UV-VIS, FT-RAMAN, AND H-1-NMR SPECTROSCOPIES OF CIS-TRANS CAROTENOIDSFROM SAFFRON (CROCUS-SATIVUS L.)

Stigmata of Crocus sativus L. were extracted in water, and the extract was analyzed by using a high-pressure liquid chromatography (HPLC) me thod. The carotenoids of saffron [cis and trans glycosyl esters of cro cetin or crocins (CRCs)] were isolated, and the two major isomer compo unds (all-trans-digentiobiosyl crocetin and 13-cis-digentiobiosyl croc etin) were characterized spectroscopically with ultraviolet-visible (U V-vis), Fourier transform (FT)-Raman, and H-1 NMR spectroscopies. The 13-cis compound showed in a UV-vis spectrum an additional peak at 330 nm, in an FT-Raman spectrum the presence of a peak at 1138 cm(-1), and in the H-1 NMR downfield shifts of protons 12 and 15 and an upheld sh ift of proton 14, with respect to the all-trans isomer, according to d ifferences in their skeletal structures. These features are shown also by the profile of their two-dimensional spectra.