Biological activity of hydroxo-vitamin B-12 degradation product formed during microwave heating

When hydroxo-vitamin B-12, which predominates in foods, is treated by micro wave heating, two degradation products with R-f of 0.16 and 0.27 are found and characterized (Watanabe et al. J. Agric. Food Chem. 1998, 46, 206-210). A novel hydroxo-vitamin Bit degradation product with a R-f of 0.12 was als o found by the use of silica gel 60 column chromatography and was the major compound among the degradation products. The degradation product with a R- f of 0.12 was purified to homogeneity and partially characterized. The puri fied degradation product had about 13% and 23% biological activity of authe ntic vitamin B-12 in hog intrinsic factor (a mammalian vitamin Bra-binding protein) and Lactobacillus Leichmannii ATCC 7830, respectively. Administrat ion of the purified degradation product (0.5 mu g/week) to rats indicates t hat the compound does not have significant activity in mammals.