Biological activities of mouth gel containing 6β-acetoxysandaracopimaradiene-1α, 9α-diol (KG6) from Kaempferia galanga rhizomes

Oral ulcers have an impact on 25% of the global population. Kaempferia galanga L. has been traditionally used for pain alleviation and wound repair. The wound healing activity of K. galanga extract has been previously described in various studies. However, the research on isopimarane diterpenes isolated from K. galanga is still limited. This study is to evaluate the biological activities related to wound healing potential of 6β‐acetoxysandaracopimaradiene‐1α,9α‐diol (KG6), isolated from K. galanga as well as to investigate the physicochemical and biological properties of the formulated KG6 mouth gels. The KG6 mouth gels at 0.10, 0.25 and 0.50% w/w were formulated using sodium carboxymethylcellulose as a gelling agent, and their physicochemical and biological stabilities were assessed through a heating-cooling acceleration test. The quantification of KG6 contents in KG6 mouth gels was determined using gas chromatography. Both KG6 and KG6 mouth gels were evaluated for their wound healing property including cell proliferation, cell migration, and antioxidant activity (H2O2-induced oxidative stress) in human gingival fibroblast (HGF-1 - ATCC CRL-2014) (HGF-1). In addition, the anti-inflammatory activity against nitric oxide (NO) production was investigated in macrophage cells (RAW 264.7). The results showed that after incubating the KG6 mouth gels under heating-cooling acceleration condition, the physicochemical properties of KG6 mouth gels remained stable across various parameters, including appearance, color, smell, texture, pH, viscosity, separation, and KG6 content. The biological studies indicated that KG6 compound possessed good wound healing potential. The 0.50% KG6 mouth gel exhibited marked anti-inflammatory activity by inhibiting NO production with an IC50 of 557.7 µg/ml, comparable to that of Khaolaor mouth gel, a positive control. The 0.25% KG6 mouth gel increased HGF-1 cell proliferation at 101.7±1.2 to 103.5±1.4%, whereas all formulars of KG6 mouth gel enhanced HGF-1 cell migration to 94.7-98.9% which was higher than 1.29 to 1.35 times of Khaolaor mouth gel (73.5%). Moreover, 0.50% KG6 mouth gel also showed good antioxidant effect under H2O2-induced oxidative stress. This study substantiates the significant biological activities related to wound healing property of KG6 mouth gel, highlighting its potential for oral ulcer treatment.