Abstract
Prunella vulgaris L., a well-known traditional Chinese herbal medicine, has anti-inflammatory and antioxidant activities. In the present study, the underlying molecular mechanisms of the protective effect of P. vulgaris extract (PVE) were investigated in UVB-irradiated normal human dermal fibroblasts (NHDFs). The mRNA expression of matrix metalloproteinases (MMPs), procollagen type I, and cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor (TNF-α), was determined by reverse transcription-polymerase chain reaction. The expression of anti-photoaging-related signaling molecules in the NF-κB, MAPK/AP-1, and TGF/Smad pathways was assessed by western blot. We observed that PVE blocked the upregulated production of radical oxygen species induced in UVB-irradiated NHDFs in a dose-dependent manner. Treatment with PVE also significantly ameliorated the mRNA levels of MMPs, procollagen type I, TNF-α, and IL-6. In addition, the phosphorylation level of c-Jun and c-Fos was decreased through the attenuated expression levels of p-ERK and p-JNK after treatment with PVE. Furthermore, cells treated with PVE showed inhibited Smad 7 and increased Smad 2/3 expression in the TGF-β/Smad signaling pathway. Hence, synthesis of procollagen type I, a precursor of collagen I, was promoted. These findings indicate that treatment with PVE has a potential protective effect against UVB-induced photoaging and photoinflammation.