Evaluation of the Effect of Phytol on the Formation of PAHs in Cigarette Smoke

Phytol or (2E,7R,11R)-3,7,11,15-tetramethyl-2-hexadecen- 1-ol (MW = 296.53 a.u.), is naturally present in tobacco at levels around 100-150 µg/g dry leaf, where it is bound in the form of an ester to a porphyrine type group (known as chlorin) with several substituents and chelated to Mg²⁺ ion, to form chlorophyll. This study evaluated the formation of PAHs when several levels of phytol up to ten times higher than typical phytol level were added on 3R4F cigarettes. The cigarettes were smoked under two different smoking conditions. One regimen (indicated as 35/60) used 35 mL puff volume, 2 s puff duration, each puff taken every 60 s, and in the other used 60 mL puff volume, 2 s puff duration, each puff taken every 30 s (indicated as 60/30). The increase in the PAHs level upon phytol addition was not significant. A statistical evaluation of the dependence of total PAHs and the added level of phytol showed that the hypothesis of a zero slope for the dependence line phytol/total PAHs cannot be rejected (with a p = 0.101 for 35/60 smoking and p = 0.626 for 60/30 smoking). Still, for 35/60 smoking conditions, an increase of about 14% in total levels of PAHs was noticed when the added phytol level was 1.5 mg phytol per cigarette. However, this PAHs increased level was not necessarily determined by the phytol addition, and can be caused by random procedural/analytical errors (as indicated by the statistical analysis) or by the modification of cigarettes during phytol addition. Also, the observed level is much lower than the expected 100% increase in the PAHs level, based on literature prediction. Intensive smoking did not show an increase in PAHs level at all. Flash pyrolysis of free phytol and of chlorophyll a provided results that indicated that phytol bound in chlorophyll is not likely to generate different PAHs level compared to free phytol. Thus, phytol has been shown not to be a significant contributor/ precursor to the PAHs formation in cigarette smoke.