Ligustrum lucidum Aiton is a flowering plant of the Oleaceae family, and its fruits have been traditionally used for skin nourishment and the treatment of
skin diseases. However, the anti-inflammatory constituents for
skin disease are not well-characterized.
Phytochemical investigation of L. lucidum fruits resulted in the isolation of a new secoiridoid, secoligulene (1), together with (E)-3-(1-oxobut-2-en-2-yl)pentanedioic
acid (2) and trans-(E)-3-(1-oxobut-2-en-2-yl)glutaric
acid (3). Secoligulene (1) displayed the potent inhibitory effect on NO production with an IC50 value of 12.0 μg/mL. Secoligulene (1) also downregulated
mRNA transcriptional levels of pro-inflammatory
cytokines such as
IL-1 α, IL-1β,
IL-6 and COX-2 in LPS-stimulated RAW264.7 cells. Further investigation showed that secoligulene (1) inhibited the phosphorylation of IκB and JNK activated by LPS. In addition, secoligulene (1) downregulated the expression of
chemokines such as CXCL8 and CCL20 in the TNF-α/IL-17/IFN-γ induced HaCaT
psoriasis model. Taken together, these findings support the beneficial effects of L. lucidum and its constituents on
inflammation-related
skin diseases and can be further developed as therapeutic treatments for related diseases.