Investigation of the Interaction Between Sodium (meta) Arsenite and Catechin via ESI Tandem Mass Spectrometry

Catechin, one of the main components of green tea, is considered to have the remedy effect of arsenic poison, although the chemical mechanism is not well known. In this study, sodium (meta) selenite, which is used as herbicide and insecticide as well as rodenticide, was simply mixed with catechin in the CH3OH/H2O (volume ratio 50:50) solution to investigate the interaction between toxic inorganic arsenic compound and catechin via ESI tandem mass spectrometry. The interaction products of mono-methylated arsenic with catechin in the presence of methanol were identified in the negative mode. Collission induced dissociation (CID) mass spectrometric measurements indicate that monomethylated arsenic was “alkylated” strongly by conjugation at the sites of C2′ and C5′ in the phenyl ring B of the catechin. The interaction mechanism between sodium (meta) arsenite and catechin was proposed. The results provide useful information to understand the chemical pathway of the detoxification of the arsenic toxicity by catechin.