Antioxidant properties of crocin from Gardenia jasminoides Ellis and studyof the reactions of crocin with linoleic acid and crocin with oxygen

Crocin-a water soluble carotenoid-is found in the fruits of gardenia (Garde nia jasminoides Ellis) and in the stigmas of saffron (Crocus sativus Linne) . For crocin purification, gardenia fruits are extracted with 50% acetone, followed by ether washing, ion exchange, and separation by preparative HPLC . Purified crocin with purity of >99.6% has an antioxidative activity at co ncentrations up to 40 ppm. At 20 ppm the antioxidative activity of crocin i s comparable to that of BHA. The antioxidant property of crocin as evaluate d by the thiocyanate method was better than with the thiobarbituric acid me thod. The adduct between the linoleic acid radical and crocin was detected by LC-MS. When crocin reacted with oxygen in the presence of FeSO4, interme diates such as monohydroperoxides and dihydroperoxides of crocin were forme d and detected by LC-MS.