Anti-inflammatory and wound healing effects of mouth gel containing kaempulchraol K from Kaempferia galanga rhizomes

Kaempferia galanga L. is one of the important medicinal plants and has been used in Thailand for treating inflammation and wound. This study aimed to investigate the efficacy of the compound from K. galanga on wound healing and anti-inflammatory activities and develop a new product in gel form to maximize the benefits of this plant. The mouth gel containing kaempulchraol K (KG2) was prepared by using 1.5% carbopol 934 as a gelling agent. Formulations of mouth gel containing KG2 at 0.10%, 0.25%, and 0.50% w/w were evaluated for color, smell, pH values, viscosity, and separation. Also, the chemical and biological stabilities of mouth gel containing KG2 were evaluated by heating-cooling test. The anti-inflammatory activity was tested against RAW 264.7 cells nitric oxide (NO) production and wound healing assay was performed using human gingival fibroblasts (HGF). Compound KG2 exhibited anti-NO production with an IC50 value of 66.8 μM and the wound healing activity of compound KG2 showed cell viability in the range of 90.9–111.4%. In addition, compound KG2 at a concentration of 3 μM induced the highest proportion of cell migration on day 3 at 90.2 ± 2.4%. The mouth gel containing KG2 both before and after the heating-cooling test exhibited good consistency, with pH values in the range of 6.64–6.71 (before) and 6.63–6.68 (after). Meanwhile, the viscosity was 81,700–96,700 cP (before) and 78,300–93,300 cP (after). For the chemical stability test of the active ingredient of mouth gel, the compound showed good stability after mixing with the gel base. The mouth gel exhibited anti-inflammation with IC50 values > 1000 μg/ml both before and after accelerating conditions. The wound healing activity of mouth gel containing KG2 (0.50% w/w) showed the highest % cell viability at 128.6% (before) and 123.8% (after). For cell migration, the result suggested that the mouth gel containing KG2 at 0.10%, 0.25%, and 0.50% w/w (3 μg/ml) on day 3 enhanced cell migration higher than that of the positive controls both before (85.0–96.8%) and after (and 84.4–94.3%) the accelerating conditions. The present study shows that mouth gel containing 0.50% KG2 is the most appropriate with good physical, chemical, and biological stabilities and might be one of the alternative sources for treatment of mouth ulcers (oral stomatitis) derived from aphthous ulcers, chemotherapy, and radiotherapy treatments.