Magnolia officinalis L. Fortified Gum Improves Resistance of Oral Epithelial Cells Against Inflammation

Inflammatory diseases of the periodontal tissues are known health problems worldwide. Therefore, anti-inflammatory active compounds are used in oral care products to reduce long-term inflammation. In addition to inducing inflammation, pathogen attack leads to an increased production of reactive oxygen species (ROS), which may lead to oxidative damage of macromolecules. Magnolia officinalis L. bark extract (MBE) has been shown to possess antioxidant and anti-inflammatory potential in vitro. In the present study, the influence of MBE-fortified chewing gum on the resistance against lipopolysaccharide (LPS)-induced inflammation and oxidative stress of oral epithelial cells was investigated in a four-armed parallel designed human intervention trial with 40 healthy volunteers. Ex vivo stimulation of oral epithelial cells with LPS from Porphyromonas gingivalis for 6h increased the mRNA expression and release of the pro-inflammatory cytokines IL-1α, IL-β, IL-8, MIP-1β, and TNFα. Chewing MBE-fortified gum for 10min reduced the ex vivo LPS-induced increase of IL-8 release by 43.8 ± 17.1% at the beginning of the intervention. In addition, after the two-week intervention with MBE-fortified chewing gum, LPS-stimulated TNFα release was attenuated by 73.4 ± 12.0% compared to chewing regular control gum. This increased resistance against LPS-induced inflammation suggests that MBE possesses anti-inflammatory activity in vivo when added to chewing gum. In contrast, the conditions used to stimulate an immune response of oral epithelial cells failed to induce oxidative stress, measured by catalase activity, or oxidative DNA damage.