Betanin--a food colorant with biological activity.

Abstract

Betalains are water-soluble nitrogen-containing pigments that are subdivided in red-violet betacyanins and yellow-orange betaxanthins. Due to glycosylation and acylation betalains exhibit a huge structural diversity. Betanin (betanidin-5-O-β-glucoside) is the most common betacyanin in the plant kingdom. According to the regulation on food additives betanin is permitted quantum satis as a natural red food colorant (E162). Moreover, betanin is used as colorant in cosmetics and pharmaceuticals. Recently, potential health benefits of betalains and betalain-rich foods (e.g. red beet, Opuntia sp.) have been discussed. Betanin is a scavenger of reactive oxygen species and exhibits gene-regulatory activity partly via nuclear factor (erythroid-derived 2)-like 2-(Nrf2) dependent signaling pathways. Betanin may induce phase II enzymes and antioxidant defense mechanisms. Furthermore, betanin possibly prevents LDL oxidation and DNA damage. Potential blood pressure lowering effects of red beet seem to be mainly mediated by dietary nitrate rather than by betanin per se.