In Vitro Evaluation of Substantivity, Staining Potential, and Biofilm Reduction of Guava Leaf Extract Mouth Rinse in Combination with its Anti-Inflammatory Effect on Human Gingival Epithelial Keratinocytes

This study aimed to assess the biofilm reduction, staining potential, and cytotoxicity of guava extract mouth rinse compared to chlorhexidine (CHX). Substantivity, staining, and antibiofilm potential were investigated by spectrophotometry, colony-forming units, and luminosity color meter, respectively. The cell viability assay was conducted using a colorimetric assay to determine nontoxic levels of guava (0.15%) and CHX in human gingival epithelial keratinocytes (HGEK-16). Cells were treated with lipopolysaccharides (LPS, 1μg/mL) and guava to assess inflammatory gene expression levels of interleukin-β1, tumor necrosis factor-α, and Prostaglandin E2. A scratch wound healing assay investigated the effects of guava on cell migration. The teeth coated in guava mouth rinse displayed 19.4% higher substantivity compared to CHX (0.2%), and the anti-biofilm reduction was observed with both guava and CHX mouth rinses (P < 0.05). The overall discoloration changes were higher with CHX and distilled water compared to guava. Also, guava significantly enhanced HGEK-16 cell viability (P < 0.05), and IL-β1, TNFα and PGE2 expression presented a 0.6-fold decrease when exposed to guava and LPS (P < 0.05). The present study showed that guava mouth rinse fulfilled the requirement for an effective and useful oral care product with desirable substantivity and anti-biofilm action. In addition, guava reduced the inflammation response in HGEK-16 and may be a potential oral rinse for oral anti-inflammatory therapies.