Suppressive effect of ethanolic Kaempferia pandurata Roxb. extract on matrix metalloproteinase-2 expression in Porphyromonas gingivalis-treated human gingival fibroblasts in vitro

Abstract

In periodontal disease, gingival fibroblasts activated by the Gram-negative anaerobic bacterium Porphyromonas gingivalis induce overexpression of matrix metalloproteinase-2 (MMP-2), which is involved in inflammatory progression. This process is followed by tissue destruction and bone loss. In the present study, we investigated the in vitro effect of the ethanolic Kaempferia pandurata Roxb. extract on expression of MMP-2 in P. gingivalis-treated human gingival fibroblast-1 (HGF-1) cells. In addition, we utilized gelatin zymography, Western blotting, and reverse transcription-PCR analysis to elucidate the molecular mechanisms underlying MMP-2 inhibition via the mitogen-activated protein kinase (MAPK) and cyclic AMP response element-binding protein (CREB) signaling pathways. Treatment with K. pandurata extract (1-10 µg/ml) dose-dependently suppressed the activity, secretion, and protein expression of MMP-2 in HGF-1 cells exposed to P. gingivalis. At the transcriptional level, inhibition of MMP-2 gene expression by K. pandurata was mediated by phosphorylation of c-Jun N-terminal kinase (JNK) and CREB signaling pathways in P. gingivalis-treated HGF-1 cells. These results suggest that K. pandurata extract suppresses MMP-2 expression at the protein and gene levels via downregulation of the principal JNK and CREB signaling pathways. Due to its efficacy in inhibiting MMP-mediated periodontal destruction, K. pandurata might represent a new, potent periodontal therapy.