Crocin Bleaching Assay Using Purified Di-gentiobiosyl Crocin [alpha-crocin] from Iranian Saffron

ABSTRACT

Crocin bleaching assay [CBA] is a new method for determination of antioxidant capacity. In CBA, addition of hydrogen to the conjugated double bonds of crocin results in reduction of crocin and increase in the absorbance at 440 nm, which is considered as a measure of antioxidant potential. Here CBA method was set up using di-gentiobiosyl crocin or a-crocin from Iranian saffron. Then, the antioxidant activity of some known antioxidants i.e. L-ascorbie acid, bilirubin, Trolox, uric acid, and some plasma samples of infants, were tested. The results were compared to that obtained by ferric reducing antioxidant power [FRAP] as a standard method. Di-gentiobiosyl crocin was extracted and purified from Iranian saffron as previously described by us. Then, the CBA procedure using alpha-crocin was done in 2 different aquatic conditions, >50% or >90% of water. Results were analyzed by both the Bors method [calculating the relative rate constants