Lipophilic compounds in garlic decrease the toxicity of methylmercury by forming sulfur adducts

Abstract

Garlic (Allium sativum L.) contains numerous sulfur compounds. We have previously found that reactive sulfur species such as glutathione persulfide, glutathione polysulfide, protein-bound persulfides, and hydrogen sulfide can bind to methylmercury to give bismethylmercury sulfide, which is less toxic than methylmercury. It was not clear, however, whether such reactive sulfur species are present in garlic. The aim of the study presented here was to determine whether garlic contains reactive sulfur species that can bind to methylmercury. We extracted garlic with organic solvents and then performed silica gel column chromatography to separate constituents that could cause bismethylmercury sulfide to form. We found numerous garlic constituents could bind to methylmercury to form bismethylmercury sulfide. A hexane extract of garlic decreased methylmercury cytotoxicity in vitro and body weight loss in mice. The results suggest that ingesting garlic may decrease methylmercury toxicity by causing the formation of sulfur adducts that inhibit adverse reactions.

Keywords: Allium sativum L.; Bismethylmercury sulfide; Garlic; Methylmercury; Persulfide; Sulfane sulfur.