Antioxidant and Antihemolytic Activity of a New Isoflavone, “Factor 2” Isolated from Tempeh

A new isoflavone assigned the trivial name “Factor 2” which was first isolated from tempeh, fermented soybean product, and identified as 6,7,4′-trihydroxyisoflavone was chemically synthesized and tested for antioxidant activity by several methods. Factor 2 was proved to be a potent antioxidant in aqueous solution at pH 7.4. However it was not effective in preventing autoxidation of soybean oil and soybean powder. Factor 2 given orally to rats fed vitamin E-deficient diet was also negative in hemolysis preventing activity. Biological activity of tempeh and the isolated Factor 2 to prevent hemolysis of red blood cells of rats fed vitamin E-deficient diet was discussed.