ABSTRACT
To explore the effect of total extract of Chrysanthemum morifolium on lipopolysaccharide (LPS)-induced acute lung injury in mice, we studied the effects of three caffeoyl quinic acids isolated from Chrysanthemum morifolium on vascular endothelial cell injury and their mechanisms of action. All animal experiments were carried out strictly in accordance with the National Animal Welfare Ethics and Protection Regulations. A mouse model of acute lung injury was established by intranasal instillation of LPS. After 6 days of oral administration of chrysanthemum extract, the lung wet weight/dry weight ratio, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) were measured in mouse bronchoalveolar lavage fluid. Human umbilical vein endothelial cells (HUVEC) were serum starved for 12 h and treated with 2.5 μg·mL-1 LPS for 24 h to establish the in vitro model of vascular endothelial cell injury. After 24 h of treatment of caffeoyl quinic acids from Chrysanthemum morifolium, the levels of TNF-α, IL-6, IL-1β, vascular cell adhesion molecule-1 (VCAM-1) and endothelin-1 (ET-1) were measured by ELISA in the cell culture supernatant, the malondialdehyde (MDA) level was detected by TBA method, the superoxide dismutase (SOD) level was determined by hydroxylamine method, and the nitric oxide (NO) level was assayed by a one-step method. The levels of p-MEK1/2, MEK1/2, p-ERK1/2, ERK1/2, p-JNK, JNK, p-P38 and P38 of mitogen-activated protein kinase (MAPK) signaling pathway were detected by Western blot. The total extract of Chrysanthemum morifolium can significantly reduce the wet weight/dry weight ratio of lung in mice and the levels of TNF-α, IL-6 and IL-1β in alveolar lavage fluid. The caffeoyl quinic acids from Chrysanthemum morifolium significantly increased the levels of SOD and NO, decreased the levels of TNF-α, IL-6, IL-1β, VCAM-1, ET-1 and MDA, and significantly reduced the levels of p-MEK1/2, p-ERK1/2. In conclusion, total extracts of Chrysanthemum morifolium exhibit certain protective effect on mice with acute lung injury, and three caffeoyl quinic acids from Chrysanthemum morifolium may improve LPS-induced vascular endothelial cell injury by inhibiting inflammatory cytokines and oxidative stress, and regulating inter-cellular adhesion molecule and vasomotor factors through ERK/MAPK signaling pathway.