Dr. Irwin Gunsalus; discovered lipoic acid, a form of vitamin B6

NEW YORK - Irwin C. Gunsalus, who discovered the vitaminlike substance lipoic acid, which has been used as a treatment for chronic liver disease, and one of the active forms of vitamin B6, essential in metabolism, died Oct. 25 at his home in Andalusia, Ala. He was 96.

The cause was congestive heart failure, said his daughter C.K. Gunsalus of Urbana, Ill.

Dr. Gunsalus, a nutritional biochemist who was long associated with the University of Illinois at Urbana-Champaign, also led genetic-engineering research as an assistant secretary general of the United Nations.

He was granted a patent on lipoic acid in 1962. His work at the University of Illinois led, in the 1970s, to the use at other medical institutions of lipoic acid to treat liver disease and more recently to experimental treatment of pancreatic and other cancers.

Lipoic acid is found naturally in a variety of organ meats, including kidney, heart, and liver, and in potatoes, broccoli, and spinach. It is proposed as a dietary supplement to prevent or delay conditions like Parkinson's and Alzheimer's diseases, but its efficacy has not been proved.

Trained as a bacteriologist and searching, in the early 1950s, for essential growth factors in the digestive system bacterium Enterococcus, Dr. Gunsalus discovered chemical forms of lipoic acid, including lipoate, which he called pyruvate oxidation factor, as well as one of the B6 (pyridoxine) vitamins, now called pyridoxal phosphate.

He later discovered the roles the compounds play in the metabolism of microbes, plants, and mammals.

Dr. Gunsalus studied first at South Dakota State University, and then transferred to Cornell University, where he earned bachelor's, master's, and doctoral degrees in bacteriology.

From 1940 to 1947, Dr. Gunsalus taught bacteriology at Cornell, while leading investigations of disease risk and food safety during World War II.

After the war he moved to Indiana University, serving as a professor of bacteriology until 1950, when he joined the Illinois faculty as a professor of microbiology. In 1955, he changed his scientific specialty to become chairman of the division of biochemistry, a department he headed at Illinois until 1966.

Together with Roger Y. Stanier, he wrote several volumes of "The Bacteria: A Treatise on Structure and Function."

His first marriage, to Merle Lamont Gunsalus, ended in divorce. His second wife, Carolyn Foust Gunsalus, his third wife, Dorothy Clark Gunsalus, and one son, Gene, all died before him.

In addition to his daughter, he leaves five other children, Ann Gunsalus Miguel, Glen, Kristin C., Richard, and Robert; a sister, Anna Gunsalus Higgs; and seven grandchildren.