Photochemistry of Fragrance Materials. II. Aromatic Compounds and Phototoxicity

Determination of 5-methoxypsoralen in human serum

A high performance liquid chromatography with fluorometric and ultraviolet detection described to quantify 5-methoxypsoralen (5-MOP) percutaneous absorption in humans after the application of an essential oil, as well as 5-MOP in bergamot oil and cosmetics by fluorometric and voltammetric measurement, respectively. A muBondapack C(18) analytical column (particle size 5 microm, 3.9 x 300 mm) eluted with acetonitrile-tetrahydrofuran-water (70:15:15, v/v/v) containing 0.07% trifluoroacetic acid. The quantification limits are 0.05 and 0.26 ng for 5-MOP and 5-geranoxypsoralen, respectively. For fluorometric measurement was found linear over the range 0.05-3.00 microg/ml for psoralens. Five volunteers blood samples were collected over a 2-day period were investigated before and after treatment with bergamot oil. Serum levels of 5-MOP were significantly increased from the 4 h after the application of bergamot essential oil. The hourly mean levels were significantly higher after the application of bergamot essential oil compared to baseline values.

Photochemical reactions of flavor compounds

Photochemical reaction is a chemical reaction which is initiated by light. In addition to light, photosensitizer and oxygen are the two important factors which contribute to the formation of photochemical products. In this contribution, photochemical reactions of flavor compounds are classified into four categories according to the factors of photosensitizer and oxygen. Photochemical reaction with or without sensitizer in the absence of oxygen and unsensitized photochemical reaction in the presence of oxygen usually involve free radical reactions; while in the presence of oxygen and sensitizer, the singlet oxygen can be generated that then reacts with flavor compounds which contain double bonds to give the oxygenated products.