Periodontitis is a common inflammatory disease that is strongly influenced by dietary habits. Coffee is one of the most common dietary components; however, current research on the relationship between coffee consumption and periodontitis, as well as its underlying mechanisms, is limited. Based on a previous report, caffeine (CA) and chlorogenic acid (CGA) were formulated into artificial coffee (AC) for this experiment. Cell viability, prostaglandin E₂ release, Western blotting, cellular reactive oxygen species (ROS) production, and NF-E2-related factor 2 (Nrf2) translocation analyses were performed to explore the effects of AC on lipopolysaccharide (LPS)-induced immortalized human oral keratinocytes (IHOKs) and elucidate their underlying mechanisms. AC pretreatment attenuated LPS-induced inflammatory mediator release, ROS production, and nuclear factor kappa B translocation in IHOKs. CA and CGA promoted AMP-activated protein kinase phosphorylation and down-regulated the nuclear factor-κB pathways to exert anti-inflammatory effects. Additionally, CGA promoted Nrf2 translocation and heme oxygenase-1 expression and showed anti-oxidative effects. Furthermore, AC, CA, and CGA components showed synergistic effects. Thus, we predict that coffee consumption may be beneficial for alleviating periodontitis. Moreover, the main coffee components CA and CGA seem to play a synergistic role in periodontitis.

Osteoblasts must acquire a considerable capacity for folding unfolded and misfolded proteins (MPs) to produce large amounts of extracellular matrix proteins and maintain bone homeostasis. MP accumulation contributes to cellular apoptosis and bone disorders. Photobiomodulation therapy has been used to treat bone diseases, but the effects of decreasing MPs with photobiomodulation remain unclear. In this study, we explored the efficacy of 625 nm light-emitting diode irradiation (LEDI) to reduce MPs in tunicamycin (TM) induced-MC3T3-E1 cells. Binding immunoglobulin protein (BiP), an adenosine triphosphate (ATP)-dependent chaperone, is used to evaluate the capacity of folding MPs. The results revealed that pretreatment with 625 nm LEDI (Pre-IR) induced reactive oxygen species (ROS) production, leading to the increased chaperone BiP through the inositol-requiring enzyme 1 (IRE1)/X-box binding protein 1s (XBP-1s) pathway, and then restoration of collagen type I (COL-I) and osteopontin (OPN) expression relieving cell apoptosis. Furthermore, the translocation of BiP into the endoplasmic reticulum (ER) lumen might be followed by a high level of ATP production. Taken together, these results suggest that Pre-IR could be beneficial to prevent MP accumulation through ROS and ATP in TM-induced MC3T3-E1cells.