The Center for Science in the Public Interest, an advocacy group for food safety and nutrition, said the company's advertising and packaging suggest that the drinks contain antioxidants from blackberries, cherries, cranberries, pomegranates and raspberries, rather than added Vitamin E.

Chris Barnes, a Dr Pepper Snapple spokesman, in an emailed statement called the lawsuit "another attempt by the food police at CSPI to mislead consumers about soft drinks."

Antioxidants help protect cells from damage caused by free radicals, which are unstable molecules associated with cancer, according to the National Cancer Institute.

In December 2008, the U.S. Food and Drug Administration objected to labeling in which Coca-Cola Co described its now-discontinued Diet Coke Plus drink as "Diet Coke with Vitamins & Minerals."

The FDA told the world's largest soft-drink maker it "does not consider it appropriate to fortify snack foods such as carbonated beverages."

Barnes said Dr Pepper Snapple's label for 7UP Cherry meets FDA regulations, and says the drink does not contain juice. He also said a new formulation of that product, to be available in February, will not contain antioxidants.

Thursday's lawsuit was filed with the U.S. District Court in Los Angeles. It seeks class-action status on behalf of purchasers nationwide of the products, a variety of financial damages, and a halt to the alleged misleading advertising.

The named plaintiff is David Green, a resident of Sherman Oaks, California, who said he would not have bought the soft drinks had he known their antioxidants did not come from fruit.

Dr Pepper Snapple launched 7UP Cherry Antioxidant in 2009. It also sells a diet version of that product, as well as 7UP Mixed Berry Antioxidant and Diet 7UP Mixed Berry Antioxidant, according to its website.

Shares of Dr Pepper Snapple closed down 30 cents at $43.24 in Thursday trading on the New York Stock Exchange.

The case is Green v. Dr Pepper Snapple Group Inc, U.S. District Court, Central District of California, No. 12-09567.

(Reporting by Jonathan Stempel in New York; Editing by Phil Berlowitz)

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