Effects of Chlorhexidine digluconate on Rotational Rate of n- (9-Anthroyloxy)stearic acid in Model Membranes of Total Lipids Extracted from Porphyromonas gingivalis Outer Membranes

The purpose of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Large unilamellar vesicles (OPGTL) were prepared with total lipids extracted from cultured Porphyromonas gingivalis outer membranes (OPG). The anthroyloxy probes were located at a graded series of depths inside a membrane, depending on its substitution position (n) in the aliphatic chain. Fluorescence polarization of n- (9-anthroyloxy)stearic acid was used to examine effects of chlorhexidine digluconate on differential rotational mobility, while changing the probes' substitution position (n) in the membrane phospholipids aliphatic chain. Magnitude of the rotational mobility of the intact six membrane components differed depending on the substitution position in the descending order of 16- (9-anthroyloxy)palmitic acid (16-AP), 12, 9, 6, 3 and 2- (9-anthroyloxy)stearic acid (12-AS, 9-AS, 6-AS, 3-AS and 2-AS). Chlorhexidine digluconate increased in a dose-dependent manner the rate of rotational mobility of hydrocarbon interior of the OPGTL prepared with total lipids extracted from cultured OPG, but decreased the mobility of membrane interface of the OPGTL. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.

Effects of Chlorhexidine Digluconate on Rotational Rate of n- (9-Anthroyloxy) stearic Acid in Porphyromonas ginginvalis Outer Membranes

The aim of this study was to provide a basis for studying the molecular mechanism of pharmacological action of chlorhexidine digluconate. Fluorescence polarization of n- (9-anthroyloxy) stearic acid was used to examine the effect of chlorhexidine digluconate on differential rotational mobility of different positions of the number of membrane bilayer phospholipid carbon atoms. The six membrane components differed with respect to 2, 3, 6, 9, 12, and 16- (9-anthroyloxy) stearic acid (2-AS, 3-AS, 6-AS, 9-AS, 12-AS and 16-AP) probes, indicating different membrane fluidity. Chlorhexidine digluconate increased the rate of rotational mobility of hydrocarbon interior of the cultured Porphyromonas gingivalis outer membranes (OPG) in a dose-dependent manner, but decreased the mobility of surface region (membrane interface) of the OPG. Disordering or ordering effects of chlorhexidine digluconate on membrane lipids may be responsible for some, but not all of its bacteriostatic and bactericidal actions.