Therapeutic effect of phycocyanin on chronic obstructive pulmonary disease in mice

•PC significantly ameliorated the pulmonary function of COPD mice and.•PC reduced cigarette smoke induced lung inflammation of COPD mice.•Molecular docking results indicate that PCB in PC had a good binding site in Keap1 and NOX2 proteins.•In vivo PC decreased p-Nrf2 and NQO1 level.•In vitro PCB-PC-peptide could depress the p-Nrf2 and NQO1 protein level in RAW264.7 cells induced by cigarette smoke extract.