The commercial development of plants as sources of antioxidants that can be used to enhance the properties of foods, for nutritional purposes and preservation as well as for prevention of oxidation-related diseases, is currently of major interest. Rosehip (Rosa canina L.) is a rich source of vitamin C and polyphenols.
Phytochemicals in rosehip tea were separated into three fractions: Fr1 (vitamin C, 39.17 mg kg(-1)), Fr2 (flavonoids, 451.05 µg kg(-1)) and Fr3 (phenolic acids, 504.69 µg kg(-1)). Quercetin and ellagic acid were the most abundant polyphenolic compounds. Rosehip fractions, primarily rosehip flavonoids (EC(50) = 49 mg L(-1)), showed high antioxidant activity towards 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH(•)). Cell growth effects of rosehip fractions were assessed in HeLa, MCF7 and HT-29 cell lines, with the lowest IC(50) values being determined for rosehip flavonoids, (80.63, 248.03 and 363.95 mg L(-1) respectively). However, the vitamin C fraction did not inhibit the growth of tested tumour cells.
The results of this study confirm that vitamin C and flavonoids are responsible for the antioxidant activity of rosehip tea, while only polyphenols contribute to its antiproliferative activity.