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A rapid and simple two-step procedure suitable for both small-and large-scale purification of pediocin-like bacteriocins and other cationic peptides has been developed. In the first step, the bacterial culture was applied directly on a cation-exchange column (1-ml cation exchanger per 100-ml cell culture). Bacteria and anionic compounds passed through the column, and cationic bacteriocins were subsequently eluted with 1 M NaCl. In the second step, the bacteriocin fraction was applied on a low-pressure, reverse-phase column and the bacteriocins were detected as major optical density peaks upon elution with propanol. More than 80% of the activity that was initially in the culture supernatant was recovered in both purification steps, and the final bacteriocin preparation was more than 90% pure as judged by analytical reverse-phase chromatography and capillary electrophoresis.Gene-encoded, ribosomally synthesized antimicrobial peptides are widely distributed in nature, being produced by bacteria, plants, and a wide variety of animals, including humans (28,29,32,34). The peptides are often cationic and amphiphilic or hydrophobic, and many of them kill bacteria by permeabilizing the target cell membrane. The peptides may be developed into new and useful antimicrobial additives and drugs. An example of this is the antimicrobial peptide nisin, which is produced by lactic acid bacteria (LAB). This peptide is used as a food preservative (9) and has been considered for use for treatment of gastric Heliobacter infections and/or ulcers (16).There has especially been considerable interest in antimicrobial peptides (bacteriocins) produced by LAB because of the "food-grade quality" and industrial importance of these bacteria. LAB are used in food production, are part of the natural microbial flora in food that humans have consumed for centuries, and constitute a significant part of the indigenous flora of mammals, including humans. Thus, LAB and the bacteriocins that they produce may be considered safe agents for preventing growth of pathogenic and/or undesirable microorganisms.Many of the LAB bacteriocins belong to the pediocin-like family; these bacteriocins are of special interest because of their antilisterial activity. The family contains at least 15 different bacteriocins, of which pediocin PA-1 (3,19,23,30), leucocin A UAL-187 (17), mesentericin Y105 (18), sakacin P (35) and curvacin A (identical to sakacin A [20,35]) were the first to be identified. All pediocin-like bacteriocins are cationic, contain between 35 and 50 amino acid residues, permeabilize target cell membranes, and have very similar primary structures but differ markedly with respect to their target cell specificity (5-7, 10-14, 22, 24, 29, 32, 37).The use of pediocin-like bacteriocins and other antimicrobial peptides as additives or drugs requires a simple and rapid method by which large quantities may be purified to homogeneity. Present methods for purification of pediocin-like bacteriocins and other cationic bacteriocins generally include a centrifugati...

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Alkaloids are natural, semisynthetic or synthetic organic compounds, normally polar with basic chemical properties and containing at least one nitrogen atom in a heterocyclic ring. Some synthetic or semisynthetic substances resemble the alkaloid architecture. Trivalent nitrogen in these substances is normal; however, some natural and semisynthetic alkaloids have pentavalent nitrogen. The drug pholcodine is a derivative of morphine. Pholcodine has very little addictiondeveloping effect. It is a semisynthetic alkaloid that was first synthesized in 1950 by Chabrier et al. Pholcodine possesses antitussive (cough relief) properties similar to codeine, morphine and ethylmorphine. The drug was used in liquid formulations as Tuxi and Tuxi Forte, and it is in present use in Tuxidrin as liquid mixture and in tablet form. Pholcodine is an Active Pharmacological Ingredient (API) in tablets and liquid mixtures. Leiras International and Weifa in Norway manufacture medical forms with pholcodine. Several impurities in pholcodine were described by J. Røe in 1997 and by Denk et al. in 2000 and. In addition, several degradation products may be formed in liquid formulations under storage. Some of these products are related not to the original production of pholcodine but rather to its oxidation under storage. The appearance of degradation products strongly depends on the storage temperature and pH of the liquid phase. Pholcodine-N-oxide and pholcodine-N,N'-dioxide are among the degradation (oxidation) products; pholcodine can also degrade to morphine. There is little information about the toxicity of the N-oxide and no information on the N,N'-dioxide of pholcodine. In this study, the fact that morphine is generated during the storage of formulations containing pholcodine is presented. Another antitussive mixture under the name Cosylan was analyzed to examine the oxidation of ethylmorphine to ethylmorphine-N-oxide. Ethylmorphine is the API in Cosylan.