This roe’s got a fish-E surprise

In looking for better antioxidants, an international team of scientists has stumbled onto a new form of vitamin E.

Because oxidants can damage cells, many species load up their eggs—the embodiment of their future—with antioxidants, especially vitamins C and E. While studying such antioxidants in the eggs of chum salmon, Yorihiro Yamamoto of the University of Tokyo and his colleagues found that 20 percent of the vitamin E, or alpha-tocopherol, exhibited a variant structure. It had a double bond at the end of its side chain where most alpha-tocopherol has a single bond.

Yamamoto’s group has found somewhat smaller proportions of the new variant—which he calls alpha- tocomonoenol—in the roe of sockeye salmon and walleye pollack. Traces of it even lace the eggs of flying fish and Pacific herring, the scientists report in the Dec. 27, 1999 Journal of Natural Products.

And this vitamin isn’t restricted to roe. Yamamoto’s latest studies show that the novel vitamin occurs in adult fish and certain plankton. He now suspects that this vitamin E reflects some adaptation to life in cold water. Indeed, he says, “we have good evidence that [it] outperforms alpha-tocopherol” as an antioxidant—at least in a cold-water environment.

Janet Raloff is the Editor, Digital of Science News Explores, a daily online magazine for middle school students. She started at Science News in 1977 as the environment and policy writer, specializing in toxicology. To her never-ending surprise, her daughter became a toxicologist.

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