Characterization of carotenoids and vitamin E in R. rugosa and R. canina: Comparative analysis.

The hips of Rosa species have gained more attention in recent years due to their high contents of antioxidant compounds. This study was designed to compare rosehips of the two roses species Rosa rugosa and Rosa canina, including different products, on carotenoid contents, including phytoene and phytofluene, as well as vitamin E. The investigation allowed the identification and quantification of types of (Z)-isomers of lycopene and rubixanthin in both rosehips and focused also on isomerisation of both carotenoids. The carotenoid identification and quantification were done using HPLC-DAD and LC-MS/MS. The statistical analysis revealed significant differences (P<0.05) in carotenoid contents and (P<0.001) in vitamin E contents between different rosehips species. The HPLC analysis showed that carotenoid contents varied between rosehips species. The isomerisation of (all-E)-rubixanthin and (all-E)-lycopene using iodine-catalysed photoisomerisation showed that the (5'Z)-isomer gazaniaxanthin is the main (Z)-isomer of rubixanthin and the (13Z)-isomer is the main (Z)-isomer of lycopene.