Abstract

Betalains are a class of pigments that are much less com- monly found in nature than anthocyanins or carotenoids. They occur only in a few edible plants such as red beetroot (Beta vulgaris), prickly pears (Opuntia ficus indica), amaranth (Amaranthus sp.) and some mushrooms. This group of pig- ments can be divided into two major groups: yellow vulgax- anthins and red betanins. Despite their structural similarity to compounds from the group of alkaloids, betalains do not show any toxic properties in human organism, that is why they are highly recommended as healthy alternative to synthetic red food colorants. Moreover, published studies showed that these compounds have antimicrobial and an- tiviral activity. The aim of our study was to compare the betalain pro- files for three prickly pear varieties (yellow, orange and red) and two beetroot varieties (white and red) to exam- ine their impact on antioxidant and biological activity of tested plant extracts. The composition of betalains and other biologically active phytochemicals was characterized using HPLC-DAD-MS, total antioxidant activity was assessed by spectrophotometric tests (ABTS, DPPH, FC and FRAP), antioxidant profiles were obtained with the aid of chromatographic techniques (TLC and HPLC with postcolumn derivatization). Biological activity was determined using MTT cytotoxicity assay, Ames test and comet assay. The highest content of betalain was observed in red beetroot, followed by red, orange and yellow opuntia, in white beetroot no betalain were detected. The strong relationship between betalain content and antioxidant activity was observed, while studies on biological activity of tested fruit extracts showed that they do not exhibit cytotoxic, genotoxic or mutagenic effects in cellular models employed.

Authors (3)