Impact of UV-B radiation on some biochemical changes and growth parameters in Echinacea purpurea callus and suspension culture

The effects of UV-B light force, exposure time and incubation period on producing caffeic acid derivatives and growth parameters in Echinacea purpurea callus and suspension culture were assessed. UV-B led to an increment of all growth parameters and antioxidant activity in callus and cell suspension and caffeic acid derivatives in cell suspension by increasing incubation period. The reverse was true for G-POD activity in cell suspension and PAL activity in both types of cultures. Incubation period 2 weeks was more effective in caffeic acid, total phenols and G-POD activity in callus cells and incubation period one week only for total phenols in cell suspension. The two exposure times 2 and 4 h increased antioxidant activity in the two types of cultures. Exposure time 2 h led to increase caffeic acid and total phenols in callus cells. The maximum increase in caffeic acid, total phenols and PAL activity in cell suspension was achieved by 4 h exposure time. Likewise, using 2 UV-B lamps for 2 h was the most effective in creating more biochemical components than the other treatments