Photolysis and cytotoxicity of the potentially toxic composition of daylily flower: colchicine

The photolysis of colchicine under ultraviolet and visible light irradiation was studied by ultraviolet (UV) scanning and HPLC-MS. The photoproduct was proposed and the cytotoxicity change before and after irradiation was investigated. Results showed that both ultraviolet and visible light irradiation could effectively degrade colchicine into deacetamido-lumicolchicine. The process conformed to first-order kinetics, in which a high degradation rate (K = 0.5862 h(− 1)) was observed when colchicine was dissolved in ethanol and irradiated by UV light. Cell viability and cell cycle studies proved that a photolysis treatment of colchicine could weaken the cytotoxicity effectively. Colchicine inhibited the division of BRL 3 A cells in G2/M phase with an IC(50) value of 0.48 µg/mL, while the toxic effect could be reduced significantly with IC(50) 2.1 µg/mL when colchicine was exposed to UV irradiation. Results are beneficial to the toxicity elimination of colchicine in the processing of daylily flower in food industry, and can also provide photochemistry reference for colchicine-related studies.