Production of dihydroxylated betalains and dopamine in cell suspension cultures of Celosia argentea var. plumosa.

Betalains are plant pigments of hydrophilic nature with demonstrated chemopreventive potential in cancer cell lines and animal models. Among the betalains, those containing an aromatic moiety with two free hydroxyl groups possess the strongest antioxidant and free radical scavenging activities. The betaxanthins dopaxanthin and miraxanthin V and the betacyanins betanidin and decarboxy-betanidin are the only natural betalains with catecholic substructures. These four pigments have been produced in cell cultures established from hypocotyls of the plant Celosia argentea. Two stable and differentially colored cell lines, yellow and red, were maintained on Murashige and Skoog medium supplemented with the plant growth regulators 6-benzylaminopurine (6.66 μM) and 2,4-dichlorophenoxyacetic acid (6.79 μM). Derived suspension cultures showed increased production of dihydroxylated betalains in the cells and secreted to the medium with a maximum reached after 8 days of culture. In addition, precursor molecules betalamic acid and dopamine, with content up to 42.08 mg/g dry weight, were also obtained. The joint presence of the bioactive betalains together with the production of dopamine and betalamic acid show the ability of cell cultures of C. argentea to become a stable source of valuable phytochemicals.