Peptide surfactants antimicrobial

Recently, Infante et al. [51] synthesized acidic and basic A -lauroyl arginine dipeptides, as methyl esters and free carboxylic acids, from pure amino acids. They found that amphoteric A -lauroyl-l-arginine dipeptide surfactants containing glutamic acid or lysine had no antimicrobial activities. However, the cationic versions of these peptides were antimicrobial, particularly the dipeptide derivatives containing lysine [51]. 

Of the PBS, amino acid surfactants have been the subject of many studies, primarily on their applications as pharmaceuticals, biomedicals, cosmetics, household cleaners, and antimicrobial agents. On the other hand, except for few fragmentary reports, experimental work on peptide surfactants is relatively scanty. Both amino acid surfactants and peptide surfactants are interesting biocompatible compounds that contain amino acid or dipeptide as the hydrophilic part and a long hydrocarbon chain as the hydrophobic part. The hydrocarbon chain can be introduced through acyl, ester, amide, or alkyl linkage. 

Previous chapters have amply demonstrated that several amino acid surfactants and peptide surfactants have good antimicrobial activities. Understandably, several of the antimicrobial surfactants are still at the experimental stage, but it is important to note that many commercial PBS have been widely used as efficient and safe antimicrobial agents. The biological activity of the PBS antimicrobial activity can range from being specifically bacteriocidal or fungicidal. 

The multiple functions of peptides in foods (antioxidants, antimicrobial agents, surfactants) and their role in the development of characteristic flavors (sweetness, bitterness), as well as the information they can provide about the genuineness of foods, make peptide analysis a necessity. Producers as well as government laboratories have considerable interest in the study of peptides, both for research purposes and for the control of raw materials and manufactured foods. For this reason, substantial attention is now being focused on the development of analytical techniques designed to separate, characterize, and quantify peptides. 

The presence of peptides can also have an effect on wine quality. In general, these compounds are known to have several biological (antioxidant, antimicrobial, antihypertensive, etc.) and chemical-physical (surfactant) properties and also to affect the taste of some foods. However, peptides have received only a little attention, mainly because of the difficulties in their isolation from wines (Moreno-Arribas et al., 2002). 

Water-soluble antimicrobial Upopeptides have been prepared by the condensation of amino acids or peptides to lV -acyl arginine residues with suitable lipophilic contents. Our data suggest that such arginine lipopeptidic surfactants have value as soft preservatives in cosmetic, food, and dermopharmaceutical formulations, as well as being tools for fundamental research. 

One important milestone in our research is the design and development of new amino acid-based surfactants with antimicrobial properties, which mimic natural amphiphilic cationic peptides [42,43]. To this end, Lys and Arg derivatives of long-chain A -acyl, COO-ester, and A-alkyl amide have been prepared. In particular, the A -acylarginine methyl ester derivatives series 1 (Scheme 1) have turned out to be an important class of cationic surface active compounds with a wide bactericidal activity, high biodegradability, and low toxicity profile. We have shown that essential structural factors for their antimicrobial activity include both the length of the fatty residue (akin with their solubility and surface activity) and the presence of the protonated guanidine function [43,44]. 

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