Chlorhexidine is a cationic bisbiguanide with broad antibacterial activity, and diverse activity encompassing gram-positive and gram-negative bacteria, yeasts, dermatophytes, and some lipophilic viruses. Chlorhexidine alters the permeability of the bacterial membrane. They also neutralize periodontal pathogens such as Streptococcus aureus, Porphyromonas gingivalis, and Prevotella intermedia. Porphyromonas gingivalis were cultured to isolate the Porphyromonas gingivalis outer membranes (OPG). Also, OPG were used to prepare large unilamellar liposomes with total lipids (OPGTL) extracted and prepared with the phospholipids mixture (PL). The effect of chlorhexidine digluconate on cell membrane kinetic changes was investigated using fluorescence polarization of n-(9-anthroyloxy) stearic acid with different rotational mobility depending on the probe substitution position (n) in the membrane phospholipid aliphatic chain. Chlorhexidine digluconate increased the hydrocarbon rotational mobility interior of the OPG, OPGTL and PL, but native and model membranes interfacial mobility were decreased. The sensitivity to increasing chlorhexidine digluconate effect on rotational mobility was proportional to the depth of probe position in descending order of 16-AP, 12-AS, 6-AS and 9-AS. Chlorhexidine digluconate disordering or ordering the effects on the membrane lipids may cause its bacteriostatic and bacteriocidal actions.

The aim of this study was to provide a basis for the molecular mechanism underlying the pharmacological action of ethanol. We studied the effects of 1-propanol on the location of n-(9-anthroyloxy)palmitic acid or stearic acid (n-AS) within the phospholipids of synaptosomal plasma membrane vesicles (SPMV). The SPMV were isolated from the bovine cerebral cortex and liposomes of total lipids (SPMVTL) and phospholipids (SPMVPL). 1-Propanol increased the rotational mobility of inner hydrocarbons, while decreasing the mobility of membrane interface, in native and model membranes. The degree of rotational mobility varied with the number of carbon atoms at positions 16, 12, 9, 6 and 2 in the aliphatic chain of phospholipids in the neuronal and model membranes. The sensitivity of increasing or decreasing rotational mobility of hydrocarbon interior or surface by 1-propanol varied with the neuronal and model membranes in the following order: SPMV, SPMVPL and SPMVTL.

To provide a basis for studying the pharmacological actions of tetracaine HCl, we analyzed the membrane activities of this local anesthetic. The n-(9-anthroyloxy) stearic and palmitic acid (n-AS) probes (n = 2, 6, 9, 12 and 16) have been used previously to examine fluorescence polarization gradients. These probes can report the environment at a graded series of depths from the surface to the center of the membrane bilayer structure. In a dosedependent manner, tetracaine HCl decreased the anisotropies of 6-AS, 9-AS, 12-AS and 16-AP in the hydrocarbon interior of synaptosomal plasma membrane vesicles isolated from bovine cerebral cortex (SPMV), and liposomes derived from total lipids (SPMVTL) and phospholipids (SPMVPL) extracted from the SPMV. However, this compound increased the anisotropy of 2-AS at the membrane interface. The magnitude of the membrane rotational mobility reflects the carbon atom numbers of the phospholipids comprising SPMV, SPMVTL and SPMVPL and was in the order of the 16, 12, 9, 6, and 2 positions of the aliphatic chains. The sensitivity of the effects of tetracaine HCl on the rotational mobility of the hydrocarbon interior or surface region was dependent on the carbon atom numbers in the descending order 16-AP, 12-AS, 9-AS, 6-AS and 2-AS and on whether neuronal or model membranes were involved in the descending order SPMV, SPMVPL and SPMVTL.