Abstract:

Magnolia biondii flower extract （MB）, which is rich in magnoliol was used to study its efficacy on alleviating UVB-induced skin damage. Immunofluorescence staining and enzyme-linked immunosorbent assay were applied to detect different key biomarkers on UVB-induced keratinocytes （HaCaT） and vascular endothelial cells （HUVEC）, which induced by HaCaT cell culture supernatant after UVB stimulated for 48 h. The results show that the levels of cyclobutane pyrimidine dimer （CPD） and high mobility group box protein B1 （HMGB1） increase significantly in HaCaT cells from 16 h to 72 h after UVB irradiation, and also HMGB1 is gradually migrated from the nucleus to the cytoplasm. The expression of heat shock family protein 27 （Hsp27） also increases, as well as the cytokines such as interleukin 6 （IL-6）, interleukin 8 （IL-8）, and prostaglandin E2 （PGE-2）. Meanwhile, the expression levels of endothelin-1 （ET-1） and intercellular adhesion molecule-1 （ICAM-1） are significantly increased after HUVEC cells stimulated by cell culture supernatant for 24 h. Under the synchronous treatment of 0.1%-0.5% MB, the levels of CPD and HMGB1 in HaCaT cells are significantly inhibited, with an increase expression of Hsp27, and a decreased of the nuclear transfer of HMGB1 and cytokines. In HUVEC cells, the expression levels of ET-1and ICAM-1 are also significantly inhibited after MB treatment. Therefore, MB can alleviate the damage of skin after UV irradiation by reducing DNA damage, reducing the synthesis and nuclear transfer of HMGB1, and inhibiting the expression of cytokines and vascular permeability.

Key words: M. biondii flower extract, UV, HMGB1, ICAM-1, skin damage