Oxidative stress is an imbalance between generation of reactive oxygen species (ROS) and ability to detoxify ROS by the antioxidant system in cells or tissues. ROS is associated with many human diseases and can be induced by environmental stressors. On molecular level, excess ROS can induce the generation of several oxidation products, in which formaldehyde is a remarkable one.

For assessing risks of oxidative stress, it is essential to develop method for monitoring biomarkers. Hence, we first monitored N6-formyl-lysine (FK), an adduct formed between formaldehyde and lysine residues in protein, using a developed liquid chromatography-tandem mass spectrometry method. It was exhibited for the first time that Aristolochic Acid I (AA-I) exposure led to organotropic increase of FK in rats,...[ Read more ]

Oxidative stress is an imbalance between generation of reactive oxygen species (ROS) and ability to detoxify ROS by the antioxidant system in cells or tissues. ROS is associated with many human diseases and can be induced by environmental stressors. On molecular level, excess ROS can induce the generation of several oxidation products, in which formaldehyde is a remarkable one.

For assessing risks of oxidative stress, it is essential to develop method for monitoring biomarkers. Hence, we first monitored N6-formyl-lysine (FK), an adduct formed between formaldehyde and lysine residues in protein, using a developed liquid chromatography-tandem mass spectrometry method. It was exhibited for the first time that Aristolochic Acid I (AA-I) exposure led to organotropic increase of FK in rats, suggesting the possible role of oxidative stress and FK formation in the pathophysiology of AA-I. Besides, we investigated a new biomarker, (S)-1-((((R)-2-amino-2-carboxyethyl)thio)methyl)-5-oxopyrrolidine-2-carboxylic acid (COCA), which is formed between formaldehyde and γ-glutamylcysteine (GGC). Results showed that COCA could serve as a potential biomarker of oxidative stress and formaldehyde exposure. Moreover, formation of COCA suggested a potential undiscovered mechanism under the protective effect of GGC against oxidative damage.

In order to reduce oxidative damage, we then explored some naturally existing dietary antioxidants in beverage (grape wine) and condiment (soy sauce). Our developed sample processing and instrumental methods successfully proved the occurrence of thiazolidine derivatives in grape wine and soy sauce samples. Furthermore, we examined their corresponding antioxidative properties in human cell model. Results suggested that thiazolidine derivatives may contribute to the health benefits of wine and soy sauce.

It is anticipated that monitoring formaldehyde conjugates can help assess risks of oxidative stress induced by environmental stressors. Furthermore, quantitation of dietary antioxidants and comparison of their antioxidative properties could contribute to facilitating evaluation of various health benefits of beverages.