Possible existence of platelet aggregation inhibitor(s) in a gas-phase extract of cigarette smoke

Present study demonstrated an existence of anti-aggregation factor(s) in water-soluble extract of a gas-phase of cigarette smoke, and studied chemical characteristics of the factor(s) evaluating its inhibitory potency on platelet aggregation of human and rabbit platelets. The water-soluble extract was prepared by passing mainstream smoke of one cigarette through a Cambridge glassfiber filter and then bubbling it through 1 ml of water. The inhibitory effects were similar in both human and rabbit platelets with the final concentrations of 1 to 5% of the aqueous extract, and were also non-specific irrespective of types of agonists such as collagen, arachidonic acid, STA2 (a stable analogue of thromboxane A2), ADP or nor-adrenaline. The inhibitory effect of water-soluble extract on platelet aggregation were not affected by treatment of the extract by erythrocytes, indicating that the factor(s) was different from the one that is adsorbed by hemoglobin, such as superoxide radicals, nitric oxide (NO), nitrogen oxides (Nox), hydrogen peroxide (H2O2), carbon monoxide (CO), aldehydes, trace elements (Cd2+, Cu2+) or carcinogenic nitrosocompounds. The inhibitor(s) was stable in acidic condition under 4 degrees C but unstable in basic condition under room temperature. The anti-platelet factor(s) was retained on a reversed phase chromatography column, and eluted with 50 to 60% methanol. The substance(s) was also adsorbed by H+ and OH- form ion exchange columns, but not by Cl- form, suggesting that the substance is both basic and acidic but not so strong as to be absorbed by Cl- form column. These facts suggest that the anti-platelet substance(s) in the water extract of cigarette smoke seems to be moderately non polar, both acidic and basic in water and not adsorbed by hemoglobin.