Nicotiana alkaloids-intervened phospholipid ozonolysis at the air-water interface

Cigarette nicotiana alkaloids associated with lung and cardiovascular diseases attack enormous attention. However, the mechanism at the molecular level between nicotiana alkaloids and phospholipid ozonolysis remains elusive. Herein, we investigated the interfacial ozonolysis of a hung droplet containing 1-palmitoyl-2-oleoyl-sn-phosphatidylglycerol (POPG) intervened by nicotiana alkaloids (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, NNK; rac-N'-nitrosonornicotine, NNN; nicotine; and (R,S)-N-nitrosoanasabine, NAT) and followed by on-line mass spectrometry analysis. NNK and NNN showed an acceleration on the interfacial ozonolysis, while nicotine and NAT inhibited this chemistry. Such acceleration/inhibition on POPG ozonolysis was positively correlated with nicotiana alkaloid concentrations. The reaction rate constants suggested that the ozonolysis of lung phospholipids exposed to cigarette smoke at the air-water interface occurred rapidly. A possible mechanism of the hydrophilic/oleophilic nature of nicotiana alkaloids mediating the packing density of POPG was proposed. NNK and NNN with a hydrophilic nature inserted into the POPG monolayer loosed the packing, but nicotine and NAT with an oleophilic nature let the POPG closely pack and shield the CC double bonds exposed to ozone (O₃₎. These results gain the knowledge of nicotiana alkaloids mediated phospholipid ozonolysis at the molecule level and provide a method for online interfacial reaction studies associated with elevated indoor pollutants on public health.