# NMR Analysis of Pulegone in Food Products
## 2 Results and Discussion
### Toxicological Assessment of Pulegone  
The toxicological assessment was conducted by comparing the pulegone exposure from recommended serving sizes to established safety thresholds (TDI, NOEL, NOAEL) using a standard 60 kg body weight reference. The toxicological impact of pulegone in food was assessed in accordance with the manufacturer's recommended consumption guidelines and typical quantities used in recipes sourced from the Internet. The manufacturer recommends dissolving 1 to 2 drops of peppermint oil in 100 to 150 mL of water. The mass of a single drop of peppermint oil was determined as being 25.0 \(\pm\) 3.1 mg (n = 10). Therefore, with two drops of peppermint oil in 100 mL of water and an average pulegone content of 1.12 \(\pm\) 0.03% in the oil, a pulegone concentration of 0.56 mg/100 mL is consumed. Thus, a 60 kg individual consumes a pulegone concentration of 0.01 mg/kg bw. The consumed concentration is one-tenth of the TDI (0.1 mg/kg bw) [21].  
One manufacturer of corn mint oil recommends the ingestion of a solution comprising three drops of oil in 100 mL of water for the purpose of maintaining fresh breath. The mass of a single drop of corn mint oil is 50.0 \(\pm\) 3.3 mg (n = 10). Therefore, 150 mg of oil in 100 mL corresponds to a pulegone concentration of 1.3 mg/100 mL. This is based on an average pulegone content of 0.89 \(\pm\) 0.05% in the oil, which was determined in this study. A 60 kg individual consumes a pulegone concentration of 0.02 mg/kg bw. This pulegone intake was one-fifth lower than the TDI. It can be reasonably assumed that corn mint oil is consumed in this dilution after each meal, with three meals consumed per day. This would result in an intake of 4.01 mg of pulegone per day. Thus, a 60 kg individual ingests a  
Figure 7: Section of a spectrum of herb mint 3, recorded in CDCl\({}_{3}\). The signal marked in green is pulegone, and to the left is the signal of carvone. I: integral, \(\delta\): chemical shift.  
pulegone concentration of 0.07 mg/kg bw, which is 30% below the TDI. It can therefore be assumed that the manufacturer's recommended intake is not of toxicological concern.  
Pennyroyal and spearmint are used as herbs in the kitchen. In online recipes, mint is typically recommended in quantities ranging from one-half to three-quarters of a tablespoon per serving [32; 33]. The mass of a tablespoon of spearmint was determined to be 3.30 \(\pm\) 0.4 g (n = 10), while the mass of a tablespoon of pennyroyal was found to be 2.44 \(\pm\) 0.2 g (n = 10). Therefore, three-quarters of a tablespoon of spearmint and pennyroyal yield 2.48 g and 1.83 g, respectively.  
The average pulegone content in spearmint determined in this study is 391 \(\pm\) 38 mg/kg. This means that 2.48 g of spearmint contains 1.21 mg of pulegone. A person weighing 60 kg consumes a pulegone concentration of 0.02 mg/kg bw with 2.48 g of spearmint. The consumption of a pulegone dose of 0.02 mg/kg bw corresponds to one-fifth of the TDI.  
The pulegone content in pennyroyal is 1504 \(\pm\) 409 mg/kg. With 1.83 g of pennyroyal, 2.75 mg of pulegone is consumed. This means that a 60 kg individual consumes 0.05 mg of pulegone per kg bw. This corresponds to approximately half of the TDI.  
Because the consumption of both pennyroyal and spearmint does not exceed the TDI for pulegone [20; 21], it can be assumed that there is no risk to human health. This result also confirms a more recent risk assessment based on benchmark dose-response modeling [34].