PubMed · 10088465
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M Kawahara, T Kitagawa, M Tokiwa, T Goto. 1999. [Prostatitis syndrome].. https://pubmed.ncbi.nlm.nih.gov/10088465/
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Suzuki cross-coupling has been used to access a wide range of 3- and 5-substituted 2-pyrones, which show remarkable inhibitory activity against bacteria, yeasts and fungi. 3-Octenyl and 5-octenyl 2-pyrones inhibit human ovarium carcinoma (A2780) and human chronic myelogenous leukaemia (K562) cell lines at the micromolar level.
Despite significant advances in cancer therapy, there is an urgent need for drugs with a new mode of action that will preferentially kill cancer cells. Several cationic antimicrobial peptides, which bind strongly to negatively charged membranes, were shown to kill cancer cells slightly better than normal cells. This was explained by a slight increase (3-9%) in the level of the negatively charged membrane phosphatidylserine (PS) in many cancer cells compared to their normal counterparts. Unfortunately, however, these peptides are inactivated by serum components. Here we synthesized and investigated the anticancer activity and the role of peptide charge, peptide structure, and phospholipid headgroup charge on the activity of a new group of diastereomeric lytic peptides (containing D- and L-forms of leucine and lysine; 15-17 amino acids long). The peptides are highly toxic to cancer cells, to a degree similar to or larger than that of mitomycin C. However, compared with mitomycin C and many native antimicrobial peptides, they are more selective for cancer cells. The peptides were investigated for (i) their binding to mono- and bilayer membranes by using the surface plasmon resonance (SPR) technique, (ii) their ability to permeate membranes by using fluorescence spectroscopy, (iii) their structure and their effect on the lipid order by using ATR-FTIR spectroscopy, and (iv) their ability to bind to cancer versus normal cells by using confocal microscopy. The data suggest that the peptides disintegrate the cell membrane in a detergent-like manner. However, in contrast to native antimicrobial peptides, the diastereomers bind and permeate similarly zwitterionic and PS-containing model membranes. Therefore, cell selectivity is probably determined mainly by improved electrostatic attraction of the peptides to acidic components on the surface of cancer cells (e.g., O-glycosylation of mucines). The simple composition of the diastereomeric peptides and their stability regarding enzymatic degradation by serum components make them excellent candidates for new chemotherapeutic drugs.
The aim of this paper is to prepare and stabilise, in situ, colloidal microsuspensions of triclosan using the polymer, hydroxypropyl methylcellulose (HPMC). The suspensions were prepared from supersaturated solutions of triclosan. The cosolvent technique was used to create supersaturation. Propylene glycol and water were used as the cosolvents. The triclosan particles had a large needle-shaped morphology, when grown in the absence of the polymer. Moreover, the particles grew rapidly to sizes greater than 5 micrometer over a period of 7h. When HPMC was added, the particle sizes were in the range 90-250 nm depending on the amount of polymer present in the solutions. The stability of the solutions was evaluated over a period of 40 days during which the particle sizes did not vary. The results were consistent with the mechanism proposed by Raghavan et al. [Int. J. Pharm. 212 (2001b) 213].