Tannic Acid-Loaded Gellan Gum Hydrogels Reduce In Vitro Chemokine Expression in Oral Cells.

Tannic acid (TA), a natural polyphenol with antiphlogistic and crosslinking properties, is a versatile component of hydrogel that can be delivered to inflammatory sites in oral applications. However, the impact of TA dampening an inflammatory response in oral cells remains to be shown. We, therefore, established a bioassay where chemokine expression is induced by exposing gingival fibroblasts and HSC2 oral squamous carcinoma cells to IL1β and TNFα. Additionally, gingival fibroblasts were stimulated with saliva and poly I:C HMW to trigger chemokine production. Our findings demonstrate that TA effectively reduced the expression of CXCL1, CXCL2, CXCL8, and CXCL10-in gingival fibroblasts and HSC2 cells-without affecting cell viability. This effect was further confirmed by immunoassays for CXCL8. Moreover, we observed that TA decreased ERK, JNK, and p65 phosphorylation in gingival fibroblasts and partially inhibited NF-κβ/p65 nuclear translocation. Notably, TA released from a gellan gum hydrogel retained its ability to suppress chemokine expression in gingival fibroblasts. These in vitro findings provide insights into the anti-inflammatory properties of TA in oral cells and introduce gellan gum hydrogel as a delivery vehicle paving the way for future preclinical research.