

Suppression of Atherogenesis with a Membrane-Active Agent-Nifedipine... 

Soon after the 1988 communication on cephalostatin 1, it was predicted41 that the compound acts on the cell membrane. Steroids are components of eukaryotic cell membranes, where they incorporate into one half of the phospholipid bilayer and provide rigidity. Taking into account the dimeric nature of the cephalostatins, these steroids may now traverse the full length of the bilayer (for example, cephalostatin 1 is 30 A x 9 A x 5 A) and adversely affect its properties. A number of other highly oxygenated marine natural products (e.g. brevetoxin, palytoxin) are also membrane active agents. 

When oat roots were used for bioassay, zoospores were first attracted and then caused lysis which raises the possibility that oat crops and their residues might be used to reduce soil populations of zoosporic plant pathogens. The cystospores were insensitive to concentrations of saponins or oat root extract that lysed zoospores. The zoospores lytic principle in oat root extract/exudate was believed to be a saponin, avenacin (61). The effects of avenacin (61) or root extracts on zoospores were identical to those of /0-aescin and consistent with a role of membrane active agents. Toxic effects of saponins on zoospores were also observed in Pseudoperonospora humuli Miyabe Takah. and Phytophthora spp. [139,140]. 

Many investigators have offered explanations for QAC mechanisms of antimicrobial action. Most theories center on the interactions between QACs and the membranes of their target cells. The surfactant nature of these agents suggests that they act as other membrane-active agents, perturbing homeostasis. However,... 

Much useful information on the mechanism of action of membrane-active agents has come from studies of their effects upon artificial lipid membranes... 

The antistaphylococcal activity of 4-n-alkylphenols increases with increasing alkyl chain length from 2 to 6 carbon atoms [95], As the length of the alkyl chain increases so the water solubility falls, the lipid solubility rises, and the molecules become more surface active [95]. Penetration into the lipid-rich interior of the cell membrane therefore appears to be an important step in the antimicrobial action of the alkylphenols. Fattened staphylococci with increased Hpid content display some resistance to the alkylphenols because the molecules are bound to the extra lipid and are thereby denied access to the membrane [95]. Conversely, lipid-depleted cells are more sensitive than normal cells to alkylphenols and other membrane-active agents [96]. 

Chlorhexidine (7) is another membrane-active agent which has an effect upon the outer membrane of Gram-negative bacteria. Hugo and Longworth [47]... 

Especially remarkable is the high activity of PCMC against lipophilic, enveloped viruses, such as Herpes, simplex, Hepatitis B or HIV viruses. As other phenolic membrane active agents also PCMC exhibits a weak effect only on naked viruses and resistant bacterial spores (e.g. bacillus spores). However, a fully virucidal effect is achievable by combining PCMC formulations with small concentrations of glutaraldehyde (2.5.). 

Sorbic acid is a naturally occurring compound, its lactone ( sorbic oil ) is found in Sorbus acuparia. It is justified to characterize sorbic acid as one of the least toxic of all the preservative agents known. In its undissociated form it is a membrane active agent which due to its unsaturated character additionally may exhibit electrophilic activity. Therefore sorbic acid is able to penetrate the microbial cell membrane and to inhibit nutrient transport... 

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