Science / Medicine : ‘Jekyll, Hyde’ Found in Wine

<i> Times science writer Thomas H. Maugh II reports from the 197th national meeting of the American Chemical Society in Dallas</i>

Many red wines contain a “Jekyll and Hyde” chemical that is both a mutagen (a chemical causing mutations in cells) and a potent anti-cancer chemical, according to microbiologist Terrance Leighton of UC Berkeley.

The chemical, called quercetin, occurs naturally in high concentrations in onions and garlic and in lower concentrations in many fruits and vegetables, including the grapes used for making red wines. Recent studies in China have shown that Chinese who eat diets high in onions and garlic have only one-quarter as much stomach cancer as the general population there.

In his study of 250 red wines from around the world, Leighton, who owns the Kalin Cellars Winery in Novato, found quercetin only in those that had not been treated with a chemical called PVPP during “fining,” the process of removing fine solids from the wine. Quercetin binds to PVPP and is removed. Leighton noted that there is no danger in drinking red wines because the anti-carcinogenic effect of the chemical is much greater than the mutagenic effect.